Remove duplicate disable/enable logic and fetch() calls

readoutUnitChanged was manually setting disabled/aria-disabled/tabindex
attributes — duplicating Turbo.StreamElement.prototype.disableElement/
enableElement which already exists for this purpose. Replace with calls
to those methods.

Also replace fetch() in setDefaultUnit and drop with form.requestSubmit()
so Turbo handles CSRF, stream responses and lifecycle natively.

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

CLAUDE.md

@@ -0,0 +1,84 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Fixin.me is a "quantified self" Rails 7.2.3 application for personal data tracking. Users define hierarchical **quantities** (metrics to track), **units** (with optional conversion hierarchies), and **readouts** (individual measurements). There is also a non-persistent **measurement** model used as a form wrapper.
+
+## Setup
+
+Configuration files are distributed as `.dist` templates — copy and customize before use:
+
+```bash
+cp config/application.rb.dist config/application.rb
+cp config/database.yml.dist config/database.yml
+cp config/puma.rb.dist config/puma.rb
+```
+
+```bash
+bundle config --local frozen true
+bundle config --local path .gem
+bundle config --local with mysql development test   # or: pg, sqlite
+bundle install
+RAILS_ENV=development bundle exec rails db:create db:migrate db:seed
+```
+
+## Common Commands
+
+```bash
+bundle exec rails s                                          # start server
+bundle exec rails test                                       # all unit/model/controller tests
+bundle exec rails test:system                                # all system tests (Capybara + Selenium)
+bundle exec rails test test/system/units_test.rb            # single test file
+bundle exec rails test --seed 64690 --name test_add_unit    # single test by name
+bundle exec rails db:seed:export                             # export default settings as seed file
+```
+
+## Architecture
+
+### Data Model
+
+- **Quantity** — hierarchical tree (self-referential `parent_id`). Cached `depth` and `pathname` fields are recomputed via recursive CTEs on write. Direct assignment to cached fields is blocked.
+- **Unit** — optional hierarchy via `base_id` and `multiplier` for unit conversion. Multiplier precision/scale is validated by a custom validator.
+- **Readout** — single measurement: `value` (IEEE 754 float), `quantity`, `unit`, `category`.
+- **Measurement** — `ActiveModel::Model` form wrapper (not database-backed); bridges the readout creation form.
+- **User** — Devise-managed with a status enum: `admin`, `active`, `restricted`, `locked`, `disabled`. Admins can disguise as other users.
+
+### Hierarchical Queries
+
+Both `Quantity` and `Unit` use recursive CTEs for tree traversal (ordered traversal, ancestors, progenies, common ancestors). `lib/core_ext/arel/` patches Arel to support CTE with `UPDATE`/`DELETE` statements, working around Rails issue #54658.
+
+### Custom Extensions (`lib/core_ext/`)
+
+- **arel/** — CTE support for UPDATE/DELETE
+- **active_model/** — precision/scale validator used by `Unit#multiplier`
+- **active_record/** — `attr_cached` mechanism (see `ApplicationRecord`)
+- **action_view/** — record identifier suffixes
+- Miscellaneous: `Array#delete_bang`, `BigDecimal` scientific notation
+
+### Response Handling
+
+Controllers respond to both HTML and Turbo Stream formats. Errors during Turbo Stream requests trigger a redirect with flash rather than rendering inline, handled in `ApplicationController`.
+
+### Numeric Precision
+
+Readout values are stored as IEEE 754 double-precision floats (not fixed-point decimals). Rationale in `DESIGN.md`: biological values span many orders of magnitude; 15-digit float precision is sufficient and avoids conversion overhead.
+
+### Routes
+
+```
+measurements   GET/POST /measurements
+readouts       GET/POST /readouts, DELETE /readouts/:id/discard
+quantities     CRUD + POST /quantities/:id/reparent
+units          CRUD + POST /units/:id/rebase
+users          CRUD + POST /users/:id/disguise, POST /users/revert
+default/       namespace for default units import/export and admin panel
+root           → /units (authenticated), /sign_in (unauthenticated)
+```
+
+## Database Requirements
+
+The database must support:
+- Recursive CTEs with `UPDATE`/`DELETE` (MySQL ≥ 8.0, PostgreSQL, or SQLite3)
+- Decimal precision of 30+ digits

app/assets/images/pictograms/view-columns.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M4,4H8V20H4V4M10,4H14V20H10V4M16,4H21V20H16V4Z"/></svg>

app/assets/images/pictograms/view-rows.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" id="icon" viewBox="0 0 24 24"><path d="M3,5H21V7H3V5M3,11H21V13H3V11M3,17H21V19H3V17Z"/></svg>

app/assets/stylesheets/application.css

@@ -36,6 +36,7 @@
   --color-blue: #009ade;
   --color-dark-red: #b21237;
   --color-red: #ff1f5b;
+  --color-purple: #8b2be2;
 
