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

@@ -77,28 +77,6 @@ default/       namespace for default units import/export and admin panel
 root           → /units (authenticated), /sign_in (unauthenticated)
 ```
 
-## JavaScript Conventions
-
-### No manual fetch() — use Turbo
-
-Never make AJAX requests with `fetch()` in JavaScript. Use Turbo's built-in mechanisms instead:
-
-- **Links/buttons that trigger server actions**: use `data: {turbo_stream: true}` on the element (link or button_to form).
-- **Dynamic form submissions from JS** (where HTML alone isn't enough): create a form element, append hidden inputs, and call `form.requestSubmit()`. Turbo intercepts it automatically — no manual CSRF handling, no `Turbo.renderStreamMessage()`.
-  ```javascript
-  var form = document.createElement('form');
-  form.action = url; form.method = 'post'; form.dataset.turboStream = 'true';
-  // append hidden inputs...
-  form.addEventListener('turbo:submit-end', function() { form.remove(); });
-  document.body.appendChild(form);
-  form.requestSubmit();
-  ```
-- **Server-rendered HTML**: use ERB partials and Turbo Stream views (`*.turbo_stream.erb`), never build HTML in JavaScript.
-
-### No HTML generation in JavaScript
-
-Never use JavaScript to build and insert HTML (no `innerHTML =`, no `createElement` trees for content). Render HTML server-side in ERB partials; update the DOM via Turbo Stream actions (`replace`, `update`, `append`, etc.).
-
 ## Database Requirements
 
 The database must support:

app/assets/stylesheets/application.css

@@ -111,11 +111,6 @@ svg {
 svg:last-child {
   margin-right: 0;
 }
-.chart-panel svg {
-  height: auto;
-  margin: 0;
-  width: auto;
-}
 textarea {
   margin: 0;
 }
@@ -671,9 +666,6 @@ body[data-measurements-view=wide] .view-toggle[data-view=wide] {
   color: white;
   fill: white;
 }
-.chart-panel {
-  width: 100%;
-}
 #measurements tr.grouped td {
   border-top: none;
 }

app/controllers/charts_controller.rb

@@ -1,12 +0,0 @@
-class ChartsController < ApplicationController
-  def index
-    readouts = current_user.readouts.includes(:quantity, :unit).order(:taken_at, :id)
-    @readouts_json = readouts.map { |r|
-      { takenAt: r.taken_at&.iso8601,
-        quantityId: r.quantity_id,
-        quantityName: r.quantity.name,
-        value: r.value.to_f,
-        unit: r.unit.symbol }
-    }.to_json
-  end
-end

app/helpers/application_helper.rb

@@ -171,7 +171,6 @@ module ApplicationHelper
       ['measurements', 'scale-bathroom', :restricted],
       ['quantities', 'axis-arrow', :restricted, 'right'],
       ['units', 'weight-gram', :restricted],
-      ['charts', 'chart-line', :restricted],
       # TODO: display users tab only if >1 user present; sole_user?/sole_admin?
       ['users', 'account-multiple-outline', :admin],
     ]

app/javascript/application.js

@@ -23,54 +23,6 @@ function groupMeasurements() {
 }
 
 
-function buildCharts() {
-  var container = document.getElementById('measurements-charts');
-  var dataEl = document.getElementById('charts-data');
-  if (!container || !dataEl) return;
-
-  var readouts = JSON.parse(dataEl.textContent);
-  container.innerHTML = '';
-  if (readouts.length === 0) return;
-
-  // Data arrives sorted by taken_at from the server; group into per-quantity traces
-  var quantities = new Map();
-  readouts.forEach(function(r) {
-    if (!r.takenAt) return;
-    if (!quantities.has(r.quantityId)) {
-      quantities.set(r.quantityId, { name: r.quantityName, unit: r.unit, x: [], y: [] });
-    }
-    var q = quantities.get(r.quantityId);
-    q.x.push(r.takenAt);
-    q.y.push(r.value);
-  });
-
-  var traces = [];
-  quantities.forEach(function(q) {
-    traces.push({
-      x: q.x,
-      y: q.y,
-      mode: 'lines+markers',
-      type: 'scatter',
-      name: q.name + ' (' + q.unit + ')',
-      marker: { size: 5 }
-    });
-  });
-
-  var div = document.createElement('div');
-  div.className = 'chart-panel';
