feat(stats): separate YouTube channels in the Library (#253)

src/core/services/anilist/cover-art-fetcher.ts

@@ -192,6 +192,16 @@ export function createCoverArtFetcher(
 
   return {
     async fetchIfMissing(db, videoId, canonicalTitle): Promise<boolean> {
+      const channel = db
+        .prepare(
+          `
+        SELECT 1 FROM imm_videos v
+        JOIN imm_anime a ON a.anime_id = v.anime_id
+        WHERE v.video_id = ? AND a.media_kind != 'anime'
+      `,
+        )
+        .get(videoId);
+      if (channel) return false;
       const existing = getCoverArt(db, videoId);
       if (existing?.coverBlob) {
         return true;

src/core/services/immersion-tracker/__tests__/anime-merge.test.ts

@@ -13,7 +13,11 @@ import {
   getOrCreateAnimeRecord,
   linkVideoToAnimeRecord,
 } from '../storage.js';
-import { mergeAnimeRecords, moveVideoToAnime } from '../anime-merge.js';
+import {
+  MEDIA_KIND_MISMATCH_MESSAGE,
+  mergeAnimeRecords,
+  moveVideoToAnime,
+} from '../anime-merge.js';
 import {
   dismissAnimeMergeRecommendation,
   getAnimeMergeRecommendations,
@@ -940,3 +944,36 @@ test('automatic AniList update onto an entry that already links elsewhere does n
     );
   });
 });
+
+test('merge and move refuse to mix anime entries with YouTube channels', () => {
+  withDb((db) => {
+    insertAnime(db, { animeId: 1, key: 'some anime', title: 'Some Anime', anilistId: 555 });
+    insertAnime(db, { animeId: 2, key: 'youtube channel uc123', title: 'Channel' });
+    db.prepare("UPDATE imm_anime SET media_kind = 'youtube' WHERE anime_id = 2").run();
+    insertEpisode(db, { videoId: 10, animeId: 1 });
+    insertEpisode(db, { videoId: 20, animeId: 2 });
+
+    assert.throws(() => mergeAnimeRecords(db, 1, [2]), { message: MEDIA_KIND_MISMATCH_MESSAGE });
+    assert.throws(() => mergeAnimeRecords(db, 2, [1]), { message: MEDIA_KIND_MISMATCH_MESSAGE });
+    assert.throws(() => moveVideoToAnime(db, 20, 1), { message: MEDIA_KIND_MISMATCH_MESSAGE });
+    assert.throws(() => moveVideoToAnime(db, 10, 2), { message: MEDIA_KIND_MISMATCH_MESSAGE });
+
+    const rows = db
+      .prepare(
+        'SELECT anime_id AS animeId, media_kind AS mediaKind FROM imm_anime ORDER BY anime_id',
+      )
+      .all() as Array<{ animeId: number; mediaKind: string }>;
+    assert.deepEqual(rows, [
+      { animeId: 1, mediaKind: 'anime' },
+      { animeId: 2, mediaKind: 'youtube' },
+    ]);
+    assert.equal(
+      (
+        db.prepare('SELECT anime_id AS animeId FROM imm_videos WHERE video_id = 20').get() as {
+          animeId: number;
+        }
+      ).animeId,
+      2,
+    );
+  });
+});

src/core/services/immersion-tracker/anime-merge-recommendations.ts

@@ -27,7 +27,7 @@ function getAnimeTitles(db: DatabaseSync, animeId: number): AnimeTitleRow | null
     .prepare(
       `SELECT canonical_title, title_romaji, title_english, title_native
        FROM imm_anime
-       WHERE anime_id = ?`,
+       WHERE anime_id = ? AND media_kind = 'anime'`,
     )
     .get(animeId) as AnimeTitleRow | null;
 }
@@ -77,6 +77,7 @@ export function shouldRecommendAnilistConflict(
   conflictAnimeId: number,
   options: AnimeConflictRecommendationOptions,
 ): boolean {
+  if (!getAnimeTitles(db, targetAnimeId) || !getAnimeTitles(db, conflictAnimeId)) return false;
   if (options.survivor === 'target' || options.matchConfidence === 'manual') return false;
   if (
     !animeSeasonsAreMergeCompatible(
@@ -99,6 +100,8 @@ export function recordAnimeMergeRecommendation(
   secondCandidateAnimeId: number,
   anilistId: number,
 ): void {
+  if (!getAnimeTitles(db, firstCandidateAnimeId) || !getAnimeTitles(db, secondCandidateAnimeId))
+    return;
   const firstAnimeId = Math.min(firstCandidateAnimeId, secondCandidateAnimeId);
   const secondAnimeId = Math.max(firstCandidateAnimeId, secondCandidateAnimeId);
   const timestamp = toDbTimestamp(nowMs());
@@ -141,6 +144,8 @@ export function getAnimeMergeRecommendations(db: DatabaseSync): AnimeMergeRecomm
                 second_anime_id AS secondAnimeId
          FROM imm_anime_merge_recommendations
          WHERE status = 'pending'
+           AND first_anime_id IN (SELECT anime_id FROM imm_anime WHERE media_kind = 'anime')
+           AND second_anime_id IN (SELECT anime_id FROM imm_anime WHERE media_kind = 'anime')
          ORDER BY recommendation_id ASC`,
       )
       .all() as Array<{

src/core/services/immersion-tracker/anime-merge.ts

@@ -1,3 +1,4 @@
+import type { MediaKind } from '../../../shared/media-kind';
 import type { DatabaseSync } from './sqlite';
 import { recomputeLifetimeAnimeAggregatesInTransaction } from './lifetime';
 import { toDbTimestamp } from './query-shared';
@@ -5,6 +6,8 @@ import { nowMs } from './time';
 
