Add book tagging mechanism

Author: opatry

Rules

@@ -35,6 +35,8 @@ preprocess do
     item.identifier =~ '/cover/*' && ignored_isbns.include?(item.identifier.without_exts.delete_prefix('/cover/'))
   end
 
+  generate_tag_items
+
   missing_covers = 0
 
   @items.select { |item| item.identifier =~ '/index.*' || book?(item) }.each do |item|
@@ -150,7 +152,6 @@ end
 %i[mini medium default].each do |repr|
   compile '/cover/**/*', rep: repr do
     isbn = item.identifier.without_exts.split('/')[-1]
-    next if repr == :medium && !@config[:last_readings_isbn].include?(isbn)
 
     width = @config[:cover][:width][repr]
     filter :thumbnailize, width: width unless @config[:dev]
@@ -174,7 +175,6 @@ compile '/book/**/*', rep: :feed do
 end
 
 compile '/book/**/*', rep: :card do
-  next unless @config[:last_readings_isbn].include?(item[:isbn])
   filter :erb
   # no need to apply kramdown, book_card only uses book metadata, not content
   filter :html_compressor, type: item[:extension] unless @config[:dev]
@@ -197,6 +197,17 @@ compile '/book/**/*' do
   write item.identifier.without_ext + '/index.html'
 end
 
+compile '/tag/*' do
+  filter :erb
+  filter :kramdown
+  filter :html_compressor, type: item[:extension] unless @config[:dev]
+
+  layout '/tag.*'
+  layout '/default.*'
+
+  write "#{item.identifier.without_exts}.html"
+end
+
 compile '/api/v1/*' do
   filter :erb
   layout item[:layout] unless item[:layout] == 'none'
@@ -257,6 +268,10 @@ route '/last-readings.*' do
   "/last-readings.html"
 end
 
+route '/all-tags.*' do
+  "/tag/index.html"
+end
+
 route '/index-noscript.*' do
   "/index-noscript.html"
 end

content/all-tags.html.erb

@@ -0,0 +1,22 @@
+---
+title: Les étiquettes
+layout: default
+---
+
+<h2>Toutes les étiquettes</h2>
+<%
+tags = tag_cloud
+if tags.empty?
+%>
+<p>Aucune étiquette n'a été associée à aucun livre.</p>
+<% else %>
+<ul class="tag-cloud">
+<% tags.each do |tag, tag_weight, books_count| %>
+  <li>
+    <span class="tag_<%= tag_weight %>">
+      <a href="<%= @items[tag_item_identifier(tag)].path %>"><span class="tag"><%= tag %></span></a>&nbsp;<span class="tag-weight">(<%= books_count %>)</span>
+    </span>
+  </li>
+<% end %>
+</ul>
+<% end %>

content/static/style.css

@@ -541,3 +541,78 @@ blockquote::before {
 #only-favorites:target .temporal-section:not(:has(.book-favorite)) {
   display: none;
 }
+
+.tag-cloud {
+  margin: 0 auto;
+  padding: 0;
+  text-align: center;
+}
+
+.tag-cloud li::before {
+  content: none;
+}
+
+.tag-cloud li {
+  display: inline;
+  margin: 0;
+  padding: 1em;
+  line-height: 3em;
+}
+
+.tag-weight {
+  font-size: .6em;
+  color: rgba(0, 0, 0, .7);
+}
+
+@media (prefers-color-scheme: dark) {
+  .tag-weight {
+    color: rgba(255, 255, 255, .7);
+  }
+}
+
+.tag-cloud a {
+  text-decoration: none;
+}
+
+.tag {
+  white-space: nowrap;
+}
+
+.tag_0 { font-size: .7em; font-weight: 100; }
+.tag_1 { font-size: .9em; font-weight: 100; }
+.tag_2 { font-size: 1.1em; font-weight: 200; }
+.tag_3 { font-size: 1.3em; font-weight: 300; }
+.tag_4 { font-size: 1.5em; font-weight: 400; }
+.tag_5 { font-size: 1.7em; font-weight: 500; }
+.tag_6 { font-size: 1.9em; font-weight: 600; }
+.tag_7 { font-size: 2.1em; font-weight: 700; }
+.tag_8 { font-size: 2.4em; font-weight: 800; }
+.tag_9 { font-size: 2.6em; font-weight: 900; }
+.tag_10 { font-size: 2.6em; font-weight: 900; }
+
+.book-tags {
+  margin: 0;
+}
+
+.book-tags li {
+  display: inline-block;
+  margin: 0 2px;
+}
+
+.book-tags li a {
+  border-radius: 4px;
+  border: 1px solid rgba(0, 0, 0, .3);
+  padding: 2px 4px;
+  font-family: sans-serif;
+  font-size: 0.7em;
+  text-transform: lowercase;
+  background-color: rgba(0, 0, 0, .05);
+  transition: background-color .6s ease;
+}
+.book-tags li a:hover {
+  background-color: rgba(0, 0, 0, .15);
+}
+
+.book-tags li::before {
+  content: none;
+}

fetch_book.sh

@@ -175,6 +175,8 @@ title: \"${title}\"
 author: \"${author}\"
 rating: ${rating}
 read_date: $(date "+%Y-%m-%d") # TBD
+tags:
+  - TBD
 ---
 
 ${description}

layouts/book.html.erb

@@ -25,7 +25,16 @@ unless @items["/cover/#{@item[:isbn]}.*"].nil?
 
