Trakt Episode Mapping for Trakt Anime

composeApp/src/commonMain/kotlin/com/nuvio/app/features/details/SeriesPlaybackResolver.kt

@@ -85,19 +85,35 @@ internal fun MetaDetails.nextReleasedEpisodeAfter(
         seasonNumber = seasonNumber,
         episodeNumber = episodeNumber,
     )
-    val candidates = sortedEpisodes
+    var watchedIndex = sortedEpisodes.indexOfFirst { episode ->
-        .dropWhile { episode ->
         buildPlaybackVideoId(
             content = WatchingContentRef(type = type, id = id),
             seasonNumber = episode.season,
             episodeNumber = episode.episode,
             fallbackVideoId = episode.id,
-            ) != watchedVideoId
+        ) == watchedVideoId
     }
-        .drop(1)
+
+    // Fallback: if the seed wasn't found by season+episode (anime with absolute
+    // numbering on Trakt vs multi-season on addon), try global index matching.
+    if (watchedIndex < 0 && seasonNumber != null && episodeNumber != null) {
+        val addonSeasons = sortedEpisodes.mapTo(mutableSetOf()) { it.season }
+        if (seasonNumber == 1 && addonSeasons.size > 1 && episodeNumber > 0) {
+            val globalIndex = episodeNumber - 1
+            if (globalIndex in sortedEpisodes.indices) {
+                watchedIndex = globalIndex
+            }
+        }
+    }
+
+    if (watchedIndex < 0) return null
+
+    val watchedEpisodeSeason = sortedEpisodes[watchedIndex].season
+    val candidates = sortedEpisodes
+        .drop(watchedIndex + 1)
         .filter { episode ->
             shouldSurfaceNextEpisode(
-                watchedSeasonNumber = seasonNumber,
+                watchedSeasonNumber = watchedEpisodeSeason,
                 candidateSeasonNumber = episode.season,
                 todayIsoDate = todayIsoDate,
                 releasedDate = episode.released,

composeApp/src/commonMain/kotlin/com/nuvio/app/features/trakt/TraktEpisodeMappingService.kt