 /** Thrown when a move names an episode or destination entry that is not there. */
 export const UNKNOWN_MOVE_TARGET_MESSAGE = 'Unknown episode or target library entry';
+/** Thrown when a merge or move would mix an anime entry with a YouTube channel. */
+export const MEDIA_KIND_MISMATCH_MESSAGE = 'Anime and YouTube channel entries cannot be combined';
 
 export interface AnimeMergeSummary {
   /** Library entry that owns every moved episode once the merge finishes. */
@@ -60,8 +63,11 @@ function readAnimeMetadata(db: DatabaseSync, animeId: number): AnimeMetadataRow
     .get(animeId) ?? null) as AnimeMetadataRow | null;
 }
 
-function animeExists(db: DatabaseSync, animeId: number): boolean {
-  return Boolean(db.prepare('SELECT 1 FROM imm_anime WHERE anime_id = ?').get(animeId));
+function readMediaKind(db: DatabaseSync, animeId: number): MediaKind | null {
+  const row = db
+    .prepare('SELECT media_kind AS mediaKind FROM imm_anime WHERE anime_id = ?')
+    .get(animeId) as { mediaKind: MediaKind } | undefined;
+  return row?.mediaKind ?? null;
 }
 
 function hasAnimeReferences(db: DatabaseSync, animeId: number): boolean {
@@ -161,7 +167,8 @@ export function mergeAnimeRecordsInTransaction(
   sourceAnimeIds: number[],
 ): AnimeMergeSummary {
   const summary = emptyMergeSummary(targetAnimeId);
-  if (!animeExists(db, targetAnimeId)) {
+  const targetKind = readMediaKind(db, targetAnimeId);
+  if (targetKind === null) {
     return summary;
   }
 
@@ -195,8 +202,13 @@ export function mergeAnimeRecordsInTransaction(
   const dropAnimeStmt = db.prepare('DELETE FROM imm_anime WHERE anime_id = ?');
 
   for (const sourceAnimeId of new Set(sourceAnimeIds)) {
-    if (sourceAnimeId === targetAnimeId || !animeExists(db, sourceAnimeId)) {
-      continue;
+    if (sourceAnimeId === targetAnimeId) continue;
+    const sourceKind = readMediaKind(db, sourceAnimeId);
+    if (sourceKind === null) continue;
+    // A channel folded into an anime would only be recreated on the next
+    // watch, because title lookups never cross kinds; refuse instead.
+    if (sourceKind !== targetKind) {
+      throw new Error(MEDIA_KIND_MISMATCH_MESSAGE);
     }
 
     const sourceMetadata = readAnimeMetadata(db, sourceAnimeId);
@@ -257,11 +269,15 @@ export function moveVideoToAnime(
     const videoRow = db
       .prepare('SELECT anime_id AS animeId FROM imm_videos WHERE video_id = ?')
       .get(videoId) as { animeId: number | null } | null;
-    if (!videoRow || !animeExists(db, targetAnimeId)) {
+    const targetKind = readMediaKind(db, targetAnimeId);
+    if (!videoRow || targetKind === null) {
       throw new Error(UNKNOWN_MOVE_TARGET_MESSAGE);
     }
 
     const previousAnimeId = videoRow.animeId;
+    if (previousAnimeId !== null && readMediaKind(db, previousAnimeId) !== targetKind) {
+      throw new Error(MEDIA_KIND_MISMATCH_MESSAGE);
+    }
     if (previousAnimeId === targetAnimeId) {
       db.prepare(
         'UPDATE imm_videos SET anime_assignment_locked = 1, LAST_UPDATE_DATE = ? WHERE video_id = ?',

src/core/services/immersion-tracker/anime-season-repair.ts

@@ -134,7 +134,7 @@ function getAnimeRow(db: DatabaseSync, animeId: number): AnimeRow | null {
           episodes_total,
           description
         FROM imm_anime
-        WHERE anime_id = ?
+        WHERE anime_id = ? AND media_kind = 'anime'
       `,
     )
     .get(animeId) as AnimeRow | null;
@@ -335,7 +335,8 @@ export function repairLegacySeasonlessAnimeRows(db: DatabaseSync): AnimeSeasonRe
           SELECT a.anime_id AS animeId
           FROM imm_anime a
           JOIN imm_videos v ON v.anime_id = a.anime_id
-          WHERE v.parsed_title IS NOT NULL
+          WHERE a.media_kind = 'anime'
+            AND v.parsed_title IS NOT NULL
             AND TRIM(v.parsed_title) != ''
             AND v.parsed_season IS NOT NULL
             AND v.parsed_season > 0
@@ -372,6 +373,11 @@ export function resolveAnimeAnilistConflict(
   anilistId: number,
   options: AnimeAnilistConflictOptions = {},
 ): AnimeSeasonRepairSummary {
+  if (!getAnimeRow(db, targetAnimeId)) {
+    const summary = emptySummary();
+    summary.anilistAssignmentBlocked = true;
+    return summary;
+  }
   const conflict = db
     .prepare(
       `
@@ -387,6 +393,11 @@ export function resolveAnimeAnilistConflict(
     return emptySummary();
   }
 
+  if (!getAnimeRow(db, conflict.animeId)) {
+    const summary = emptySummary();
+    summary.anilistAssignmentBlocked = true;
+    return summary;
+  }
   return runInTransaction(db, () => {
     const targetRow = getAnimeRow(db, targetAnimeId);
     if (

src/core/services/immersion-tracker/query-library.ts

@@ -33,6 +33,7 @@ export function getAnimeLibrary(db: DatabaseSync): AnimeLibraryRow[] {
     SELECT
       a.anime_id AS animeId,
       a.canonical_title AS canonicalTitle,
+      a.media_kind AS mediaKind,
       a.anilist_id AS anilistId,
       COALESCE(lm.total_sessions, 0) AS totalSessions,
       COALESCE(lm.total_active_ms, 0) AS totalActiveMs,
@@ -63,6 +64,7 @@ export function getAnimeDetail(db: DatabaseSync, animeId: number): AnimeDetailRo
     SELECT
       a.anime_id AS animeId,
       a.canonical_title AS canonicalTitle,
+      a.media_kind AS mediaKind,
       a.anilist_id AS anilistId,
       a.title_romaji AS titleRomaji,
       a.title_english AS titleEnglish,

