Prevent sole admin from deleting their account

Without this guard, the last admin in the system could delete their own
account, making the application unmanageable. This adds a model method
`User#sole_admin?`, a controller guard in `RegistrationsController#destroy`,
and disables the delete button in the profile edit view when the current
user is the only remaining admin.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -15,9 +15,6 @@
 /config/master.key
 /config/puma.rb
 
-# Ignore test database.
-/db/test.sqlite3
-
 # Ignore all logfiles and tempfiles.
 /log/*
 /tmp/*
@@ -33,7 +30,7 @@
 
 /tmp/restart.txt
 
-# Ignore user files.
+# Ignore user files
 /.bash_history
 /.byebug_history
 /.config
@@ -41,7 +38,6 @@
 /.lesshst
 /.local
 /.mysql_history
-/.sqlite_history
 /.ssh
 /.vim
 /.viminfo

DESIGN.md

@@ -1,45 +0,0 @@
-DESIGN
-======
-
-Below is a list of design decisions. The justification is to be consulted
-whenever a change is considered, to avoid regressions.
-
-### Data type for DB storage of numeric values (`decimal` vs `float`)
-
-* among database engines supported (by Rails), SQLite offers storage of
-  `decimal` data type with the lowest precision, equal to the precision of
-  `REAL` type (double precision float value, IEEE 754), but in a floating point
-  format,
-    * decimal types in other database engines offer greater precision, but store
-      data in a fixed point format,
-* biology-related values differ by several orders of magnitude; storing them in
-  fixed point format would only make sense if required precision would be
-  greater than that offered by floating point format,
-    * even then, fixed point would mean either bigger memory requirements or
-      worse precision for numbers close to scale limit,
-        * for a fixed point format to use the same 8 bytes of storage as IEEE
-          754, precision would need to be limited to 18 digits (4 bytes/9 digits)
-          and scale approximately half of that - 9,
-    * double precision floating point guarantees 15 digits of precision, which
-      is more than enough for all expected use cases,
-        * single precision floating point only guarntees 6 digits of precision,
-          which is estimated to be too low for some use cases (e.g. storing
-          latitude/longitude with a resolution grater than 100m)
-* double precision floating point (IEEE 754) is a standard that ensures
-  compatibility with all database engines,
-    * the same data format is used internally by Ruby as a `Float`; it
-      guarantees no conversions between storage and computation,
-    * as a standard with hardware implementations ensures both: computing
-      efficiency and hardware/3rd party library compatibility as opposed to Ruby
-      custom `BigDecimal` type
-
-### Database layer vs application layer data model constraints
-* database constraints are the final guard against data integrity corruption,
-    * they should safeguard against data referential integrity loss under _all_
-      data (not schema) manipulation scenarios, including application level
-      logic errors and direct data manipulation (e.g. through `dbconsole`),
-* application constraints can be as restrictive as database constraints or more,
-  but not less, as it doesn't serve any use case,
-    * proper application level constraints should prevent unhandled database
-      exception occurences, e.g `ActiveRecord::InvalidForeignKey` for operations
-      performed through Models (i.e. not `#delete_all` etc.)

Gemfile

@@ -1,18 +1,14 @@
 source "https://rubygems.org"
 
 # The requirement for the Ruby version comes from Rails
-# NOTE: after updating Rails make sure that schema dump is not sorted:
-#   v8.1.3/activerecord/lib/active_record/schema_dumper.rb#L195
-# Waiting for this change to be reverted/configuration setting added:
-# https://github.com/rails/rails/pull/56842, https://github.com/rails/rails/pull/55414
-gem "rails", "~> 8.1.3"
+gem "rails", "~> 7.2.3"
 gem "sprockets-rails"
 gem "puma", "~> 6.0"
 gem "sassc-rails"
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem "tzinfo-data", platforms: %i[ mingw mswin x64_mingw jruby ]
 
-# TODO: select db gems automatically?
+# TODO: select db gems automatically
 #   database_config = ERB.new(File.read("config/database.yml")).result
 #   YAML.load(database_config, aliases: true).values.map { |env| env["adapter"] }.uniq
 group :mysql, optional: true do
@@ -46,4 +42,11 @@ group :test do
   # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
   gem "capybara"
   gem "selenium-webdriver"
+
+  # Remove minitest version restriction after error fixed:
+  #   railties-7.2.3/lib/rails/test_unit/line_filtering.rb:7:in `run':
+  #     wrong number of arguments (given 3, expected 1..2) (ArgumentError)
+  #   from /var/www/.gem/ruby/3.3.0/gems/minitest-6.0.2/lib/minitest.rb:473:in
+  #     `block (2 levels) in run_suite'
+  gem "minitest", "< 6"
 end

Gemfile.lock

@@ -1,85 +1,85 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    action_text-trix (2.1.18)
-      railties
-    actioncable (8.1.3)
-      actionpack (= 8.1.3)
-      activesupport (= 8.1.3)
+    actioncable (7.2.3)
+      actionpack (= 7.2.3)
+      activesupport (= 7.2.3)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
       zeitwerk (~> 2.6)
-    actionmailbox (8.1.3)
-      actionpack (= 8.1.3)
-      activejob (= 8.1.3)
-      activerecord (= 8.1.3)
-      activestorage (= 8.1.3)
-      activesupport (= 8.1.3)
+    actionmailbox (7.2.3)
+      actionpack (= 7.2.3)
+      activejob (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       mail (>= 2.8.0)
-    actionmailer (8.1.3)
-      actionpack (= 8.1.3)
-      actionview (= 8.1.3)
-      activejob (= 8.1.3)
-      activesupport (= 8.1.3)
+    actionmailer (7.2.3)
+      actionpack (= 7.2.3)
+      actionview (= 7.2.3)
+      activejob (= 7.2.3)
+      activesupport (= 7.2.3)
       mail (>= 2.8.0)
       rails-dom-testing (~> 2.2)
-    actionpack (8.1.3)
-      actionview (= 8.1.3)
-      activesupport (= 8.1.3)
+    actionpack (7.2.3)
+      actionview (= 7.2.3)
+      activesupport (= 7.2.3)
+      cgi
       nokogiri (>= 1.8.5)
-      rack (>= 2.2.4)
+      racc
+      rack (>= 2.2.4, < 3.3)
       rack-session (>= 1.0.1)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
       useragent (~> 0.16)
-    actiontext (8.1.3)
-      action_text-trix (~> 2.1.15)
-      actionpack (= 8.1.3)
-      activerecord (= 8.1.3)
-      activestorage (= 8.1.3)
-      activesupport (= 8.1.3)
+    actiontext (7.2.3)
+      actionpack (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       globalid (>= 0.6.0)
       nokogiri (>= 1.8.5)
-    actionview (8.1.3)
-      activesupport (= 8.1.3)
+    actionview (7.2.3)
+      activesupport (= 7.2.3)
       builder (~> 3.1)
+      cgi
       erubi (~> 1.11)
       rails-dom-testing (~> 2.2)
       rails-html-sanitizer (~> 1.6)
-    activejob (8.1.3)
-      activesupport (= 8.1.3)
+    activejob (7.2.3)
+      activesupport (= 7.2.3)
       globalid (>= 0.3.6)
-    activemodel (8.1.3)
-      activesupport (= 8.1.3)
-    activerecord (8.1.3)
-      activemodel (= 8.1.3)
-      activesupport (= 8.1.3)
+    activemodel (7.2.3)
+      activesupport (= 7.2.3)
+    activerecord (7.2.3)
+      activemodel (= 7.2.3)
+      activesupport (= 7.2.3)
       timeout (>= 0.4.0)
-    activestorage (8.1.3)
-      actionpack (= 8.1.3)
-      activejob (= 8.1.3)
-      activerecord (= 8.1.3)
-      activesupport (= 8.1.3)
+    activestorage (7.2.3)
+      actionpack (= 7.2.3)
+      activejob (= 7.2.3)
+      activerecord (= 7.2.3)
+      activesupport (= 7.2.3)
       marcel (~> 1.0)
-    activesupport (8.1.3)
+    activesupport (7.2.3)
       base64
+      benchmark (>= 0.3)
       bigdecimal
       concurrent-ruby (~> 1.0, >= 1.3.1)
       connection_pool (>= 2.2.5)
       drb
       i18n (>= 1.6, < 2)
-      json
       logger (>= 1.4.2)
       minitest (>= 5.1)
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
-      uri (>= 0.13.1)
-    addressable (2.9.0)
+    addressable (2.8.8)
       public_suffix (>= 2.0.2, < 8.0)
     base64 (0.3.0)
-    bcrypt (3.1.22)
-    bigdecimal (4.1.2)
+    bcrypt (3.1.21)
+    benchmark (0.5.0)
+    bigdecimal (4.0.1)
     bindex (0.8.1)
     builder (3.3.0)
     byebug (13.0.0)
@@ -93,27 +93,28 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
+    cgi (0.5.1)
     concurrent-ruby (1.3.6)
     connection_pool (3.0.2)
     crass (1.0.6)
     date (3.5.1)
-    devise (5.0.3)
+    devise (5.0.2)
       bcrypt (~> 3.0)
       orm_adapter (~> 0.1)
       railties (>= 7.0)
       responders
       warden (~> 1.2.3)
     drb (2.2.3)
-    erb (6.0.4)
+    erb (6.0.2)
     erubi (1.13.1)
-    ffi (1.17.4-aarch64-linux-gnu)
-    ffi (1.17.4-aarch64-linux-musl)
-    ffi (1.17.4-arm-linux-gnu)
-    ffi (1.17.4-arm-linux-musl)
-    ffi (1.17.4-arm64-darwin)
-    ffi (1.17.4-x86_64-darwin)
-    ffi (1.17.4-x86_64-linux-gnu)
-    ffi (1.17.4-x86_64-linux-musl)
+    ffi (1.17.3-aarch64-linux-gnu)
+    ffi (1.17.3-aarch64-linux-musl)
+    ffi (1.17.3-arm-linux-gnu)
+    ffi (1.17.3-arm-linux-musl)
+    ffi (1.17.3-arm64-darwin)
+    ffi (1.17.3-x86_64-darwin)
+    ffi (1.17.3-x86_64-linux-gnu)
+    ffi (1.17.3-x86_64-linux-musl)
     globalid (1.3.0)
       activesupport (>= 6.1)
     i18n (1.14.8)
@@ -123,14 +124,13 @@ GEM
       activesupport (>= 6.0.0)
       railties (>= 6.0.0)
     io-console (0.8.2)
-    irb (1.18.0)
+    irb (1.17.0)
       pp (>= 0.6.0)
       prism (>= 1.3.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
-    json (2.19.4)
     logger (1.7.0)
-    loofah (2.25.1)
+    loofah (2.25.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.12.0)
     mail (2.9.0)
@@ -142,12 +142,10 @@ GEM
     marcel (1.1.0)
     matrix (0.4.3)
     mini_mime (1.1.5)
-    minitest (6.0.6)
-      drb (~> 2.0)
-      prism (~> 1.5)
+    minitest (5.27.0)
     mysql2 (0.5.7)
       bigdecimal
-    net-imap (0.6.4)
+    net-imap (0.6.3)
       date
       net-protocol
     net-pop (0.1.2)
@@ -157,21 +155,21 @@ GEM
     net-smtp (0.5.1)
       net-protocol
     nio4r (2.7.5)
-    nokogiri (1.19.3-aarch64-linux-gnu)
+    nokogiri (1.19.1-aarch64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.19.3-aarch64-linux-musl)
+    nokogiri (1.19.1-aarch64-linux-musl)
       racc (~> 1.4)
-    nokogiri (1.19.3-arm-linux-gnu)
+    nokogiri (1.19.1-arm-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.19.3-arm-linux-musl)
+    nokogiri (1.19.1-arm-linux-musl)
       racc (~> 1.4)
-    nokogiri (1.19.3-arm64-darwin)
+    nokogiri (1.19.1-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.19.3-x86_64-darwin)
+    nokogiri (1.19.1-x86_64-darwin)
       racc (~> 1.4)
-    nokogiri (1.19.3-x86_64-linux-gnu)
+    nokogiri (1.19.1-x86_64-linux-gnu)
       racc (~> 1.4)
-    nokogiri (1.19.3-x86_64-linux-musl)
+    nokogiri (1.19.1-x86_64-linux-musl)
       racc (~> 1.4)
     orm_adapter (0.5.0)
     pg (1.6.3)
@@ -188,32 +186,32 @@ GEM
     psych (5.3.1)
       date
       stringio
-    public_suffix (7.0.5)
+    public_suffix (7.0.2)
     puma (6.6.1)
       nio4r (~> 2.0)
     racc (1.8.1)
-    rack (3.2.6)
-    rack-session (2.1.2)
+    rack (3.2.5)
+    rack-session (2.1.1)
       base64 (>= 0.1.0)
       rack (>= 3.0.0)
     rack-test (2.2.0)
       rack (>= 1.3)
     rackup (2.3.1)
       rack (>= 3)
-    rails (8.1.3)
-      actioncable (= 8.1.3)
-      actionmailbox (= 8.1.3)
-      actionmailer (= 8.1.3)
-      actionpack (= 8.1.3)
-      actiontext (= 8.1.3)
-      actionview (= 8.1.3)
-      activejob (= 8.1.3)
-      activemodel (= 8.1.3)
-      activerecord (= 8.1.3)
-      activestorage (= 8.1.3)
-      activesupport (= 8.1.3)
+    rails (7.2.3)
+      actioncable (= 7.2.3)
+      actionmailbox (= 7.2.3)
+      actionmailer (= 7.2.3)
+      actionpack (= 7.2.3)
+      actiontext (= 7.2.3)
+      actionview (= 7.2.3)
+      activejob (= 7.2.3)
+      activemodel (= 7.2.3)
+      activerecord (= 7.2.3)
+      activestorage (= 7.2.3)
+      activesupport (= 7.2.3)
       bundler (>= 1.15.0)
-      railties (= 8.1.3)
+      railties (= 7.2.3)
     rails-dom-testing (2.3.0)
       activesupport (>= 5.0.0)
       minitest
@@ -221,28 +219,29 @@ GEM
     rails-html-sanitizer (1.7.0)
       loofah (~> 2.25)
       nokogiri (>= 1.15.7, != 1.16.7, != 1.16.6, != 1.16.5, != 1.16.4, != 1.16.3, != 1.16.2, != 1.16.1, != 1.16.0.rc1, != 1.16.0)
-    railties (8.1.3)
-      actionpack (= 8.1.3)
-      activesupport (= 8.1.3)
+    railties (7.2.3)
+      actionpack (= 7.2.3)
+      activesupport (= 7.2.3)
+      cgi
       irb (~> 1.13)
       rackup (>= 1.0.0)
       rake (>= 12.2)
       thor (~> 1.0, >= 1.2.2)
       tsort (>= 0.2)
       zeitwerk (~> 2.6)
-    rake (13.4.2)
+    rake (13.3.1)
     rdoc (7.2.0)
       erb
       psych (>= 4.0.0)
       tsort
-    regexp_parser (2.12.0)
+    regexp_parser (2.11.3)
     reline (0.6.3)
       io-console (~> 0.5)
     responders (3.2.0)
       actionpack (>= 7.0)
       railties (>= 7.0)
     rexml (3.4.4)
-    rubyzip (3.3.0)
+    rubyzip (3.2.2)
     sassc (2.4.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
@@ -252,7 +251,7 @@ GEM
       sprockets-rails
       tilt
     securerandom (0.4.1)
-    selenium-webdriver (4.43.0)
+    selenium-webdriver (4.41.0)
       base64 (~> 0.2)
       logger (~> 1.4)
       rexml (~> 3.2, >= 3.2.5)
@@ -266,32 +265,32 @@ GEM
       actionpack (>= 6.1)
       activesupport (>= 6.1)
       sprockets (>= 3.0.0)
-    sqlite3 (2.9.3-aarch64-linux-gnu)
-    sqlite3 (2.9.3-aarch64-linux-musl)
-    sqlite3 (2.9.3-arm-linux-gnu)
-    sqlite3 (2.9.3-arm-linux-musl)
-    sqlite3 (2.9.3-arm64-darwin)
-    sqlite3 (2.9.3-x86_64-darwin)
-    sqlite3 (2.9.3-x86_64-linux-gnu)
-    sqlite3 (2.9.3-x86_64-linux-musl)
+    sqlite3 (2.9.0-aarch64-linux-gnu)
+    sqlite3 (2.9.0-aarch64-linux-musl)
+    sqlite3 (2.9.0-arm-linux-gnu)
+    sqlite3 (2.9.0-arm-linux-musl)
+    sqlite3 (2.9.0-arm64-darwin)
+    sqlite3 (2.9.0-x86_64-darwin)
+    sqlite3 (2.9.0-x86_64-linux-gnu)
+    sqlite3 (2.9.0-x86_64-linux-musl)
     stringio (3.2.0)
     thor (1.5.0)
     tilt (2.7.0)
-    timeout (0.6.1)
+    timeout (0.6.0)
     tsort (0.2.0)
     turbo-rails (2.0.23)
       actionpack (>= 7.1.0)
       railties (>= 7.1.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
-    uri (1.1.1)
     useragent (0.16.11)
     warden (1.2.9)
       rack (>= 2.0.9)
-    web-console (4.3.0)
-      actionview (>= 8.0.0)
+    web-console (4.2.1)
+      actionview (>= 6.0.0)
+      activemodel (>= 6.0.0)
       bindex (>= 0.4.0)
-      railties (>= 8.0.0)
+      railties (>= 6.0.0)
     websocket (1.2.11)
     websocket-driver (0.8.0)
       base64
@@ -316,10 +315,11 @@ DEPENDENCIES
   capybara
   devise
   importmap-rails
+  minitest (< 6)
   mysql2 (~> 0.5)
   pg (~> 1.5)
   puma (~> 6.0)
-  rails (~> 8.1.3)
+  rails (~> 7.2.3)
   sassc-rails
   selenium-webdriver
   sprockets-rails