   --depth: 0;
 
@@ -231,6 +232,10 @@ textarea:invalid {
   text-decoration: underline 1px var(--color-border-gray);
   text-underline-offset: 0.25em;
 }
+button.link {
+  border: none;
+  padding: 0;
+}
 [name=cancel],
 .auxiliary {
   border-color: var(--color-border-gray);
@@ -252,6 +257,13 @@ textarea:invalid {
   background-color: var(--color-red);
   border-color: var(--color-red);
 }
+tr:has(select[data-changed]) button[name="button"],
+.set-default-unit:not([disabled]) {
+  background-color: var(--color-purple);
+  border-color: var(--color-purple);
+  color: white;
+  fill: white;
+}
 .link:focus-visible {
   text-decoration-color: var(--color-gray);
 }
@@ -361,7 +373,7 @@ header {
   pointer-events: auto;
 }
 .flash:before {
-  filter: invert();
+  filter: invert(100%);
   height: 1.4em;
   margin: 0 0.5em;
   width: 1.4em;
@@ -513,7 +525,7 @@ header {
   cursor: grab;
 }
 .items-table .form td {
-  vertical-align: top;
+  vertical-align: middle;
 }
 .items-table td:not(:first-child),
 .grayed {
@@ -640,3 +652,42 @@ li::marker {
   min-width: 66%;
   width: max-content;
 }
+.measurements-section {
+  overflow-x: auto;
+}
+body[data-measurements-view=wide] .measurements-compact,
+body[data-measurements-view=compact] .measurements-wide {
+  display: none;
+}
+body[data-measurements-view=compact] .view-toggle[data-view=compact],
+body[data-measurements-view=wide] .view-toggle[data-view=wide] {
+  background-color: var(--color-blue);
+  border-color: var(--color-blue);
+  color: white;
+  fill: white;
+}
+#measurements tr.grouped td {
+  border-top: none;
+}
+#measurements tr.grouped .taken-at,
+#measurements tr.grouped .created-at {
+  visibility: hidden;
+}
+.measurements-wide td {
+  vertical-align: middle;
+  white-space: nowrap;
+}
+.wide-cell {
+  align-items: center;
+  display: inline-flex;
+  gap: 0.25em;
+}
+.wide-cell .button {
+  border: none;
+  font-size: inherit;
+  height: auto;
+  padding: 0;
+}
+.wide-cell button.link::after {
+  content: none;
+}

app/controllers/measurements_controller.rb

@@ -1,7 +1,12 @@
 class MeasurementsController < ApplicationController
+  before_action :find_readout, only: [:destroy, :edit, :update]
+
+  before_action except: :index do
+    raise AccessForbidden unless current_user.at_least(:active)
+  end
+
   def index
-    @measurements = []
+    load_measurements
-    #@measurements = current_user.units.ordered.includes(:base, :subunits)
   end
 
   def new
@@ -9,8 +14,49 @@ class MeasurementsController < ApplicationController
   end
 
   def create
+    taken_at = params.permit(:taken_at)[:taken_at]
+    readout_params = params.permit(readouts: Readout::ATTRIBUTES).fetch(:readouts, [])
+    @readouts = readout_params.map { |rp| current_user.readouts.build(rp.merge(taken_at: taken_at)) }
+
+    if @readouts.present? && @readouts.all?(&:valid?)
+      ActiveRecord::Base.transaction { @readouts.each(&:save!) }
+      load_measurements
+      flash.now[:notice] = t('.success', count: @readouts.size)
+    else
+      errors = @readouts.flat_map { |r| r.errors.full_messages }
+      flash.now[:alert] = errors.present? ? errors.first : t('.no_readouts')
+    end
+  end
+
+  def edit
+    @user_units = current_user.units.ordered
+  end
+
+  def update
+    if @readout.update(params.require(:readout).permit(:value, :unit_id, :taken_at))
+      load_measurements
+      flash.now[:notice] = t('.success')
+    else
+      @user_units = current_user.units.ordered
+      render :edit
+    end
   end
 
   def destroy
+    @readout.destroy!
+    load_measurements
+    flash.now[:notice] = t('.success')
+  end
+
+  private
+
+  def find_readout
+    @readout = current_user.readouts.find(params[:id])
+  end
+
+  def load_measurements
+    @measurements = current_user.readouts.includes(:quantity, :unit).order(taken_at: :desc, id: :desc)
+    @wide_groups = @measurements.group_by(&:taken_at)
+    @wide_quantities = @measurements.map(&:quantity).uniq.sort_by(&:name)
   end
 end

app/controllers/quantities_controller.rb

@@ -8,6 +8,10 @@ class QuantitiesController < ApplicationController
     raise AccessForbidden unless current_user.at_least(:active)
   end
 
