posts: rework post events page.

* Add a global /post_events page that shows the history of all approvals,
  disapprovals, flags, appeals, and replacements on a single page.

* Redesign the /posts/:id/events page to show all approval, disapproval,
  flag, appeal, and replacement events for a single post (before it only
  showed approvals, flags, and appeals).

* Remove the replacement history link from the post show page. Replacements
  are now included in the post events page (closes #4948: Highlighed replacements).

* Add /post_approvals/:id and /post_replacements/:id routes (these are
  used by the "Details" link on the post events page).

app/controllers/post_approvals_controller.rb

@@ -15,4 +15,12 @@ class PostApprovalsController < ApplicationController
 
     respond_with(@post_approvals)
   end
+
+  def show
+    @approval = authorize PostApproval.find(params[:id])
+
+    respond_with(@approval) do |format|
+      format.html { redirect_to post_approvals_path(search: { id: @approval.id }) }
+    end
+  end
 end

app/controllers/post_events_controller.rb

@@ -4,7 +4,13 @@ class PostEventsController < ApplicationController
   respond_to :html, :xml, :json
 
   def index
-    @events = PostEvent.find_for_post(params[:post_id])
-    respond_with(@events)
+    if post_id = params[:post_id] || params.dig(:search, :post_id)
+      @post = Post.find(post_id)
+    end
+
+    @post_events = authorize PostEvent.paginated_search(params, defaults: { post_id: @post&.id }, count_pages: @post.present?)
+    @post_events = @post_events.includes(:creator, :post, model: [:post]) if request.format.html?
+
+    respond_with(@post_events)
   end
 end

app/controllers/post_replacements_controller.rb

@@ -35,4 +35,12 @@ class PostReplacementsController < ApplicationController
 
     respond_with(@post_replacements)
   end
+
+  def show
+    @post_replacement = authorize PostReplacement.find(params[:id])
+
+    respond_with(@post_replacement) do |format|
+      format.html { redirect_to post_replacements_path(search: { id: @post_replacement.id }) }
+    end
+  end
 end

app/logical/bigquery_export_service.rb

@@ -41,7 +41,7 @@ class BigqueryExportService
     Rails.application.eager_load!
 
     models = ApplicationRecord.descendants.sort_by(&:name)
-    models -= [GoodJob::BaseRecord, GoodJob::Process, GoodJob::Execution, GoodJob::ActiveJobJob, GoodJob::Job, GoodJob::Setting, TagRelationship, ArtistVersion, ArtistCommentaryVersion, NoteVersion, PoolVersion, PostVersion, WikiPageVersion, Post, PostVote, MediaAsset, Favorite, AITag]
+    models -= [GoodJob::BaseRecord, GoodJob::Process, GoodJob::Execution, GoodJob::ActiveJobJob, GoodJob::Job, GoodJob::Setting, TagRelationship, ArtistVersion, ArtistCommentaryVersion, NoteVersion, PoolVersion, PostVersion, WikiPageVersion, Post, PostEvent, PostVote, MediaAsset, Favorite, AITag, UserAction]
     models
   end
 

app/logical/source/url.rb

@@ -185,6 +185,10 @@ module Source
       nil
     end
 
+    def self.site_name(url)
+      Source::URL.parse(url)&.site_name
+    end
+
     def self.image_url?(url)
       Source::URL.parse(url)&.image_url?
     end

app/models/post.rb

@@ -70,6 +70,7 @@ class Post < ApplicationRecord
   has_many :favorites, dependent: :destroy
   has_many :replacements, class_name: "PostReplacement", :dependent => :destroy
   has_many :ai_tags, through: :media_asset
+  has_many :events, class_name: "PostEvent"
 
   attr_accessor :old_tag_string, :old_parent_id, :old_source, :old_rating, :has_constraints, :disable_versioning, :post_edit
 
@@ -1631,7 +1632,7 @@ class Post < ApplicationRecord
   def self.available_includes
     # attributes accessible through the ?only= parameter
     %i[
-      uploader approver flags appeals parent children notes
+      uploader approver flags appeals events parent children notes
       comments approvals disapprovals replacements pixiv_ugoira_frame_data
       artist_commentary media_asset ai_tags
     ]

app/models/post_event.rb

@@ -1,82 +1,40 @@
 # frozen_string_literal: true
 
-class PostEvent
-  include ActiveModel::Model
-  include ActiveModel::Serializers::JSON
-  include ActiveModel::Serializers::Xml
+class PostEvent < ApplicationRecord
+  belongs_to :model, polymorphic: true
+  belongs_to :creator, class_name: "User"
+  belongs_to :post
 
