Chapter health card on the admin chapter page

app/components/admin/dashboard/health_card_component.html.erb

@@ -0,0 +1,24 @@
+<div class="card border-info mb-4">
+  <div class="card-body">
+    <h3>Chapter Health</h3>
+    <div class="row">
+      <% tiles.each do |tile| %>
+        <div class="col-6 col-md-3 text-center mb-2">
+          <div class="small text-muted"><%= tile[:label] %></div>
+          <% if tile[:label] == 'Status' %>
+            <span class="badge fs-6 <%= bucket_badge_class %>"><%= health.bucket %></span>
+          <% elsif tile[:title] %>
+            <span title="<%= tile[:title] %>"><%= tile[:value] %></span>
+          <% else %>
+            <span><%= tile[:value] %></span>
+          <% end %>
+        </div>
+      <% end %>
+    </div>
+    <div class="row mt-3">
+      <div class="col-12">
+        <%= content %>
+      </div>
+    </div>
+  </div>
+</div>

app/components/admin/dashboard/health_card_component.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+module Admin
+  module Dashboard
+    # The Chapter Health card on /admin/chapters/:id: status badge, workshop
+    # recency and countdown, median cadence, eligible members, organisers.
+    # Yield the timeline (or anything else) into the card body via content.
+    class HealthCardComponent < ViewComponent::Base
+      BUCKET_CLASSES = { inactive: 'bg-secondary', dormant: 'bg-warning text-dark',
+                         active: 'bg-success' }.freeze
+
+      def initialize(health:) # rubocop:disable Lint/MissingSuper
+        @health = health
+      end
+
+      private
+
+      attr_reader :health
+
+      def bucket_badge_class = BUCKET_CLASSES.fetch(health.bucket)
+
+      def tile(label, value, title: nil)
+        { label:, value:, title: }
+      end
+
+      def tiles
+        [
+          tile('Status', health.bucket),
+          tile('Previous workshop', previous_workshop_value, title: previous_workshop_title),
+          tile('Next workshop', next_workshop_value),
+          tile('Cadence (days, median, 180d)', cadence_value),
+          tile('Eligible members', eligible_members_value),
+          tile('Organisers', number_value(health.organiser_count))
+        ]
+      end
+
+      def previous_workshop_value
+        health.days_since_last_workshop ? "#{number_value(health.days_since_last_workshop)} days ago" : 'never'
+      end
+
+      def previous_workshop_title
+        health.last_workshop_date&.to_date&.to_fs(:long)
+      end
+
+      def next_workshop_value
+        health.days_until_next_workshop ? "#{number_value(health.days_until_next_workshop)} days away" : 'none'
+      end
+
+      def cadence_value
+        health.median_cadence_days ? number_value(health.median_cadence_days) : '—'
+      end
+
+      def eligible_members_value
+        number_value(health.eligible_students + health.eligible_coaches)
+      end
+
+      def number_value(value)
+        number_with_delimiter(value)
+      end
+    end
+  end
+end