README.md

@@ -89,10 +89,14 @@ Running
 
 ### Standalone Rails server + Apache proxy
 
-Copy and customize Puma config template if required:
+Customize Puma config template:
 
     cp -a config/puma.rb.dist config/puma.rb
 
+and specify server IP/port, either with `port` or `bind`, e.g.:
+
+    bind 'tcp://0.0.0.0:3000'
+
 #### (option 1) Start server manually
 
     bundle exec rails s -e production
@@ -119,10 +123,9 @@ Contributing
 
 ### Gems
 
-Install development and testing gems, including at least MySQL and SQLite
-database adapters:
+Apart from database adapter, install development and testing gems:
 
-    bundle config --local with development test mysql sqlite
+    bundle config --local with mysql development test
 
 ### Configuration
 
@@ -135,29 +138,20 @@ assets.
 
 ### Database
 
-Grant database user privileges for development and test environments. Example
-below shows how to grant privileges to all databases which names start with
-`fixinme-` on MySQL:
+Grant database user privileges for development and test environments,
+possibly with different Ruby versions:
 
     > mysql -p
     mysql> create user `fixinme-dev`@localhost identified by '<some password>';
     mysql> grant all privileges on `fixinme-%`.* to `fixinme-dev`@localhost;
     mysql> flush privileges;
 
-Dumping development data before database reset:
-
-    mysqldump -h <address> -u <user> -p --no-create-info --no-tablespaces --complete-insert <database> > tmp/data.sql
-
 ### Development environment
 
 Starting application server in development environment:
 
     bundle exec rails s -e development
 
-Accessing database console when more than one test db is present:
-
-    bundle exec rails dbconsole -e test --db sqlite3
-
 For running rake tasks, prepend command with environment:
 
     RAILS_ENV=development bundle exec rails ...
@@ -170,22 +164,14 @@ Tests need to be run from within toplevel application directory:
 
         bundle exec rails test:system
 
-* system test(s) with seed or test name specified:
+* system test(s) with seed/test name specified:
 
-        bundle exec rails test:system --include test_add_unit --seed 64690
+        bundle exec rails test:system --seed 64690 --name test_add_unit
 
-* all tests from one file, optionally with seed:
+* all tests from one file, with optional seed:
 
         bundle exec rails test test/system/users_test.rb --seed 1234
 
-* system tests for selected database configuration (if multiple present):
-
-        bundle exec rails test:system --include /^test_sqlite3_/
-
-* single system test for all database configurations (if multiple present):
-
-        bundle exec rails test:system --include /^test_\\w+_add_unit$/
-
 ### Icons
 
 Pictogrammers Material Design Icons: https://pictogrammers.com/library/mdi/

app/assets/images/pictograms/alert-outline.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M12,2L1,21H23M12,6L19.53,19H4.47M11,10V14H13V10M11,16V18H13V16" /></svg>
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path fill="#ffffff" d="M12,2L1,21H23M12,6L19.53,19H4.47M11,10V14H13V10M11,16V18H13V16" /></svg>

app/assets/images/pictograms/check-circle-outline.svg

@@ -1 +1 @@
-<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M12 2C6.5 2 2 6.5 2 12S6.5 22 12 22 22 17.5 22 12 17.5 2 12 2M12 20C7.59 20 4 16.41 4 12S7.59 4 12 4 20 7.59 20 12 16.41 20 12 20M16.59 7.58L10 14.17L7.41 11.59L6 13L10 17L18 9L16.59 7.58Z" /></svg>
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path fill="#ffffff" d="M12 2C6.5 2 2 6.5 2 12S6.5 22 12 22 22 17.5 22 12 17.5 2 12 2M12 20C7.59 20 4 16.41 4 12S7.59 4 12 4 20 7.59 20 12 16.41 20 12 20M16.59 7.58L10 14.17L7.41 11.59L6 13L10 17L18 9L16.59 7.58Z" /></svg>

app/assets/stylesheets/application.css

@@ -18,12 +18,10 @@
 /* Strive for simplicity:
  * * style elements/tags only - if possible,
  * * replace element/tag name with class name - if element has to be styled
- * differently depending on context (e.g. <form>, <table>, <a> as link/button),
- * * styles with multiple selectors should have all selectors with same
- * specificity, to allow proper rule specificity vs order management.
+ * differently depending on context (e.g. form)
  *
- * NOTE: style in a modular way, similar to how CSS @scope would be used,
- * to make transition easier once @scope is widely available. */
+ * NOTE: Style in a modular way, similar to how CSS @scope would be used,
+ * to make transition easier once @scope is widely available */
 :root {
   --color-focus-gray: #f3f3f3;
   --color-border-gray: #dddddd;
@@ -55,36 +53,17 @@
 :focus-visible {
   outline: none;
 }
-/* NOTE: move to higher priority layer instead of using !important?; add CSS
- * @layer requirements in README */
-[disabled] {
-  border-color: var(--color-border-gray) !important;
-  color: var(--color-border-gray) !important;
-  /* NOTE: cannot set cursor when `pointer-events: none`; can be fixed by setting
-   * `cursor` on wrapping element.
-  cursor: not-allowed; */
-  fill: var(--color-border-gray) !important;
-  pointer-events: none !important;
-}
-/* Styles set `display` without distinguishing between [hidden] elements, making
- * them visible. */
-[hidden] {
-  display: none !important;
-}
 
 
 /* Color coding of input controls' background:
- *  blue - target for interaction with pointer,
- *  gray - target for interaction with keyboard,
- *  red - destructive, non-undoable action.
+ *  blue - target for interaction with pointer
+ *  gray - target for interaction with keyboard
+ *  red - destructive, non-undoable action
  */
-/* TODO: merge selectors using :is() */
-a,
 button,
 details,
 input,
 select,
-summary,
 textarea {
   background-color: inherit;
   font: inherit;
@@ -94,24 +73,56 @@ input,
 select {
   text-align: inherit;
 }
+a,
+button,
+input[type=submit] {
+  cursor: pointer;
+  text-decoration: none;
+  white-space: nowrap;
+}
+/* [hidden] submit controls cannot have `display` set as it makes them visible */
+.button,
+button:not([hidden]),
+input[type=submit]:not([hidden]),
+.tab {
+  align-items: center;
+  color: var(--color-gray);
+  display: flex;
+  fill: var(--color-gray);
+  font-weight: bold;
+}
+.button,
+button,
+input[type=submit] {
+  font-size: 0.8rem;
+  padding: 0.6em 0.5em;
+  width: fit-content;
+}
+input:not([type=submit]):not([type=checkbox]),
+select,
+summary,
+textarea {
+  padding: 0.2em 0.4em;
+}
+.button,
+button,
 input,
 select,
 summary,
 textarea {
-  border: 1px solid var(--color-gray);
+  border: solid 1px var(--color-gray);
   border-radius: 0.25em;
-  padding: 0.2em 0.4em;
 }
-svg {
-  height: 1.4em;
-  margin: 0 0.2em 0 0;
-  width: 1.4em;
-}
-svg:last-child {
-  margin-right: 0;
+[name=cancel],
+.auxiliary {
+  border-color: var(--color-border-gray);
+  color: var(--color-nav-gray);
+  fill: var(--color-nav-gray);
 }
+input[type=checkbox],
+svg,
 textarea {
-  margin: 0;
+  margin: 0
 }
 input[type=checkbox] {
   accent-color: var(--color-blue);
@@ -119,20 +130,17 @@ input[type=checkbox] {
   -webkit-appearance: none;
   display: flex;
   height: 1.1em;
-  margin: 0;
-  padding: 0;
   width: 1.1em;
 }
 input[type=checkbox]:checked {
   appearance: checkbox;
   -webkit-appearance: checkbox;
 }
-/* Hide spin buttons of <input type=number>. */
-/* TODO: add spin buttons inside <input type=number>: before (-) and after (+) input. */
+/* Hide spin buttons in input number fields */
+/* TODO: add spin buttons inside input[number]: before (-) and after (+) input */
 input[type=number] {
   appearance: textfield;
   -moz-appearance: textfield;
-  text-align: end;
 }
 input::-webkit-inner-spin-button {
   -webkit-appearance: none;
@@ -141,113 +149,37 @@ input::-webkit-outer-spin-button {
   -webkit-appearance: none;
   margin: 0;
 }
-/* Text color of table form controls:
- *  - black for row/table forms,
- *  - inherited for internal (column specific) buttons/forms. */
-table input,
-table select,
-table summary,
-table textarea {
-  border-color: var(--color-border-gray);
+.button > svg,
+.tab > svg,
+button > svg {
+  height: 1.4em;
+  width: 1.4em;
 }
-table input,
-table select,
-table textarea {
-  padding-block: 0.375em;
+.button > svg:not(:last-child),
+.tab > svg:not(:last-child),
+button > svg:not(:last-child) {
+  margin-right: 0.2em;
 }
-table form input,
-table form select,
-table form summary,
-table form textarea {
-  color: inherit;
-}
-table svg:not(:only-child) {
-  height: 1.25em;
-  width: 1.25em;
+/* TODO: move normal non-button links (<a>:hover/:focus) styling here (i.e.
+ * page-wide, top-level) and remove from table.items - as the style should be
+ * same everywhere */
+.button:focus-visible,
+button:focus-visible,
+input[type=submit]:focus-visible {
+  background-color: var(--color-focus-gray);
 }
 input:focus-visible,
 select:focus-visible,
 select:focus-within,
-/* TODO: how to achieve `summary:focus-within` for `::details-content`? */
+/* TODO: how to achieve summary:focus-within for ::details-content? */
 summary:focus-visible,
 textarea:focus-visible {
   accent-color: var(--color-dark-blue);
   background-color: var(--color-focus-gray);
-  color: black;
 }
-input:hover,
-select:hover,
-summary:hover,
-textarea:hover {
-  border-color: var(--color-blue);
-  outline: 1px solid var(--color-blue);
-}
-select:hover,
-summary:hover {
-  color: black;
-  cursor: pointer;
-}
-/* TODO: style <details>/<summary> focus to match <select> as much as possible.
-summary:focus-visible::before,
-summary:hover::before {
-  background-color: black;
-}
- */
-input:invalid,
-select:invalid,
-textarea:invalid {
-  border-color: var(--color-red);
-  outline-color: var(--color-red);
-}
-
-/* `.button`: button-styled <a>, <button>, <input type=submit>.
- * `.link`: any other <a>.
- * `.tab`: tab-styled <a>.
- */
-.button,
-.link,
-.tab {
-  cursor: pointer;
-  text-decoration: none;
-  white-space: nowrap;
-}
-.button,
-.tab {
-  align-items: center;
-  color: var(--color-gray);
-  display: flex;
-  fill: var(--color-gray);
-  font-weight: bold;
-}
-.button {
-  border: 1px solid var(--color-gray);
-  border-radius: 0.25em;
-  font-size: 0.8rem;
-  padding: 0.6em 0.5em;
-  width: fit-content;
-}
-.link {
-  color: inherit;
-  text-decoration: underline 1px var(--color-border-gray);
-  text-underline-offset: 0.25em;
-}
-.auxiliary {
-  border-color: var(--color-nav-gray);
-  color: var(--color-nav-gray);
-  fill: var(--color-nav-gray);
-}
-table .button {
-  border-color: var(--color-border-gray);
-  font-weight: normal;
-  height: 100%;
-  padding: 0.4em;
-}
-.button:focus-visible,
-.tab:focus-visible,
-.tab:hover {
-  background-color: var(--color-focus-gray);
-}
-.button:hover {
+.button:hover,
+button:hover,
+input[type=submit]:hover {
   background-color: var(--color-blue);
   border-color: var(--color-blue);
   color: white;
@@ -257,17 +189,32 @@ table .button {
   background-color: var(--color-red);
   border-color: var(--color-red);
 }
-.link:focus-visible {
-  text-decoration-color: var(--color-gray);
+input:hover,
+select:hover,
+summary:hover,
+textarea:hover {
+  border-color: var(--color-blue);
+  outline: solid 1px var(--color-blue);
 }
-.link:hover {
-  color: var(--color-blue);
-  text-decoration-color: var(--color-blue);
+select:hover,
+summary:hover {
+  cursor: pointer;
+}
+input:invalid,
+select:invalid,
+textarea:invalid {
+  border-color: var(--color-red);
+  outline: solid 1px var(--color-red);
+}
+input[type=text]:read-only,
+textarea:read-only {
+  border: none;
+  padding-inline: 0;
 }
 