-  attr_accessor :event
-
-  delegate :created_at, to: :event
-
-  def self.find_for_post(post_id)
-    post = Post.find(post_id)
-    (post.appeals + post.flags + post.approvals).sort_by(&:created_at).reverse.map { |e| new(event: e) }
+  def self.model_types
+    %w[Post PostAppeal PostApproval PostDisapproval PostFlag PostReplacement]
   end
 
-  def type_name
-    case event
-    when PostFlag
-      "flag"
-    when PostAppeal
-      "appeal"
-    when PostApproval
-      "approval"
-    end
+  def self.visible(user)
+    all
   end
 
-  def type
-    type_name.first
-  end
+  def self.search(params, current_user)
+    q = search_attributes(params, [:model, :post, :creator, :event_at], current_user: current_user)
 
-  def reason
-    event.try(:reason) || ""
-  end
-
-  def creator_id
-    event.try(:creator_id) || event.try(:user_id)
-  end
-
-  def creator
-    event.try(:creator) || event.try(:user)
-  end
-
-  def status
-    if event.is_a?(PostApproval)
-      "approved"
-    elsif (event.is_a?(PostAppeal) && event.succeeded?) || (event.is_a?(PostFlag) && event.rejected?)
-      "approved"
-    elsif (event.is_a?(PostAppeal) && event.rejected?) || (event.is_a?(PostFlag) && event.succeeded?)
-      "deleted"
+    case params[:order]
+    when "event_at_asc"
+      q = q.order(event_at: :asc, model_id: :asc)
     else
-      "pending"
+      q = q.apply_default_order(params)
     end
+
+    q
   end
 
-  def is_creator_visible?(user = CurrentUser.user)
-    case event
-    when PostAppeal, PostApproval
-      true
-    when PostFlag
-      flag = event
-      Pundit.policy!(user, flag).can_view_flagger?
-    end
+  def self.default_order
+    order(event_at: :desc, model_id: :desc)
   end
 
-  def attributes
-    {
-      creator_id: nil,
-      created_at: nil,
-      reason: nil,
-      status: nil,
-      type: nil,
-    }
+  def self.available_includes
+    [:post, :model] # XXX creator isn't included because it leaks flagger/disapprover names
   end
 
-  # XXX can't use hidden_attributes because we don't inherit from ApplicationRecord.
-  def serializable_hash(options = {})
-    hash = super
-    hash = hash.except(:creator_id) unless is_creator_visible?
-    hash
+  def readonly?
+    true
   end
 end

app/models/user.rb

@@ -115,6 +115,7 @@ class User < ApplicationRecord
   has_many :post_appeals, foreign_key: :creator_id
   has_many :post_approvals, :dependent => :destroy
   has_many :post_disapprovals, :dependent => :destroy
+  has_many :post_events, class_name: "PostEvent", foreign_key: :creator_id
   has_many :post_flags, foreign_key: :creator_id
   has_many :post_votes
   has_many :post_versions, foreign_key: :updater_id

app/policies/post_event_policy.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+class PostEventPolicy < ApplicationPolicy
+  def can_see_creator?
+    case event.model_type
+    when "PostFlag"
+      policy(event.model).can_view_flagger?
+    when "PostDisapproval"
+      policy(event.model).can_view_creator?
+    else
+      true
+    end
+  end
+
+  def api_attributes
+    [:model_type, :model_id, :post_id, (:creator_id if can_see_creator?), :event_at].compact
+  end
+
+  def visible_for_search(events, attribute)
+    case attribute
+    in :creator | :creator_id
+      events.model_types.map do |type|
+        attr = attribute
+        attr = attr.to_s.gsub("creator", "uploader").to_sym if type == "Post"
+        attr = attr.to_s.gsub("creator", "user").to_sym if type in "PostApproval" | "PostDisapproval"
+
+        # XXX ordering by created_at desc is a query planner hack to make Postgres use the right indexes.
+        events.where(model: type.constantize.visible_for_search(attr, user).order(created_at: :desc))
+      end.reduce(:or)
+    else
+      events
+    end
+  end
+
+  alias_method :event, :record
+end

app/views/post_appeals/index.html.erb

@@ -43,3 +43,5 @@
     <%= numbered_paginator(@post_appeals) %>
   </div>
 </div>
+
+<%= render "post_events/secondary_links" %>

app/views/post_approvals/index.html.erb

@@ -23,3 +23,5 @@
     <%= numbered_paginator(@post_approvals) %>
   </div>
 </div>
+
+<%= render "post_events/secondary_links" %>

app/views/post_disapprovals/index.html.erb

@@ -39,3 +39,5 @@
     <%= numbered_paginator(@post_disapprovals) %>
   </div>
 </div>
+
+<%= render "post_events/secondary_links" %>