src/core/services/immersion-tracker/storage.ts

@@ -1,3 +1,4 @@
+import type { MediaKind } from '../../../shared/media-kind';
 import { createHash } from 'node:crypto';
 import path from 'node:path';
 import { parseMediaInfo } from '../../../jimaku/utils';
@@ -24,6 +25,7 @@ export interface TrackerPreparedStatements {
 }
 
 export interface AnimeRecordInput {
+  mediaKind?: MediaKind;
   parsedTitle: string;
   canonicalTitle: string;
   seasonScope?: number | null;
@@ -569,6 +571,8 @@ function ensureSubtitleLineEventIndex(db: DatabaseSync): void {
 }
 
 export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput): number {
+  const mediaKind = input.mediaKind ?? 'anime';
+  const anilistId = mediaKind === 'anime' ? input.anilistId : null;
   const seasonScope = normalizeSeasonScope(input.seasonScope);
   const identityTitle = buildSeasonScopedAnimeTitle(input.parsedTitle, seasonScope);
   const canonicalTitle =
@@ -580,17 +584,23 @@ export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput
   }
 
   const byAnilistId =
-    input.anilistId !== null
-      ? (db.prepare('SELECT anime_id FROM imm_anime WHERE anilist_id = ?').get(input.anilistId) as {
+    anilistId !== null
+      ? (db
+          .prepare("SELECT anime_id FROM imm_anime WHERE anilist_id = ? AND media_kind = 'anime'")
+          .get(anilistId) as {
           anime_id: number;
         } | null)
       : null;
   const byNormalizedTitle = db
-    .prepare('SELECT anime_id FROM imm_anime WHERE normalized_title_key = ?')
-    .get(normalizedTitleKey) as { anime_id: number } | null;
+    .prepare('SELECT anime_id FROM imm_anime WHERE normalized_title_key = ? AND media_kind = ?')
+    .get(normalizedTitleKey, mediaKind) as { anime_id: number } | null;
   const byTitleAlias = db
-    .prepare('SELECT anime_id FROM imm_anime_title_aliases WHERE normalized_title_key = ?')
-    .get(normalizedTitleKey) as { anime_id: number } | null;
+    .prepare(
+      `SELECT a.anime_id FROM imm_anime_title_aliases AS alias
+      JOIN imm_anime AS a ON a.anime_id = alias.anime_id
+      WHERE alias.normalized_title_key = ? AND a.media_kind = ?`,
+    )
+    .get(normalizedTitleKey, mediaKind) as { anime_id: number } | null;
   const existing = byAnilistId ?? byNormalizedTitle ?? byTitleAlias;
   if (existing?.anime_id) {
     // An alias remembers an intentionally merged-away spelling. Reusing it
@@ -601,7 +611,7 @@ export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput
         UPDATE imm_anime
         SET
           canonical_title = COALESCE(NULLIF(?, ''), canonical_title),
-          anilist_id = COALESCE(?, anilist_id),
+          anilist_id = CASE WHEN ? = 'youtube' THEN NULL ELSE COALESCE(?, anilist_id) END,
           title_romaji = COALESCE(?, title_romaji),
           title_english = COALESCE(?, title_english),
           title_native = COALESCE(?, title_native),
@@ -611,7 +621,8 @@ export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput
       `,
     ).run(
       canonicalTitleUpdate,
-      input.anilistId,
+      mediaKind,
+      anilistId,
       input.titleRomaji,
       input.titleEnglish,
       input.titleNative,
@@ -627,6 +638,7 @@ export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput
     .prepare(
       `
         INSERT INTO imm_anime(
+          media_kind,
           normalized_title_key,
           canonical_title,
           anilist_id,
@@ -636,13 +648,14 @@ export function getOrCreateAnimeRecord(db: DatabaseSync, input: AnimeRecordInput
           metadata_json,
           CREATED_DATE,
           LAST_UPDATE_DATE
-        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
+        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
       `,
     )
     .run(
+      input.mediaKind ?? 'anime',
       normalizedTitleKey,
       canonicalTitle,
-      input.anilistId,
+      anilistId,
       input.titleRomaji,
       input.titleEnglish,
       input.titleNative,
@@ -803,6 +816,7 @@ export function linkYoutubeVideoToAnimeRecord(
   }
 
   const animeId = getOrCreateAnimeRecord(db, {
+    mediaKind: 'youtube',
     parsedTitle: identity.parsedTitle,
     canonicalTitle: identity.canonicalTitle,
     anilistId: null,
@@ -875,6 +889,70 @@ function migrateLegacyAnimeMetadata(db: DatabaseSync): void {
   }
 }
 
