Make headline images explicit, add asset credits

- related_assets gains a `headline` boolean (DB-enforced: at most one
  per page), replacing "first image by position" as the headline
  rule. A rake task backfills the current first image on every live
  head/draft, so nothing changes visually until an editor changes it.
- The image picker sidebar gets a star toggle reflecting the flag;
  the TinyMCE inline-image picker's badge now reads it too, instead
  of assuming position 0.
- No headline chosen (or none attached) now falls back to the
  gallery-count caption itself becoming the lightbox trigger, instead
  of the gallery being unreachable.
- Assets gain creator, source_url, and license_key (against a new
  config/asset_licenses.yml dictionary). asset_credit renders a
  degrading attribution line, reused as a hidden per-image glightbox
  caption so credit is one click away for every image, not only the
  headline's always-visible one.
- Fixed: asset thumbnails rendered unconditionally regardless of
  whether a real variant exists on disk. Asset#has_variant? checks
  file existence, not content type -- some legacy PDFs have real
  pre-rewrite thumbnails a content-type check would have hidden.
- assets#new/edit rebuilt onto the same node_description/node_content
  layout as assets#show, picking up the three new fields in the
  process.

20 files changed, 228 insertions, 56 deletions

diff --git a/app/controllers/assets_controller.rb b/app/controllers/assets_controller.rb
index d150e06..becfe13 100644
--- a/app/controllers/assets_controller.rb
+++ b/app/controllers/assets_controller.rb
@@ -89,6 +89,6 @@ class AssetsController < ApplicationController
   private
 
     def asset_params
-      params.require(:asset).permit(:name, :upload)
+      params.require(:asset).permit(:name, :upload, :creator, :source_url, :license_key)
     end
 end
diff --git a/app/controllers/related_assets_controller.rb b/app/controllers/related_assets_controller.rb
index 5af73fc..da82cde 100644
--- a/app/controllers/related_assets_controller.rb
+++ b/app/controllers/related_assets_controller.rb
@@ -39,7 +39,17 @@ class RelatedAssetsController < ApplicationController
   end
 
   def update
-    @node.editable_page.related_assets.find(params[:id]).insert_at(params[:position].to_i)
+    related = @node.editable_page.related_assets.find(params[:id])
+
+    if params.key?(:headline)
+      RelatedAsset.transaction do
+        @node.editable_page.related_assets.update_all(headline: false)
+        related.update!(headline: true) if params[:headline] == "true"
+      end
+    else
+      related.insert_at(params[:position].to_i)
+    end
+
     head :ok
   end
 
diff --git a/app/helpers/content_helper.rb b/app/helpers/content_helper.rb
index 5810966..5b67259 100644
--- a/app/helpers/content_helper.rb
+++ b/app/helpers/content_helper.rb
@@ -53,11 +53,8 @@ module ContentHelper
   end
 
   def headline_image
-    @images = @page.assets.images
-
-    unless @images.empty?
-      render :partial => 'content/headline_image'
-    end
+    @headline_asset = @page.related_assets.find_by(headline: true)&.asset
+    render :partial => 'content/headline_image' if @headline_asset || @page.assets.images.any?
   end
 
   # Returns the published_at attribute of a page if it is not nil, otherwise
@@ -154,4 +151,26 @@ module ContentHelper
     )
   end
 