app/components/admin/dashboard/workshop_timeline_component.html.erb

@@ -0,0 +1,80 @@
+<div class="mb-1">
+  <strong class="small">Workshops and events timeline</strong>
+</div>
+<svg viewBox="0 0 1000 122" class="w-100" role="img" aria-label="Workshop and event timeline, 180 days past to 90 days future">
+  <% # 30-day ticks: 7 on the past side (180 days ago .. today), 3 ahead %>
+  <% (0..6).each do |ticks_ago| %>
+    <% tick_x = (667 - (ticks_ago * 667 / 6.0)).round(1) %>
+    <line x1="<%= tick_x %>" y1="14" x2="<%= tick_x %>" y2="70" stroke="#dee2e6" stroke-width="1" />
+    <% if (ticks_ago % 2).zero? %>
+      <text x="<%= tick_x %>" y="86" font-size="9" fill="#6c757d" text-anchor="middle">
+        <%= (range_start + (ticks_ago * 30).days).to_fs(:short) %>
+      </text>
+    <% end %>
+  <% end %>
+  <% (1..3).each do |ticks_ahead| %>
+    <% tick_x = (667 + (ticks_ahead * 333 / 3.0)).round(1) %>
+    <line x1="<%= tick_x %>" y1="14" x2="<%= tick_x %>" y2="70" stroke="#dee2e6" stroke-width="1" />
+    <text x="<%= tick_x %>" y="86" font-size="9" fill="#6c757d" text-anchor="middle">
+      <%= (Time.zone.today + (ticks_ahead * 30).days).to_fs(:short) %>
+    </text>
+  <% end %>
+
+  <line x1="667" y1="6" x2="667" y2="74" stroke="#212529" stroke-width="2" stroke-dasharray="4 3" />
+  <text x="667" y="10" font-size="9" fill="#212529" text-anchor="middle">today</text>
+
+  <% # single-chapter events, complementary colour (amber) with square-ish markers %>
+  <% stacked_markers(event_past).each do |m| %>
+    <% if m[:stack] %>
+      <text x="<%= m[:x] %>" y="<%= m[:y] - 12 %>" font-size="8" fill="#fd7e14" text-anchor="middle">x<%= m[:stack] %></text>
+    <% end %>
+    <rect x="<%= m[:x] - 5 %>" y="<%= m[:y] - 5 %>" width="10" height="10" fill="#fd7e14" class="marker">
+      <title><%= m[:date].to_date.to_fs(:iso8601) %> (event)</title>
+    </rect>
+  <% end %>
+
+  <% stacked_markers(event_future).each do |m| %>
+    <rect x="<%= m[:x] - 5 %>" y="<%= m[:y] - 5 %>" width="10" height="10" fill="white" stroke="#fd7e14" stroke-width="2" class="marker">
+      <title><%= m[:date].to_date.to_fs(:iso8601) %> (event, planned)</title>
+    </rect>
+  <% end %>
+
+  <% stacked_markers(past).each do |m| %>
+    <% if m[:stack] %>
+      <text x="<%= m[:x] %>" y="<%= m[:y] - 12 %>" font-size="8" fill="#0d6efd" text-anchor="middle">x<%= m[:stack] %></text>
+    <% end %>
+    <circle cx="<%= m[:x] %>" cy="<%= m[:y] %>" r="5" fill="#0d6efd" class="marker">
+      <title><%= m[:date].to_date.to_fs(:iso8601) %></title>
+    </circle>
+  <% end %>
+
+  <% stacked_markers(future).each do |m| %>
+    <% if m[:stack] %>
+      <text x="<%= m[:x] %>" y="<%= m[:y] - 12 %>" font-size="8" fill="#0d6efd" text-anchor="middle">x<%= m[:stack] %></text>
+    <% end %>
+    <circle cx="<%= m[:x] %>" cy="<%= m[:y] %>" r="5" fill="white" stroke="#0d6efd" stroke-width="2" class="marker">
+      <title><%= m[:date].to_date.to_fs(:iso8601) %> (planned)</title>
+    </circle>
+  <% end %>
+
+  <% # legend, inside the SVG so it scales with the axis %>
+  <% legend = [
+       { x: 40,  label: 'workshop',         marker: 'circle-filled' },
+       { x: 240, label: 'planned workshop', marker: 'circle-hollow' },
+       { x: 500, label: 'chapter event',    marker: 'rect-filled' },
+       { x: 740, label: 'planned event',    marker: 'rect-hollow' }
+     ] %>
+  <% legend.each do |item| %>
+    <% if %w[circle-filled circle-hollow].include?(m = item[:marker]) %>
+      <circle cx="<%= item[:x] %>" cy="108" r="5"
+              fill="<%= m == 'circle-filled' ? '#0d6efd' : 'white' %>"
+              stroke="<%= m == 'circle-filled' ? 'none' : '#0d6efd' %>" stroke-width="2" />
+    <% else %>
+      <rect x="<%= item[:x] - 5 %>" y="103" width="10" height="10"
+            fill="<%= m == 'rect-filled' ? '#fd7e14' : 'white' %>"
+            stroke="<%= m == 'rect-filled' ? 'none' : '#fd7e14' %>" stroke-width="2" />
+    <% end %>
+    <text x="<%= item[:x] + 12 %>" y="112" font-size="11" fill="#6c757d"><%= item[:label] %></text>
+  <% end %>
+</svg>
+