+// SQLite cannot drop a table-level UNIQUE constraint. Rebuild with IDs intact
+// and foreign keys disabled so dependent history and manual assignments survive.
+function migrateAnimeTitleUniqueness(db: DatabaseSync): void {
+  const schema = db.prepare("SELECT sql FROM sqlite_master WHERE name = 'imm_anime'").get() as {
+    sql: string;
+  };
+  if (/normalized_title_key TEXT NOT NULL UNIQUE/i.test(schema.sql)) {
+    const foreignKeys = db.prepare('PRAGMA foreign_keys').get() as { foreign_keys: number };
+    const sequence = db
+      .prepare("SELECT seq FROM sqlite_sequence WHERE name = 'imm_anime'")
+      .get() as { seq: number } | null;
+    db.exec('PRAGMA foreign_keys = OFF');
+    try {
+      db.exec('BEGIN IMMEDIATE');
+      db.exec(
+        schema.sql
+          .replace(
+            /CREATE TABLE (?:IF NOT EXISTS )?["`]?imm_anime["`]?/i,
+            'CREATE TABLE imm_anime_new',
+          )
+          .replace(
+            /normalized_title_key TEXT NOT NULL UNIQUE/i,
+            'normalized_title_key TEXT NOT NULL',
+          ),
+      );
+      db.exec(`INSERT INTO imm_anime_new SELECT * FROM imm_anime;
+        DROP TABLE imm_anime;
+        ALTER TABLE imm_anime_new RENAME TO imm_anime;`);
+      if (sequence) {
+        db.prepare("UPDATE sqlite_sequence SET seq = MAX(seq, ?) WHERE name = 'imm_anime'").run(
+          sequence.seq,
+        );
+      }
+      db.exec('COMMIT');
+    } catch (error) {
+      db.exec('ROLLBACK');
+      throw error;
+    } finally {
+      db.exec(`PRAGMA foreign_keys = ${foreignKeys.foreign_keys}`);
+    }
+  }
+  db.exec(`CREATE UNIQUE INDEX IF NOT EXISTS idx_anime_kind_title
+    ON imm_anime(media_kind, normalized_title_key)`);
+}
+
+// Older builds can create channel rows with the default anime kind even after
+// the schema upgrade. Repair classification on every startup without moving videos.
+function classifyYoutubeChannels(db: DatabaseSync): void {
+  db.exec(`
+    UPDATE imm_anime
+    SET media_kind = 'youtube', anilist_id = NULL
+    WHERE media_kind = 'anime'
+      AND NOT EXISTS (SELECT 1 FROM imm_anime AS channel
+        WHERE channel.media_kind = 'youtube'
+          AND channel.normalized_title_key = imm_anime.normalized_title_key)
+      AND (
+        normalized_title_key LIKE 'youtube channel %'
+        OR CASE WHEN json_valid(metadata_json)
+           THEN json_extract(metadata_json, '$.source') = 'youtube-channel'
+           ELSE 0 END
+      )
+  `);
+}
+
 export function ensureSchema(db: DatabaseSync): void {
   db.exec(`
     CREATE TABLE IF NOT EXISTS imm_schema_version (
@@ -897,6 +975,7 @@ export function ensureSchema(db: DatabaseSync): void {
     .prepare('SELECT schema_version FROM imm_schema_version ORDER BY schema_version DESC LIMIT 1')
     .get() as { schema_version: number } | null;
   if (currentVersion?.schema_version === SCHEMA_VERSION) {
+    classifyYoutubeChannels(db);
     ensureLexicalDailyRollupTables(db);
     ensureLifetimeSummaryTables(db);
     ensureStatsExcludedWordsTable(db);
@@ -908,7 +987,7 @@ export function ensureSchema(db: DatabaseSync): void {
   db.exec(`
     CREATE TABLE IF NOT EXISTS imm_anime(
       anime_id INTEGER PRIMARY KEY AUTOINCREMENT,
-      normalized_title_key TEXT NOT NULL UNIQUE,
+      normalized_title_key TEXT NOT NULL,
       canonical_title TEXT NOT NULL,
       anilist_id INTEGER UNIQUE,
       title_romaji TEXT,
@@ -921,6 +1000,12 @@ export function ensureSchema(db: DatabaseSync): void {
       LAST_UPDATE_DATE TEXT
     );
   `);
+  addColumnIfMissing(
+    db,
+    'imm_anime',
+    'media_kind',
+    "TEXT NOT NULL DEFAULT 'anime' CHECK(media_kind IN ('anime', 'youtube'))",
+  );
   db.exec(`
     CREATE TABLE IF NOT EXISTS imm_videos(
       video_id INTEGER PRIMARY KEY AUTOINCREMENT,
@@ -1464,6 +1549,8 @@ export function ensureSchema(db: DatabaseSync): void {
     );
   }
 
+  migrateAnimeTitleUniqueness(db);
+  classifyYoutubeChannels(db);
   migrateSessionEventTimestampsToText(db);
 
   ensureLexicalDailyRollupTables(db);

src/core/services/immersion-tracker/types.ts

@@ -1,4 +1,6 @@
-export const SCHEMA_VERSION = 23;
+import type { MediaKind } from '../../../shared/media-kind';
+
+export const SCHEMA_VERSION = 25;
 export const DEFAULT_QUEUE_CAP = 1_000;
 export const DEFAULT_BATCH_SIZE = 25;
 export const DEFAULT_FLUSH_INTERVAL_MS = 500;
@@ -518,6 +520,7 @@ export interface YoutubeVideoMetadata {
 }
 
 export interface AnimeLibraryRow {
+  mediaKind: MediaKind;
   animeId: number;
   canonicalTitle: string;
   anilistId: number | null;
@@ -531,6 +534,7 @@ export interface AnimeLibraryRow {
 }
 
 export interface AnimeDetailRow {
+  mediaKind: MediaKind;
   animeId: number;
   canonicalTitle: string;
   anilistId: number | null;