 
-/* NOTE: collapse gaps around empty rows (`topside`) once possible with
- * `grid-collapse` property and remove alternative `grid-template-areas`.
+/* NOTE: collapse gaps around empty rows (`topside`) once possible
+ * with grid-collapse property and remove alternative grid-template
  * https://github.com/w3c/csswg-drafts/issues/5813 */
 body {
   display: grid;
@@ -275,16 +222,16 @@ body {
   grid-template-areas:
     "header    header  header"
     "nav       nav     nav"
+    "leftside  topside rightside"
     "leftside  main    rightside";
   grid-template-columns: 1fr minmax(max-content, 2fr) 1fr;
   font-family: system-ui;
   margin: 0.4em;
 }
-body:has(> .topside-area) {
+body:not(:has(.topside-area)) {
   grid-template-areas:
     "header    header  header"
     "nav       nav     nav"
-    "leftside  topside rightside"
     "leftside  main    rightside";
 }
 
@@ -300,14 +247,18 @@ header {
   margin-inline-start: 4%;
 }
 .navigation > .tab {
-  border-bottom: 2px solid var(--color-nav-gray);
+  border-bottom: solid 2px var(--color-nav-gray);
   flex: 1;
   font-size: 1rem;
   justify-content: center;
   padding-block: 0.4em;
 }
+.navigation > .tab:hover,
+.navigation > .tab:focus-visible {
+  background-color: var(--color-focus-gray);
+}
 .navigation > .tab.active {
-  border-bottom: 4px solid var(--color-blue);
+  border-bottom: solid 4px var(--color-blue);
   color: var(--color-blue);
   fill: var(--color-blue);
 }
@@ -339,7 +290,7 @@ header {
 
 #flashes {
   display: grid;
-  row-gap: 0.4em;
+  gap: 0.2em;
   grid-template-columns: 1fr auto auto auto 1fr;
   left: 0;
   pointer-events: none;
@@ -355,42 +306,49 @@ header {
   display: grid;
   grid-column: 2/5;
   grid-template-columns: subgrid;
-  line-height: 2.2em;
   pointer-events: auto;
 }
-.flash::before {
-  filter: invert(1);
+.flash.alert:before {
+  content: url('pictograms/alert-outline.svg');
   height: 1.4em;
   margin: 0 0.5em;
   width: 1.4em;
 }
-.flash.alert::before {
-  content: url('pictograms/alert-outline.svg');
-}
 .flash.alert {
   border-color: var(--color-red);
   background-color: var(--color-red);
 }
-.flash.notice::before {
+.flash.notice:before {
   content: url('pictograms/check-circle-outline.svg');
+  height: 1.4em;
+  margin: 0 0.5em;
+  width: 1.4em;
 }
 .flash.notice {
   border-color: var(--color-blue);
   background-color: var(--color-blue);
 }
-.flash svg {
-  cursor: pointer;
-  fill: white;
-  height: 2.2em;
-  opacity: 0.6;
-  padding: 0.4em 0.5em;
-  width: 2.4em;
+.flash > div {
+  grid-column: 2;
 }
-.flash svg:hover {
+/* NOTE: currently flash button inherits some unnecessary styles from generic
+ * button. */
+.flash > button {
+  border: none;
+  color: inherit;
+  cursor: pointer;
+  font-size: 1.4em;
+  font-weight: bold;
+  grid-column: 3;
+  opacity: 0.6;
+  padding: 0.2em 0.4em;
+}
+.flash > button:hover {
   opacity: 1;
 }
 
 
+/* TODO: Hover over invalid should work like in measurements (thin vs thick border) */
 .labeled-form {
   align-items: center;
   display: grid;
@@ -407,7 +365,7 @@ header {
 .labeled-form label.required {
   font-weight: bold;
 }
-/* Don't style `label.error + input` if case already covered by `input:invalid`. */
+/* Don't style `label.error + input` if case already covered by input:invalid */
 .labeled-form label.error {
   color: var(--color-red);
 }
@@ -427,120 +385,200 @@ header {
 .labeled-form .auxiliary {
   grid-column: 3;
   /* If more buttons are needed, `grid-row` can be replaced with
-   * `reading-flow: grid-columns` to ensure proper [tabindex] order. */
+   * `reading-flow: grid-columns` to ensure proper tabindex order */
   grid-row: 1;
   height: 100%;
   padding-block: 0;
 }
 
-.tabular-form table {
-  border: none;
-  border-spacing: 0;
-}
-.tabular-form table td {
-  border: none;
-  padding-inline-start: 0.4em;
-  vertical-align: middle;
-}
-.tabular-form table td:first-child {
-  padding-inline-start: 0;
-}
-.tabular-form table td:last-child {
-  padding-inline-end: 0;
-}
-.tabular-form table :is(form, input, select, textarea):only-child {
-  margin-inline-start: 0;
-}
 
-
-.items-table {
+/* TODO: remove .items class (?) and make 'form table' work properly */
+table.items {
   border-spacing: 0;
-  border: 1px solid var(--color-border-gray);
+  border: solid 1px var(--color-border-gray);
   border-radius: 0.25em;
   font-size: 0.85rem;
   text-align: left;
 }
-.items-table thead {
+table:not(:has(tr)) {
+  display: none;
+}
+table.items thead {
   font-size: 0.8rem;
 }
-.items-table thead,
-.items-table tbody tr:hover {
+table.items thead,
+table.items tbody tr:hover {
   background-color: var(--color-focus-gray);
 }
-.items-table th {
-  padding: 0.75em 0 0.75em 1em;
+table.items th {
+  padding-block: 0.75em;
   text-align: center;
 }
-.items-table th:last-child {
-  padding-inline-end: 0.4em;
+table.items th,
+table.items td {
+  padding-inline: 1em 0;
 }
-.items-table td {
-  border-top: 1px solid var(--color-border-gray);
-  height: 2.4em;
-  padding: 0.1em 0 0.1em calc(1em + var(--depth) * 0.8em);
-}
-.items-table td:last-child {
-  padding-inline-end: 0.1em;
-}
-.items-table :is(form, input, select, textarea):only-child {
-  margin-inline-start: calc(-0.4em - 0.9px);
-}
-/* For <a> to fill table cell completely, we use an `::after` pseudoelement. */
-/* TODO: expand to whole row? will require adjusting z-index on inputs/buttons */
-.items-table td:has(> .link) {
+/* For <a> to fill <td> completely, we use an ::after pseudoelement. */
+table.items td.link {
+  padding: 0;
   position: relative;
 }
-.items-table .link::after {
+table.items td.link a {
+  color: inherit;
+  font: inherit;
+}
+table.items td.link a::after {
   content: '';
-  inset: -1px 0 0 0;
+  inset: 0;
   position: absolute;
 }
-.items-table .flex {
+table.items td:first-child {
+  padding-inline-start: calc(1em + var(--depth) * 0.8em);
+}
+table.items td:has(input, select, textarea) {
+  padding-inline-start: calc(0.6em - 0.9px);
+}
+table.items td:first-child:has(input, select, textarea) {
+  padding-inline-start: calc(0.6em + var(--depth) * 0.8em - 0.9px);
+}
+table.items th:last-child {
+  padding-inline-end: 0.4em;
+}
+table.items td:last-child {
+  padding-inline-end: 0.1em;
+}
+table.items td {
+  border-top: solid 1px var(--color-border-gray);
+  height: 2.4em;
+  padding-block: 0.1em;
+}
+table.items .actions {
+  display: flex;
   gap: 0.4em;
   justify-content: end;
 }
-.items-table .dropzone {
+table.items .actions.centered {
+  justify-content: center;
+}
+table.items tr.dropzone {
   position: relative;
 }
-.items-table .dropzone::after {
+table.items tr.dropzone::after {
   content: '';
   inset: 1px 0 0 0;
   position: absolute;
-  outline: 2px dashed var(--color-blue);
+  outline: dashed 2px var(--color-blue);
   outline-offset: -1px;
   z-index: var(--z-index-table-row-outline);
 }
-.items-table .handle {
-  cursor: grab;
+table.items td.handle {
+  cursor: move;
 }
-.items-table .form td {
+table.items tr.form td {
   vertical-align: top;
 }
-.items-table td:not(:first-child),
+
+/* TODO: replace :hover:focus-visible combos with proper LOVE stye order */
+/* TODO: Update table styling: simplify selectors, deduplicate, remove non-font rem. */
+table.items td.link a:hover,
+table.items td.link a:focus-visible,
+table.items td.link a:hover:focus-visible {
+  text-decoration: underline;
+  text-decoration-thickness: 0.05rem;
+  text-underline-offset: 0.2rem;
+}
+table.items td.link a:hover {
+  color: var(--color-blue);
+}
+table.items td.link a:focus-visible {
+  text-decoration-color: var(--color-gray);
+}
+table.items td.link a:hover:focus-visible {
+  color: var(--color-dark-blue);
+}
+
+table.items td:not(:first-child),
 .grayed {
   color: var(--color-table-gray);
-  fill: var(--color-gray);
+  fill: var(--color-table-gray);
 }
-.items-table td:has(> svg:only-child) {
+table.items svg {
+  height: 1rem;
+  vertical-align: middle;
+  width: 1rem;
+}
+table.items svg:last-child {
+  height: 1.2rem;
+  width: 1.2rem;
+}
+table.items td.svg {
   text-align: center;
 }
+table.items td.number {
+  text-align: right;
+}
+table.items .button,
+table.items button,
+table.items input[type=submit] {
+  font-weight: normal;
+  height: 100%;
+  padding: 0.4em;
+}
+table.items input:not([type=submit]):not([type=checkbox]),
+table.items select,
+table.items textarea {
+  padding-block: 0.375em;
+}
+/* TODO: find a way (layers?) to style inputs differently while making sure
+ * hover works properly without using :not(:hover) selectors here. */
+table.items .button:not(:hover),
+table.items button:not(:hover),
+table.items input:not(:hover),
+table.items select:not(:hover),
+table.items textarea:not(:hover) {
+  border-color: var(--color-border-gray);
+}
+table.items .button:not(:hover),
+table.items button:not(:hover),
+table.items input[type=submit]:not(:hover),
+table.items select:not(:hover) {
+  color: var(--color-table-gray);
+}
+table.items select:focus-within,
+table.items select:focus-visible {
+  color: black;
+}
+form table.items {
+  border: none;
+}
+form table.items td {
+  border: none;
+  text-align: left;
+  vertical-align: middle;
+}
+form table.items td:first-child {
+  color: inherit;
+}
 
 
-.center {
+.centered {
   margin: 0 auto;
 }
+.extendedright {
+  margin-right: auto;
+}
 .hexpand {
   width: 100%;
 }
-.flex {
+.hflex {
   display: flex;
   gap: 0.8em;
 }
-.flex.reverse {
+.hflex.reverse {
   flex-direction: row-reverse;
 }
-.flex.vertical {
-  flex-direction: column;
+.hflex.centered {
+  justify-content: center;
 }
 .hint {
   color: var(--color-table-gray);
@@ -548,18 +586,21 @@ header {
   font-size: 0.9rem;
   text-align: center;
 }
-.hmin50 {
-  min-width: 50%;
+.vflex {
+  display: flex;
+  gap: 0.8em;
+  flex-direction: column;
 }
-.italic {
-  color: var(--color-gray);
-  font-style: italic;
-}
-.ralign {
-  text-align: right;
-}
-.rextend {
-  margin-right: auto;
+[disabled] {
+/* label:has(input[disabled]) {
+ * TODO: disabled checkbox blue square focus removal; disabled label styling;
+ * focused label styling (currently only checkbox has focus)
+ * */
+  border-color: var(--color-border-gray) !important;
+  color: var(--color-border-gray) !important;
+  cursor: not-allowed;
+  fill: var(--color-border-gray) !important;
+  pointer-events: none;
 }
 
 
@@ -571,12 +612,12 @@ summary {
   align-items: center;
   color: var(--color-gray);
   display: flex;
-  gap: 0.4em;
+  gap: 0.2em;
   height: 100%;
   white-space: nowrap;
 }
 summary::before {
-  background-color: currentColor;
+  background-color: #000;
   content: "";
   height: 1em;
   mask-image: url('pictograms/chevron-down.svg');
@@ -588,7 +629,7 @@ summary:has(.button) {
   padding-inline-end: 0;
 }
 summary .button {
-  border: 1px solid var(--color-border-gray);
+  border: solid 1px var(--color-border-gray);
   border-radius: inherit;
   border-top-left-radius: 0;
   border-bottom-left-radius: 0;
@@ -599,15 +640,15 @@ summary span {
   width: 100%;
 }
 details[open] summary::before {
-  transform: scaleY(-1);
+  transform: rotate(180deg);
 }
 summary::marker {
   padding-left: 0.25em;
 }
-/* NOTE: use `details[open]::details-content` once widely available. */
+/* NOTE: use details[open]::details-content once widely available */
 details[open] ul {
-  background-color: white;
-  border: 1px solid var(--color-border-gray);
+  background: white;
+  border: solid 1px var(--color-border-gray);
   border-radius: 0.25em;
   box-shadow: 1px 1px 3px var(--color-border-gray);
   margin: -1px 0 0 0;
@@ -629,15 +670,3 @@ li input[type=checkbox] {
 li::marker {
   content: '';
 }
-/*
- * TODO:
- * * disable <label> containing disabled checkbox: `label:has(input[disabled])`,
- * * disabled label styling,
- * * focused label styling (currently only checkbox has focus),
- * * disabled checkbox blue square focus removal.
- * */
-
-#measurement_form {
-  min-width: 66%;
-  width: max-content;
-}

app/controllers/readouts_controller.rb

@@ -6,7 +6,7 @@ class ReadoutsController < ApplicationController
   def new
     @quantities -= @prev_quantities
     # TODO: raise ParameterInvalid if new_quantities.empty?
-    @readouts = @quantities.map { |q| q.readouts.build }
+    @readouts = current_user.readouts.build(@quantities.map { |q| {quantity: q} })
 