+  def asset_credit(asset)
+    return nil unless asset
+    return nil if asset.creator.blank? && asset.source_url.blank? && asset.license_key.blank?
+
+    license = AssetLicense.find(asset.license_key)
+
+    photo_label = t("asset_credits.photo", name: asset.name)
+    photo = asset.source_url.present? ? link_to(photo_label, asset.source_url) : photo_label
+
+    attribution_parts = [photo]
+    attribution_parts << t("asset_credits.by", creator: asset.creator) if asset.creator.present?
+    attribution = safe_join(attribution_parts, " ")
+
+    license_text = if license
+      name = t("asset_licenses.#{license.key}", default: license.key)
+      phrase = license.style == "license" ? t("asset_credits.licensed_under", license: name) : name
+      license.url.present? ? link_to(phrase, license.url) : phrase
+    end
+
+    full = license_text ? safe_join([attribution, license_text], ", ") : attribution
+    safe_join([full, "."])
+  end
 end
diff --git a/app/models/asset.rb b/app/models/asset.rb
index aca0ee8..8bea1b3 100644
--- a/app/models/asset.rb
+++ b/app/models/asset.rb
@@ -1,12 +1,18 @@
 class Asset < ApplicationRecord
+  IMAGE_CONTENT_TYPES = ["image/gif", "image/jpeg", "image/png", "image/webp"]
 
   include FileAttachment
   
   has_many :related_assets, :dependent => :destroy
   has_many :pages, :through => :related_assets
 
-  scope :images,    -> { where(:upload_content_type => ["image/gif", "image/jpeg", "image/png", "image/webp"]) }
+  scope :images,    -> { where(:upload_content_type => IMAGE_CONTENT_TYPES) }
   scope :documents, -> { where(:upload_content_type => ["application/pdf", "text/plain", "text/rtf"]) }
   scope :audio,     -> { where(:upload_content_type => ["audio/mpeg", "audio/x-m4a", "audio/wav", "audio/x-wav"]) }
 
+  validates :license_key, inclusion: { in: -> { AssetLicense.keys } }, allow_blank: true
+
+  def image?
+    IMAGE_CONTENT_TYPES.include?(upload_content_type)
+  end
 end
diff --git a/app/models/asset_license.rb b/app/models/asset_license.rb
new file mode 100644
index 0000000..ca66d40
--- /dev/null
+++ b/app/models/asset_license.rb
@@ -0,0 +1,15 @@
+class AssetLicense
+  Entry = Struct.new(:key, :url, :requires_attribution, :style, keyword_init: true)
+
+  DICTIONARY = YAML.load_file(Rails.root.join("config", "asset_licenses.yml")).freeze
+
+  def self.keys
+    DICTIONARY.keys
+  end
+
+  def self.find(key)
+    entry = DICTIONARY[key.to_s] if key.present?
+    return nil unless entry
+    Entry.new(key: key.to_s, url: entry["url"], requires_attribution: entry["requires_attribution"], style: entry["style"])
+  end
+end
diff --git a/app/models/concerns/file_attachment.rb b/app/models/concerns/file_attachment.rb
index 3c09456..e7a33c5 100644
--- a/app/models/concerns/file_attachment.rb
+++ b/app/models/concerns/file_attachment.rb
@@ -52,6 +52,14 @@ module FileAttachment
     build_upload_proxy
   end
 
+  def has_variant?(style)
+    upload_file_name.present? && File.exist?(file_path(style))
+  end
+
+  def previewable?
+    has_variant?(:medium)
+  end
+
   private
 
   def build_upload_proxy
diff --git a/app/models/related_asset.rb b/app/models/related_asset.rb
index 8f16460..62000cc 100644
--- a/app/models/related_asset.rb
+++ b/app/models/related_asset.rb
@@ -5,4 +5,13 @@ class RelatedAsset < ApplicationRecord
   acts_as_list :scope => :page_id
 
   default_scope -> { order("position ASC") }
+
+  validate :headline_only_for_images
+
+  private
+
+    def headline_only_for_images
+      return unless asset
+      errors.add(:headline, "can only be set on image assets") if headline? && !asset.image?
+    end
 end
diff --git a/app/views/assets/edit.html.erb b/app/views/assets/edit.html.erb
index f198600..3ef8fea 100644
--- a/app/views/assets/edit.html.erb
+++ b/app/views/assets/edit.html.erb
@@ -1,24 +1,44 @@
-<h1>Editing asset</h1>
+<div id="page_editor">
+  <h1>Editing asset</h1>
 