src/core/services/immersion-tracker/youtube-kind.test.ts

@@ -0,0 +1,310 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { Database, type DatabaseSync } from './sqlite';
+import {
+  ensureSchema,
+  getOrCreateAnimeRecord,
+  getOrCreateVideoRecord,
+  linkYoutubeVideoToAnimeRecord,
+} from './storage';
+import { getAnimeDetail, getAnimeLibrary } from './query-library';
+import { updateAnimeAnilistInfo } from './query-maintenance';
+import {
+  repairLegacySeasonlessAnimeRows,
+  resolveAnimeAnilistConflict,
+} from './anime-season-repair';
+import {
+  getAnimeMergeRecommendations,
+  recordAnimeMergeRecommendation,
+} from './anime-merge-recommendations';
+import { createCoverArtFetcher } from '../anilist/cover-art-fetcher';
+import { SCHEMA_VERSION, SOURCE_TYPE_REMOTE, type YoutubeVideoMetadata } from './types';
+
+const metadata: YoutubeVideoMetadata = {
+  youtubeVideoId: 'video1',
+  videoUrl: 'https://www.youtube.com/watch?v=video1',
+  videoTitle: 'Video title',
+  videoThumbnailUrl: null,
+  channelId: 'UC123',
+  channelName: 'Channel name',
+  channelUrl: 'https://www.youtube.com/channel/UC123',
+  channelThumbnailUrl: null,
+  uploaderId: null,
+  uploaderUrl: null,
+  description: null,
+  metadataJson: null,
+};
+
+function createVideo(db: DatabaseSync, key: string): number {
+  return getOrCreateVideoRecord(db, key, {
+    canonicalTitle: 'Video title',
+    sourcePath: null,
+    sourceUrl: metadata.videoUrl,
+    sourceType: SOURCE_TYPE_REMOTE,
+  });
+}
+
+function createAnime(
+  db: DatabaseSync,
+  parsedTitle: string,
+  metadataJson: string | null = null,
+): number {
+  return getOrCreateAnimeRecord(db, {
+    parsedTitle,
+    canonicalTitle: parsedTitle,
+    metadataJson,
+    anilistId: null,
+    titleRomaji: null,
+    titleEnglish: null,
+    titleNative: null,
+  });
+}
+
+test('schema 23 channel migration preserves history and manual assignments and is idempotent', () => {
+  const db = new Database(':memory:');
+  try {
+    ensureSchema(db);
+    const ids = [
+      createAnime(db, 'youtube-channel:UC123'),
+      createAnime(db, 'youtube-channel-url:https://www.youtube.com/@creator'),
+      createAnime(db, 'youtube-channel-name:Creator'),
+      createAnime(db, 'Renamed channel', '{ "source": "youtube-channel" }'),
+    ];
+    const animeId = createAnime(db, 'Anime title', 'legacy non-JSON metadata');
+    const videoId = createVideo(db, 'manual');
+    db.prepare(
+      'UPDATE imm_videos SET anime_id = ?, anime_assignment_locked = 1 WHERE video_id = ?',
+    ).run(animeId, videoId);
+    db.prepare(
+      'INSERT INTO imm_lifetime_anime(anime_id, total_active_ms, total_cards) VALUES (?, 123456, 7)',
+    ).run(animeId);
+    const history = getAnimeLibrary(db);
+    // Reproduce the previous schema, including its lack of a media kind column.
+    db.exec(
+      'DROP INDEX idx_anime_kind_title; ALTER TABLE imm_anime DROP COLUMN media_kind; DELETE FROM imm_schema_version; INSERT INTO imm_schema_version VALUES (23, 0)',
+    );
+    ensureSchema(db);
+    ensureSchema(db);
+    for (const id of ids) {
+      const row = db.prepare('SELECT media_kind FROM imm_anime WHERE anime_id = ?').get(id);
+      assert.ok(row && typeof row === 'object' && 'media_kind' in row);
+      assert.equal(row.media_kind, 'youtube');
+    }
+    assert.deepEqual(getAnimeLibrary(db), history);
+    assert.equal(linkYoutubeVideoToAnimeRecord(db, videoId, metadata), animeId);
+    const version = db
+      .prepare('SELECT MAX(schema_version) AS version FROM imm_schema_version')
+      .get();
+    assert.ok(version && typeof version === 'object' && 'version' in version);
+    assert.equal(version.version, SCHEMA_VERSION);
+  } finally {
+    db.close();
+  }
+});
+
+test('channel creation and repeated linking expose youtube in library and detail without losing totals', async () => {
+  const db = new Database(':memory:');
+  try {
+    ensureSchema(db);
+    const videoId = createVideo(db, 'first');
+    const channelId = linkYoutubeVideoToAnimeRecord(db, videoId, metadata);
+    assert.ok(channelId);
+    const secondVideoId = createVideo(db, 'second');
+    assert.equal(linkYoutubeVideoToAnimeRecord(db, secondVideoId, metadata), channelId);
+    db.prepare(
+      'INSERT INTO imm_lifetime_anime(anime_id, total_active_ms, total_cards) VALUES (?, 123456, 7)',
+    ).run(channelId);
+    assert.equal(getAnimeLibrary(db)[0]?.mediaKind, 'youtube');
+    const detail = getAnimeDetail(db, channelId);
+    assert.equal(detail?.mediaKind, 'youtube');
+    assert.equal(detail?.episodeCount, 2);
+    assert.equal(detail?.totalActiveMs, 123456);
+    assert.equal(detail?.totalCards, 7);
+
+    // Even parsed season numbers and a matching anime name must not trigger repairs.
+    db.prepare('UPDATE imm_videos SET parsed_season = video_id').run();
+    assert.equal(repairLegacySeasonlessAnimeRows(db).repaired, 0);
+    const animeId = createAnime(db, 'Channel name');
+    for (const matchConfidence of ['exact', 'weak', 'manual'] as const) {
+      assert.equal(
+        resolveAnimeAnilistConflict(db, channelId, 123, { matchConfidence })
+          .anilistAssignmentBlocked,
+        true,
+      );
+    }
+    updateAnimeAnilistInfo(db, videoId, {
+      anilistId: 123,
+      titleRomaji: 'Wrong title',
+      titleEnglish: null,
+      titleNative: null,
+      episodesTotal: 12,
+    });
+    recordAnimeMergeRecommendation(db, channelId, animeId, 123);
+    assert.deepEqual(getAnimeMergeRecommendations(db), []);
+    assert.equal(getAnimeDetail(db, channelId)?.anilistId, null);
+    const fetcher = createCoverArtFetcher(
+      {
+        acquire: async () => {
+          assert.fail('YouTube must not query AniList');
+        },
+        recordResponse: () => {},
+      },
+      console,
+    );
+    assert.equal(await fetcher.fetchIfMissing(db, videoId, 'Channel name'), false);
+  } finally {
+    db.close();
+  }
+});
+
+test('startup reclassifies channels created by an older build after the schema upgrade', () => {