     @user_units = current_user.units.ordered
 

app/controllers/user/profiles_controller.rb

@@ -1,6 +1,10 @@
 class User::ProfilesController < Devise::RegistrationsController
   def destroy
-    # TODO: Disallow/disable deletion for last admin account; update :edit view
+    if current_user.sole_admin?
+      redirect_back fallback_location: edit_user_registration_path,
+        alert: t(".sole_admin")
+      return
+    end
     super
   end
 

app/helpers/application_helper.rb

@@ -12,12 +12,6 @@ module ApplicationHelper
       labeled_field_for(method, options) { super }
     end
 
-    def submit(value = nil, options = {})
-      value, options = nil, value if value.is_a?(Hash)
-      options[:class] = @template.class_names('button', options[:class])
-      super
-    end
-
     private
 
     def labeled_field_for(method, options)
@@ -102,28 +96,20 @@ module ApplicationHelper
 
     def number_field(method, options = {})
       attr_type = object.type_for_attribute(method)
-      case attr_type.type
-      when :decimal
+      if attr_type.type == :decimal
         options[:value] = object.public_send(method)&.to_scientific
         options[:step] ||= BigDecimal(10).power(-attr_type.scale)
         options[:max] ||= BigDecimal(10).power(attr_type.precision - attr_type.scale) -
           options[:step]
         options[:min] = options[:min] == :step ? options[:step] : options[:min]
         options[:min] ||= -options[:max]
-        options[:size] ||= attr_type.precision / 2
-      when :float
-        options[:size] ||= 6
       end
       super
     end
 
     def button(value = nil, options = {}, &block)
-      # #button does not use #objectify_options/@default_options
-      value, options = nil, value if value.is_a?(Hash)
-      options = options.merge(
-        @default_options.slice(:form),
-        class: @template.class_names('button', options[:class])
-      )
+      # button does not use #objectify_options
+      options.merge!(@options.slice(:form))
       super
     end
 
@@ -152,14 +138,12 @@ module ApplicationHelper
   end
 
   def tabular_form_with(**options, &block)
-    extra_options = {builder: TabularFormBuilder, class: 'tabular-form',
-                     html: {autocomplete: 'off'}}
+    extra_options = {builder: TabularFormBuilder, html: {autocomplete: 'off'}}
     form_with(**merge_attributes(options, extra_options), &block)
   end
 
   def svg_tag(source, label = nil, options = {})
-    label, options = nil, label if label.is_a? Hash
-    svg_tag = tag.svg(**options) do
+    svg_tag = tag.svg(options) do
       tag.use(href: "#{image_path(source + ".svg")}#icon")
     end
     label.blank? ? svg_tag : svg_tag + tag.span(label)
@@ -208,7 +192,9 @@ module ApplicationHelper
 
   def image_link_to_unless_current(name, image = nil, options = nil, html_options = {})
     name, html_options = link_or_button_options(:link, name, image, html_options)
-    if current_page?(options, method: [:get, :post])
+    # NOTE: Starting from Rails 8.1.0, below condition can be replaced with:
+    #   current_page?(options, method: [:get, :post])
+    if request.path == url_for(options)
       html_options = html_options.deep_merge DISABLED_ATTRIBUTES
     end
     link_to name, options, html_options
@@ -226,8 +212,9 @@ module ApplicationHelper
       # Conversion of flash to Array only required because of Devise
       Array(messages).map do |message|
         tag.div class: "flash #{entry}" do
-          tag.span(sanitize(message)) +
-            svg_tag('pictograms/close-outline', {onclick: "this.parentElement.remove()"})
+          # TODO: change button text to svg to make it aligned vertically
+          tag.div(sanitize(message)) + tag.button(sanitize("×"), tabindex: -1,
+                                                  onclick: "this.parentElement.remove();")
         end
       end
     end.join.html_safe

app/helpers/quantities_helper.rb

@@ -1,9 +1,9 @@
 module QuantitiesHelper
-  def quantities_check_boxes(quantities)
+  def quantities_check_boxes
     # Closing <details> on focusout event depends on relatedTarget for internal
     # actions being non-null. To ensure this, all top-layer elements of
     # ::details-content must accept focus, e.g. <label> needs tabindex="-1" */
-    collection_check_boxes(nil, :quantity, quantities, :id, :to_s_with_depth,
+    collection_check_boxes(nil, :quantity, @quantities, :id, :to_s_with_depth,
                            include_hidden: false) do |b|
       content_tag :li, b.label(tabindex: -1) { b.check_box + b.text }
     end

app/models/note.rb

@@ -1,3 +0,0 @@
-class Note < ApplicationRecord
-  ATTRIBUTES = [:text]
-end

app/models/quantity.rb

@@ -6,7 +6,6 @@ class Quantity < ApplicationRecord
   belongs_to :parent, optional: true, class_name: "Quantity"
   has_many :subquantities, ->{ order(:name) }, class_name: "Quantity",
     inverse_of: :parent, dependent: :restrict_with_error
-  has_many :readouts, dependent: :restrict_with_error
 
   validate if: ->{ parent.present? } do
     errors.add(:parent, :user_mismatch) unless user_id == parent.user_id

app/models/readout.rb

@@ -4,6 +4,4 @@ class Readout < ApplicationRecord
   belongs_to :user
   belongs_to :quantity
   belongs_to :unit
-
-  # TODO: validate quantity.user_id == unit.user_id != NULL
 end

app/models/unit.rb

@@ -77,14 +77,16 @@ class Unit < ApplicationRecord
       .from(units).group(:base_id, :symbol)
   }
   scope :ordered, ->{
-    left_outer_joins(:base).order([
-      arel_table.coalesce(Arel::Table.new(:bases_units)[:symbol], arel_table[:symbol]),
-      arel_table[:base_id].not_eq(nil),
-      arel_table[:multiplier],
-      arel_table[:symbol]
-    ])
+    left_outer_joins(:base).order(ordering)
   }
 
+  def self.ordering
+    [arel_table.coalesce(Arel::Table.new(:bases_units)[:symbol], arel_table[:symbol]),
+     arel_table[:base_id].not_eq(nil),
+     :multiplier,
+     :symbol]
+  end
+
   before_destroy do
     # TODO: disallow destruction if any object depends on this unit
     nil
@@ -112,10 +114,11 @@ class Unit < ApplicationRecord
 
   def successive
     units = Unit.arel_table
-    Unit.with(units_with_lag: user.units.ordered.select(
-      units[Arel.star],
-      Arel::Nodes::NamedFunction.new('LAG', [units[:id]]).over.as('lag_id')
-    )).from(Arel::Table.new(:units_with_lag).as(:units))
-      .where(units[:lag_id].eq(id)).first
+    lead = Arel::Nodes::NamedFunction.new('LAG', [units[:id]])
+    window = Arel::Nodes::Window.new.order(*Unit.ordering)
+    lag_id = lead.over(window).as('lag_id')
+    Unit.with(
+      units: user.units.left_outer_joins(:base).select(units[Arel.star], lag_id)
+    ).where(units[:lag_id].eq(id)).first
   end
 end

app/models/user.rb

@@ -29,4 +29,11 @@ class User < ApplicationRecord
   def at_least(status)
     User.statuses[self.status] >= User.statuses[status]
   end
+
+  # Returns true when this user is the only admin account in the system.
+  # Used to block actions that would leave the application without an admin
+  # (account deletion, status demotion).
+  def sole_admin?
+    admin? && !User.admin.where.not(id: id).exists?
+  end
 end

app/views/default/units/_unit.html.erb

@@ -5,7 +5,7 @@
   </td>
 
   <% if current_user.at_least(:active) %>
-    <td class="flex">
+    <td class="actions">
       <% unless unit.portable.nil? %>
         <% if unit.default? %>
           <%= image_button_to_if unit.portable?, t('.import'), 'download-outline',

app/views/default/units/index.html.erb

@@ -8,7 +8,7 @@
     class: 'tools-area' %>
 </div>
 
-<table class="main-area items-table">
+<table class="main-area items">
   <thead>
     <tr>
       <th><%= Unit.human_attribute_name(:symbol) %></th>

app/views/layouts/application.html.erb

@@ -23,10 +23,10 @@
   </head>
 
   <body>
-    <header class="flex">
+    <header class="hflex">
       <%= image_link_to t(".source_code"), "code-braces", source_code_url %>
       <%= image_link_to t(".issue_tracker"), "bug-outline", issue_tracker_url,
-        class: "rextend" %>
+            class: "extendedright" %>
       <% if user_signed_in? %>
         <%= image_link_to_unless_current(current_user, "account-wrench-outline",
           edit_user_registration_path) %>

app/views/measurements/_form.html.erb

@@ -1,39 +1,30 @@
 <%= tabular_form_with model: Measurement.new, id: :measurement_form,
-  class: 'topside-area flex vertical center',
-  html: {onkeydown: 'formProcessKey(event)'} do |form| %>
-
-  <table class="items-table center">
-    <tbody id="readouts">
-      <%= tabular_fields_for @measurement do |form| %>
-        <tr class="italic">
-          <td class="hexpand hmin50"><%= t '.taken_at_html' %></td>
-          <td colspan="3" class="ralign">
-            <%= form.datetime_field :taken_at, required: true %>
-          </td>
-        </tr>
-      <% end %>
-    </tbody>
+  class: 'topside-area vflex', html: {onkeydown: 'formProcessKey(event)'} do |form| %>
+  <table class="items centered">
+    <tbody id="readouts"></tbody>
   </table>
 
-  <%# TODO: right-click selection; unnecessary with hierarchical tags? %>
-  <details id="quantity_select" class="center hexpand" open
-           onkeydown="detailsProcessKey(event)">
-    <summary autofocus>
-      <!-- TODO: Set content with CSS when span empty to avoid duplication -->
-      <span data-prompt="<%= t('.select_quantity') %>">
-        <%= t('.select_quantity') %>
-      </span>
-      <%= image_button_tag t(:apply), "update", name: nil, disabled: true,
-        formaction: new_readout_path, formmethod: :get, formnovalidate: true,
-        data: {turbo_stream: true} %>
-    </summary>
-    <ul><%= quantities_check_boxes(@quantities) %></ul>
-  </details>
-
-  <div class="flex reverse">
+  <div class="hflex">
+    <%# TODO: right-click selection %>
+    <details id="quantity_select" class="hexpand" open
+             onkeydown="detailsProcessKey(event)">
+      <summary autofocus>
+        <!-- TODO: Set content with CSS when span empty to avoid duplication -->
+        <span data-prompt="<%= t('.select_quantity') %>">
+          <%= t('.select_quantity') %>
+        </span>
+        <%= image_button_tag t(:apply), "update", name: nil, disabled: true,
+          formaction: new_readout_path, formmethod: :get, formnovalidate: true,
+          data: {turbo_stream: true} %>
+      </summary>
+      <ul><%= quantities_check_boxes %></ul>
+    </details>
     <%= form.button id: :create_measurement_button, disabled: true -%>
+  </div>
+
+  <div class="hflex reverse">
     <%= image_link_to t(:cancel), "close-outline", measurements_path, name: :cancel,
-      class: 'auxiliary dangerous', onclick: render_turbo_stream('form_close') %>
+      class: 'dangerous', onclick: render_turbo_stream('form_close') %>
   </div>
 <% end %>
 

app/views/quantities/_form.html.erb

@@ -9,7 +9,7 @@
       <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
     </td>
 
-    <td class="flex">
+    <td class="actions">
       <%= form.button %>
       <%= image_link_to t(:cancel), "close-outline", quantities_path, class: 'dangerous',
         name: :cancel, onclick: render_turbo_stream('form_close', {row: row}) %>

app/views/quantities/_quantity.html.erb

@@ -5,14 +5,14 @@
            data: {drag_path: reparent_quantity_path(quantity), drop_id: dom_id(quantity),
                   drop_id_param: "quantity[parent_id]"} do %>
 
-  <td style="--depth:<%= quantity.depth %>">
-    <%= link_to quantity, edit_quantity_path(quantity), class: 'link',
-      onclick: 'this.blur();', data: {turbo_stream: true} %>
+  <td class="link" style="--depth:<%= quantity.depth %>">
+    <%= link_to quantity, edit_quantity_path(quantity), onclick: 'this.blur();',
+      data: {turbo_stream: true} %>
   </td>
   <td><%= quantity.description %></td>
 
   <% if current_user.at_least(:active) %>
-    <td class="flex">
+    <td class="actions">
       <%= image_link_to t('.new_subquantity'), 'plus-outline', new_quantity_path(quantity),
         id: dom_id(quantity, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>
 

app/views/quantities/index.html.erb

@@ -8,14 +8,13 @@
     class: 'tools-area' %>
 </div>
 
-<%# TODO: remove? form can be inserted directly, e.g. at the end of index %>
 <%= tag.div class: 'main-area', id: :quantity_form %>
 
-<table class="main-area items-table">
+<table class="main-area items">
   <thead>
     <tr>
       <th><%= Quantity.human_attribute_name(:name) %></th>
-      <th class="hexpand"><%= Quantity.human_attribute_name(:description) %></th>
+      <th><%= Quantity.human_attribute_name(:description) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t :actions %></th>
         <th></th>

app/views/readouts/_form.html.erb

@@ -1,24 +1,25 @@
 <%# TODO: add readout reordering by dragging %>
 <%= tabular_fields_for 'readouts[]', readout do |form| %>
   <%- tag.tr id: dom_id(readout.quantity, :new, :readout) do %>
-    <td>
-      <%# TODO: add grayed readout index (in separate column?) %>
-      <%= readout.quantity.relative_pathname(@superquantity) %>
-      <%= form.hidden_field :quantity_id %>
-    </td>
-    <td>
-      <%= form.number_field :value, required: true, autofocus: readout_counter == 0 %>
-    </td>
-    <td>
-      <%= form.collection_select :unit_id, @user_units, :id,
-        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
-        {prompt: '', disabled: '', selected: ''}, required: true %>
-    </td>
-    <td class="flex">
+    <td class="actions">
       <%# TODO: change to _link_ after giving up displaying relative paths %>
       <%= image_button_tag '', 'delete-outline', class: 'dangerous', name: nil,
         formaction: discard_readouts_path(readout.quantity),
         formmethod: :get, formnovalidate: true, data: {turbo_stream: true} %>
     </td>
+    <td>
+      <%= readout.quantity.relative_pathname(@superquantity) %>
+    </td>
+    <td>
+      <%= form.number_field :value, required: true,
+        size: readout.type_for_attribute(:value).precision / 2,
+        autofocus: readout_counter == 0 %>
+    </td>
+    <td>
+      <%= form.hidden_field :quantity_id %>
+      <%= form.collection_select :unit_id, @user_units, :id,
+        ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
+        {prompt: t('.select_unit'), disabled: '', selected: ''}, required: true %>
+    </td>
   <% end %>
 <% end %>

app/views/units/_form.html.erb

@@ -8,11 +8,11 @@
     <td>
       <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
     </td>
-    <td>
+    <td class="number">
       <%= form.number_field :multiplier, required: true, size: 10, min: :step if @unit.base_id? %>
     </td>
 