-  container.appendChild(div);
-
-  Plotly.newPlot(div, traces, {
-    xaxis: { type: 'date', tickformat: '%Y-%m-%d %H:%M' },
-    yaxis: {},
-    margin: { t: 20, r: 20, b: 80, l: 60 },
-    paper_bgcolor: 'transparent',
-    plot_bgcolor: 'transparent',
-    font: { family: 'system-ui' },
-    legend: { orientation: 'h', y: -0.25 }
-  }, { responsive: true, displayModeBar: false });
-}
-
 function getMeasurementsView() {
   return localStorage.getItem('measurements-view') || 'compact';
 }
@@ -86,10 +38,6 @@ function setMeasurementsView(view) {
 window.setMeasurementsView = setMeasurementsView
 
 document.addEventListener('turbo:load', function() {
-  if (document.getElementById('charts-data')) {
-    buildCharts();
-    return;
-  }
   var tbody = document.getElementById('measurements');
   if (!tbody) return;
   groupMeasurements();
@@ -134,13 +82,9 @@ window.detailsObserver = new MutationObserver((mutations) => {
 function readoutUnitChanged(select) {
   var button = select.closest('tr').querySelector('.set-default-unit');
   if (select.value && select.value !== select.dataset.defaultUnitId) {
-    button.removeAttribute('disabled');
-    button.removeAttribute('aria-disabled');
-    button.removeAttribute('tabindex');
+    Turbo.StreamElement.prototype.enableElement(button);
   } else {
-    button.setAttribute('disabled', 'disabled');
-    button.setAttribute('aria-disabled', 'true');
-    button.setAttribute('tabindex', '-1');
+    Turbo.StreamElement.prototype.disableElement(button);
   }
 }
 window.readoutUnitChanged = readoutUnitChanged

app/views/charts/index.html.erb

@@ -1,2 +0,0 @@
-<div class="main-area" id="measurements-charts"></div>
-<script id="charts-data" type="application/json"><%= raw @readouts_json %></script>

app/views/layouts/application.html.erb

@@ -14,7 +14,6 @@
     <%= csp_meta_tag %>
 
     <%= stylesheet_link_tag "spreadsheet" %>
-    <script src="https://cdn.plot.ly/plotly-basic-2.35.2.min.js"></script>
     <%= javascript_importmap_tags %>
 
     <%#= turbo_page_requires_reload_tag %>

app/views/measurements/index.html.erb

@@ -11,7 +11,6 @@
   <%= 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">

config/locales/en.yml

@@ -89,8 +89,6 @@ en:
   readouts:
     form:
       set_default_unit: Set as default unit
-  charts:
-    navigation: Charts
   measurements:
     navigation: Measurements
     no_items: There are no measurements taken. You can Add some now.
@@ -101,7 +99,6 @@ en:
       new_measurement: Add measurement
       view_compact: Compact view
       view_wide: Wide view
-      view_charts: Charts
     readout:
       edit: Edit
       destroy: Delete

config/routes.rb

@@ -1,6 +1,5 @@
 Rails.application.routes.draw do
   resources :measurements
-  resources :charts, only: [:index]
 
   resources :readouts, only: [:new] do
     collection {get 'new/:id/discard', action: :discard, as: :discard}

db/migrate/20260402000000_add_taken_at_to_readouts.rb

@@ -1,6 +1,5 @@
 class AddTakenAtToReadouts < ActiveRecord::Migration[7.2]
   def change
     add_column :readouts, :taken_at, :datetime
-    add_index :readouts, [:user_id, :taken_at]
   end
 end

db/schema.rb

@@ -39,7 +39,6 @@ ActiveRecord::Schema[7.2].define(version: 2026_04_03_000000) do
     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"
-    t.index ["user_id", "taken_at"], name: "index_readouts_on_user_id_and_taken_at"
   end
 
   create_table "units", charset: "utf8mb4", collation: "utf8mb4_0900_as_ci", force: :cascade do |t|

db/seeds.rb

@@ -21,4 +21,3 @@ end
 #[Source, Quantity, Unit].each { |model| model.defaults.delete_all }
 
 require_relative 'seeds/units.rb'
-require_relative 'seeds/demo.rb'

db/seeds/demo.rb

@@ -1,87 +0,0 @@
-demo_email = 'demo@localhost'
-
-User.transaction do
-  break if User.find_by(email: demo_email)
-
-  demo = User.create! email: demo_email, password: 'demo123', status: :active do |user|
-    user.skip_confirmation!