 <%= yield  %>
 
-<div style="clear: left;"></div>
+<div style="clear: left; margin-bottom: 1em;"></div>
+
+<% unless @item[:tags].nil? || @item[:tags].empty? %>
+<ul class="book-tags">
+  <li><span title="Étiquettes">🏷️</span></li>
+  <% @item[:tags].each do |tag| %>
+  <li><%= link_to_tag(tag) %></li>
+  <% end %>
+</ul>
+<% end %>
 
 <%
 linked_books = @item.fetch(:linked_books, []).map do |isbn|

layouts/head_book.html.erb

@@ -2,6 +2,11 @@
   <meta property="book:author" content="<%= @item[:author] %>" />
   <meta property="book:isbn" content="<%= format_isbn(@item[:isbn]) %>" />
   <%# <meta property="book:release_date" content="TODO" /> %>
+<% unless @item[:tags].nil? %>
+<% @item[:tags].each do |tag| %>
+  <meta property="book:tag" content="<%= tag %>">
+<% end %>
+<% end %>
 <%
   picture = @items["/cover/#{@item[:isbn]}.*"]
   unless picture.nil?

layouts/tag.html.erb

@@ -0,0 +1,13 @@
+<h2>Les livres étiquettés "<%= @item[:title] %>" <span class="title-more"><%= link_to('🏷️ Toutes les étiquettes', @items['/all-tags.*']) %></a></h2>
+<% if @item[:books].nil? || @item[:books].empty? %>
+<%= yield %>
+<% else %>
+<div class="book-grid">
+<%
+@item[:books].each do |book_identifier|
+  book = @items[book_identifier]
+%>
+  <%= book.reps[:card].compiled_content(snapshot: :card) %>
+<% end %>
+</div>
+<% end %>

lib/helpers.rb

@@ -6,6 +6,7 @@
 require 'cgi'
 
 use_helper Nanoc::Helpers::Rendering
+use_helper Nanoc::Helpers::LinkTo
 
 def h(text)
   CGI.escapeHTML(text.nil? ? '' : text)
@@ -28,6 +29,7 @@ def to_json(book, url: :relative)
     'favorite': book[:favorite] || false,
     'cover': "#{url_prefix}#{cover_path}" || '',
     'cover_mini': "#{url_prefix}#{cover_mini_path}" || '',
+    'tags': book[:tags] || []
   }
 end
 
@@ -151,4 +153,70 @@ def recent_books()
 
 def feed_books()
   last_readings(@config[:site][:feed][:max_entries])
+end
+
+def all_tags
+  tags = {}
+  @items.each do |item|
+    next if item[:tags].nil? || item[:tags].empty? || !item[:tag].nil?
+
+    item[:tags].each do |tag|
+      tags[tag] = [] if tags[tag].nil?
+      tags[tag] << item unless tags[tag].include? item
+    end
+  end
+  # tags.each do |tag, _|
+  #   tags[tag] = tags[tag].sort_by { |item| Date.parse(item[:datetime].to_s) }.reverse
+  # end
+  tags
+end
+
+def tag_cloud
+  # sort on hash sort by key which is what we want
+  tags = all_tags.sort
+  result = []
+  return result if tags.empty?
+  # tag_<weight> goes from tag_0 to tag_10, map tag weight value to [0,10]
+  max = tags.max_by { |_, v| v.size }[1].size
+  min = tags.min_by { |_, v| v.size }[1].size
+  tags.each do |tag, posts|
+    posts_count = posts.size
+    tag_weight = (((posts_count - min) * 10.0) / max).round
+    result << [tag, tag_weight, posts_count]
+  end
+  result
+end
+
+def tag_slug(tag)
+  I18n.transliterate(tag.downcase).gsub(/\W/, '-').gsub(/-+/, '-').strip
+end
+
+def tag_item_identifier(tag)
+  "/tag/#{tag_slug(tag)}.*"
+end
+
+def link_to_tag(tag)
+  tag_item = @items[tag_item_identifier(tag)]
+  link_to(tag_item[:title], tag_item)
+end
+
+def generate_tag_items
+  all_tags.each do |tag, books|
+    # item's content is used as fallback when no post can be found.
+    @items.create("
+Aucun livre n'est étiquetté avec \"<%= @item[:title] %>\".
+
+Voir la liste des <%= link_to('autres étiquettes', @items['/all-tags.*']) %>.
+      ", {
+        title: tag,
+        tag: tag_slug(tag),
+        layout: 'tags',
+        # can't store item ref, from the preprocess block, the item view isn't suitable for future use
+        # such as compiled_content, path, reps and so on.
+        # only store identifier and request item from identifier at call site
+        books: natural_sort(books).map { |p| p.identifier.to_s },
+        extension: 'md'
+      }, Nanoc::Identifier.new(tag_item_identifier(tag))
+    )
+  end
 end