-    <td class="flex">
+    <td class="actions">
       <%= form.button %>
       <%= image_link_to t(:cancel), "close-outline", units_path, class: 'dangerous',
         name: :cancel, onclick: render_turbo_stream('form_close', {row: row}) %>

app/views/units/_unit.html.erb

@@ -6,15 +6,14 @@
                   drop_id: dom_id(unit.base || unit),
                   drop_id_param: "unit[base_id]"} do %>
 
-  <td style="--depth:<%= unit.base_id? ? 1 : 0 %>">
-    <%= link_to unit, edit_unit_path(unit), class: 'link', onclick: 'this.blur();',
-      data: {turbo_stream: true} %>
+  <td class="link" style="--depth:<%= unit.base_id? ? 1 : 0 %>">
+    <%= link_to unit, edit_unit_path(unit), onclick: 'this.blur();', data: {turbo_stream: true} %>
   </td>
   <td><%= unit.description %></td>
-  <td class="ralign"><%= unit.multiplier.to_html %></td>
+  <td class="number"><%= unit.multiplier.to_html %></td>
 
   <% if current_user.at_least(:active) %>
-    <td class="flex">
+    <td class="actions">
       <% unless unit.base_id? %>
         <%= image_link_to t('.new_subunit'), 'plus-outline', new_unit_path(unit),
           id: dom_id(unit, :new, :link), onclick: 'this.blur();', data: {turbo_stream: true} %>

app/views/units/index.html.erb

@@ -7,14 +7,13 @@
     class: 'tools-area' %>
 </div>
 
-<%# TODO: remove? form can be inserted directly, e.g. at the end of index %>
 <%= tag.div id: :unit_form %>
 
-<table class="main-area items-table">
+<table class="main-area items">
   <thead>
     <tr>
       <th><%= Unit.human_attribute_name(:symbol) %></th>
-      <th class="hexpand"><%= Unit.human_attribute_name(:description) %></th>
+      <th><%= Unit.human_attribute_name(:description) %></th>
       <th><%= Unit.human_attribute_name(:multiplier) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t :actions %></th>

app/views/users/index.html.erb

@@ -1,4 +1,4 @@
-<table class="main-area items-table" id="users">
+<table class="main-area items" id="users">
   <thead>
     <tr>
       <th><%= User.human_attribute_name(:email) %></th>
@@ -11,7 +11,7 @@
   <tbody>
     <% @users.each do |user| %>
       <tr>
-        <td><%= link_to user, user_path(user), class: 'link' %></td>
+        <td class="link"><%= link_to user, user_path(user) %></td>
         <td>
           <% if user == current_user %>
             <%= user.status %>
@@ -22,11 +22,11 @@
             <% end %>
           <% end %>
         </td>
-        <td>
+        <td class="svg">
           <%= svg_tag 'pictograms/checkbox-marked-outline' if user.confirmed_at.present? %>
         </td>
         <td><%= l user.created_at, format: :without_tz %></td>
-        <td class="flex">
+        <td class="actions">
           <% if allow_disguise?(user) %>
             <%= image_link_to t('.disguise'), 'incognito', disguise_user_path(user) %>
           <% end %>

app/views/users/profiles/edit.html.erb

@@ -4,9 +4,8 @@
 <% end %>
 
 <div class="rightside-area buttongrid">
-  <%#= TODO: Disallow/disable deletion for last admin account, image_button_to_if %>
-  <%= image_button_to t('.delete'), 'account-remove-outline', user_registration_path,
-    form_class: 'tools-area', method: :delete, data: {turbo: false},
+  <%= image_button_to_if !current_user.sole_admin?, t('.delete'), 'account-remove-outline',
+    user_registration_path, form_class: 'tools-area', method: :delete, data: {turbo: false},
     onclick: {confirm: t('.confirm_delete')} %>
 </div>
 

app/views/users/profiles/new.html.erb

@@ -10,6 +10,7 @@
 
   <%= f.submit t(:register), data: {turbo: false} %>
 
+  <%# TODO: fix button text color after change link -> button %>
   <%= image_button_tag t(:resend_confirmation), 'email-sync-outline',
     class: 'auxiliary', formaction: user_confirmation_path, formnovalidate: true,
     data: {validate: f.field_id(:email)} %>

app/views/users/unlocks/new.html.erb

@@ -8,7 +8,7 @@
     <%= f.email_field :email, autofocus: true, autocomplete: "email" %>
   </div>
 
-  <div class="flex">
+  <div class="actions">
     <%= f.submit "Resend unlock instructions" %>
   </div>
 <% end %>

bin/ci

@@ -1,6 +0,0 @@
-#!/usr/bin/env ruby
-require_relative "../config/boot"
-require "active_support/continuous_integration"
-
-CI = ActiveSupport::ContinuousIntegration
-require_relative "../config/ci.rb"

bin/dev

@@ -1,2 +0,0 @@
-#!/usr/bin/env ruby
-exec "./bin/rails", "server", *ARGV

bin/setup

@@ -1,10 +1,11 @@
 #!/usr/bin/env ruby
 require "fileutils"
 
+# path to your application root.
 APP_ROOT = File.expand_path("..", __dir__)
 
 def system!(*args)
-  system(*args, exception: true)
+  system(*args) || abort("\n== Command #{args} failed ==")
 end
 
 FileUtils.chdir APP_ROOT do
@@ -13,6 +14,7 @@ FileUtils.chdir APP_ROOT do
   # Add necessary setup steps to this file.
 
   puts "== Installing dependencies =="
+  system! "gem install bundler --conservative"
   system("bundle check") || system!("bundle install")
 
   # puts "\n== Copying sample files =="
@@ -22,14 +24,10 @@ FileUtils.chdir APP_ROOT do
 
   puts "\n== Preparing database =="
   system! "bin/rails db:prepare"
-  system! "bin/rails db:reset" if ARGV.include?("--reset")
 
   puts "\n== Removing old logs and tempfiles =="
   system! "bin/rails log:clear tmp:clear"
 
-  unless ARGV.include?("--skip-server")
-    puts "\n== Starting development server =="
-    STDOUT.flush # flush the output before exec(2) so that it displays
-    exec "bin/dev"
-  end
+  puts "\n== Restarting application server =="
+  system! "bin/rails restart"
 end

config/application.rb.dist

@@ -18,17 +18,14 @@ require "rails/test_unit/railtie"
 # you've limited to :test, :development, or :production.
 Bundler.require(*Rails.groups)
 
-require_relative '../lib/default_settings_strategy'
-
 module FixinMe
   class Application < Rails::Application
     # Initialize configuration defaults for originally generated Rails version.
-    config.load_defaults 8.1
+    config.load_defaults 7.0
 
-    # Please, add to the `ignore` list any other `lib` subdirectories that do
-    # not contain `.rb` files, or that should not be reloaded or eager loaded.
-    # Common ones are `templates`, `generators`, or `middleware`, for example.
-    config.autoload_lib(ignore: %w[assets tasks])
+    # Autoload lib/, required e.g. for core library extensions.
+    # https://guides.rubyonrails.org/autoloading_and_reloading_constants.html#config-autoload-lib-ignore.
+    config.autoload_lib(ignore: %w(assets tasks))
 
     # Configuration for the application, engines, and railties goes here.
     #
@@ -41,19 +38,16 @@ module FixinMe
     config.action_dispatch.rescue_responses['ApplicationController::AccessForbidden'] = :forbidden
     config.action_dispatch.rescue_responses['ApplicationController::ParameterInvalid'] = :unprocessable_entity
 
-    # Set default migrations parameters.
-    config.active_record.migration_strategy = DefaultSettingsStrategy
-
     # SETUP: Below settings need to be updated on a per-installation basis.
     #
-    # Set host to be used by links generated in mailer templates.
-    config.action_mailer.default_url_options = {host: 'localhost', protocol: 'https'}
+    # URL to use in sent e-mails.
+    config.action_mailer.default_url_options = {host: 'localhost', :protocol => 'https'}
     # https://guides.rubyonrails.org/configuring.html#config-action-mailer-delivery-method
     config.action_mailer.delivery_method = :sendmail
 
     # List of hosts this app is available at.
     # https://guides.rubyonrails.org/configuring.html#actiondispatch-hostauthorization
-    config.hosts |= ['localhost']
+    config.hosts += ['localhost', 'example.com', IPAddr.new('1.2.3.4/32')]
 
     # Email address of admin account
     config.admin = 'admin@localhost'

config/ci.rb

@@ -1,20 +0,0 @@
-# Run using bin/ci
-
-CI.run do
-  step "Setup", "bin/setup --skip-server"
-
-  step "Security: Importmap vulnerability audit", "bin/importmap audit"
-  step "Tests: Rails", "bin/rails test"
-  step "Tests: Seeds", "env RAILS_ENV=test bin/rails db:seed:replant"
-
-  # Optional: Run system tests
-  # step "Tests: System", "bin/rails test:system"
-
-  # Optional: set a green GitHub commit status to unblock PR merge.
-  # Requires the `gh` CLI and `gh extension install basecamp/gh-signoff`.
-  # if success?
-  #   step "Signoff: All systems go. Ready for merge and deploy.", "gh signoff"
-  # else
-  #   failure "Signoff: CI failed. Do not merge or deploy.", "Fix the issues and try again."
-  # end
-end

config/database.yml.dist

@@ -24,45 +24,27 @@
 # Read https://guides.rubyonrails.org/configuring.html#configuring-a-database
 # for a full overview on how database connection configuration can be specified.
 default: &default
-  pool: <%= ENV.fetch('RAILS_MAX_THREADS', 3) %>
-
-#mysql_default: &mysql_default
-#  <<: *default
-#  username: fixinme
-#  password: Some-password1%
-#  host: 127.0.0.1
-#  encoding: utf8mb4
-#  collation: utf8mb4_0900_as_ci
+  adapter: mysql2
+  encoding: utf8mb4
+  collation: utf8mb4_0900_as_ci
+  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
+  username: fixinme
+  password: Some-password1%
+  socket: /run/mysqld/mysqld.sock
 
 production:
   <<: *default
-  adapter: sqlite3
-  database: db/production.sqlite3
+  database: fixinme
 
-# Unless you're planning on developing the application, you can skip/remove
+# Unless you're planning on developing the application, you can skip
 # configurations for development and test databases altogether.
 #development:
-#  <<: *mysql_default
-#  adapter: mysql2
+#  <<: *default
 #  database: fixinme_dev
 
-# Warning: The database(s) defined as "test" will be erased and
+# Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 #test:
-#  <<: *mysql_default
-#  adapter: mysql2
+#  <<: *default
 #  database: fixinme_test
-
-# Multiple test databases can be provided. When more than one test db is
-# present, every test task (test, test:models, test:system, etc.) runs against
-# all of them.
-#test:
-#  mysql2:
-#    <<: *mysql_default
-#    adapter: mysql2
-#    database: fixinme_test
-#  sqlite3:
-#    <<: *default
-#    adapter: sqlite3
-#    database: db/test.sqlite3

config/environments/development.rb

@@ -3,8 +3,10 @@ require "active_support/core_ext/integer/time"
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
-  # Make code changes take effect immediately without server restart.
-  config.enable_reloading = true
+  # In the development environment your application's code is reloaded any time
+  # it changes. This slows down response time but is perfect for development
+  # since you don't have to restart the web server when you make code changes.
+  config.cache_classes = false
 
   # Do not eager load code on boot.
   config.eager_load = false
@@ -12,52 +14,54 @@ Rails.application.configure do
   # Show full error reports.
   config.consider_all_requests_local = true
 
-  # Enable server timing.
+  # Enable server timing
   config.server_timing = true
 
-  # Enable/disable Action Controller caching. By default Action Controller caching is disabled.
-  # Run rails dev:cache to toggle Action Controller caching.
+  # Enable/disable caching. By default caching is disabled.
+  # Run rails dev:cache to toggle caching.
   if Rails.root.join("tmp/caching-dev.txt").exist?
     config.action_controller.perform_caching = true
     config.action_controller.enable_fragment_cache_logging = true
-    config.public_file_server.headers = { "cache-control" => "public, max-age=#{2.days.to_i}" }
+
+    config.cache_store = :memory_store
+    config.public_file_server.headers = {
+      "Cache-Control" => "public, max-age=#{2.days.to_i}"
+    }
   else
     config.action_controller.perform_caching = false
-  end
 
-  # Change to :null_store to avoid any caching.
-  config.cache_store = :memory_store
+    config.cache_store = :null_store
+  end
 
   # Don't care if the mailer can't send.
   config.action_mailer.raise_delivery_errors = false
 
-  # Make template changes take effect immediately.
   config.action_mailer.perform_caching = false
 
   # Print deprecation notices to the Rails logger.
   config.active_support.deprecation = :log
 
+  # Raise exceptions for disallowed deprecations.
+  config.active_support.disallowed_deprecation = :raise
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
   # Raise an error on page load if there are pending migrations.
   config.active_record.migration_error = :page_load
 
   # Highlight code that triggered database queries in logs.
   config.active_record.verbose_query_logs = true
 
-  # Append comments with runtime information tags to SQL queries in logs.
-  config.active_record.query_log_tags_enabled = true
-
-  # Highlight code that enqueued background job in logs.
-  config.active_job.verbose_enqueue_logs = true
-
-  # Highlight code that triggered redirect in logs.
-  config.action_dispatch.verbose_redirect_logs = true
+  # Suppress logger output for asset requests.
+  config.assets.quiet = true
 
   # Raises error for missing translations.
   # config.i18n.raise_on_missing_translations = true
 
   # Annotate rendered view with file names.
-  config.action_view.annotate_rendered_view_with_filenames = true
+  # config.action_view.annotate_rendered_view_with_filenames = true
 
