7 files changed, 202 insertions, 1 deletions

diff --git a/app/helpers/nodes_helper.rb b/app/helpers/nodes_helper.rb
index 4293628..329bcc5 100644
--- a/app/helpers/nodes_helper.rb
+++ b/app/helpers/nodes_helper.rb
@@ -43,4 +43,20 @@ module NodesHelper
       link_to('add event', new_event_path(:node_id => @node.id))
     ])
   end
+
+  def event_schedule_text(event)
+    if event.rrule.present?
+      recurrence = event.humanize_rrule(I18n.locale)
+      if recurrence
+        time = event.start_time&.strftime("%H:%M")
+        time ? "#{recurrence} #{t(:event_schedule_time, time: time)}" : recurrence
+      else
+        "#{event.rrule} (#{t(:event_schedule_unrecognized)})"
+      end
+    elsif event.start_time
+      I18n.l(event.start_time, format: :long)
+    else
+      t(:event_schedule_none)
+    end
+  end
 end
diff --git a/app/models/concerns/rrule_humanizer.rb b/app/models/concerns/rrule_humanizer.rb
new file mode 100644
index 0000000..6cee711
--- /dev/null
+++ b/app/models/concerns/rrule_humanizer.rb
@@ -0,0 +1,82 @@
+module RruleHumanizer
+  extend ActiveSupport::Concern
+
+  WEEKDAY_NAMES = {
+    de: { "MO"=>"Montag","TU"=>"Dienstag","WE"=>"Mittwoch","TH"=>"Donnerstag","FR"=>"Freitag","SA"=>"Samstag","SU"=>"Sonntag" },
+    en: { "MO"=>"Monday","TU"=>"Tuesday","WE"=>"Wednesday","TH"=>"Thursday","FR"=>"Friday","SA"=>"Saturday","SU"=>"Sunday" }
+  }.freeze
+
+  WEEKDAY_NAMES_ADVERBIAL = {
+    de: { "MO"=>"montags","TU"=>"dienstags","WE"=>"mittwochs","TH"=>"donnerstags","FR"=>"freitags","SA"=>"samstags","SU"=>"sonntags" }
+  }.freeze
+
+  ORDINAL_NAMES = {
+    de: { 1=>"ersten", 2=>"zweiten", 3=>"dritten", 4=>"vierten", -1=>"letzten", -2=>"vorletzten" },
+    en: { 1=>"first", 2=>"second", 3=>"third", 4=>"fourth", -1=>"last", -2=>"second-to-last" }
+  }.freeze
+
+  MONTH_NAMES = {
+    de: %w[Januar Februar März April Mai Juni Juli August September Oktober November Dezember],
+    en: %w[January February March April May June July August September October November December]
+  }.freeze
+
+  def humanize_rrule(locale = I18n.locale)
+    return nil if rrule.blank?
+    parts = Hash[rrule.split(";").map { |p| p.split("=", 2) }]
+    return nil if parts["COUNT"] || parts["UNTIL"] # old one-off data, don't guess
+
+    freq, interval, byday, bymonth = parts["FREQ"], parts["INTERVAL"].to_i, parts["BYDAY"], parts["BYMONTH"]
+    loc = locale.to_sym
+    weekdays = WEEKDAY_NAMES[loc] || WEEKDAY_NAMES[:en]
+    ordinals = ORDINAL_NAMES[loc] || ORDINAL_NAMES[:en]
+    months   = MONTH_NAMES[loc]   || MONTH_NAMES[:en]
+
+    days = byday&.split(",")&.map do |d|
+     if d =~ /^(-?\d+)([A-Z]{2})$/
+        "#{ordinals[$1.to_i]} #{weekdays[$2]}"
+      else
+        weekdays[d]
+      end
+    end
+
+    base =
+      case loc
+      when :de
+        case freq
+        when "WEEKLY"
+          if days
+            if interval == 2
+              adverbial = byday.split(",").map { |d| WEEKDAY_NAMES_ADVERBIAL[:de][d] }
+              "Alle zwei Wochen #{adverbial.join(' und ')}"
+            else
+              "Jeden #{days.join(' und ')}"
+            end
+          else
+            interval == 2 ? "Alle zwei Wochen" : "Wöchentlich"