app/components/admin/dashboard/workshop_timeline_component.rb

@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Admin
+  module Dashboard
+    # Horizontal SVG timeline: 180 days past, 90 days future. SVG viewBox is
+    # 1000x122; today sits at x=667 (2/3). No JS — <title> provides tooltips.
+    class WorkshopTimelineComponent < ViewComponent::Base
+      def initialize(past:, future:, event_past: [], event_future: []) # rubocop:disable Lint/MissingSuper
+        @past = past.sort
+        @future = future.sort
+        @event_past = event_past.sort
+        @event_future = event_future.sort
+      end
+
+      private
+
+      attr_reader :past, :future, :event_past, :event_future
+
+      def range_start = (Time.zone.today - 180.days).beginning_of_day
+      def range_end = (Time.zone.today + 90.days).end_of_day
+
+      def x_for(date)
+        fraction = (date.to_time - range_start) / (range_end - range_start)
+        (fraction * 1000).round(1)
+      end
+
+      MAX_STACK = 3
+
+      def stacked_markers(dates)
+        dates.group_by(&:to_date).flat_map do |_day, day_dates|
+          sorted = day_dates.sort_by(&:to_time)
+          sorted.first(MAX_STACK).each_with_index.map do |date, i|
+            { x: x_for(date), y: 40 - (i * 14), date:, stack: sorted.size > 1 ? sorted.size : nil }
+          end
+        end
+      end
+    end
+  end
+end

app/controllers/admin/chapters_controller.rb

@@ -27,6 +27,9 @@ def show
     authorize(@chapter)
 
     @workshops = @chapter.workshops.today_and_upcoming
+    @chapter_health = Admin::Dashboard::ChapterHealth.row(chapter: @chapter)
+    @past_workshop_dates, @planned_workshop_dates = timeline_dates(@chapter.workshops)
+    @past_event_dates, @planned_event_dates = timeline_dates(@chapter.events.single_chapter)
     @sponsors = @chapter.sponsors.uniq
     @groups = @chapter.groups
     @subscribers = @chapter.subscriptions.last(20).reverse
@@ -126,4 +129,9 @@ def member_emails(chapter, type)
       end
     members.distinct.pluck(:email).join("\n")
   end
+
+  def timeline_dates(collection)
+    [collection.where(date_and_time: ..Time.zone.now).pluck(:date_and_time),
+     collection.where(date_and_time: Time.zone.now..90.days.from_now).pluck(:date_and_time)]
+  end
 end

app/models/event.rb

@@ -18,6 +18,10 @@ class Event < ApplicationRecord
   has_and_belongs_to_many :chapters, join_table: 'chapters_events'
   has_many :invitations
 
+  # Events linked to exactly one chapter — a per-chapter signal, unlike
+  # multi-chapter events which list dozens of chapters.
+  scope :single_chapter, -> { left_joins(:chapters).group(:id).having('COUNT(chapters.id) = 1') }
+
   validates :name, :slug, :info, :schedule, :description, presence: true
   validates :slug, uniqueness: true
   validate :invitability, if: :invitable?