+  const db = new Database(':memory:');
+  try {
+    ensureSchema(db);
+    // An old build omits media_kind when creating a channel in the upgraded DB.
+    const channelId = createAnime(db, 'youtube-channel:UCnew');
+    db.prepare('UPDATE imm_anime SET anilist_id = 321 WHERE anime_id = ?').run(channelId);
+    const animeId = createAnime(db, 'Regular anime');
+    const videoId = createVideo(db, 'older-build');
+    db.prepare(
+      'UPDATE imm_videos SET anime_id = ?, anime_assignment_locked = 1 WHERE video_id = ?',
+    ).run(channelId, videoId);
+    db.prepare(
+      'INSERT INTO imm_lifetime_anime(anime_id, total_active_ms, total_cards) VALUES (?, 120000, 5)',
+    ).run(channelId);
+    assert.equal(getAnimeLibrary(db)[0]?.mediaKind, 'anime');
+    ensureSchema(db);
+    const channel = getAnimeLibrary(db)[0];
+    assert.equal(channel?.animeId, channelId);
+    assert.equal(channel?.mediaKind, 'youtube');
+    assert.equal(
+      (
+        db.prepare('SELECT anilist_id FROM imm_anime WHERE anime_id = ?').get(channelId) as {
+          anilist_id: number | null;
+        }
+      ).anilist_id,
+      null,
+    );
+    assert.equal(channel?.totalActiveMs, 120000);
+    assert.equal(channel?.totalCards, 5);
+    assert.equal(linkYoutubeVideoToAnimeRecord(db, videoId, metadata), channelId);
+    const anime = db.prepare('SELECT media_kind FROM imm_anime WHERE anime_id = ?').get(animeId);
+    assert.ok(anime && typeof anime === 'object' && 'media_kind' in anime);
+    assert.equal(anime.media_kind, 'anime');
+  } finally {
+    db.close();
+  }
+});
+
+test('title identity and aliases never cross media kinds', () => {
+  const db = new Database(':memory:');
+  try {
+    ensureSchema(db);
+    const animeId = createAnime(db, 'Shared title');
+    const input = {
+      mediaKind: 'youtube' as const,
+      parsedTitle: 'Shared title',
+      canonicalTitle: 'Shared title',
+      anilistId: null,
+      titleRomaji: null,
+      titleEnglish: null,
+      titleNative: null,
+      metadataJson: null,
+    };
+    const channelId = getOrCreateAnimeRecord(db, input);
+    assert.notEqual(channelId, animeId);
+    db.prepare('UPDATE imm_anime SET anilist_id = 123 WHERE anime_id = ?').run(channelId);
+    assert.equal(getOrCreateAnimeRecord(db, input), channelId);
+    assert.equal(
+      (
+        db.prepare('SELECT anilist_id FROM imm_anime WHERE anime_id = ?').get(channelId) as {
+          anilist_id: number | null;
+        }
+      ).anilist_id,
+      null,
+    );
+    assert.equal(createAnime(db, 'Shared title'), animeId);
+    db.prepare(
+      'INSERT INTO imm_anime_title_aliases(normalized_title_key, anime_id) VALUES (?, ?)',
+    ).run('alias title', animeId);
+    assert.notEqual(getOrCreateAnimeRecord(db, { ...input, parsedTitle: 'Alias title' }), animeId);
+    assert.throws(() =>
+      db
+        .prepare(
+          "INSERT INTO imm_anime(normalized_title_key, canonical_title, media_kind) VALUES ('shared title', 'duplicate', 'youtube')",
+        )
+        .run(),
+    );
+  } finally {
+    db.close();
+  }
+});
+
+test('schema 24 title constraint migration preserves referenced data', () => {
+  const db = new Database(':memory:');
+  try {
+    // Reproduce the original table-level uniqueness constraint.
+    db.exec(`CREATE TABLE imm_anime(
+      anime_id INTEGER PRIMARY KEY AUTOINCREMENT,
+      normalized_title_key TEXT NOT NULL UNIQUE,
+      canonical_title TEXT NOT NULL,
+      anilist_id INTEGER UNIQUE,
+      title_romaji TEXT, title_english TEXT, title_native TEXT,
+      episodes_total INTEGER, description TEXT, metadata_json TEXT,
+      CREATED_DATE TEXT, LAST_UPDATE_DATE TEXT,
+      media_kind TEXT NOT NULL DEFAULT 'anime' CHECK(media_kind IN ('anime', 'youtube'))
+    )`);
+    ensureSchema(db);
+    const animeId = createAnime(db, 'Shared title');
+    const videoId = createVideo(db, 'migration-video');
+    db.prepare(
+      'UPDATE imm_videos SET anime_id = ?, anime_assignment_locked = 1 WHERE video_id = ?',
+    ).run(animeId, videoId);
+    db.prepare(
+      'INSERT INTO imm_lifetime_anime(anime_id, total_active_ms, total_cards) VALUES (?, 123, 4)',
+    ).run(animeId);
+    // Restore the old constraint while leaving child rows populated.
+    db.exec(`PRAGMA foreign_keys = OFF;
+      CREATE TABLE old_anime AS SELECT * FROM imm_anime;
+      DROP TABLE imm_anime;
+      CREATE TABLE imm_anime(
+        anime_id INTEGER PRIMARY KEY AUTOINCREMENT, normalized_title_key TEXT NOT NULL UNIQUE,
+        canonical_title TEXT NOT NULL, anilist_id INTEGER UNIQUE,
+        title_romaji TEXT, title_english TEXT, title_native TEXT, episodes_total INTEGER,
+        description TEXT, metadata_json TEXT, CREATED_DATE TEXT, LAST_UPDATE_DATE TEXT,
+        media_kind TEXT NOT NULL DEFAULT 'anime' CHECK(media_kind IN ('anime', 'youtube')));
+      INSERT INTO imm_anime SELECT * FROM old_anime;
+      DROP TABLE old_anime;
+      DELETE FROM imm_schema_version;
+      INSERT INTO imm_schema_version VALUES (24, 0);
+      PRAGMA foreign_keys = ON;`);
+    ensureSchema(db);
+    ensureSchema(db);
+    assert.deepEqual(db.prepare('PRAGMA foreign_key_check').all(), []);
+    assert.equal(
+      (db.prepare('PRAGMA foreign_keys').get() as { foreign_keys: number }).foreign_keys,
+      1,
+    );
+    assert.equal(
+      (
+        db.prepare('SELECT anime_id FROM imm_videos WHERE video_id = ?').get(videoId) as {
+          anime_id: number;
+        }
+      ).anime_id,
+      animeId,
+    );
+    assert.equal(
+      (
+        db
+          .prepare('SELECT total_active_ms FROM imm_lifetime_anime WHERE anime_id = ?')
+          .get(animeId) as { total_active_ms: number }
+      ).total_active_ms,
+      123,
+    );
+    db.prepare(
+      "INSERT INTO imm_anime(normalized_title_key, canonical_title, media_kind) VALUES ('shared title', 'Channel', 'youtube')",
+    ).run();
+  } finally {
+    db.close();
+  }
+});