+          end
+        when "MONTHLY"
+          days ? "Jeden #{days.join(' und ')} im Monat" : "Monatlich"
+        end
+      else
+        case freq
+        when "WEEKLY"
+          days ? "#{interval == 2 ? 'Every other' : 'Every'} #{days.join(' and ')}" : (interval == 2 ? "Every other week" : "Weekly")
+        when "MONTHLY"
+          days ? "Every #{days.join(' and ')} of the month" : "Monthly"
+        end
+      end
+    return nil unless base
+
+    if bymonth
+      included = bymonth.split(",").map(&:to_i)
+      missing = ((1..12).to_a - included)
+      if missing.size == 1
+        excluded_name = months[missing.first - 1]
+        base += (loc == :de ? ", außer im #{excluded_name}" : ", except in #{excluded_name}")
+      end
+      # more than one missing month: bymonth pattern more complex than we handle, leave base as-is silently
+    end
+
+    base
+  end
+end
diff --git a/app/models/event.rb b/app/models/event.rb
index 26c79e4..de82674 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -1,4 +1,5 @@
 class Event < ApplicationRecord
+  include RruleHumanizer
 
   belongs_to :node, optional: true
   has_many   :occurrences
diff --git a/app/views/nodes/show.html.erb b/app/views/nodes/show.html.erb
index de4d8a2..7223219 100644
--- a/app/views/nodes/show.html.erb
+++ b/app/views/nodes/show.html.erb
@@ -42,6 +42,18 @@
       <td class="description">Tagged with:</td>
       <td><%= @page.tag_list %></td>
     </tr>
+    <% if @node.events.any? %>
+    <tr>
+      <td class="description">Events</td>
+      <td>
+        <ul>
+        <% @node.events.order(:start_time).each do |event| %>
+          <li><%= event_schedule_text(event) %><%= " (primary)" if event.is_primary? %></li>
+        <% end %>
+        </ul>
+      </td>
+    </tr>
+    <% end %>
     <tr>
       <td class="description"><strong>Title</strong></td>
       <td><%= sanitize( @page.title ) %></td>
@@ -59,4 +71,4 @@
       <td class="right"></td>
     </tr>
   </table>
-</div>
\ No newline at end of file
+</div>
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 5f77d79..0b42dd3 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -7,6 +7,9 @@ de:
   sponsors: Sponsoren
   show_tag_headline: "Seiten mit dem Tag:"
   old_ccc_de: das alte ccc.de
+  event_schedule_time: "um %{time} Uhr"
+  event_schedule_unrecognized: "Termin-Regel nicht automatisch lesbar"
+  event_schedule_none: "Kein Termin"
   date:
     formats:
       default: "%d.%m.%Y"
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 2458d4d..93a0d55 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -8,6 +8,9 @@ en:
   hello: "Hello world"
   show_tag_headline: "Pages tagged with:"
   old_ccc_de: the old ccc.de
+  event_schedule_time: "at %{time}"
+  event_schedule_unrecognized: "Schedule not automatically readable"
+  event_schedule_none: "No schedule"
 
   time:
     formats:
diff --git a/test/models/concerns/rrule_humanizer_test.rb b/test/models/concerns/rrule_humanizer_test.rb
new file mode 100644
index 0000000..500dbc7
--- /dev/null
+++ b/test/models/concerns/rrule_humanizer_test.rb
@@ -0,0 +1,84 @@
+require 'test_helper'
+
+class RruleHumanizerTest < ActiveSupport::TestCase