+  before_action only: [:new, :edit, :create, :update] do
+    @user_units = current_user.units.ordered
+  end
+
   def index
     @quantities = current_user.quantities.ordered.includes(:parent, :subquantities)
   end

app/helpers/application_helper.rb

@@ -86,6 +86,7 @@ module ApplicationHelper
     def initialize(...)
       super(...)
       @default_options.merge!(@options.slice(:form))
+      @default_html_options.merge!(@options.slice(:form))
     end
 
     [:text_field, :password_field, :text_area].each do |selector|

app/javascript/application.js

@@ -9,6 +9,47 @@ function showPage(event) {
 }
 document.addEventListener('turbo:load', showPage)
 
+function groupMeasurements() {
+  var tbody = document.getElementById('measurements');
+  if (!tbody) return;
+  var prevTakenAt = null;
+  Array.from(tbody.querySelectorAll('tr[data-taken-at]'))
+    .filter(function(row) { return row.style.display !== 'none' })
+    .forEach(function(row) {
+      var takenAt = row.dataset.takenAt;
+      row.classList.toggle('grouped', takenAt !== null && takenAt === prevTakenAt);
+      prevTakenAt = takenAt;
+    });
+}
+
+
+function getMeasurementsView() {
+  return localStorage.getItem('measurements-view') || 'compact';
+}
+
+function applyMeasurementsView(view) {
+  document.body.dataset.measurementsView = view;
+}
+
+function setMeasurementsView(view) {
+  localStorage.setItem('measurements-view', view);
+  applyMeasurementsView(view);
+}
+window.setMeasurementsView = setMeasurementsView
+
+document.addEventListener('turbo:load', function() {
+  var tbody = document.getElementById('measurements');
+  if (!tbody) return;
+  groupMeasurements();
+  applyMeasurementsView(getMeasurementsView());
+  new MutationObserver(function() {
+    groupMeasurements();
+  }).observe(tbody, {
+    childList: true, subtree: true,
+    attributes: true, attributeFilter: ['style']
+  });
+})
+
 function detailsChange(event) {
   var target = event.currentTarget
   var count = target.querySelectorAll('input:checked:not([disabled])').length
@@ -37,6 +78,41 @@ window.detailsObserver = new MutationObserver((mutations) => {
   mutations[0].target.dispatchEvent(new Event('change', {bubbles: true}))
 });
 
+
+function readoutUnitChanged(select) {
+  var button = select.closest('tr').querySelector('.set-default-unit');
+  if (select.value && select.value !== select.dataset.defaultUnitId) {
+    Turbo.StreamElement.prototype.enableElement(button);
+  } else {
+    Turbo.StreamElement.prototype.disableElement(button);
+  }
+}
+window.readoutUnitChanged = readoutUnitChanged
+
+function setDefaultUnit(button) {
+  var select = button.closest('tr').querySelector('select[data-default-unit-id]');
+  var form = document.createElement('form');
+  form.action = button.dataset.path;
+  form.method = 'post';
+  form.dataset.turboStream = 'true';
+  var methodInput = document.createElement('input');
+  methodInput.type = 'hidden'; methodInput.name = '_method'; methodInput.value = 'patch';
+  var unitInput = document.createElement('input');
+  unitInput.type = 'hidden'; unitInput.name = 'quantity[default_unit_id]'; unitInput.value = select.value;
+  form.appendChild(methodInput);
+  form.appendChild(unitInput);
+  form.addEventListener('turbo:submit-end', function(event) {
+    if (event.detail.success) {
+      select.dataset.defaultUnitId = select.value;
+      readoutUnitChanged(select);
+    }
+    form.remove();
+  });
+  document.body.appendChild(form);
+  form.requestSubmit();
+}
+window.setDefaultUnit = setDefaultUnit
+
 function formValidate(event) {
   var id = event.submitter.getAttribute("data-validate")
   if (!id) return;
@@ -206,22 +282,17 @@ window.dragEnd = dragEnd
 
 function drop(event) {
   event.preventDefault()
-
+  var idParam = event.currentTarget.getAttribute("data-drop-id-param")
-  var params = new URLSearchParams()
-  var id_param = event.currentTarget.getAttribute("data-drop-id-param")
   var id = event.currentTarget.getAttribute("data-drop-id").split("_").pop()
-  params.append(id_param, id)
+  var form = document.createElement('form');
-
+  form.action = event.dataTransfer.getData("text/plain");
-  fetch(event.dataTransfer.getData("text/plain"), {
+  form.method = 'post';
-    body: params,
+  form.dataset.turboStream = 'true';
-    headers: {
+  var input = document.createElement('input');
-      "Accept": "text/vnd.turbo-stream.html",
+  input.type = 'hidden'; input.name = idParam; input.value = id;
-      "X-CSRF-Token": document.head.querySelector("meta[name=csrf-token]").content,
+  form.appendChild(input);
-      "X-Requested-With": "XMLHttpRequest"
+  form.addEventListener('turbo:submit-end', function() { form.remove(); });
-    },
+  document.body.appendChild(form);
-    method: "POST"
+  form.requestSubmit();
-  })
-  .then(response => response.text())
-  .then(html => Turbo.renderStreamMessage(html))
 }
 window.drop = drop