-  # Raise error when a before_action's only/except options reference missing actions.
-  config.action_controller.raise_on_missing_callback_actions = true
+  # Uncomment if you wish to allow Action Cable access from any origin.
+  # config.action_cable.disable_request_forgery_protection = true
 end

config/environments/production.rb

@@ -4,83 +4,78 @@ Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
   # Code is not reloaded between requests.
-  config.enable_reloading = false
+  config.cache_classes = true
 
-  # Eager load code on boot for better performance and memory savings (ignored by Rake tasks).
+  # Eager load code on boot. This eager loads most of Rails and
+  # your application in memory, allowing both threaded web servers
+  # and those relying on copy on write to perform better.
+  # Rake tasks automatically ignore this option for performance.
   config.eager_load = true
 
-  # Full error reports are disabled.
-  config.consider_all_requests_local = false
-
-  # Turn on fragment caching in view templates.
+  # Full error reports are disabled and caching is turned on.
+  config.consider_all_requests_local       = false
   config.action_controller.perform_caching = true
 
-  # Cache assets for far-future expiry since they are all digest stamped.
-  config.public_file_server.headers = { "cache-control" => "public, max-age=#{1.year.to_i}" }
+  # Ensures that a master key has been made available in either ENV["RAILS_MASTER_KEY"]
+  # or in config/master.key. This key is used to decrypt credentials (and other encrypted files).
+  # config.require_master_key = true
+
+  # Disable serving static files from the `/public` folder by default since
+  # Apache or NGINX already handles this.
+  config.public_file_server.enabled = ENV["RAILS_SERVE_STATIC_FILES"].present?
+
+  # Compress CSS using a preprocessor.
+  # config.assets.css_compressor = :sass
+
+  # Do not fallback to assets pipeline if a precompiled asset is missed.
+  config.assets.compile = false
 
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
   # config.asset_host = "http://assets.example.com"
 
-  # Assume all access to the app is happening through a SSL-terminating reverse proxy.
-  config.assume_ssl = true
+  # Specifies the header that your server uses for sending files.
+  # config.action_dispatch.x_sendfile_header = "X-Sendfile" # for Apache
+  # config.action_dispatch.x_sendfile_header = "X-Accel-Redirect" # for NGINX
 
   # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
-  config.force_ssl = true
+  # config.force_ssl = true
 
-  # Skip http-to-https redirect for the default health check endpoint.
-  # config.ssl_options = { redirect: { exclude: ->(request) { request.path == "/up" } } }
+  # Include generic and useful information about system operation, but avoid logging too much
+  # information to avoid inadvertent exposure of personally identifiable information (PII).
+  config.log_level = :info
 
-  # Log to STDOUT with the current request id as a default log tag.
+  # Prepend all log lines with the following tags.
   config.log_tags = [ :request_id ]
-  config.logger   = ActiveSupport::TaggedLogging.logger(STDOUT)
 
-  # Change to "debug" to log everything (including potentially personally-identifiable information!).
-  config.log_level = ENV.fetch("RAILS_LOG_LEVEL", "info")
-
-  # Prevent health checks from clogging up the logs.
-  config.silence_healthcheck_path = "/up"
-
-  # Don't log any deprecations.
-  config.active_support.report_deprecations = false
-
-  # Replace the default in-process memory cache store with a durable alternative.
+  # Use a different cache store in production.
   # config.cache_store = :mem_cache_store
 
-  # Replace the default in-process and non-durable queuing backend for Active Job.
-  # config.active_job.queue_adapter = :resque
+  config.action_mailer.perform_caching = false
 
   # Ignore bad email addresses and do not raise email delivery errors.
   # Set this to true and configure the email server for immediate delivery to raise delivery errors.
   # config.action_mailer.raise_delivery_errors = false
 
-  # Specify outgoing SMTP server. Remember to add smtp/* credentials via bin/rails credentials:edit.
-  # config.action_mailer.smtp_settings = {
-  #   user_name: Rails.application.credentials.dig(:smtp, :user_name),
-  #   password: Rails.application.credentials.dig(:smtp, :password),
-  #   address: "smtp.example.com",
-  #   port: 587,
-  #   authentication: :plain
-  # }
-
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation cannot be found).
   config.i18n.fallbacks = true
 
+  # Don't log any deprecations.
+  config.active_support.report_deprecations = false
+
+  # Use default logging formatter so that PID and timestamp are not suppressed.
+  config.log_formatter = ::Logger::Formatter.new
+
+  # Use a different logger for distributed setups.
+  # require "syslog/logger"
+  # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new "app-name")
+
+  if ENV["RAILS_LOG_TO_STDOUT"].present?
+    logger           = ActiveSupport::Logger.new(STDOUT)
+    logger.formatter = config.log_formatter
+    config.logger    = ActiveSupport::TaggedLogging.new(logger)
+  end
+
   # Do not dump schema after migrations.
   config.active_record.dump_schema_after_migration = false
-
-  # Only use :id for inspections in production.
-  config.active_record.attributes_for_inspect = [ :id ]
-
-  # Enable DNS rebinding protection and other `Host` header attacks.
-  # config.hosts = [
-  #   "example.com",     # Allow requests from example.com
-  #   /.*\.example\.com/ # Allow requests from subdomains like `www.example.com`
-  # ]
-  #
-  # Skip DNS rebinding protection for the default health check endpoint.
-  # config.host_authorization = { exclude: ->(request) { request.path == "/up" } }
-
-  # Protect e-mail addresses from being logged only in production.
-  config.filter_parameters += [:email]
 end

config/environments/test.rb

@@ -1,3 +1,5 @@
+require "active_support/core_ext/integer/time"
+
 # The test environment is used exclusively to run your application's
 # test suite. You never need to work with it otherwise. Remember that
 # your test database is "scratch space" for the test suite and is wiped
@@ -6,49 +8,54 @@
 Rails.application.configure do
   # Settings specified here will take precedence over those in config/application.rb.
 
-  # While tests run files are not watched, reloading is not necessary.
-  config.enable_reloading = false
+  # Turn false under Spring and add config.action_view.cache_template_loading = true.
+  config.cache_classes = true
 
-  # Eager loading loads your entire application. When running a single test locally,
-  # this is usually not necessary, and can slow down your test suite. However, it's
-  # recommended that you enable it in continuous integration systems to ensure eager
-  # loading is working properly before deploying your code.
+  # Eager loading loads your whole application. When running a single test locally,
+  # this probably isn't necessary. It's a good idea to do in a continuous integration
+  # system, or in some way before deploying your code.
   config.eager_load = ENV["CI"].present?
 
-  # Configure public file server for tests with cache-control for performance.
-  config.public_file_server.headers = { "cache-control" => "public, max-age=3600" }
+  # Configure public file server for tests with Cache-Control for performance.
+  config.public_file_server.enabled = true
+  config.public_file_server.headers = {
+    "Cache-Control" => "public, max-age=#{1.hour.to_i}"
+  }
 
-  # Behave as in `production`.
-  config.consider_all_requests_local = false
+  # Hide full error reports.
+  config.consider_all_requests_local     = false
+  # Render exception templates instead of raising exceptions.
+  config.action_dispatch.show_exceptions = :all
 
+  # Disable caching.
+  config.action_controller.perform_caching = false
   config.cache_store = :null_store
 
   # Disable request forgery protection in test environment.
   config.action_controller.allow_forgery_protection = false
 
+  config.action_mailer.perform_caching = false
+
   # Tell Action Mailer not to deliver emails to the real world.
   # The :test delivery method accumulates sent emails in the
   # ActionMailer::Base.deliveries array.
   config.action_mailer.delivery_method = :test
-
-  # Set host to be used by links generated in mailer templates.
-  config.action_mailer.default_url_options = {host: Capybara.server_host,
-                                              protocol: 'http'}
+  config.action_mailer.default_url_options = {host: '127.0.0.1', :protocol => 'http'}
 
   # Print deprecation notices to the stderr.
   config.active_support.deprecation = :stderr
 
+  # Raise exceptions for disallowed deprecations.
+  config.active_support.disallowed_deprecation = :raise
+
+  # Tell Active Support which deprecation messages to disallow.
+  config.active_support.disallowed_deprecation_warnings = []
+
   # Raises error for missing translations.
   config.i18n.raise_on_missing_translations = true
 
   # Annotate rendered view with file names.
   # config.action_view.annotate_rendered_view_with_filenames = true
 
-  # Raise error when a before_action's only/except options reference missing actions.
-  config.action_controller.raise_on_missing_callback_actions = true
-
-  # Allow Capybara application server IP
-  config.hosts |= [IPAddr.new(Capybara.server_host)]
-
   config.log_level = :info
 end

config/initializers/assets.rb

@@ -5,3 +5,8 @@ Rails.application.config.assets.version = "1.0"
 
 # Add additional assets to the asset load path.
 # Rails.application.config.assets.paths << Emoji.images_path
+
+# Precompile additional assets.
+# application.js, application.css, and all non-JS/CSS in the app/assets
+# folder are already added.
+Rails.application.config.assets.precompile += %w( '*.svg' )

config/initializers/content_security_policy.rb

@@ -16,13 +16,9 @@
 #     # policy.report_uri "/csp-violation-report-endpoint"
 #   end
 #
-#   # Generate session nonces for permitted importmap, inline scripts, and inline styles.
+#   # Generate session nonces for permitted importmap and inline scripts
 #   config.content_security_policy_nonce_generator = ->(request) { request.session.id.to_s }
-#   config.content_security_policy_nonce_directives = %w(script-src style-src)
-#
-#   # Automatically add `nonce` to `javascript_tag`, `javascript_include_tag`, and `stylesheet_link_tag`
-#   # if the corresponding directives are specified in `content_security_policy_nonce_directives`.
-#   # config.content_security_policy_nonce_auto = true
+#   config.content_security_policy_nonce_directives = %w(script-src)
 #
 #   # Report violations without enforcing the policy.
 #   # config.content_security_policy_report_only = true

config/initializers/devise.rb

@@ -179,7 +179,7 @@ Devise.setup do |config|
 
   # ==> Configuration for :validatable
   # Range for password length.
-  config.password_length = 5..32
+  config.password_length = 5..128
 
   # Email regex used to validate email formats. It simply asserts that
   # one (and only one) @ exists in the given string. This is mainly

config/initializers/filter_parameter_logging.rb

@@ -1,8 +1,8 @@
 # Be sure to restart your server when you modify this file.
 
-# Configure parameters to be partially matched (e.g. passw matches password) and filtered from the log file.
-# Use this to limit dissemination of sensitive information.
-# See the ActiveSupport::ParameterFilter documentation for supported notations and behaviors.
+# Configure parameters to be filtered from the log file. Use this to limit dissemination of
+# sensitive information. See the ActiveSupport::ParameterFilter documentation for supported
+# notations and behaviors.
 Rails.application.config.filter_parameters += [
-  :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn, :cvv, :cvc
+  :passw, :secret, :token, :_key, :crypt, :salt, :certificate, :otp, :ssn
 ]

config/locales/en.yml

@@ -85,10 +85,12 @@ en:
     navigation: Measurements
     no_items: There are no measurements taken. You can Add some now.
     form:
-      select_quantity: select quantities...
-      taken_at_html: Measurement taken at 
+      select_quantity: select the measured quantities...
     index:
       new_measurement: Add measurement
+  readouts:
+    form:
+      select_unit: ...
   quantities:
     navigation: Quantities
     no_items: There are no configured quantities. You can Add some or Import from defaults.
@@ -160,6 +162,9 @@ en:
           New password:
           <br><em>leave blank to keep unchanged</em>
           %{password_length_hint_html}
+  registrations:
+    destroy:
+      sole_admin: You cannot delete the only admin account.
   actions: Actions
   add: Add
   apply: Apply

config/puma.rb.dist

@@ -1,41 +1,43 @@
-# This configuration file will be evaluated by Puma. The top-level methods that
-# are invoked here are part of Puma's configuration DSL. For more information
-# about methods provided by the DSL, see https://puma.io/puma/Puma/DSL.html.
+# Puma can serve each request in a thread from an internal thread pool.
+# The `threads` method setting takes two numbers: a minimum and maximum.
+# Any libraries that use thread pools should be configured to match
+# the maximum value specified for Puma. Default is set to 5 threads for minimum
+# and maximum; this matches the default thread size of Active Record.
 #
-# Puma starts a configurable number of processes (workers) and each process
-# serves each request in a thread from an internal thread pool.
+max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
+min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
+threads min_threads_count, max_threads_count
+
+# Specifies the `worker_timeout` threshold that Puma will use to wait before
+# terminating a worker in development environments.
 #
-# You can control the number of workers using ENV["WEB_CONCURRENCY"]. You
-# should only set this value when you want to run 2 or more workers. The
-# default is already 1.
-#
-# The ideal number of threads per worker depends both on how much time the
-# application spends waiting for IO operations and on how much you wish to
-# prioritize throughput over latency.
-#
-# As a rule of thumb, increasing the number of threads will increase how much
-# traffic a given process can handle (throughput), but due to CRuby's
-# Global VM Lock (GVL) it has diminishing returns and will degrade the
-# response time (latency) of the application.
-#
-# The default is set to 3 threads as it's deemed a decent compromise between
-# throughput and latency for the average Rails application.
-#
-# Any libraries that use a connection pool or another resource pool should
-# be configured to provide at least as many connections as the number of
-# threads. This includes Active Record's `pool` parameter in `database.yml`.
-threads_count = ENV.fetch("RAILS_MAX_THREADS", 3)
-threads threads_count, threads_count
+worker_timeout 3600 if ENV.fetch("RAILS_ENV", "development") == "development"
 
 # Specifies the `port` that Puma will listen on to receive requests; default is 3000.
-port ENV.fetch("PORT", 3000), '127.0.0.1'
+#
+port ENV.fetch("PORT") { 3000 }
+
+# Specifies the `environment` that Puma will run in.
+#
+environment ENV.fetch("RAILS_ENV") { "development" }
+
+# Specifies the `pidfile` that Puma will use.
+pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }
+
+# Specifies the number of `workers` to boot in clustered mode.
+# Workers are forked web server processes. If using threads and workers together
+# the concurrency of the application would be max `threads` * `workers`.
+# Workers do not work on JRuby or Windows (both of which do not support
+# processes).
+#
+# workers ENV.fetch("WEB_CONCURRENCY") { 2 }
+
+# Use the `preload_app!` method when specifying a `workers` number.
+# This directive tells Puma to first boot the application and load code
+# before forking the application. This takes advantage of Copy On Write
+# process behavior so workers use less memory.
+#
+# preload_app!
 