src/core/services/stats-server/library-routes.ts

@@ -1,6 +1,9 @@
 import type { Hono } from 'hono';
 import { statsJson } from '../../../types/stats-http-contract.js';
-import { UNKNOWN_MOVE_TARGET_MESSAGE } from '../immersion-tracker/anime-merge.js';
+import {
+  MEDIA_KIND_MISMATCH_MESSAGE,
+  UNKNOWN_MOVE_TARGET_MESSAGE,
+} from '../immersion-tracker/anime-merge.js';
 import type { ImmersionTrackerService } from '../immersion-tracker-service.js';
 import {
   buildSentenceSearchOptions,
@@ -245,7 +248,15 @@ export function registerStatsLibraryRoutes(
     const body = await c.req.json().catch(() => null);
     const sourceAnimeIds = parsePositiveIdList(body?.sourceAnimeIds).filter((id) => id !== animeId);
     if (sourceAnimeIds.length === 0) return c.body(null, 400);
-    const summary = await tracker.mergeAnime(animeId, sourceAnimeIds);
+    let summary: Awaited<ReturnType<typeof tracker.mergeAnime>>;
+    try {
+      summary = await tracker.mergeAnime(animeId, sourceAnimeIds);
+    } catch (error) {
+      if (error instanceof Error && error.message === MEDIA_KIND_MISMATCH_MESSAGE) {
+        return c.text(MEDIA_KIND_MISMATCH_MESSAGE, 409);
+      }
+      throw error;
+    }
     // Nothing folded means the target or every source was already gone, so the
     // caller should not be told the merge succeeded.
     if (summary.mergedAnimeIds.length === 0) return c.body(null, 404);
@@ -281,6 +292,9 @@ export function registerStatsLibraryRoutes(
       if (error instanceof Error && error.message === UNKNOWN_MOVE_TARGET_MESSAGE) {
         return c.body(null, 404);
       }
+      if (error instanceof Error && error.message === MEDIA_KIND_MISMATCH_MESSAGE) {
+        return c.text(MEDIA_KIND_MISMATCH_MESSAGE, 409);
+      }
       throw error;
     }
   });

src/core/services/stats-sync/merge-catalog.ts

@@ -2,6 +2,7 @@ import { selectAll, selectOne, type SqlRow, type SyncDb } from './libsql-driver'
 import { insertRow, tableExists, type SyncMergeSummary } from './shared';
 
 const ANIME_COPY_COLUMNS = [
+  'media_kind',
   'normalized_title_key',
   'canonical_title',
   'anilist_id',
@@ -98,11 +99,28 @@ export function mergeAnime(
   summary: SyncMergeSummary,
 ): Map<number, number> {
   const map = new Map<number, number>();
-  const byAnilist = local.query('SELECT anime_id FROM imm_anime WHERE anilist_id = ?');
-  const byTitleKey = local.query('SELECT anime_id FROM imm_anime WHERE normalized_title_key = ?');
+  const byAnilist = local.query(
+    "SELECT anime_id FROM imm_anime WHERE anilist_id = ? AND media_kind = 'anime'",
+  );
+  const byTitleKey = local.query(
+    'SELECT anime_id FROM imm_anime WHERE normalized_title_key = ? AND media_kind = ?',
+  );
+  // A pre-classification channel can be repaired, but a genuine anime sharing
+  // its title must remain a separate entry.
+  const legacyChannel = local.query(`SELECT anime_id FROM imm_anime
+    WHERE normalized_title_key = ? AND media_kind = 'anime' AND (
+      normalized_title_key LIKE 'youtube channel %'
+      OR CASE WHEN json_valid(metadata_json)
+        THEN json_extract(metadata_json, '$.source') = 'youtube-channel' ELSE 0 END
+    )`);
+  const releaseChannelAnilistId = local.query(
+    "UPDATE imm_anime SET anilist_id = NULL WHERE media_kind = 'youtube' AND anilist_id = ?",
+  );
   const fillMissing = local.query(
     `UPDATE imm_anime
      SET
+       media_kind = ?,
+       anilist_id = CASE WHEN ? = 'youtube' THEN NULL ELSE anilist_id END,
        title_romaji = COALESCE(title_romaji, ?),
        title_english = COALESCE(title_english, ?),
        title_native = COALESCE(title_native, ?),
@@ -116,12 +134,24 @@ export function mergeAnime(
     `SELECT anime_id, ${ANIME_COPY_COLUMNS.join(', ')} FROM imm_anime`,
   )) {
     const remoteId = Number(row.anime_id);
-    const existing = ((row.anilist_id !== null ? byAnilist.get(row.anilist_id) : undefined) ??
-      byTitleKey.get(row.normalized_title_key)) as SqlRow | undefined;
+    if (row.media_kind === 'anime' && row.anilist_id !== null) {
+      // AniList identifiers belong to anime, including when an older peer
+      // incorrectly attached one to a channel.
+      releaseChannelAnilistId.run(row.anilist_id);
+    }
+    const existing = ((row.media_kind === 'anime' && row.anilist_id !== null
+      ? byAnilist.get(row.anilist_id)
+      : undefined) ??
+      byTitleKey.get(row.normalized_title_key, row.media_kind) ??
+      (row.media_kind === 'youtube' ? legacyChannel.get(row.normalized_title_key) : undefined)) as
+      | SqlRow
+      | undefined;
     if (existing) {
       const localId = Number(existing.anime_id);
       map.set(remoteId, localId);
       fillMissing.run(
+        row.media_kind,
+        row.media_kind,
         row.title_romaji,
         row.title_english,
         row.title_native,
@@ -133,7 +163,9 @@ export function mergeAnime(
     }
     // No local row matched by anilist_id (checked first in `existing` above)
     // or title key, so the remote anilist_id — if any — is free to insert as-is.
-    const values = ANIME_COPY_COLUMNS.map((column) => row[column]);
+    const values = ANIME_COPY_COLUMNS.map((column) =>
+      column === 'anilist_id' && row.media_kind !== 'anime' ? null : row[column],
+    );
     map.set(remoteId, insertRow(local, 'imm_anime', ANIME_COPY_COLUMNS, values));
     summary.animeAdded += 1;
   }