app/models/quantity.rb

@@ -1,9 +1,10 @@
 class Quantity < ApplicationRecord
-  ATTRIBUTES = [:name, :description, :parent_id]
+  ATTRIBUTES = [:name, :description, :parent_id, :default_unit_id]
   attr_cached :depth, :pathname
 
   belongs_to :user, optional: true
   belongs_to :parent, optional: true, class_name: "Quantity"
+  belongs_to :default_unit, optional: true, class_name: "Unit"
   has_many :subquantities, ->{ order(:name) }, class_name: "Quantity",
     inverse_of: :parent, dependent: :restrict_with_error
 

app/models/readout.rb

@@ -1,5 +1,5 @@
 class Readout < ApplicationRecord
-  ATTRIBUTES = [:quantity_id, :value, :unit_id]
+  ATTRIBUTES = [:quantity_id, :value, :unit_id, :taken_at]
 
   belongs_to :user
   belongs_to :quantity

app/views/measurements/_edit_form.html.erb

@@ -0,0 +1,24 @@
+<%= tabular_fields_for @readout, form: form_tag do |form| %>
+  <%- tag.tr id: row, class: "form", onkeydown: "formProcessKey(event)",
+    data: {form: form_tag, hidden_row: hidden_row, link: link} do %>
+    <td><%= @readout.quantity %></td>
+    <td class="ralign">
+      <%= form.number_field :value, required: true, autofocus: true %>
+    </td>
+    <td>
+      <%= form.collection_select :unit_id, @user_units, :id,
+        ->(u){ sanitize('&emsp;' * (u.base_id? ? 1 : 0) + u.symbol) },
+        {}, required: true %>
+    </td>
+    <td>
+      <%= form.datetime_field :taken_at %>
+    </td>
+    <td></td>
+    <td class="flex">
+      <%= form.button %>
+      <%= image_link_to t(:cancel), "close-outline", measurements_path,
+        class: 'dangerous', name: :cancel,
+        onclick: render_turbo_stream('edit_form_close', {row: row}) %>
+    </td>
+  <% end %>
+<% end %>

app/views/measurements/_edit_form_close.html.erb

@@ -0,0 +1,2 @@
+<%= turbo_stream.close_form row %>
+<%= turbo_stream.update :flashes %>

app/views/measurements/_edit_panel.html.erb

@@ -0,0 +1,33 @@
+<% form_tag = dom_id(@readout, :edit, :form) %>
+<% row = dom_id(@readout, :edit) %>
+<% hidden_row = dom_id(@readout) %>
+
+<%= tabular_form_with model: @readout, url: measurement_path(@readout),
+  id: form_tag do |form| %>
+  <table class="items-table">
+    <tbody>
+      <%= tag.tr id: row, class: "form", onkeydown: "formProcessKey(event)",
+        data: {form: form_tag, hidden_row: hidden_row} do %>
+        <td><%= @readout.quantity %></td>
+        <td class="ralign">
+          <%= form.number_field :value, required: true, autofocus: true %>
+        </td>
+        <td>
+          <%= form.collection_select :unit_id, @user_units, :id,
+            ->(u){ sanitize('&emsp;' * (u.base_id? ? 1 : 0) + u.symbol) },
+            {}, required: true %>
+        </td>
+        <td>
+          <%= form.datetime_field :taken_at %>
+        </td>
+        <td></td>
+        <td class="flex">
+          <%= form.button %>
+          <%= image_link_to t(:cancel), "close-outline", measurements_path,
+            class: 'dangerous', name: :cancel,
+            onclick: render_turbo_stream('edit_form_close', {row: row}) %>
+        </td>
+      <% end %>
+    </tbody>
+  </table>
+<% end %>

app/views/measurements/_form.html.erb

@@ -8,7 +8,7 @@
         <tr class="italic">
           <td class="hexpand hmin50"><%= t '.taken_at_html' %></td>
           <td colspan="3" class="ralign">
-            <%= form.datetime_field :taken_at, required: true %>
+            <%= form.datetime_field :taken_at, required: true, value: Time.current.strftime('%Y-%m-%dT%H:%M') %>
           </td>
         </tr>
       <% end %>

