post_versions.tags_json への移行 (#354) (#415)

画面テストまだ．

Reviewed-on: #415
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/app/models/post.rb

@@ -137,6 +137,34 @@ class Post < ApplicationRecord
     end
   end
 
+  def self.tag_snapshot_literal tag
+    sections = tag.fetch('sections', []).map do |sec|
+      begin_ms = sec.fetch('begin_ms')
+      end_ms = sec['end_ms']
+
+      "[#{ Post.ms_to_time(begin_ms) }-#{ end_ms ? Post.ms_to_time(end_ms) : '' }]"
+    end
+
+    "#{ tag.fetch('name') }#{ sections.join }"
+  end
+
+  def snapshot_tags_json
+    post_tags
+        .kept
+        .joins(tag: :tag_name)
+        .includes(:sections, tag: :tag_name)
+        .order('tags.id')
+        .map do |pt|
+      { 'id' => pt.tag.id,
+        'version_no' => pt.tag.version_no,
+        'name' => pt.tag.name,
+        'category' => pt.tag.category,
+        'sections' => pt.sections.sort_by(&:begin_ms).map {
+          { 'begin_ms' => _1.begin_ms, 'end_ms' => _1.end_ms }
+        } }
+    end
+  end
+
   def self.section_literal section
     end_ms =
         section.end_ms ? Post.ms_to_time(section.end_ms) : ''