backend/app/controllers/theatre_skip_events_controller.rb

@@ -6,15 +6,15 @@ class TheatreSkipEventsController < ApplicationController
     events =
         TheatreSkipEvent
         .where(theatre_id: params[:theatre_id])
-        .includes(:tags, post: { tags: :tag_name })
+        .includes(:post, tags: :tag_name)
         .order(created_at: :desc)
         .limit(limit)
 
     render json: events.map { |event|
       { id: event.id,
         theatre_id: event.theatre_id,
-        post: PostRepr.base(event.post),
-        tags: event.tags.map { |tag| TagRepr.inline(tag) },
+        post: { id: event.post.id, title: event.post.title, url: event.post.url },
+        tags: event.tags.map { |tag| { id: tag.id, name: tag.name } },
         programme_position: event.programme_position,
         created_at: event.created_at }
     }

backend/app/services/theatre_post_selector.rb

@@ -24,11 +24,9 @@ class TheatrePostSelector
     candidates = weighted_candidates
     sorted = candidates.sort_by { |candidate| [candidate.weight, candidate.post.id] }
 
-    {
-      tag_penalties: tag_penalty_json,
+    { tag_penalties: tag_penalty_json,
       lightest_posts: post_weight_json(sorted.first(limit)),
-      heaviest_posts: post_weight_json(sorted.reverse.first(limit))
-    }
+      heaviest_posts: post_weight_json(sorted.reverse.first(limit)) }
   end
 
   private
@@ -48,8 +46,7 @@ class TheatrePostSelector
             post:,
             penalty:,
             tags: post_tags,
-          weight: 1.0 / (1.0 + penalty)
-        )
+            weight: 1.0 / (1.0 + penalty))
       end
     end
   end
@@ -87,10 +84,8 @@ class TheatrePostSelector
         tag = tags[tag_id]
         next unless tag
 
-        {
-          tag: light_tag_json(tag),
-          penalty:
-        }
+        { tag: light_tag_json(tag),
+          penalty: }
       }
       .compact
       .sort_by { |row| [-row[:penalty], row[:tag][:name].to_s] }
@@ -98,27 +93,22 @@ class TheatrePostSelector
 
   def post_weight_json candidates
     candidates.map { |candidate|
-      {
-        post: light_post_json(candidate.post),
+      { post: light_post_json(candidate.post),
         weight: candidate.weight,
         penalty: candidate.penalty,
-        tags: candidate.tags.map { |tag| light_tag_json(tag) }
-      }
+        tags: candidate.tags.map { |tag| light_tag_json(tag) } }
     }
   end
 
   def light_post_json post
-    {
-      id: post.id,
+    { id: post.id,
       title: post.title,
-      url: post.url
-    }
+      url: post.url }
   end
 
   def light_tag_json tag
-    {
-      id: tag.id,
-      name: tag.name
-    }
+    { id: tag.id,
+      name: tag.name,
+      category: tag.category }
   end
 end

backend/db/schema.rb

@@ -339,7 +339,6 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_06_000000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.index ["expires_at"], name: "index_theatre_watching_users_on_expires_at"
-    t.index ["theatre_id", "expires_at"], name: "idx_on_theatre_id_skip_expires_at_4c8de1dd42"
     t.index ["theatre_id", "expires_at"], name: "index_theatre_watching_users_on_theatre_id_and_expires_at"
     t.index ["theatre_id"], name: "index_theatre_watching_users_on_theatre_id"
     t.index ["user_id"], name: "index_theatre_watching_users_on_user_id"

frontend/src/pages/theatres/TheatreDetailPage.tsx

@@ -22,6 +22,7 @@ import { useValidationErrors } from '@/lib/useValidationErrors'
 import type { FC, FormEvent, ReactNode } from 'react'
 
 import type { NiconicoMetadata,
+	      NiconicoVideoInfo,
 	      NiconicoViewerHandle,
 	      Post,
 	      Category,
@@ -459,6 +460,19 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
     await advancePost ()
   }
 
+  const handleNiconicoLoadComplete = (info: NiconicoVideoInfo) => {
+    const lengthMs = info.lengthInSeconds * 1_000
+    setVideoLength (lengthMs)
+
+    if (lengthMs <= 0)
+      {
+	void handlePlaybackError ()
+	return
+      }
+
+    embedRef.current?.play ()
+  }
+
   const handleSkipVote = async () => {
     if (!(id) || !(post))
       return
@@ -797,10 +811,7 @@ const TheatreDetailPage: FC<Props> = ({ user }: Props) => {
 			  key={post.id}
 			  ref={embedRef}
 			  post={post}
-			  onLoadComplete={info => {
-			    embedRef.current?.play ()
-			    setVideoLength (info.lengthInSeconds * 1_000)
-			  }}
+			  onLoadComplete={handleNiconicoLoadComplete}
 			  onMetadataChange={syncPlayback}
 			  onError={handlePlaybackError}/>) : (
 		      <div className="grid min-h-72 place-items-center text-zinc-400">