-<%= form_for(@asset, html: { multipart: true }) do |f| %>
-  <%= form_error_messages(f) %>
+  <%= form_for(@asset, html: { multipart: true }) do |f| %>
+    <%= form_error_messages(f) %>
 
-  <% if @asset.upload.present? %>
-    <p>
-      <strong>Current file:</strong>
-      <%= @asset.upload.url %>
-      (<%= number_to_human_size(@asset.upload.size) %>)
-    </p>
-  <% end %>
+    <div id="content">
+      <div class="node_description"><%= f.label :name %></div>
+      <div class="node_content"><%= f.text_field :name %></div>
+
+      <% if @asset.upload.present? %>
+        <div class="node_description">Current File</div>
+        <div class="node_content"><%= @asset.upload.url %> (<%= number_to_human_size(@asset.upload.size) %>)</div>
+      <% end %>
+
+      <div class="node_description"><%= f.label :upload, "Replace file" %></div>
+      <div class="node_content"><%= f.file_field :upload %></div>
 
-  <p>
-    <label>Replace file:</label><br>
-    <%= f.file_field :upload %>
-  </p>
+      <div class="node_description"><%= f.label :creator %></div>
+      <div class="node_content"><%= f.text_field :creator %></div>
 
-  <p>
-    <%= f.submit 'Update' %>
-  </p>
-<% end %>
+      <div class="node_description"><%= f.label :source_url, "Source URL" %></div>
+      <div class="node_content"><%= f.text_field :source_url %></div>
 
-<%= link_to 'Show', @asset %> | <%= link_to 'Back', assets_path %>
+      <div class="node_description"><%= f.label :license_key, "License" %></div>
+      <div class="node_content">
+        <%= f.select :license_key,
+              options_for_select(
+                [["— none —", ""]] + AssetLicense.keys.map { |key| [t("asset_licenses.#{key}"), key] },
+                @asset.license_key
+              ) %>
+      </div>
+
+      <div class="node_description">Actions</div>
+      <div class="node_content node_info_group">
+        <div class="node_info_group_items">
+          <div class="node_info_item"><%= f.submit 'Update' %></div>
+          <div class="node_info_item"><%= link_to 'Show', @asset %></div>
+          <div class="node_info_item"><%= link_to 'Back', assets_path %></div>
+        </div>
+      </div>
+    </div>
+  <% end %>
+</div>
diff --git a/app/views/assets/index.html.erb b/app/views/assets/index.html.erb
index 8c35561..ff1300a 100644
--- a/app/views/assets/index.html.erb
+++ b/app/views/assets/index.html.erb
@@ -17,7 +17,7 @@
   </tr>
 <% @assets.each do |asset| %>
   <tr>
-    <td><%= image_tag asset.upload.url(:thumb), style: "max-width: 100px; max-height: 100px;" %></td>
+    <td><% if asset.has_variant?(:thumb) %><%= image_tag asset.upload.url(:thumb), style: "max-width: 100px; max-height: 100px;" %><% end %></td>
     <td><%= link_to asset.name, asset.upload.url %></td>
     <td><%= asset.upload.content_type %></td>
     <td><%= link_to 'Show', asset %></td>
diff --git a/app/views/assets/new.html.erb b/app/views/assets/new.html.erb
index 6c1310a..2cf8865 100644
--- a/app/views/assets/new.html.erb
+++ b/app/views/assets/new.html.erb
@@ -1,17 +1,38 @@
-<h1>New asset</h1>
+<div id="page_editor">
+  <h1>New asset</h1>
 
-<%= form_for(@asset, :html => { :multipart => true }) do |f| %>
-  <%= form_error_messages(f) %>
-  
-  <p>
-    <%= f.label :name %><br />
-    <%= f.text_field :name %>
-  </p>
+  <%= form_for(@asset, :html => { :multipart => true }) do |f| %>
+    <%= form_error_messages(f) %>
 
-  <p>
-    <%= f.file_field :upload %>
-    <%= f.submit 'Create' %>
-  </p>
-<% end %>
+    <div id="content">
+      <div class="node_description"><%= f.label :name %></div>
+      <div class="node_content"><%= f.text_field :name %></div>
 