-    print "Creating demo account '#{user.email}' with password '#{user.password}'..."
-  end
-  puts "done."
-
-  # --- Units ---
-  u = {}
-  u[:kg]  = demo.units.create! symbol: 'kg',  description: 'kilogram'
-  u[:g]   = demo.units.create! symbol: 'g',   description: 'gram',       base: u[:kg], multiplier: 1e-3
-  u[:cm]  = demo.units.create! symbol: 'cm',  description: 'centimetre'
-  u[:bpm] = demo.units.create! symbol: 'bpm', description: 'beats per minute'
-  u[:pct] = demo.units.create! symbol: '%',   description: 'percent'
-  u[:h]   = demo.units.create! symbol: 'h',   description: 'hour'
-  u[:min] = demo.units.create! symbol: 'min', description: 'minute',     base: u[:h], multiplier: (1.0/60).round(10)
-  u[:kcal]= demo.units.create! symbol: 'kcal',description: 'kilocalorie'
-  u[:mg]  = demo.units.create! symbol: 'mg',  description: 'milligram',  base: u[:kg], multiplier: 1e-6
-  u[:mmhg]= demo.units.create! symbol: 'mmHg',description: 'millimetre of mercury'
-
-  # --- Quantities ---
-  body      = demo.quantities.create! name: 'Body'
-  weight    = demo.quantities.create! name: 'Weight',        parent: body
-  height    = demo.quantities.create! name: 'Height',        parent: body
-  fat       = demo.quantities.create! name: 'Body fat',      parent: body
-
-  cardio    = demo.quantities.create! name: 'Cardiovascular'
-  hr_rest   = demo.quantities.create! name: 'Resting HR',    parent: cardio
-  hr_peak   = demo.quantities.create! name: 'Peak HR',       parent: cardio
-  bp_sys    = demo.quantities.create! name: 'BP systolic',   parent: cardio
-  bp_dia    = demo.quantities.create! name: 'BP diastolic',  parent: cardio
-
-  activity  = demo.quantities.create! name: 'Activity'
-  sleep_dur = demo.quantities.create! name: 'Sleep',         parent: activity
-  calories  = demo.quantities.create! name: 'Calories out',  parent: activity
-
-  nutrition = demo.quantities.create! name: 'Nutrition'
-  cal_in    = demo.quantities.create! name: 'Calories in',   parent: nutrition
-  caffeine  = demo.quantities.create! name: 'Caffeine',      parent: nutrition
-
-  # --- Readouts (60 days of daily-ish data) ---
-  base_time = 60.days.ago.beginning_of_day
-  rng = Random.new(42)
-
-  weight_val  = 82.4
-  fat_val     = 21.5
-  hr_rest_val = 62.0
-
-  60.times do |i|
-    t = base_time + i.days + rng.rand(3600 * 2)
-
-    weight_val  += rng.rand(-0.3..0.3)
-    fat_val     += rng.rand(-0.15..0.15)
-    hr_rest_val += rng.rand(-1.5..1.5)
-    hr_rest_val  = hr_rest_val.clamp(52, 72)
-
-    demo.readouts.create! quantity: weight,   unit: u[:kg],  value: weight_val.round(1),  created_at: t
-    demo.readouts.create! quantity: fat,      unit: u[:pct], value: fat_val.round(1),     created_at: t
-    demo.readouts.create! quantity: hr_rest,  unit: u[:bpm], value: hr_rest_val.round,    created_at: t
-
-    if i % 2 == 0
-      demo.readouts.create! quantity: bp_sys,  unit: u[:mmhg], value: (115 + rng.rand(-8..8)).round, created_at: t
-      demo.readouts.create! quantity: bp_dia,  unit: u[:mmhg], value: (75  + rng.rand(-5..5)).round,  created_at: t
-    end
-
-    if i % 3 == 0
-      demo.readouts.create! quantity: hr_peak, unit: u[:bpm], value: (155 + rng.rand(-10..10)).round, created_at: t
-    end
-
-    demo.readouts.create! quantity: sleep_dur, unit: u[:h],   value: (6.5 + rng.rand(-1.5..1.5)).round(1), created_at: t
-    demo.readouts.create! quantity: calories,  unit: u[:kcal],value: (2100 + rng.rand(-300..300)).round,    created_at: t
-    demo.readouts.create! quantity: cal_in,    unit: u[:kcal],value: (1900 + rng.rand(-400..400)).round,    created_at: t
-
-    if i % 4 == 0
-      demo.readouts.create! quantity: caffeine, unit: u[:mg], value: (200 + rng.rand(-80..80)).round, created_at: t
-    end
-  end
-
-  # height is stable — record once
-  demo.readouts.create! quantity: height, unit: u[:cm], value: 178.0, created_at: base_time
-
-  puts "  Created #{demo.units.count} units, #{demo.quantities.count} quantities, #{demo.readouts.count} readouts."