 # Allow puma to be restarted by `bin/rails restart` command.
 plugin :tmp_restart
-
-# Run the Solid Queue supervisor inside of Puma for single-server deployments
-plugin :solid_queue if ENV["SOLID_QUEUE_IN_PUMA"]
-
-# Specify the PID file. Defaults to tmp/pids/server.pid in development.
-# In other environments, only set the PID file if requested.
-pidfile ENV["PIDFILE"] if ENV["PIDFILE"]

config/routes.rb

@@ -15,10 +15,7 @@ Rails.application.routes.draw do
 
   namespace :default do
     resources :units, only: [:index, :destroy] do
-      member {
-        post :import
-        post :export
-      }
+      member { post :import, :export }
       #collection { post :import_all }
     end
   end

db/migrate/20230309185340_create_users.rb

@@ -1,11 +1,11 @@
-class CreateUsers < ActiveRecord::Migration[8.1]
+class CreateUsers < ActiveRecord::Migration[7.0]
   def change
     create_table :users do |t|
       t.string :email, null: false, limit: 64
       t.integer :status, null: false, default: 0
 
-      t.timestamps
+      t.timestamps null: false
     end
-    add_index :users, :email
+    add_index :users, :email, unique: true
   end
 end

db/migrate/20230311220654_add_devise_to_users.rb

@@ -1,4 +1,4 @@
-class AddDeviseToUsers < ActiveRecord::Migration[8.1]
+class AddDeviseToUsers < ActiveRecord::Migration[7.0]
   def change
     change_table :users do |t|
       ## NOTE: commented fields left for reference/inclusion in future migrations
@@ -34,8 +34,8 @@ class AddDeviseToUsers < ActiveRecord::Migration[8.1]
       # t.integer :failed_attempts, default: 0, null: false 
     end
 
-    add_index :users, :reset_password_token
-    add_index :users, :confirmation_token
+    add_index :users, :reset_password_token, unique: true
+    add_index :users, :confirmation_token, unique: true
     # add_index :users, :unlock_token, unique: true
   end
 end

db/migrate/20230602185352_create_units.rb

@@ -1,15 +1,14 @@
-class CreateUnits < ActiveRecord::Migration[8.1]
+class CreateUnits < ActiveRecord::Migration[7.0]
   def change
     create_table :units do |t|
-      t.references :user, foreign_key: {on_delete: :cascade}
+      t.references :user, foreign_key: true
       t.string :symbol, null: false, limit: 15
       t.text :description
       t.decimal :multiplier, null: false, precision: 30, scale: 15, default: 1.0
       t.references :base, foreign_key: {to_table: :units, on_delete: :cascade}
 
-      t.timestamps
+      t.timestamps null: false
     end
-    add_index :units, [:user_id, :symbol]
-    add_index :units, [:id, :user_id]
+    add_index :units, [:user_id, :symbol], unique: true
   end
 end

db/migrate/20250104194343_create_quantities.rb

@@ -1,18 +1,17 @@
-class CreateQuantities < ActiveRecord::Migration[8.1]
+class CreateQuantities < ActiveRecord::Migration[7.2]
   def change
     create_table :quantities do |t|
-      t.references :user, foreign_key: {on_delete: :cascade}
+      t.references :user, foreign_key: true
       t.string :name, null: false, limit: 31
       t.text :description
       t.references :parent, foreign_key: {to_table: :quantities, on_delete: :cascade}
 
-      t.timestamps
+      t.timestamps null: false
 
       # Caches; can be computed from other attributes
       t.integer :depth, null: false, default: 0
       t.string :pathname, null: false, limit: 511
     end
-    add_index :quantities, [:user_id, :parent_id, :name]
-    add_index :quantities, [:id, :user_id]
+    add_index :quantities, [:user_id, :parent_id, :name], unique: true
   end
 end

db/migrate/20250121230456_create_readouts.rb

@@ -1,69 +1,15 @@
-class CreateReadouts < ActiveRecord::Migration[8.1]
+class CreateReadouts < ActiveRecord::Migration[7.2]
   def change
-    create_table :notes do |t|
-      t.text :text, null: false
-
-      t.timestamps
-    end
-
-    create_table :measurements do |t|
-      t.datetime :taken_at, null: false
+    create_table :readouts do |t|
+      t.references :user, null: false, foreign_key: true
+      t.references :quantity, null: false, foreign_key: true
+      t.references :unit, foreign_key: true
+      t.decimal :value, null: false, precision: 30, scale: 15
       #t.references :collector, foreign_key: true
       #t.references :device, foreign_key: true
-      t.references :note, foreign_key: {on_delete: :nullify}
 
-      t.timestamps
+      t.timestamps null: false
     end
-    add_index :measurements, :taken_at
-
-    # Defining Readouts as a super-/subclass polymorphic relations for different
-    # subclass data types (numeric, string, file) is not possible with proper
-    # referential integrity constraints. The required constraints are:
-    # * for every subclass record to have superclass record,
-    # * for every superclass record to have only one type of subclass record,
-    # * for every superclass record to have subclass record (unenforcable).
-    #   * this can be partially remedied by making superlass an abstract class in
-    #     Rails and disallow direct creation of records, but direct data
-    #     manipulation can still break referential integrity.
-    # Defining separate {Numeric,Text,File}_Readouts tables would make the
-    # unique index constraint unenforcable.
-    create_table :readouts do |t|
-      t.references :user, null: false, foreign_key: {on_delete: :cascade}
-      t.references :measurement, foreign_key: {on_delete: :cascade}
-      t.references :quantity, null: false, foreign_key: {on_delete: :cascade}
-      t.integer :category, null: false, default: 0
-      t.float :value, null: false, limit: Float::MANT_DIG
-      t.references :unit, null: false, foreign_key: {on_delete: :cascade}
-      # TODO: consider additional columns to allow wider range of value types
-      # t.text :text
-      # t.datetime :time
-      # t.references :file
-      # Possibly mutually exclusive with :unit or check constraint for:
-      #   :unit is not null <=> :value is not null
-
-      t.timestamps
-    end
-    add_index :readouts, [:measurement_id, :quantity_id, :category]
-    add_foreign_key :readouts, :quantities, column: [:quantity_id, :user_id],
-      primary_key: [:id, :user_id]
-    add_foreign_key :readouts, :units, column: [:unit_id, :user_id],
-      primary_key: [:id, :user_id]
-
-    # TODO: remove below tables after current setup verified
-    #create_table :numeric_values do |t|
-    #  t.references :readout, null: false, foreign_key: {on_delete: :cascade}
-    #  t.float :value, null: false, limit: Float::MANT_DIG
-    #  t.references :unit, null: false, foreign_key: {on_delete: :cascade}
-    #  # + generated, not stored column :value_type
-    #  # + foreign key constraint to readouts: [:readout_id, :value_id, :value_type]
-    #  # or 2 constraints: [:readout_id, :value_id], [:value_id, :value_type]
-    #  # if readouts.value_id needed, otherwise just one constraint:
-    #  # [:readout_id, :value_type]
-    #end
-
-    #create_table :string_values do |t|
-    #  t.references :readout, null: false, foreign_key: {on_delete: :cascade}
-    #  t.string :value, null: false, limit: 32
-    #end
+    add_index :readouts, [:quantity_id, :created_at], unique: true
   end
 end

db/schema.rb

@@ -10,22 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
-  create_table "measurements", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
-    t.datetime "taken_at", null: false
-    t.bigint "note_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["note_id"], name: "index_measurements_on_note_id"
-    t.index ["taken_at"], name: "index_measurements_on_taken_at", unique: true
-  end
-
-  create_table "notes", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
-    t.text "text", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-  end
-
+ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
   create_table "quantities", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
     t.bigint "user_id"
     t.string "name", limit: 31, null: false
@@ -35,7 +20,6 @@ ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
     t.datetime "updated_at", null: false
     t.integer "depth", default: 0, null: false
     t.string "pathname", limit: 511, null: false
-    t.index ["id", "user_id"], name: "index_quantities_on_id_and_user_id", unique: true
     t.index ["parent_id"], name: "index_quantities_on_parent_id"
     t.index ["user_id", "parent_id", "name"], name: "index_quantities_on_user_id_and_parent_id_and_name", unique: true
     t.index ["user_id"], name: "index_quantities_on_user_id"
@@ -43,18 +27,13 @@ ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
 
   create_table "readouts", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
-    t.bigint "measurement_id"
     t.bigint "quantity_id", null: false
-    t.integer "category", default: 0, null: false
-    t.float "value", limit: 53, null: false
-    t.bigint "unit_id", null: false
+    t.bigint "unit_id"
+    t.decimal "value", precision: 30, scale: 15, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["measurement_id", "quantity_id", "category"], name: "index_readouts_on_measurement_id_and_quantity_id_and_category", unique: true
-    t.index ["measurement_id"], name: "index_readouts_on_measurement_id"
-    t.index ["quantity_id", "user_id"], name: "fk_rails_9d92eaafc6"
+    t.index ["quantity_id", "created_at"], name: "index_readouts_on_quantity_id_and_created_at", unique: true
     t.index ["quantity_id"], name: "index_readouts_on_quantity_id"
-    t.index ["unit_id", "user_id"], name: "fk_rails_348b0fb4c5"
     t.index ["unit_id"], name: "index_readouts_on_unit_id"
     t.index ["user_id"], name: "index_readouts_on_user_id"
   end
@@ -68,7 +47,6 @@ ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["base_id"], name: "index_units_on_base_id"
-    t.index ["id", "user_id"], name: "index_units_on_id_and_user_id", unique: true
     t.index ["user_id", "symbol"], name: "index_units_on_user_id_and_symbol", unique: true
     t.index ["user_id"], name: "index_units_on_user_id"
   end
@@ -91,15 +69,11 @@ ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
     t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
   end
 
-  add_foreign_key "measurements", "notes", on_delete: :nullify
   add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
-  add_foreign_key "quantities", "users", on_delete: :cascade
-  add_foreign_key "readouts", "measurements", on_delete: :cascade
-  add_foreign_key "readouts", "quantities", column: ["quantity_id", "user_id"], primary_key: ["id", "user_id"]
-  add_foreign_key "readouts", "quantities", on_delete: :cascade
-  add_foreign_key "readouts", "units", column: ["unit_id", "user_id"], primary_key: ["id", "user_id"]
-  add_foreign_key "readouts", "units", on_delete: :cascade
-  add_foreign_key "readouts", "users", on_delete: :cascade
+  add_foreign_key "quantities", "users"
+  add_foreign_key "readouts", "quantities"
+  add_foreign_key "readouts", "units"
+  add_foreign_key "readouts", "users"
   add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
-  add_foreign_key "units", "users", on_delete: :cascade
+  add_foreign_key "units", "users"
 end

db/seeds.rb

@@ -7,21 +7,17 @@
 User.transaction do
   break if User.find_by status: :admin
 
-  email = Rails.configuration.admin
-  password_length = SecureRandom.rand(Rails.configuration.devise.password_length)
-  password = SecureRandom.alphanumeric(password_length)
-
-  User.create!(email: email, password: password, status: :admin) do |user|
+  User.create! email: Rails.configuration.admin, password: 'admin', status: :admin do |user|
     user.skip_confirmation!
-    print "Creating #{user.status} account '#{user.email}'" \
-      " with password '#{user.password}'..."
+    print "Creating #{user.status} account '#{user.email}' with password '#{user.password}'..."
   end
   puts "done."
+
 rescue ActiveRecord::RecordInvalid => exception
-  puts "failed.", exception.message
+  puts "failed. #{exception.message}"
 end
 
 # Formulas will be deleted as dependent on Quantities
 #[Source, Quantity, Unit].each { |model| model.defaults.delete_all }
 
-load "db/seeds/units.rb"
+require_relative 'seeds/units.rb'

db/sqlite3_schema.rb

@@ -1,103 +0,0 @@
-# This file is auto-generated from the current state of the database. Instead
-# of editing this file, please use the migrations feature of Active Record to
-# incrementally modify your database, and then regenerate this schema definition.
-#
-# This file is the source Rails uses to define your schema when running `bin/rails
-# db:schema:load`. When creating a new database, `bin/rails db:schema:load` tends to
-# be faster and is potentially less error prone than running all of your
-# migrations from scratch. Old migrations may fail to apply correctly if those
-# migrations use external dependencies or application code.
-#
-# It's strongly recommended that you check this file into your version control system.
-
-ActiveRecord::Schema[8.1].define(version: 2025_01_21_230456) do
-  create_table "measurements", force: :cascade do |t|
-    t.datetime "taken_at", null: false
-    t.integer "note_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["note_id"], name: "index_measurements_on_note_id"
-    t.index ["taken_at"], name: "index_measurements_on_taken_at", unique: true
-  end
-
-  create_table "notes", force: :cascade do |t|
-    t.text "text", limit: 65535, null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-  end
-
-  create_table "quantities", force: :cascade do |t|
-    t.integer "user_id"
-    t.string "name", limit: 31, null: false
-    t.text "description", limit: 65535
-    t.integer "parent_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.integer "depth", default: 0, null: false
-    t.string "pathname", limit: 511, null: false
-    t.index ["id", "user_id"], name: "index_quantities_on_id_and_user_id", unique: true
-    t.index ["parent_id"], name: "index_quantities_on_parent_id"
-    t.index ["user_id", "parent_id", "name"], name: "index_quantities_on_user_id_and_parent_id_and_name", unique: true
-    t.index ["user_id"], name: "index_quantities_on_user_id"
-  end
-
-  create_table "readouts", force: :cascade do |t|
-    t.integer "user_id", null: false
-    t.integer "measurement_id"
-    t.integer "quantity_id", null: false
-    t.integer "category", default: 0, null: false
-    t.float "value", limit: 53, null: false
-    t.integer "unit_id", null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["measurement_id", "quantity_id", "category"], name: "index_readouts_on_measurement_id_and_quantity_id_and_category", unique: true
-    t.index ["measurement_id"], name: "index_readouts_on_measurement_id"
-    t.index ["quantity_id"], name: "index_readouts_on_quantity_id"
-    t.index ["unit_id"], name: "index_readouts_on_unit_id"
-    t.index ["user_id"], name: "index_readouts_on_user_id"
-  end
-
-  create_table "units", force: :cascade do |t|
-    t.integer "user_id"
-    t.string "symbol", limit: 15, null: false
-    t.text "description", limit: 65535
-    t.decimal "multiplier", precision: 30, scale: 15, default: "1.0", null: false
-    t.integer "base_id"
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.index ["base_id"], name: "index_units_on_base_id"
-    t.index ["id", "user_id"], name: "index_units_on_id_and_user_id", unique: true
-    t.index ["user_id", "symbol"], name: "index_units_on_user_id_and_symbol", unique: true
-    t.index ["user_id"], name: "index_units_on_user_id"
-  end
-
-  create_table "users", force: :cascade do |t|
-    t.string "email", limit: 64, null: false
-    t.integer "status", default: 0, null: false
-    t.datetime "created_at", null: false
-    t.datetime "updated_at", null: false
-    t.string "encrypted_password", default: "", null: false
-    t.string "reset_password_token"
-    t.datetime "reset_password_sent_at"
-    t.datetime "remember_created_at"
-    t.string "confirmation_token"
-    t.datetime "confirmed_at"
-    t.datetime "confirmation_sent_at"
-    t.string "unconfirmed_email", limit: 64
-    t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true
-    t.index ["email"], name: "index_users_on_email", unique: true
-    t.index ["reset_password_token"], name: "index_users_on_reset_password_token", unique: true
-  end
-
-  add_foreign_key "measurements", "notes", on_delete: :nullify
-  add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
-  add_foreign_key "quantities", "users", on_delete: :cascade
-  add_foreign_key "readouts", "measurements", on_delete: :cascade
-  add_foreign_key "readouts", "quantities", column: ["quantity_id", "user_id"], primary_key: ["id", "user_id"]
-  add_foreign_key "readouts", "quantities", on_delete: :cascade
-  add_foreign_key "readouts", "units", column: ["unit_id", "user_id"], primary_key: ["id", "user_id"]
-  add_foreign_key "readouts", "units", on_delete: :cascade
-  add_foreign_key "readouts", "users", on_delete: :cascade
-  add_foreign_key "units", "units", column: "base_id", on_delete: :cascade
-  add_foreign_key "units", "users", on_delete: :cascade
-end

