Some gross optimization of the post index display

app/controllers/posts_controller.rb

@@ -11,7 +11,7 @@ class PostsController < ApplicationController
       end
     else
       @post_set = PostSets::Post.new(tag_query, params[:page], params[:limit], raw: params[:raw], random: params[:random], format: params[:format], read_only: params[:ro])
-      @posts = @post_set.posts
+      @posts = PostsDecorator.decorate_collection(@post_set.posts)
       respond_with(@posts) do |format|
         format.atom
       end

app/decorators/posts_decorator.rb

@@ -0,0 +1,166 @@
+class PostsDecorator < ApplicationDecorator
+  def self.collection_decorator_class
+    PaginatedDecorator
+  end
+
+  delegate_all
+
+  def preview_class(options)
+    post = object
+    klass = ["post-preview", "captioned"]
+    # Always captioned with new post stats section.
+    # klass << "captioned" if pool || size || similarity
+    klass << "post-status-pending" if post.is_pending?
+    klass << "post-status-flagged" if post.is_flagged?
+    klass << "post-status-deleted" if post.is_deleted?
+    klass << "post-status-has-parent" if post.parent_id
+    klass << "post-status-has-children" if post.has_visible_children?
+    klass << "post-pos-score" if post.score >= 3
+    klass << "post-neg-score" if post.score <= -3
+    klass << "post-rating-safe" if post.rating == 's'
+    klass << "post-rating-questionable" if post.rating == 'q'
+    klass << "post-rating-explicit" if post.rating == 'e'
+    klass << "post-no-blacklist" if options[:no_blacklist]
+    klass
+  end
+
+  def data_attributes
+    post = object
+    attributes = {
+        "data-id" => post.id,
+        "data-has-sound" => post.has_tag?('video_with_sound|flash_with_sound'),
+        "data-tags" => post.tag_string,
+        "data-rating" => post.rating,
+        "data-flags" => post.status_flags,
+        "data-uploader-id" => post.uploader_id,
+        "data-uploader" => post.uploader_name
+    }
+
+    if post.visible?
+      attributes["data-file-url"] = post.file_url
+      attributes["data-large-file-url"] = post.large_file_url
+      attributes["data-preview-file-url"] = post.preview_file_url
+    end
+
+    attributes
+  end
+
+  def cropped_url(options)
+    cropped_url = if Danbooru.config.enable_image_cropping && options[:show_cropped] && object.has_cropped? && !CurrentUser.user.disable_cropped_thumbnails?
+                    object.crop_file_url
+                  else
+                    object.preview_file_url
+                  end
+
+    cropped_url = Danbooru.config.deleted_preview_url if object.deleteblocked?
+    cropped_url
+  end
+
+  def score_class(score)
+    return 'score-neutral' if score == 0
+    score > 0 ? 'score-positive' : 'score-negative'
+  end
+
+  def stats_section(t)
+    post = object
+    status_flags = []
+    status_flags << 'P' if post.parent_id
+    status_flags << 'C' if post.has_children?
+    status_flags << 'U' if post.is_pending?
+    status_flags << 'F' if post.is_flagged?
+
+    post_score_icon = "#{"&uarr;" if post.score > 0}#{"&darr;" if post.score < 0}#{"&varr;" if post.score == 0}"
+    score = t.tag.span("#{post_score_icon}#{post.score}".html_safe, class: "post-score-score " + score_class(post.score))
+    favs =  t.tag.span("&hearts;#{post.fav_count}".html_safe, class: 'post-score-faves')
+    comments = t.tag.span "C#{post.comment_count}", class: 'post-score-comments'
+    rating =  t.tag.span(post.rating.upcase, class: "post-score-rating")
+    status = t.tag.span(status_flags.join(''), class: 'post-score-extras')
+    t.tag.div score + favs + comments + rating + status, class: 'post-score', id: "post-score-#{post.id}"
+  end
+
+  def preview_html(t, options = {})
+    post = object
+    if post.nil?
+      return "<em>none</em>".html_safe
+    end
+
+    if !options[:show_deleted] && post.is_deleted? && options[:tags] !~ /(?:status:(?:all|any|deleted))|(?:deletedby:)|(?:delreason:)/ && !options[:raw]
+      return ""
+    end
+
+    if post.loginblocked? || post.safeblocked?
+      return ""
+    end
+
+    if post.is_ugoira? && !post.has_ugoira_webm?
+      # ugoira preview gen is async so dont render it immediately
+      return ""
+    end
+
+    options[:stats] |= !options[:avatar] && !options[:inline]
+
+    article_attrs = {
+        "id" => "post_#{post.id}",
+        "class" => preview_class(options).join(" ")
+    }.merge(data_attributes)
+
+    link_target = options[:link_target] || post
+
+    link_params = {}
+    if options[:tags].present?
+      link_params["q"] = options[:tags]
+    end
+    if options[:pool_id]
+      link_params["pool_id"] = options[:pool_id]
+    end
+    if options[:post_set_id]
+      link_params["post_set_id"] = options[:post_set_id]
+    end
+
+    tooltip = "Rating: #{post.rating}\nID: #{post.id}\nDate: #{post.created_at}\nStatus: #{post.status}\nScore: #{post.score}\n\n#{post.tag_string}"
+
+    cropped_url = if Danbooru.config.enable_image_cropping && options[:show_cropped] && post.has_cropped? && !CurrentUser.user.disable_cropped_thumbnails?
+                             post.crop_file_url
+                           else
+                             post.preview_file_url
+                           end
+
+    cropped_url = Danbooru.config.deleted_preview_url if post.deleteblocked?
+    preview_url = if post.deleteblocked?
+                             Danbooru.config.deleted_preview_url
+                           else
+                             post.preview_file_url
+                           end
+
+    alt_text = post.tag_string
+
+    has_cropped = post.has_cropped?
+
+    pool = options[:pool]
+
+    width = post.image_width
+    height = post.image_height
+
+    similarity = options[:similarity]&.round
+
+    size = options[:size] ? post.file_size : nil
+
+    img_contents = t.link_to t.polymorphic_path(link_target, link_params) do
+      t.content_tag(:picture) do
+        t.concat t.tag.source media: "(max-width: 800px)", srcset: cropped_url
+        t.concat t.tag.source media: "(min-width: 800px)", srcset: preview_url
+        t.concat t.tag.img class: "has-cropped-#{has_cropped}", src: preview_url, title: tooltip, alt: alt_text
+      end
+    end
+    desc_contents = if options[:stats] || pool || similarity || size
+                      t.tag.div class: "desc" do
+                        stats_section(t) if options[:stats]
+                      end
+                    else
+                      "".html_safe
+                    end
+    t.content_tag(:article, nil, article_attrs) do
+      img_contents + desc_contents
+    end
+  end
+end

app/views/posts/partials/index/_posts.html.erb

@@ -1,6 +1,12 @@
 <div id="posts" class="user-disable-cropped-<%= Danbooru.config.enable_image_cropping && CurrentUser.user.disable_cropped_thumbnails? %>">
   <div id="posts-container">
-    <%= post_set.presenter.post_previews_html(self) %>
+    <% if @posts.empty? %>
+      <%= render "posts/blank" %>
+    <% else %>
+      <% @posts.each do |post| %>
+        <%= post.preview_html(self, {tags: @post_set.public_tag_string, raw: @post_set.raw, show_cropped: true}) %>
+      <% end %>
+    <% end %>
   </div>
 
   <% if post_set.hidden_posts.present? %>