-end

test/controllers/charts_controller_test.rb

@@ -1,63 +0,0 @@
-require "test_helper"
-
-class ChartsControllerTest < ActionDispatch::IntegrationTest
-  setup do
-    host! '127.0.0.1'
-    @user = users(:alice)
-    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 "requires authentication" do
-    delete destroy_user_session_path
-    get charts_path
-    assert_response :redirect
-  end
-
-  test "index returns ok" do
-    get charts_path
-    assert_response :success
-  end
-
-  test "embeds readout data as JSON in script tag" do
-    users(:alice).readouts.create!(quantity: @quantity, unit: @unit, value: 82.5, taken_at: 1.day.ago)
-
-    get charts_path
-
-    assert_select 'script#charts-data[type="application/json"]' do |elements|
-      data = JSON.parse(elements.first.children.first.to_s)
-      assert_equal 1, data.size
-      assert_equal 'Weight', data.first['quantityName']
-      assert_in_delta 82.5, data.first['value']
-      assert_equal 'kg', data.first['unit']
-      assert_not_nil data.first['takenAt']
-    end
-  end
-
-  test "orders readouts by taken_at ascending" do
-    older = users(:alice).readouts.create!(quantity: @quantity, unit: @unit, value: 80.0, taken_at: 2.days.ago)
-    newer = users(:alice).readouts.create!(quantity: @quantity, unit: @unit, value: 82.5, taken_at: 1.day.ago)
-
-    get charts_path
-
-    assert_select 'script#charts-data[type="application/json"]' do |elements|
-      data = JSON.parse(elements.first.children.first.to_s)
-      assert_equal older.taken_at.iso8601, data.first['takenAt']
-      assert_equal newer.taken_at.iso8601, data.last['takenAt']
-    end
-  end
-
-  test "does not expose other users readouts" do
-    bob_quantity = users(:bob).quantities.create!(name: 'Steps')
-    bob_unit = users(:bob).units.create!(symbol: 'steps')
-    users(:bob).readouts.create!(quantity: bob_quantity, unit: bob_unit, value: 5000, taken_at: 1.day.ago)
-
-    get charts_path
-
-    assert_select 'script#charts-data[type="application/json"]' do |elements|
-      data = JSON.parse(elements.first.children.first.to_s)
-      assert data.none? { |r| r['quantityName'] == 'Steps' }, "Bob's data must not appear"
-    end
-  end
-end

test/system/charts_test.rb

@@ -1,26 +0,0 @@
-require "application_system_test_case"
-
-class ChartsTest < ApplicationSystemTestCase
-  setup do
-    @user = sign_in(user: users(:alice))
-    @quantity = @user.quantities.create!(name: 'Weight')
-    @unit = @user.units.create!(symbol: 'kg')
-    @user.readouts.create!(quantity: @quantity, unit: @unit, value: 82.5, taken_at: 1.day.ago)
-    @user.readouts.create!(quantity: @quantity, unit: @unit, value: 83.1, taken_at: Time.now)
-    visit charts_path
-  end
-
-  test "charts page is reachable from navigation" do
-    visit root_path
-    click_on t('charts.navigation')
-    assert_current_path charts_path
-  end
-
-  test "renders Plotly chart panel" do
-    assert_selector '#measurements-charts .chart-panel', wait: 5
-  end
-
-  test "chart legend shows quantity name with unit" do
-    assert_text 'Weight (kg)', wait: 5
-  end
-end