lib/default_settings_strategy.rb

@@ -1,55 +0,0 @@
-class DefaultSettingsStrategy < ActiveRecord::Migration::DefaultStrategy
-  COLUMN_DEFAULTS = {
-    # TODO: all types `null: false` ?
-    # TODO: references `foreign_key: {on_delete: :cascade}` ?
-    # `timestamps` - Rails defaults to `null: false, precision: true`.
-    # `limit:` for `text` - `text` can be theoretically up to 1GB or
-    #   longer, so roughly unlimited for practical purposes. But:
-    #   * the actual usable length depends on additional factors, like compile
-    #     time limits (`SQLITE_MAX_LENGTH` in SQLite), runtime settings
-    #     (`max_allowed_packet` in MySQL) and probably other,
-    #   * Rails does not report limit for `text` column types, unless it is
-    #     explicitly set.
-    #   The decision is to always set safe limit and enforce it by validations, to
-    #   avoid surprises (e.g. text truncation) when saving to dabatase.
-    text: {limit: 2**16 - 1}
-  }
-  COLUMN_DEFAULTS.default = {}
-  COLUMN_DEFAULTS.freeze
-
-  module ColumnSettingsStrategy
-    def column(name, type, **options)
-      super(name, type, **COLUMN_DEFAULTS[type].merge(options))
-    end
-  end
-  ActiveRecord::ConnectionAdapters::TableDefinition.prepend ColumnSettingsStrategy
-
-  # `force: :cascade` - does nothing on MySQL, so `force:` is useless.
-  # `if_not_exists: true`/`if_exists: true` - without these options it's impossible
-  #   to change migration status once migration fails partially. If `up` migration
-  #   creates some, but not all objects, its status is not updated from `down` to
-  #   `up`. Then it's impossible to migrate: a) up - due to `already exists`
-  #   errors and b) down - due to migration status.
-  MIGRATION_DEFAULTS = {
-    add_check_constraint: {if_not_exists: true},
-    add_column:           {if_not_exists: true},
-    add_foreign_key:      {if_not_exists: true},
-    add_index:            {if_not_exists: true, unique: true},
-    add_timestamps:       {if_not_exists: true},
-    create_table:         {if_not_exists: true},
-    drop_table:               {if_exists: true},
-    remove_check_constraint:  {if_exists: true},
-    remove_column:            {if_exists: true},
-    remove_foreign_key:       {if_exists: true},
-    remove_index:             {if_exists: true},
-    remove_timestamps:        {if_exists: true},
-  }
-  MIGRATION_DEFAULTS.default = {}
-  MIGRATION_DEFAULTS.freeze
-
-  def method_missing(method, *args, **kwargs, &)
-    conflicts = kwargs.has_key?(:force) ? [:if_not_exists, :if_exists] : []
-    defaults = MIGRATION_DEFAULTS[method.to_sym].except(*conflicts)
-    super(method, *args, **defaults.merge(kwargs), &)
-  end
-end

public/icon.svg

@@ -1,3 +0,0 @@
-<svg width="512" height="512" xmlns="http://www.w3.org/2000/svg">
-  <circle cx="256" cy="256" r="256" fill="red"/>
-</svg>

test/application_system_test_case.rb

@@ -25,10 +25,9 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
     user
   end
 
-  def inject_button_to(inside, *button_options)
+  def inject_button_to(after, *button_options)
     button = button_to *button_options
-    inside.evaluate_script("this.insertAdjacentHTML('beforeend', arguments[0]);",
-                           button.html_safe)
+    evaluate_script("arguments[0].insertAdjacentHTML('beforeend', '#{button.html_safe}');", after)
   end
 
   # Allow skipping interpolations when translating for testing purposes
@@ -39,32 +38,6 @@ class ApplicationSystemTestCase < ActionDispatch::SystemTestCase
   end
   alias :t :translate
 
-  DB_CONFIGS = ActiveRecord::Base.configurations.configs_for(env_name: "test")
-  TEST_CONFIGS = Hash.new(DB_CONFIGS.first.name.to_sym)
-  class << self
-    # NOTE: alternative to current solution is to create shards:
-    #   ActiveRecord::Base.connects_to(
-    #     shards: {mysql2: {writing: :mysql2}, sqlite3: {writing: :sqlite3}}
-    #   )
-    # and use them in one of the following ways:
-    # * set config.active_record.shard_selector/shard_resolver
-    # * run tests within: ActiveRecord::Base.connected_to(shard: :sqlite3) { test_ }
-    # Remove this note once current solution is confirmed to work.
-    #
-    # Test block should not be modified here, as it would change its binding from
-    # instance level to class level.
-    if DB_CONFIGS.many?
-      def test(name, ...)
-        DB_CONFIGS.each do |config|
-          TEST_CONFIGS[super("#{config.name} #{name}", ...)] = config.name.to_sym
-        end
-      end
-    end
-  end
-  setup do
-    ActiveRecord::Base.establish_connection(TEST_CONFIGS[name.to_sym])
-  end
-
   #def assert_stale(element)
   #  assert_raises(Selenium::WebDriver::Error::StaleElementReferenceError) { element.tag_name }
   #end

test/controllers/measurements_controller_test.rb

@@ -0,0 +1,8 @@
+require "test_helper"
+
+class MeasurementsControllerTest < ActionDispatch::IntegrationTest
+  #test "should get index" do
+  #  get measurements_index_url
+  #  assert_response :success
+  #end
+end

test/controllers/quantities_controller_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class QuantitiesControllerTest < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/controllers/registrations_controller_test.rb

@@ -0,0 +1,18 @@
+require "test_helper"
+
+class RegistrationsControllerTest < ActionDispatch::IntegrationTest
+  test "sole admin cannot delete account" do
+    sign_in users(:admin)
+    delete user_registration_path
+    assert_redirected_to edit_user_registration_path
+    assert_equal t("registrations.destroy.sole_admin"), flash[:alert]
+    assert User.exists?(users(:admin).id)
+  end
+
+  test "non-admin can delete account" do
+    sign_in users(:alice)
+    assert_difference ->{ User.count }, -1 do
+      delete user_registration_path
+    end
+  end
+end

test/controllers/units_controller_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class UnitsControllerTest < ActionDispatch::IntegrationTest
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/controllers/users_controller_test.rb

@@ -1,7 +1,5 @@
 require "test_helper"
 
-# TODO: make sure tested actions are covered by system tests and remove all
-# controller tests.
 class UsersControllerTest < ActionDispatch::IntegrationTest
   setup do
     @user = users(:one)

test/models/user_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class UserTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/system/tasks_test.rb

@@ -1,20 +0,0 @@
-require 'application_system_test_case'
-
-Rails.application.load_tasks
-# NOTE: for some reason task for checking pending migrations messes up
-# transaction when run during test. It causes all DB changes made before its
-# execution to be rolled back.
-# Run it before tests, so any rake task dependent on it will see it as
-# #already_invoked and won't run it during test. It is redundant anyway, as
-# migrations are run before starting test suite.
-Rake::Task['db:abort_if_pending_migrations'].invoke
-
-class TasksTest < ApplicationSystemTestCase
-  test "db:seed creates admin account" do
-    User.admin.delete_all
-    assert_output /Creating admin account/ do
-      Rake::Task['db:seed'].execute
-    end
-    assert User.admin.exists?
-  end
-end

test/system/units_test.rb

@@ -44,12 +44,10 @@ class UnitsTest < ApplicationSystemTestCase
     within 'tbody > tr:has(input[type=text], textarea)' do
       assert_selector ':focus'
 
-      maxlength = all(:fillable_field).to_h do |field|
-        [field[:name], field[:maxlength].to_i || 2**16]
-      end
+      maxlength = all(:fillable_field).to_h { |f| [f[:name], f[:maxlength].to_i || 2**16] }
       values = {
-        symbol: random_string(deep_rand(1..3, 4..maxlength['unit[symbol]']),
-                              except: units.map(&:symbol), allow_blank: false),
+        symbol: random_string(rand([1..3, 4..maxlength['unit[symbol]']].sample),
+                              except: units.map(&:symbol)),
         description: random_string(rand(0..maxlength['unit[description]']))
       }.with_indifferent_access
       within :field, 'unit[multiplier]' do |field|
@@ -63,8 +61,7 @@ class UnitsTest < ApplicationSystemTestCase
       end
     end
 
-    assert_selector '.flash.notice',
-      text: t('units.create.success', unit: Unit.last.symbol)
+    assert_selector '.flash.notice', text: t('units.create.success', unit: Unit.last.symbol)
     within 'tbody' do
       assert_no_selector :fillable_field
       assert_selector 'tr', count: @user.units.count

test/system/users_test.rb

@@ -182,8 +182,8 @@ class UsersTest < ApplicationSystemTestCase
     assert_title 'Access is forbidden to this page (403)'
   end
 
-  test 'delete profile' do
-    user = sign_in
+  test "delete profile" do
+    user = sign_in user: users.reject(&:admin?).select(&:confirmed?).sample
     # TODO: remove condition after root_url changed to different path than
     # profile in routes.rb
     unless has_current_path?(edit_user_registration_path)
@@ -196,7 +196,15 @@ class UsersTest < ApplicationSystemTestCase
     assert_text t("devise.registrations.destroyed")
   end
 
-  test 'index forbidden for non admin' do
+  test "sole admin cannot delete profile" do
+    sign_in user: users(:admin)
+    unless has_current_path?(edit_user_registration_path)
+      first(:link_or_button, users(:admin).email).click
+    end
+    assert find(:button, t("users.registrations.edit.delete"))[:disabled]
+  end
+
+  test "index forbidden for non admin" do
     sign_in user: users.reject(&:admin?).select(&:confirmed?).sample
     visit users_path
     assert_title "Access is forbidden to this page (403)"
@@ -204,7 +212,6 @@ class UsersTest < ApplicationSystemTestCase
 
   test 'update profile' do
     # TODO
-    assert true
   end
 
   test 'update status' do
@@ -228,8 +235,7 @@ class UsersTest < ApplicationSystemTestCase
 
     within all(:xpath, "//tbody//tr[not(descendant::select)]").sample do |tr|
       user = User.find_by_email!(first(:link).text)
-      inject_button_to find('td', exact_text: user.status), "update status",
-        user_path(user), method: :patch,
+      inject_button_to first('td:not(.link)'), "update status", user_path(user), method: :patch,
         params: {user: {status: User.statuses.keys.sample}}, data: {turbo: false}
       click_on "update status"
     end
@@ -239,8 +245,8 @@ class UsersTest < ApplicationSystemTestCase
   test 'update status forbidden for non admin' do
     sign_in user: users.reject(&:admin?).select(&:confirmed?).sample
     visit units_path
-    inject_button_to find('body'), "update status", user_path(User.all.sample),
-      method: :patch, params: {user: {status: User.statuses.keys.sample}}
+    inject_button_to find('body'), "update status", user_path(User.all.sample), method: :patch,
+      params: {user: {status: User.statuses.keys.sample}}
     click_on "update status"
     assert_text t('actioncontroller.exceptions.status.forbidden')
   end

test/test_helper.rb

@@ -13,36 +13,27 @@ class ActiveSupport::TestCase
   include ActionView::Helpers::TranslationHelper
 
   # List of categorized Unicode characters:
-  #   * source: http://www.unicode.org/Public/UNIDATA/UnicodeData.txt
-  #   * file format: http://www.unicode.org/L2/L1999/UnicodeData.html
-  #   * select from graphic ranges: L, M, N, P, S, Zs
-  UNICODE_CHARS = [
-    *"\u0020".."\u007E",
-    *"\u00A0".."\u00AC",
-    *"\u00AE".."\u05FF",
-    *"\u0606".."\u061B",
-    *"\u061D".."\u06DC",
-    *"\u06DE".."\u070E",
-    *"\u0710".."\u07FF"
-  ]
-  def random_string(length, except: [], allow_blank: true)
+  # * http://www.unicode.org/Public/UNIDATA/UnicodeData.txt
+  # File format: http://www.unicode.org/L2/L1999/UnicodeData.html
+  # Select from graphic ranges: L, M, N, P, S, Zs
+  UNICODE_CHARS = {
+    1 => [*"\u0020".."\u007E"],
+    2 => [*"\u00A0".."\u00AC",
+          *"\u00AE".."\u05FF",
+          *"\u0606".."\u061B",
+          *"\u061D".."\u06DC",
+          *"\u06DE".."\u070E",
+          *"\u0710".."\u07FF"]
+  }
+  UNICODE_CHARS.default = UNICODE_CHARS[1] + UNICODE_CHARS[2]
+  def random_string(bytes = 10, except: [])
     begin
-      result = UNICODE_CHARS.sample(length).join
-    end while except.include?(result) || (!allow_blank && result.blank?)
+      result = ''
+      result += UNICODE_CHARS[bytes - result.bytesize].sample while bytes > result.bytesize
+    end while except.include?(result)
     result
   end
 
-  def deep_rand(*args)
-    case args
-    when Array
-      args = args.sample
-    when Range
-      args = rand(args)
-    else
-      return args
-    end while true
-  end
-
   # Assumes: max >= step and step = 1e[-]N, both as strings
   def random_number(max, step)
     max.delete!('.')