app/views/post_events/_secondary_links.html.erb

@@ -0,0 +1,17 @@
+<% content_for(:secondary_links) do %>
+  <% case controller_name %>
+  <% when "post_approvals" %>
+    <%= quick_search_form_for(:user_name, post_approvals_path, "user", autocomplete: "user") %>
+  <% when "post_disapprovals" %>
+    <%= quick_search_form_for(:user_name, post_disapprovals_path, "user", autocomplete: "user") %>
+  <% else %>
+    <%= quick_search_form_for(:creator_name, url_for, "user", autocomplete: "user") %>
+  <% end %>
+
+  <%= subnav_link_to "Events", post_events_path %>
+  <%= subnav_link_to "Appeals", post_appeals_path %>
+  <%= subnav_link_to "Approvals", post_approvals_path %>
+  <%= subnav_link_to "Disapprovals", post_disapprovals_path %>
+  <%= subnav_link_to "Flags", post_flags_path %>
+  <%= subnav_link_to "Replacements", post_replacements_path %>
+<% end %>

app/views/post_events/index.html.erb

@@ -1,25 +1,106 @@
 <div id="c-post-events">
   <div id="a-index">
-    <h1>Post Events</h1>
+    <% if @post %>
+      <h1>Events: <%= link_to @post.dtext_shortlink, @post %></h1>
+      <%= link_to "« Back", post_events_path, class: "text-xs" %>
+    <% else %>
+      <h1>Events</h1>
+    <% end %>
 
-    <%= table_for @events, class: "striped autofit", width: "100%" do |t| %>
-      <% t.column :type_name, name: "Type" %>
-      <% t.column "Description", td: { class: "col-expand" } do |event| %>
-        <div class="prose">
-          <%= format_text event.reason %>
-        </div>
+    <% unless @post %>
+      <%= search_form_for(post_events_path) do |f| %>
+        <%= f.input :creator_name, label: "User", input_html: { value: params[:search][:creator_name], "data-autocomplete": "user" } %>
+        <%= f.input :post_tags_match, label: "Tags", input_html: { value: params[:search][:post_tags_match], "data-autocomplete": "tag-query" } %>
+        <%= f.input :model_type, label: "Category", collection: PostEvent.model_types.map { |type| [type.titleize.delete_prefix("Post "), type] }, include_blank: true, selected: params[:search][:model_type] %>
+        <%= f.input :order, collection: [%w[Newest event_at], %w[Oldest event_at_asc]], include_blank: true, selected: params[:search][:order] %>
+        <%= f.submit "Search" %>
       <% end %>
-      <% t.column "Status" do |event| %>
-        <%= event.status %>
+    <% end %>
+
+    <%= table_for @post_events, class: "striped autofit mt-4", width: "100%" do |t| %>
+      <% t.column "Event", td: { class: "col-expand" } do |event| %>
+        <% post = event.post %>
+        <% model = event.model %>
+        <% creator = event.creator %>
+
+        <% case event.model_type %>
+        <% when "Post" %>
+          <%= link_to post.dtext_shortlink, post %> was uploaded by <%= link_to_user creator %>.
+        <% when "PostAppeal" %>
+          <div class="prose">
+            <%= link_to post.dtext_shortlink, post %> was appealed by <%= link_to_user creator %><%= " (#{format_text(model.reason.strip.chomp("."), inline: true)})".html_safe if model.reason.present? %>.
+          </div>
+        <% when "PostApproval" %>
+          <%= link_to post.dtext_shortlink, post %> was approved by <%= link_to_user creator %>.
+        <% when "PostDisapproval" %>
+          <div class="prose">
+            <% if policy(model).can_view_creator? %>
+              <%= link_to post.dtext_shortlink, post %> was disapproved by <%= link_to_user creator %> (<%= model.reason.titleize.downcase %><%= ": ".html_safe + format_text(model.message.strip.chomp("."), inline: true) if model.message.present? %>).
+            <% else %>
+              <%= link_to post.dtext_shortlink, post %> was disapproved (<%= model.reason.titleize.downcase %><%= ": ".html_safe + format_text(model.message.strip.chomp("."), inline: true) if model.message.present? %>).
+            <% end %>
+          </div>
+        <% when "PostFlag" %>
+          <div class="prose">
+            <% if policy(model).can_view_flagger? %>
+              <%= link_to post.dtext_shortlink, post %> was flagged by <%= link_to_user creator %> (<%= format_text(model.reason.strip.chomp("."), inline: true) %>).
+            <% else %>
+              <%= link_to post.dtext_shortlink, post %> was flagged (<%= format_text(model.reason.strip.chomp("."), inline: true) %>).
+            <% end %>
+          </div>
+        <% when "PostReplacement" %>
+          <% if model.old_file_size && model.old_file_ext && model.old_image_width && model.old_image_height && model.file_size && model.file_ext && model.image_width && model.image_height %>
+            <%= link_to post.dtext_shortlink, post %> was replaced by <%= link_to_user creator %>
+            (<%= external_link_to model.original_url.presence || "none", Source::URL.site_name(model.original_url) || model.original_url %>,
+            <%= model.old_file_size.to_formatted_s(:human_size, precision: 4) %> .<%= model.old_file_ext %>, <%= model.old_image_width %>x<%= model.old_image_height %> ->
+            <%= external_link_to model.replacement_url, Source::URL.site_name(model.replacement_url) || model.replacement_url %>,
+            <%= model.file_size.to_formatted_s(:human_size, precision: 4) %> .<%= model.file_ext %>, <%= model.image_width %>x<%= model.image_height %>).
+          <% else %>
+            <%= link_to post.dtext_shortlink, post %> was replaced by <%= link_to_user creator %>
+            (<%= external_link_to model.original_url.presence || "none", Source::URL.site_name(model.original_url) || model.original_url %> ->
+            <%= external_link_to model.replacement_url, Source::URL.site_name(model.replacement_url) || model.replacement_url %>).
+          <% end %>
+        <% end %>
       <% end %>
+
+      <% t.column "Category" do |event| %>
+        <%= link_to event.model_type.titleize.delete_prefix("Post "), post_events_path(search: { model_type: event.model_type, **search_params }) %>
+      <% end %>
+
       <% t.column "User" do |event| %>
-        <% if event.is_creator_visible? %>
-          <%= link_to_user event.creator %>
+        <% if policy(event).can_see_creator? %>
+          <%= link_to_user event.creator %> <%= link_to "»", post_events_path(search: { **search_params, creator_name: event.creator.name }) %>
         <% else %>
           <i>hidden</i>
         <% end %>
-        <br><%= time_ago_in_words_tagged event.created_at %>
+        <div><%= time_ago_in_words_tagged(event.event_at) %></div>
+      <% end %>
+
+      <% t.column column: "control" do |event| %>
+        <%= render PopupMenuComponent.new do |menu| %>
+          <% unless @post %>
+            <% menu.item do %>
+              <%= link_to "Post history", post_post_events_path(event.post) %>
+            <% end %>
+          <% end %>
+
+          <% if policy(event).can_see_creator? %>
+            <% menu.item do %>
+              <%= link_to "User history", post_events_path(search: { creator_name: event.creator.name }) %>
+            <% end %>
+          <% end %>
+
+          <% if policy(event).can_see_creator? %>
+            <% menu.item do %>
+              <%= link_to "Details", event.model %>
+            <% end %>
+          <% end %>
+        <% end %>
       <% end %>
     <% end %>
+
+    <%= numbered_paginator(@post_events) %>
   </div>
 </div>
+
+<%= render "secondary_links" %>