src/core/services/stats-sync/merge-occurrences.test.ts

@@ -98,3 +98,122 @@ for (const legacyOccurrences of [false, true]) {
     }
   });
 }
+
+test('sync preserves the YouTube media kind when adding a channel', () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-sync-youtube-'));
+  try {
+    const localPath = buildDb(dir, 'local.sqlite', {
+      word: '猫',
+      seenMs: BASE_MS,
+      legacyOccurrences: false,
+    });
+    const remotePath = buildDb(dir, 'remote.sqlite', {
+      word: '犬',
+      seenMs: BASE_MS,
+      legacyOccurrences: false,
+    });
+    const remote = new Database(remotePath);
+    remote.exec("UPDATE imm_anime SET media_kind = 'youtube'");
+    remote.close();
+    mergeSnapshotIntoDb(localPath, remotePath);
+    const local = new Database(localPath);
+    try {
+      const row = local
+        .prepare(
+          "SELECT media_kind FROM imm_anime WHERE normalized_title_key = 'key-remote.sqlite'",
+        )
+        .get();
+      assert.ok(row && typeof row === 'object' && 'media_kind' in row);
+      assert.equal(row.media_kind, 'youtube');
+    } finally {
+      local.close();
+    }
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});
+
+test('sync separates same-title kinds and repairs only identifiable legacy channels', () => {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'subminer-sync-kinds-'));
+  const localPath = buildDb(dir, 'local', {
+    word: 'local',
+    seenMs: BASE_MS,
+    legacyOccurrences: false,
+  });
+  const remotePath = buildDb(dir, 'remote', {
+    word: 'remote',
+    seenMs: BASE_MS,
+    legacyOccurrences: false,
+  });
+  try {
+    const local = new Database(localPath);
+    local.exec(`UPDATE imm_anime SET normalized_title_key = 'shared', anilist_id = 42;
+      INSERT INTO imm_anime(anime_id, normalized_title_key, canonical_title, metadata_json, title_english, LAST_UPDATE_DATE)
+        VALUES (2, 'legacy', 'Local channel', '{"source":"youtube-channel"}', 'Keep local', '9999999999999');
+      UPDATE imm_anime SET anilist_id = 99 WHERE anime_id = 2;
+      INSERT INTO imm_anime(anime_id, normalized_title_key, canonical_title, media_kind, anilist_id)
+        VALUES (3, 'other shared', 'Channel with bad ID', 'youtube', 77);`);
+    local.close();
+    const remote = new Database(remotePath);
+    remote.exec(`UPDATE imm_anime SET normalized_title_key = 'shared', media_kind = 'youtube', anilist_id = 42;
+      INSERT INTO imm_anime(anime_id, normalized_title_key, canonical_title, media_kind, title_english, description, LAST_UPDATE_DATE)
+        VALUES (2, 'legacy', 'Remote channel', 'youtube', 'Remote title', 'Fill missing', '1');
+      INSERT INTO imm_anime(anime_id, normalized_title_key, canonical_title, media_kind, anilist_id)
+        VALUES (3, 'other shared', 'Real anime', 'anime', 77);`);
+    remote.close();
+    mergeSnapshotIntoDb(localPath, remotePath);
+    mergeSnapshotIntoDb(localPath, remotePath);
+    const db = new Database(localPath);
+    try {
+      const rows = db
+        .prepare(
+          'SELECT media_kind FROM imm_anime WHERE normalized_title_key = ? ORDER BY media_kind',
+        )
+        .all('shared');
+      assert.deepEqual(rows, [{ media_kind: 'anime' }, { media_kind: 'youtube' }]);
+      assert.deepEqual(
+        db
+          .prepare(
+            "SELECT media_kind FROM imm_anime WHERE normalized_title_key = 'other shared' ORDER BY media_kind",
+          )
+          .all(),
+        [{ media_kind: 'anime' }, { media_kind: 'youtube' }],
+      );
+      assert.equal(
+        (
+          db.prepare('SELECT media_kind FROM imm_anime WHERE anilist_id = 77').get() as {
+            media_kind: string;
+          }
+        ).media_kind,
+        'anime',
+      );
+      assert.deepEqual(
+        db
+          .prepare(
+            'SELECT media_kind, anilist_id, title_english, description FROM imm_anime WHERE anime_id = 2',
+          )
+          .all()[0],
+        {
+          media_kind: 'youtube',
+          anilist_id: null,
+          title_english: 'Keep local',
+          description: 'Fill missing',
+        },
+      );
+      assert.equal(
+        (
+          db
+            .prepare(
+              "SELECT a.media_kind FROM imm_videos v JOIN imm_anime a ON a.anime_id = v.anime_id WHERE v.video_key = 'video-remote'",
+            )
+            .get() as { media_kind: string }
+        ).media_kind,
+        'youtube',
+      );
+    } finally {
+      db.close();
+    }
+  } finally {
+    fs.rmSync(dir, { recursive: true, force: true });
+  }
+});