app/views/measurements/_readout.html.erb

@@ -0,0 +1,22 @@
+<%= tag.tr id: dom_id(readout), data: {taken_at: readout.taken_at&.iso8601,
+  quantity_id: readout.quantity_id, quantity_name: readout.quantity.name,
+  value: format("%.10g", readout.value), unit: readout.unit.symbol} do %>
+  <td>
+    <% if current_user.at_least(:active) %>
+      <%= link_to readout.quantity, edit_measurement_path(readout),
+        class: 'link', onclick: 'this.blur();', data: {turbo_stream: true} %>
+    <% else %>
+      <%= readout.quantity %>
+    <% end %>
+  </td>
+  <td class="ralign"><%= format("%.10g", readout.value) %></td>
+  <td><%= readout.unit %></td>
+  <td class="taken-at"><%= l(readout.taken_at) if readout.taken_at %></td>
+  <td class="created-at"><%= l(readout.created_at) %></td>
+  <% if current_user.at_least(:active) %>
+    <td class="flex">
+      <%= image_button_to t('.destroy'), 'delete-outline', measurement_path(readout),
+        method: :delete, data: {turbo_stream: true} %>
+    </td>
+  <% end %>
+<% end %>

app/views/measurements/_wide_table.html.erb

@@ -0,0 +1,41 @@
+<table class="items-table">
+  <thead>
+    <tr>
+      <th><%= Readout.human_attribute_name(:taken_at) %></th>
+      <% wide_quantities.each do |q| %>
+        <th><%= q.name %></th>
+      <% end %>
+      <th><%= Readout.human_attribute_name(:created_at) %></th>
+    </tr>
+  </thead>
+  <tbody>
+    <% wide_groups.each do |taken_at, readouts| %>
+      <tr>
+        <td><%= l(taken_at) if taken_at %></td>
+        <% wide_quantities.each do |q| %>
+          <% readout = readouts.find { |r| r.quantity_id == q.id } %>
+          <td class="ralign">
+            <% if readout %>
+              <span class="wide-cell">
+                <% if current_user.at_least(:active) %>
+                  <%= link_to format("%.10g", readout.value),
+                    edit_measurement_path(readout, view: :wide),
+                    class: 'link', onclick: 'this.blur();',
+                    data: {turbo_stream: true} %>
+                <% else %>
+                  <%= format("%.10g", readout.value) %>
+                <% end %>
+                &nbsp;<%= readout.unit.symbol %>
+                <% if current_user.at_least(:active) %>
+                  <%= image_button_to '', 'delete-outline', measurement_path(readout),
+                    method: :delete, data: {turbo_stream: true} %>
+                <% end %>
+              </span>
+            <% end %>
+          </td>
+        <% end %>
+        <td><%= l(readouts.first.created_at) %></td>
+      </tr>
+    <% end %>
+  </tbody>
+</table>

app/views/measurements/create.turbo_stream.erb

@@ -0,0 +1,13 @@
+<% if @readouts.present? && @readouts.all?(&:persisted?) %>
+  <%= turbo_stream.update :flashes %>
+  <%= turbo_stream.remove :measurement_form %>
+  <%= turbo_stream.enable :new_measurement_link %>
+  <%= turbo_stream.remove :no_items %>
+  <% @readouts.each do |readout| %>
+    <%= turbo_stream.prepend :measurements, partial: 'readout', locals: {readout: readout} %>
+  <% end %>
+  <%= turbo_stream.update 'measurements-wide', partial: 'wide_table',
+    locals: {wide_groups: @wide_groups, wide_quantities: @wide_quantities} %>
+<% else %>
+  <%= turbo_stream.update :flashes %>
+<% end %>

app/views/measurements/destroy.turbo_stream.erb

@@ -0,0 +1,5 @@
+<%= turbo_stream.update :flashes %>
+<%= turbo_stream.remove @readout %>
+<%= turbo_stream.append(:measurements, render_no_items) if current_user.readouts.empty? %>
+<%= turbo_stream.update 'measurements-wide', partial: 'wide_table',
+  locals: {wide_groups: @wide_groups, wide_quantities: @wide_quantities} %>

app/views/measurements/edit.turbo_stream.erb

@@ -0,0 +1,18 @@
+<% ids = {row: dom_id(@readout, :edit),
+          hidden_row: dom_id(@readout),
+          link: nil,
+          form_tag: dom_id(@readout, :edit, :form)} %>
+
+<% if params[:view] == 'wide' %>
+  <%= turbo_stream.update :measurement_edit_form, partial: 'edit_panel' %>
+  <%= turbo_stream.hide ids[:hidden_row] %>
+<% else %>
+  <%= turbo_stream.append :measurement_edit_form do %>
+    <%- tabular_form_with model: @readout, url: measurement_path(@readout),
+      html: {id: ids[:form_tag]} do %>
+    <% end %>
+  <% end %>
+  <%= turbo_stream.hide ids[:hidden_row] %>
+  <%= turbo_stream.remove ids[:row] %>
+  <%= turbo_stream.after @readout, partial: 'edit_form', locals: ids -%>
+<% end %>