+  def humanize(rrule, locale = :de)
+    Event.new(rrule: rrule).humanize_rrule(locale)
+  end
+
+  test "weekly single day" do
+    assert_equal "Jeden Dienstag", humanize("FREQ=WEEKLY;BYDAY=TU")
+    assert_equal "Every Tuesday", humanize("FREQ=WEEKLY;BYDAY=TU", :en)
+  end
+
+  test "weekly two days" do
+    assert_equal "Jeden Mittwoch und Freitag", humanize("FREQ=WEEKLY;BYDAY=WE,FR")
+    assert_equal "Every Wednesday and Friday", humanize("FREQ=WEEKLY;BYDAY=WE,FR", :en)
+  end
+
+  test "weekly no byday" do
+    assert_equal "Wöchentlich", humanize("FREQ=WEEKLY")
+    assert_equal "Weekly", humanize("FREQ=WEEKLY", :en)
+  end
+
+  test "biweekly with day" do
+    assert_equal "Alle zwei Wochen donnerstags", humanize("FREQ=WEEKLY;INTERVAL=2;BYDAY=TH")
+    assert_equal "Every other Thursday", humanize("FREQ=WEEKLY;INTERVAL=2;BYDAY=TH", :en)
+  end
+
+  test "biweekly no day" do
+    assert_equal "Alle zwei Wochen", humanize("FREQ=WEEKLY;INTERVAL=2")
+    assert_equal "Every other week", humanize("FREQ=WEEKLY;INTERVAL=2", :en)
+  end
+
+  test "monthly nth weekday" do
+    assert_equal "Jeden ersten Dienstag im Monat", humanize("FREQ=MONTHLY;BYDAY=1TU")
+    assert_equal "Jeden zweiten Freitag im Monat", humanize("FREQ=MONTHLY;BYDAY=2FR")
+    assert_equal "Jeden dritten Sonntag im Monat", humanize("FREQ=MONTHLY;BYDAY=3SU")
+    assert_equal "Jeden letzten Mittwoch im Monat", humanize("FREQ=MONTHLY;BYDAY=-1WE")
+  end
+
+  test "monthly nth weekday english" do
+    assert_equal "Every first Tuesday of the month", humanize("FREQ=MONTHLY;BYDAY=1TU", :en)
+    assert_equal "Every last Wednesday of the month", humanize("FREQ=MONTHLY;BYDAY=-1WE", :en)
+  end
+
+  test "monthly second-to-last" do
+    assert_equal "Jeden vorletzten Donnerstag im Monat", humanize("FREQ=MONTHLY;BYDAY=-2TH")
+    assert_equal "Every second-to-last Thursday of the month", humanize("FREQ=MONTHLY;BYDAY=-2TH", :en)
+  end
+
+  test "monthly no byday" do
+    assert_equal "Monatlich", humanize("FREQ=MONTHLY")
+    assert_equal "Monthly", humanize("FREQ=MONTHLY", :en)
+  end
+
+  test "monthly with single excluded month" do
+    assert_equal "Jeden letzten Donnerstag im Monat, außer im Dezember",
+      humanize("FREQ=MONTHLY;BYDAY=-1TH;BYMONTH=1,2,3,4,5,6,7,8,9,10,11")
+    assert_equal "Every last Thursday of the month, except in December",
+      humanize("FREQ=MONTHLY;BYDAY=-1TH;BYMONTH=1,2,3,4,5,6,7,8,9,10,11", :en)
+  end
+
+  test "monthly excluding january" do
+    assert_equal "Jeden zweiten Mittwoch im Monat, außer im Januar",
+      humanize("FREQ=MONTHLY;BYMONTH=2,3,4,5,6,7,8,9,10,11,12;BYDAY=2WE")
+  end
+
+  test "blank rrule returns nil" do
+    assert_nil humanize(nil)
+    assert_nil humanize("")
+  end
+
+  test "count and until are not guessed at" do
+    assert_nil humanize("FREQ=MONTHLY;BYDAY=1WE;COUNT=36")
+    assert_nil humanize("FREQ=MONTHLY;BYDAY=1WE;UNTIL=20050105T222222Z")
+  end
+
+  test "unrecognized freq returns nil" do
+    assert_nil humanize("FREQ=YEARLY;BYMONTH=12")
+  end
+
+  test "falls back to english for unknown locale" do
+    assert_equal "Every Tuesday", humanize("FREQ=WEEKLY;BYDAY=TU", :fr)
+  end
+end