-<%= link_to 'Back', assets_path %>
+      <div class="node_description"><%= f.label :upload, "File" %></div>
+      <div class="node_content"><%= f.file_field :upload %></div>
+
+      <div class="node_description"><%= f.label :creator %></div>
+      <div class="node_content"><%= f.text_field :creator %></div>
+
+      <div class="node_description"><%= f.label :source_url, "Source URL" %></div>
+      <div class="node_content"><%= f.text_field :source_url %></div>
+
+      <div class="node_description"><%= f.label :license_key, "License" %></div>
+      <div class="node_content">
+        <%= f.select :license_key,
+              options_for_select(
+                [["— none —", ""]] + AssetLicense.keys.map { |key| [t("asset_licenses.#{key}"), key] },
+                @asset.license_key
+              ) %>
+      </div>
+
+      <div class="node_description">Actions</div>
+      <div class="node_content node_info_group">
+        <div class="node_info_group_items">
+          <div class="node_info_item"><%= f.submit 'Create' %></div>
+          <div class="node_info_item"><%= link_to 'Back', assets_path %></div>
+        </div>
+      </div>
+    </div>
+  <% end %>
+</div>
diff --git a/app/views/assets/show.html.erb b/app/views/assets/show.html.erb
index ff00883..a0e4e46 100644
--- a/app/views/assets/show.html.erb
+++ b/app/views/assets/show.html.erb
@@ -17,7 +17,10 @@
     </div>
 
     <div class="node_description">Thumbnail</div>
-    <div class="node_content"><%= image_tag @asset.upload.url(:medium), style: "max-width: 300px; max-height: 300px;" %></div>
+    <% if @asset.has_variant?(:medium) %>
+      <div class="node_description">Thumbnail</div>
+      <div class="node_content"><%= image_tag @asset.upload.url(:medium), style: "max-width: 300px; max-height: 300px;" %></div>
+    <% end %>
 
     <div class="node_description">Public Path</div>
     <div class="node_content">
@@ -30,6 +33,27 @@
       </button>
     </div>
 
+    <div class="node_description">Creator</div>
+    <div class="node_content"><%= @asset.creator.presence || "—" %></div>
+
+    <div class="node_description">Source</div>
+    <div class="node_content">
+      <% if @asset.source_url.present? %>
+        <%= link_to @asset.source_url, @asset.source_url %>
+      <% else %>
+        —
+      <% end %>
+    </div>
+
+    <div class="node_description">License</div>
+    <div class="node_content">
+      <% if (license = AssetLicense.find(@asset.license_key)) %>
+        <%= t("asset_licenses.#{license.key}") %>
+      <% else %>
+        —
+      <% end %>
+    </div>
+
     <div class="node_description">Content Type</div>
     <div class="node_content"><%= @asset.upload.content_type %></div>
 
diff --git a/app/views/content/_asset_credits.html.erb b/app/views/content/_asset_credits.html.erb
new file mode 100644
index 0000000..85739d0
--- /dev/null
+++ b/app/views/content/_asset_credits.html.erb
@@ -0,0 +1,12 @@
+<% if @page.assets.images.any? %>
+  <div id="asset_credits">
+    <% @page.assets.images.each do |image| %>
+      <% credit = asset_credit(image) %>
+      <% next unless credit %>
+      <div id="credit_for_asset_<%= image.id %>"
+           class="glightbox-desc<%= " headline_credit" if image == @headline_asset %>">
+        <%= credit %>
+      </div>
+    <% end %>
+  </div>
+<% end %>
diff --git a/app/views/content/_headline_image.html.erb b/app/views/content/_headline_image.html.erb
index 243be40..c764d22 100644
--- a/app/views/content/_headline_image.html.erb
+++ b/app/views/content/_headline_image.html.erb
@@ -1,16 +1,28 @@
-<%= link_to(
-  image_tag(@images[0].upload.url(:headline)),
-  @images[0].upload.url,
-  :class => "glightbox",
-  :data  => { :gallery => "page-#{@page.node.id}" }
-) %>
+<% gallery_images = @page.assets.images %>
 