app/views/measurements/index.html.erb

@@ -5,10 +5,36 @@
       id: :new_measurement_link, onclick: 'this.blur();',
       data: {turbo_stream: true} %>
   <% end %>
+  <%= image_button_tag '', 'view-rows', name: nil, type: 'button',
+    class: 'view-toggle', title: t('.view_compact'),
+    data: {view: 'compact'}, onclick: "setMeasurementsView('compact')" %>
+  <%= image_button_tag '', 'view-columns', name: nil, type: 'button',
+    class: 'view-toggle', title: t('.view_wide'),
+    data: {view: 'wide'}, onclick: "setMeasurementsView('wide')" %>
+</div>
+
+<div class="main-area measurements-section">
+  <%= tag.div id: :measurement_edit_form %>
+  <table class="items-table measurements-compact">
+    <thead>
+      <tr>
+        <th><%= Quantity.model_name.human %></th>
+        <th><%= Readout.human_attribute_name(:value) %></th>
+        <th><%= Unit.model_name.human %></th>
+        <th data-column="taken-at"><%= Readout.human_attribute_name(:taken_at) %></th>
+        <th data-column="created-at"><%= Readout.human_attribute_name(:created_at) %></th>
+        <% if current_user.at_least(:active) %>
+          <th></th>
+        <% end %>
+      </tr>
+    </thead>
+    <tbody id="measurements">
+      <%= render(partial: 'readout', collection: @measurements, as: :readout) || render_no_items %>
+    </tbody>
+  </table>
+
+  <div id="measurements-wide" class="measurements-wide">
+    <%= render 'wide_table', wide_groups: @wide_groups, wide_quantities: @wide_quantities %>
+  </div>
 </div>
 
-<table class="main-area">
-  <tbody id="measurements">
-    <%= render(@measurements) || render_no_items %>
-  </tbody>
-</table>

app/views/measurements/update.turbo_stream.erb

@@ -0,0 +1,4 @@
+<%= turbo_stream.close_form dom_id(@readout, :edit) %>
+<%= turbo_stream.replace @readout, partial: 'measurements/readout', locals: {readout: @readout} %>
+<%= turbo_stream.update 'measurements-wide', partial: 'wide_table',
+  locals: {wide_groups: @wide_groups, wide_quantities: @wide_quantities} %>

app/views/quantities/_form.html.erb

@@ -8,6 +8,11 @@
     <td>
       <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
     </td>
+    <td>
+      <%= form.collection_select :default_unit_id, @user_units, :id,
+        ->(u){ sanitize('&emsp;' * (u.base_id? ? 1 : 0) + u.symbol) },
+        {include_blank: true}, onchange: "this.dataset.changed = ''" %>
+    </td>
 
     <td class="flex">
       <%= form.button %>

app/views/quantities/_quantity.html.erb

@@ -10,6 +10,7 @@
       onclick: 'this.blur();', data: {turbo_stream: true} %>
   </td>
   <td><%= quantity.description %></td>
+  <td><%= quantity.default_unit&.symbol %></td>
 
   <% if current_user.at_least(:active) %>
     <td class="flex">

app/views/quantities/index.html.erb

@@ -16,6 +16,7 @@
     <tr>
       <th><%= Quantity.human_attribute_name(:name) %></th>
       <th class="hexpand"><%= Quantity.human_attribute_name(:description) %></th>
+      <th><%= Quantity.human_attribute_name(:default_unit) %></th>
       <% if current_user.at_least(:active) %>
         <th><%= t :actions %></th>
         <th></th>
@@ -25,7 +26,7 @@
                ondragover: "dragOver(event)", ondrop: "drop(event)",
                ondragenter: "dragEnter(event)", ondragleave: "dragLeave(event)",
                data: {drop_id: "quantity_", drop_id_param: "quantity[parent_id]"} do %>
-      <th colspan="4"><%= t '.top_level_drop' %></th>
+      <th colspan="5"><%= t '.top_level_drop' %></th>
     <% end %>
   </thead>
   <tbody id="quantities">

app/views/readouts/_form.html.erb

@@ -12,10 +12,17 @@
     <td>
       <%= form.collection_select :unit_id, @user_units, :id,
         ->(u){ sanitize('&emsp;' * (u.base_id ? 1 : 0) + u.symbol) },
-        {prompt: '', disabled: '', selected: ''}, required: true %>
+        {prompt: '', disabled: '', selected: readout.quantity.default_unit_id || ''}, required: true,
+        data: {default_unit_id: readout.quantity.default_unit_id || ''},
+        onchange: "readoutUnitChanged(this)" %>
     </td>
     <td class="flex">
       <%# TODO: change to _link_ after giving up displaying relative paths %>
+      <%= image_button_tag '', 'check-circle-outline',
+        class: 'set-default-unit', name: nil, type: 'button', disabled: true,
+        title: t('readouts.form.set_default_unit'),
+        data: {path: quantity_path(readout.quantity)},
+        onclick: 'setDefaultUnit(this)' %>
       <%= image_button_tag '', 'delete-outline', class: 'dangerous', name: nil,
         formaction: discard_readouts_path(readout.quantity),
         formmethod: :get, formnovalidate: true, data: {turbo_stream: true} %>