app/views/post_flags/index.html.erb

@@ -48,3 +48,5 @@
     <%= numbered_paginator(@post_flags) %>
   </div>
 </div>
+
+<%= render "post_events/secondary_links" %>

app/views/post_replacements/index.html.erb

@@ -66,3 +66,5 @@
     <%= numbered_paginator(@post_replacements) %>
   </div>
 </div>
+
+<%= render "post_events/secondary_links" %>

app/views/posts/show.html.erb

@@ -188,9 +188,8 @@
       <li id="post-history-tags"><%= link_to "Tags", post_versions_path(search: { post_id: @post.id }) %></li>
       <li id="post-history-pools"><%= link_to "Pools", pool_versions_path(search: { post_id: @post.id }) %></li>
       <li id="post-history-notes"><%= link_to "Notes", note_versions_path(search: { post_id: @post.id }) %></li>
-      <li id="post-history-moderation"><%= link_to "Moderation", post_events_path(@post.id) %></li>
+      <li id="post-history-moderation"><%= link_to "Moderation", post_post_events_path(@post.id) %></li>
       <li id="post-history-commentary"><%= link_to "Commentary", artist_commentary_versions_path(search: { post_id: @post.id }) %></li>
-      <li id="post-history-replacements"><%= link_to "Replacements", post_replacements_path(search: {post_id: @post.id }) %></li>
     </ul>
   </section>
 <% end %>

app/views/static/site_map.html.erb

@@ -18,9 +18,10 @@
       <ul>
         <li><h2>Post Events</h2></li>
         <li><%= link_to("Tag History", post_versions_path) %></li>
+        <li><%= link_to("Events", post_events_path) %></li>
+        <li><%= link_to("Appeals", post_appeals_path) %></li>
         <li><%= link_to("Approvals", post_approvals_path) %></li>
         <li><%= link_to("Disapprovals", post_disapprovals_path) %></li>
-        <li><%= link_to("Appeals", post_appeals_path) %></li>
         <li><%= link_to("Flags", post_flags_path) %></li>
         <li><%= link_to("Replacements", post_replacements_path) %></li>
       </ul>