-<% if 1 < @images.length %>
-  <div class="right">
-    <%= "#{@images.length} #{t(:images)}" %>
-  </div>
+<% if @headline_asset %>
+  <%= link_to(
+    image_tag(@headline_asset.upload.url(:headline)),
+    @headline_asset.upload.url,
+    :class => "glightbox",
+    :data  => { :gallery => "page-#{@page.node.id}", :title => @headline_asset.name,
+                :description => "#credit_for_asset_#{@headline_asset.id}" }
+  ) %>
+  <% if gallery_images.size > 1 %>
+    <div class="right"><%= "#{gallery_images.size} #{t(:images)}" %></div>
+  <% end %>
+<% elsif gallery_images.any? %>
+  <%= link_to "#{gallery_images.size} #{t(:images)}, #{t(:open_gallery)}",
+        gallery_images.first.upload.url,
+        :class => "glightbox right",
+        :data  => { :gallery => "page-#{@page.node.id}", :title => gallery_images.first.name,
+                    :description => "#credit_for_asset_#{gallery_images.first.id}" } %>
 <% end %>
 
-<% @images[1..-1].each do |image| %>
-  <%= link_to "", image.upload.url, :class => "glightbox", :style => "display: none", :data => { :gallery => "page-#{@page.node.id}" } %>
+<% gallery_images.each do |image| %>
+  <% next if image == @headline_asset %>
+  <% next if !@headline_asset && image == gallery_images.first %>
+  <%= link_to "", image.upload.url, :class => "glightbox", :style => "display: none",
+        :data => { :gallery => "page-#{@page.node.id}", :title => image.name,
+                   :description => "#credit_for_asset_#{image.id}" } %>
 <% end %>
diff --git a/app/views/custom/page_templates/public/chapter_detail.html.erb b/app/views/custom/page_templates/public/chapter_detail.html.erb
index c4c2598..18449b8 100644
--- a/app/views/custom/page_templates/public/chapter_detail.html.erb
+++ b/app/views/custom/page_templates/public/chapter_detail.html.erb
@@ -31,4 +31,5 @@
       </ul>
     </div>
   <% end %>
+  <%= render partial: 'content/asset_credits' %>
 </div>
diff --git a/app/views/custom/page_templates/public/no_date_and_author.html.erb b/app/views/custom/page_templates/public/no_date_and_author.html.erb
index fa39e54..ec7e850 100644
--- a/app/views/custom/page_templates/public/no_date_and_author.html.erb
+++ b/app/views/custom/page_templates/public/no_date_and_author.html.erb
@@ -3,6 +3,7 @@
   <p><%= sanitize( @page.abstract ) %></p>
   <div id="headline_image"><%= headline_image %></div>
   <%= aggregate?(@page.body) %>
+  <%= render partial: 'content/asset_credits' %>
 </div>
 
 <%= will_paginate(@content_collection) if @content_collection %>
diff --git a/app/views/custom/page_templates/public/no_title_abstract_date_and_author.html.erb b/app/views/custom/page_templates/public/no_title_abstract_date_and_author.html.erb
index 64e2a7c..c486684 100644
--- a/app/views/custom/page_templates/public/no_title_abstract_date_and_author.html.erb
+++ b/app/views/custom/page_templates/public/no_title_abstract_date_and_author.html.erb
@@ -1,6 +1,7 @@
 <div class="article" lang="<%= @page.effective_lang %>">
   <div id="headline_image"><%= headline_image %></div>
   <%= aggregate?(@page.body) %>
+  <%= render partial: 'content/asset_credits' %>
 </div>
 