config/environments/test.rb

@@ -58,4 +58,7 @@ Rails.application.configure do
   # config.action_view.annotate_rendered_view_with_filenames = true
 
   config.log_level = :info
+
+  # Allow Capybara's dynamic test server host (127.0.0.1:<random_port>)
+  config.hosts << '127.0.0.1'
 end

config/locales/en.yml

@@ -11,8 +11,13 @@ en:
   activerecord:
     attributes:
       quantity:
+        default_unit: Default unit
         description: Description
         name: Name
+      readout:
+        created_at: Recorded at
+        taken_at: Taken at
+        value: Value
       unit:
         base: Base unit
         description: Description
@@ -81,6 +86,9 @@ en:
       revert: Revert
       sign_out: Sign out
       source_code: Get code
+  readouts:
+    form:
+      set_default_unit: Set as default unit
   measurements:
     navigation: Measurements
     no_items: There are no measurements taken. You can Add some now.
@@ -89,6 +97,20 @@ en:
       taken_at_html: Measurement taken at 
     index:
       new_measurement: Add measurement
+      view_compact: Compact view
+      view_wide: Wide view
+    readout:
+      edit: Edit
+      destroy: Delete
+    create:
+      success:
+        one: Recorded 1 measurement.
+        other: Recorded %{count} measurements.
+      no_readouts: No readouts selected.
+    update:
+      success: Measurement updated.
+    destroy:
+      success: Measurement deleted.
   quantities:
     navigation: Quantities
     no_items: There are no configured quantities. You can Add some or Import from defaults.

db/migrate/20260402000000_add_taken_at_to_readouts.rb

@@ -0,0 +1,5 @@
+class AddTakenAtToReadouts < ActiveRecord::Migration[7.2]
+  def change
+    add_column :readouts, :taken_at, :datetime
+  end
+end

db/migrate/20260403000000_add_default_unit_to_quantities.rb

@@ -0,0 +1,5 @@
+class AddDefaultUnitToQuantities < ActiveRecord::Migration[7.2]
+  def change
+    add_reference :quantities, :default_unit, foreign_key: {to_table: :units}, null: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
+ActiveRecord::Schema[7.2].define(version: 2026_04_03_000000) 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
@@ -20,6 +20,8 @@ ActiveRecord::Schema[7.2].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.bigint "default_unit_id"
+    t.index ["default_unit_id"], name: "index_quantities_on_default_unit_id"
     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"
@@ -32,6 +34,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
     t.decimal "value", precision: 30, scale: 15, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
+    t.datetime "taken_at"
     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"], name: "index_readouts_on_unit_id"
@@ -70,6 +73,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_01_21_230456) do
   end
 
   add_foreign_key "quantities", "quantities", column: "parent_id", on_delete: :cascade
+  add_foreign_key "quantities", "units", column: "default_unit_id"
   add_foreign_key "quantities", "users"
   add_foreign_key "readouts", "quantities"
   add_foreign_key "readouts", "units"

test/controllers/measurements_controller_test.rb

@@ -1,8 +1,65 @@
 require "test_helper"
 
 class MeasurementsControllerTest < ActionDispatch::IntegrationTest
-  #test "should get index" do
+  setup do
-  #  get measurements_index_url
+    host! '127.0.0.1'
-  #  assert_response :success
+    @user = users(:alice)
-  #end
+    post new_user_session_path, params: { user: { email: @user.email, password: 'alice' } }
+    @quantity = @user.quantities.create!(name: 'Weight')
+    @unit = @user.units.create!(symbol: 'kg')
+  end
+
+  test "index returns ok" do
+    get measurements_path
+    assert_response :success
+  end
+
+  test "index requires authentication" do
+    delete destroy_user_session_path
+    get measurements_path
+    assert_response :redirect
+  end
+
+  test "create records readout with taken_at" do
+    taken_at = 1.day.ago.change(usec: 0)
+    assert_difference -> { @user.readouts.count } do
+      post measurements_path, params: {
+        taken_at: taken_at.iso8601,
+        readouts: [{ quantity_id: @quantity.id, value: '82.5', unit_id: @unit.id }]
+      }, as: :turbo_stream
+    end
+    assert_response :success
+    assert_equal taken_at, @user.readouts.last.taken_at
+  end
+
+  test "create with no readouts selected shows alert" do
+    post measurements_path, params: { taken_at: Time.now.iso8601 }, as: :turbo_stream
+    assert_response :success
+  end
+
+  test "destroy removes readout" do
+    readout = @user.readouts.create!(quantity: @quantity, unit: @unit, value: 82.5, taken_at: 1.day.ago)
+    assert_difference -> { @user.readouts.count }, -1 do
+      delete measurement_path(readout), as: :turbo_stream
+    end
+    assert_response :success
+  end
+
+  test "destroy cannot remove another user's readout" do
+    other_quantity = users(:bob).quantities.create!(name: 'Weight')
+    other_unit = users(:bob).units.create!(symbol: 'kg')
+    readout = users(:bob).readouts.create!(quantity: other_quantity, unit: other_unit, value: 70.0, taken_at: 1.day.ago)
+    assert_no_difference -> { users(:bob).readouts.count } do
+      delete measurement_path(readout), as: :turbo_stream
+    end
+  end
+
+  test "update changes readout value" do
+    readout = @user.readouts.create!(quantity: @quantity, unit: @unit, value: 82.5, taken_at: 1.day.ago)
+    patch measurement_path(readout), params: {
+      readout: { value: '83.0', unit_id: @unit.id, taken_at: readout.taken_at.iso8601 }
+    }, as: :turbo_stream
+    assert_response :success
+    assert_in_delta 83.0, readout.reload.value
+  end
 end