app/services/admin/dashboard/chapter_health.rb

@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+
+module Admin
+  module Dashboard
+    # Health data for one chapter, shown in the Chapter Health card on
+    # /admin/chapters/:id. Mirrors the classification rules used by
+    # Admin::ChaptersController#status.
+    class ChapterHealth
+      Row = Data.define(:chapter, :bucket, :last_workshop_date, :next_workshop_date,
+                        :days_since_last_workshop, :days_until_next_workshop,
+                        :organiser_count, :eligible_students, :eligible_coaches,
+                        :median_cadence_days)
+
+      class << self
+        # Health row for one chapter; per-chapter queries are fine on a show page.
+        # rubocop:disable Metrics/AbcSize, Metrics/MethodLength — one entry per Row field
+        def row(chapter:)
+          in_window = chapter.workshops
+                             .exists?(date_and_time: 180.days.ago.beginning_of_day..90.days.from_now)
+
+          Row.new(
+            chapter:,
+            bucket: bucket_for(chapter, in_window),
+            last_workshop_date: last_workshop_date = chapter.workshops.where(date_and_time: ..Time.zone.now)
+                                                            .maximum(:date_and_time),
+            next_workshop_date: next_workshop_date = chapter.workshops.today_and_upcoming.minimum(:date_and_time),
+            days_since_last_workshop: recency_days(last_workshop_date),
+            days_until_next_workshop: countdown_days(next_workshop_date),
+            organiser_count: chapter.organisers.count,
+            eligible_students: chapter.eligible_students.count,
+            eligible_coaches: chapter.eligible_coaches.count,
+            median_cadence_days: median_cadence(
+              chapter.workshops.where(date_and_time: 180.days.ago..Time.zone.now).order(:date_and_time)
+                              .pluck(:date_and_time)
+            )
+          )
+        end
+        # rubocop:enable Metrics/AbcSize, Metrics/MethodLength
+
+        private
+
+        def recency_days(date)
+          date && ((Time.zone.now - date) / 1.day).floor
+        end
+
+        def countdown_days(date)
+          date && ((date - Time.zone.now) / 1.day).ceil
+        end
+
+        def median_cadence(dates) # rubocop:disable Metrics/AbcSize
+          gaps = dates.sort.each_cons(2).map { |a, b| ((b - a) / 1.day).round }
+          return nil if gaps.empty?
+
+          mid = gaps.length / 2
+          gaps.length.odd? ? gaps[mid] : ((gaps[mid - 1] + gaps[mid]) / 2.0).round
+        end
+
+        def bucket_for(chapter, in_window)
+          return :inactive unless chapter.active?
+          return :active if in_window
+
+          :dormant
+        end
+      end
+    end
+  end
+end

app/views/admin/chapters/show.html.haml

@@ -58,6 +58,8 @@
             %div.text-muted.small= "Based on #{pluralize(@how_you_found_us.total_responses, 'response')}"
 
     .col-12.col-lg-8
+      = render Admin::Dashboard::HealthCardComponent.new(health: @chapter_health) do
+        = render Admin::Dashboard::WorkshopTimelineComponent.new(past: @past_workshop_dates, future: @planned_workshop_dates, event_past: @past_event_dates, event_future: @planned_event_dates)
       .mb-4.mt-md-4.mt-lg-0
         .d-md-flex.justify-content-between.align-items-center
           %h3 Upcoming Workshops

spec/components/admin/dashboard/health_card_component_spec.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Admin::Dashboard::HealthCardComponent do
+  let(:chapter) { Fabricate(:chapter) }
+
+  it 'renders the six stat tiles with formatted values' do
+    Fabricate(:workshop, chapter:, date_and_time: 30.days.ago)
+    health = Admin::Dashboard::ChapterHealth.row(chapter:)
+
+    render_inline(described_class.new(health:))
+
+    expect(page).to have_text('Chapter Health')
+    expect(page).to have_css('.badge', text: 'active')
+    expect(page).to have_text('30 days ago')
+    expect(page).to have_text('never', count: 0)
+    expect(page).to have_text('Cadence (days, median, 180d)')
+    expect(page).to have_text('Organisers')
+  end
+
+  it 'renders never/none fallbacks for a chapter without workshops' do
+    health = Admin::Dashboard::ChapterHealth.row(chapter:)
+
+    render_inline(described_class.new(health:))
+
+    expect(page).to have_css('.badge', text: 'dormant')
+    expect(page).to have_text('never')
+    expect(page).to have_text('none')
+  end
+
+  it 'classifies a disabled chapter as inactive' do
+    chapter = Fabricate(:chapter, active: false)
+    health = Admin::Dashboard::ChapterHealth.row(chapter:)
+
+    render_inline(described_class.new(health:))
+
+    expect(page).to have_css('.badge', text: 'inactive')
+  end
+
+  it 'renders the yielded content inside the card' do
+    health = Admin::Dashboard::ChapterHealth.row(chapter:)
+
+    render_inline(described_class.new(health:)) { 'TIMELINE-CONTENT' }
+
+    expect(page).to have_text('TIMELINE-CONTENT')
+  end
+end