 <%= will_paginate(@content_collection) if @content_collection %>
diff --git a/app/views/custom/page_templates/public/standard_template.html.erb b/app/views/custom/page_templates/public/standard_template.html.erb
index bbc8cd0..e1e2eb0 100644
--- a/app/views/custom/page_templates/public/standard_template.html.erb
+++ b/app/views/custom/page_templates/public/standard_template.html.erb
@@ -3,6 +3,7 @@
   <div class="abstract"><p><%= sanitize( @page.abstract )%></p></div>
   <div id="headline_image"><%= headline_image %></div>
   <div class="body"><%= aggregate?(@page.body) %></div>
+  <%= render partial: 'content/asset_credits' %>
 </div>
 
 <%= will_paginate(@content_collection) if @content_collection %>
diff --git a/app/views/custom/page_templates/public/title_only.html.erb b/app/views/custom/page_templates/public/title_only.html.erb
index 42fe9a6..d706e9d 100644
--- a/app/views/custom/page_templates/public/title_only.html.erb
+++ b/app/views/custom/page_templates/public/title_only.html.erb
@@ -2,6 +2,7 @@
   <h2 class="headline"><%= @page.title %></h2>
   <div id="headline_image"><%= headline_image %></div>
   <%= aggregate?(@page.body) %>
+  <%= render partial: 'content/asset_credits' %>
 </div>
 
 <%= will_paginate(@content_collection) if @content_collection %>
diff --git a/app/views/custom/page_templates/public/update.html.erb b/app/views/custom/page_templates/public/update.html.erb
index d5995ac..0ff1bb2 100644
--- a/app/views/custom/page_templates/public/update.html.erb
+++ b/app/views/custom/page_templates/public/update.html.erb
@@ -4,6 +4,7 @@
   <div class="abstract"><p><%= sanitize( @page.abstract )%></p></div>
   <div id="headline_image"><%= headline_image %></div>
   <div class="body"><%= aggregate?(@page.body) %></div>
+  <%= render partial: 'content/asset_credits' %>
 </div>
 
 <%= will_paginate(@content_collection) if @content_collection %>
diff --git a/app/views/nodes/edit.html.erb b/app/views/nodes/edit.html.erb
index 25f15c2..2c1e975 100644
--- a/app/views/nodes/edit.html.erb
+++ b/app/views/nodes/edit.html.erb
@@ -82,11 +82,18 @@
           <ul id="related_asset_list" class="thumbnail_list">
             <% @page.related_assets.includes(:asset).each do |related| %>
               <li data-url="<%= node_related_asset_path(@node, related) %>"
+                  data-asset-id="<%= related.asset.id %>"
                   data-large-url="<%= related.asset.upload.url(:large) %>"
                   data-original-url="<%= related.asset.upload.url %>"
-                  data-name="<%= related.asset.name %>">
+                  data-name="<%= related.asset.name %>"
+                  data-headline="<%= related.headline? %>"
+                  class="<%= "is_headline" if related.headline? %>">
                 <span class="related_asset_handle"><%= icon("grip-vertical", library: "tabler", "aria-hidden": true) %></span>
                 <%= image_tag related.asset.upload.url(:thumb) %>
+                <button type="button" class="related_asset_set_headline"
+                        aria-pressed="<%= related.headline? %>" aria-label="Set as headline image">
+                  <%= icon("star", library: "tabler", "aria-hidden": true) %>
+                </button>
                 <button type="button" class="related_asset_remove" aria-label="Remove image">
                   <%= icon("x", library: "tabler", "aria-hidden": true) %>
                 </button>
@@ -102,6 +109,9 @@
         <li>
           <span class="related_asset_handle"><%= icon("grip-vertical", library: "tabler", "aria-hidden": true) %></span>
           <img src="">
+          <button type="button" class="related_asset_set_headline" aria-pressed="false" aria-label="Set as headline image">
+            <%= icon("star", library: "tabler", "aria-hidden": true) %>
+          </button>
           <button type="button" class="related_asset_remove" aria-label="Remove image">
             <%= icon("x", library: "tabler", "aria-hidden": true) %>
           </button>