test/system/measurements_test.rb

@@ -0,0 +1,64 @@
+require "application_system_test_case"
+
+class MeasurementsTest < ApplicationSystemTestCase
+  setup do
+    @user = sign_in(user: users(:alice))
+
+    @quantity = @user.quantities.create!(name: 'Weight')
+    @unit = @user.units.create!(symbol: 'kg')
+    @readout = @user.readouts.create!(quantity: @quantity, unit: @unit, value: 82.5)
+
+    visit measurements_path
+  end
+
+  test "index shows quantity name as edit link for active user" do
+    within 'tbody' do
+      assert_selector :link, exact_text: @quantity.name
+    end
+  end
+
+  test "edit opens inline form on quantity link click" do
+    within 'tbody' do
+      click_on @quantity.name
+      assert_selector ':focus'
+      assert_selector 'input[name="readout[value]"]'
+    end
+  end
+
+  test "edit and update measurement value" do
+    within 'tbody' do
+      click_on @quantity.name
+      fill_in 'readout[value]', with: '83.1'
+      assert_difference ->{ @readout.reload.value }, 83.1 - @readout.value do
+        click_on t('helpers.submit.update')
+      end
+      assert_no_selector :fillable_field
+      assert_selector :link, exact_text: @quantity.name
+    end
+    assert_selector '.flash.notice', text: t('measurements.update.success')
+  end
+
+  test "cancel edit restores original row" do
+    within 'tbody' do
+      click_on @quantity.name
+      assert_selector 'input[name="readout[value]"]'
+      click_on t(:cancel)
+      assert_no_selector :fillable_field
+      assert_selector :link, exact_text: @quantity.name
+    end
+  end
+
+  test "wide view edit opens panel form" do
+    @readout.update!(taken_at: Time.now)
+    visit measurements_path
+    execute_script("localStorage.removeItem('measurements-view')")
+    visit measurements_path
+
+    find('button[data-view="wide"]').click
+    within '#measurements-wide' do
+      assert_text format("%.10g", 82.5), wait: 3
+      find('button.link').click
+    end
+    assert_selector '#measurement_edit_form input[name="readout[value]"]', wait: 5
+  end
+end

test/system/quantities_test.rb

@@ -0,0 +1,45 @@
+require "application_system_test_case"
+
+class QuantitiesTest < ApplicationSystemTestCase
+  setup do
+    @user = sign_in(user: users(:alice))
+    @unit = @user.units.create!(symbol: 'kg')
+    @quantity = @user.quantities.create!(name: 'Weight')
+    visit quantities_path
+  end
+
+  test "update button turns red when default unit changes" do
+    click_on 'Weight'
+
+    button = find('button[name=button]')
+    initial_color = evaluate_script("getComputedStyle(arguments[0]).backgroundColor", button)
+
+    select 'kg', from: 'quantity[default_unit_id]'
+
+    changed_color = evaluate_script("getComputedStyle(arguments[0]).backgroundColor", button)
+    refute_equal initial_color, changed_color, "Button color should change when default unit is altered"
+  end
+
+  test "saving default unit pre-selects it in measurements form" do
+    click_on 'Weight'
+    select 'kg', from: 'quantity[default_unit_id]'
+    click_on t('helpers.submit.update')
+    assert_selector '.flash.notice'
+
+    @quantity.reload
+    assert_equal @unit.id, @quantity.default_unit_id
+
+    visit measurements_path
+    find(:link_or_button, t('measurements.index.new_measurement')).click
+    assert_selector '#measurement_form'
+
+    within '#quantity_select' do
+      check 'Weight'
+    end
+    find('button[formaction]').click
+
+    within 'tbody#readouts' do
+      assert_selector "option[value='#{@unit.id}'][selected]"
+    end
+  end
+end

test/system/users_test.rb

@@ -229,7 +229,7 @@ class UsersTest < ApplicationSystemTestCase
       user = User.find_by_email!(first(:link).text)
       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"
+      execute_script("arguments[0].click()", find_button("update status"))
     end
     assert_title 'The change you wanted was rejected (422)'
   end