FEATURE: Implement edit functionality for post notices (#11140)

All post notice related custom fields were moved to a single one.

db/migrate/20201105190351_move_post_notices_to_json.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+class MovePostNoticesToJson < ActiveRecord::Migration[6.0]
+  def up
+    execute <<~SQL
+      INSERT INTO post_custom_fields(post_id, name, value, created_at, updated_at)
+      SELECT
+        posts.id,
+        'notice',
+        CASE
+          WHEN pcf_type.value = 'custom'         THEN json_build_object('type', pcf_type.value, 'raw', pcf_args.value, 'cooked', pcf_args.value)
+          WHEN pcf_type.value = 'new_user'       THEN json_build_object('type', pcf_type.value)
+          WHEN pcf_type.value = 'returning_user' THEN json_build_object('type', pcf_type.value, 'last_posted_at', pcf_args.value)
+        END,
+        pcf_type.created_at created_at,
+        pcf_type.updated_at updated_at
+      FROM posts
+      JOIN post_custom_fields pcf_type ON posts.id = pcf_type.post_id AND pcf_type.name = 'notice_type'
+      LEFT JOIN post_custom_fields pcf_args ON posts.id = pcf_args.post_id AND pcf_args.name = 'notice_args'
+    SQL
+
+    execute "DELETE FROM post_custom_fields WHERE name = 'notice_type' OR name = 'notice_args'"
+
+    add_index :post_custom_fields, :post_id, unique: true, name: "index_post_custom_fields_on_notice", where: "name = 'notice'"
+
+    remove_index :post_custom_fields, name: "index_post_custom_fields_on_notice_type"
+    remove_index :post_custom_fields, name: "index_post_custom_fields_on_notice_args"
+  end
+
+  def down
+    execute <<~SQL
+      INSERT INTO post_custom_fields(post_id, name, value, created_at, updated_at)
+      SELECT post_id, 'notice_type', value::json->>'type', created_at, updated_at
+      FROM post_custom_fields
+      WHERE name = 'notice'
+    SQL
+
+    execute <<~SQL
+      INSERT INTO post_custom_fields(post_id, name, value, created_at, updated_at)
+      SELECT post_id, 'notice_args', COALESCE(value::json->>'cooked', value::json->>'last_posted_at'), created_at, updated_at
+      FROM post_custom_fields
+      WHERE name = 'notice'
+    SQL
+
+    execute "DELETE FROM post_custom_fields WHERE name = 'notice'"
+
+    add_index :post_custom_fields, :post_id, unique: true, name: "index_post_custom_fields_on_notice_type", where: "name = 'notice_type'"
+    add_index :post_custom_fields, :post_id, unique: true, name: "index_post_custom_fields_on_notice_args", where: "name = 'notice_args'"
+
+    remove_index :index_post_custom_fields_on_notice
+  end
+end