@@ -0,0 +1,492 @@
+package com.nuvio.app.features.trakt
+
+import co.touchlab.kermit.Logger
+import com.nuvio.app.features.addons.httpGetTextWithHeaders
+import com.nuvio.app.features.details.MetaDetailsRepository
+import com.nuvio.app.features.details.MetaVideo
+import kotlinx.coroutines.CompletableDeferred
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.coroutines.withTimeoutOrNull
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+
+private const val BASE_URL = "https://api.trakt.tv"
+
+/**
+ * Handles episode number remapping between addon metadata (which may use multi-season
+ * numbering for anime) and Trakt (which often uses absolute/single-season numbering).
+ *
+ * Example: An addon lists "Attack on Titan" as S1E1–S1E25, S2E1–S2E12, etc.
+ * Trakt may list it as S1E1–S1E87 (absolute numbering).
+ *
+ * This service detects the mismatch and provides bidirectional mapping.
+ */
+object TraktEpisodeMappingService {
+    private val log = Logger.withTag("TraktEpMapSvc")
+    private val json = Json { ignoreUnknownKeys = true }
+
+    private val cacheMutex = Mutex()
+    private val mappingCache = mutableMapOf<String, EpisodeMappingEntry>()
+    private val reverseMappingCache = mutableMapOf<String, EpisodeMappingEntry>()
+    private val addonEpisodesCache = mutableMapOf<String, List<EpisodeMappingEntry>>()
+    private val traktEpisodesCache = mutableMapOf<String, List<EpisodeMappingEntry>>()
+    // In-flight dedup: prevents multiple concurrent coroutines from fetching
+    // the same show's addon episodes simultaneously.
+    private val addonEpisodesInFlight = mutableMapOf<String, CompletableDeferred<List<EpisodeMappingEntry>>>()
+
+    // ── Public API ────────────────────────────────────────────────────────
+
+    /**
+     * Resolves the Trakt-side season/episode for a given addon season/episode.
+     * Used when pushing watched status TO Trakt (forward mapping: addon → Trakt).
+     *
+     * Returns null if no remapping is needed (same structure) or if mapping fails.
+     */
+    suspend fun resolveEpisodeMapping(
+        contentId: String?,
+        contentType: String?,
+        videoId: String?,
+        season: Int?,
+        episode: Int?,
+    ): EpisodeMappingEntry? {
+        val key = cacheKey(contentId, contentType, videoId, season, episode) ?: return null
+        cacheMutex.withLock {
+            mappingCache[key]?.let { return it }
+        }
+
+        val requestedSeason = season ?: return null
+        val requestedEpisode = episode ?: return null
+        val resolvedContentId = contentId?.takeIf { it.isNotBlank() } ?: return null
+        val resolvedContentType = contentType?.takeIf { it.isNotBlank() } ?: return null
+
+        val addonEpisodes = getAddonEpisodes(resolvedContentId, resolvedContentType)
+        if (addonEpisodes.isEmpty()) return null
+
+        val showLookupId = resolveShowLookupId(contentId = resolvedContentId, videoId = videoId) ?: return null
+        val traktEpisodes = getTraktEpisodes(showLookupId)
+        if (traktEpisodes.isEmpty()) return null
+
+        if (hasSameSeasonStructure(addonEpisodes, traktEpisodes)) {
+            return null
+        }
+
+        val mapped = remapEpisodeByTitleOrIndex(
+            requestedSeason = requestedSeason,
+            requestedEpisode = requestedEpisode,
+            requestedVideoId = videoId,
+            requestedTitle = null,
+            addonEpisodes = addonEpisodes,
+            traktEpisodes = traktEpisodes,
+        ) ?: return null
+
+        cacheMutex.withLock {
+            mappingCache[key] = mapped
+        }
+        return mapped
+    }
+
+    /**
+     * Resolves the addon-side season/episode for a given Trakt season/episode.
+     * Used when reading progress FROM Trakt to find the correct addon episode
+     * (reverse mapping: Trakt → addon).
+     *
+     * Returns null if no remapping is needed or if mapping fails.
+     */
+    suspend fun resolveAddonEpisodeMapping(
+        contentId: String?,
+        contentType: String?,
+        season: Int?,
+        episode: Int?,
+        episodeTitle: String? = null,
+    ): EpisodeMappingEntry? {
+        val requestedSeason = season ?: return null
+        val requestedEpisode = episode ?: return null
+        val resolvedContentId = contentId?.takeIf { it.isNotBlank() } ?: return null
+        val resolvedContentType = contentType?.takeIf { it.isNotBlank() } ?: return null
+
+        val reverseKey = reverseCacheKey(
+            contentId = resolvedContentId,
+            contentType = resolvedContentType,
+            season = requestedSeason,
+            episode = requestedEpisode,
+            title = episodeTitle,
+        )
+        cacheMutex.withLock {
+            reverseMappingCache[reverseKey]?.let { return it }
+        }
+
+        val addonEpisodes = getAddonEpisodes(resolvedContentId, resolvedContentType)
+        if (addonEpisodes.isEmpty()) return null
+
+        val showLookupId = resolveShowLookupId(contentId = resolvedContentId, videoId = null) ?: return null
+        val traktEpisodes = getTraktEpisodes(showLookupId)
+        if (traktEpisodes.isEmpty()) return null
+
+        val addonHasEpisode = addonEpisodes.any {
+            it.season == requestedSeason && it.episode == requestedEpisode
+        }
+        if (addonHasEpisode && hasSameSeasonStructure(addonEpisodes, traktEpisodes)) {
+            return null
+        }
+
+        val mapped = reverseRemapEpisodeByTitleOrIndex(
+            requestedSeason = requestedSeason,
+            requestedEpisode = requestedEpisode,
+            requestedTitle = episodeTitle,
+            addonEpisodes = addonEpisodes,
+            traktEpisodes = traktEpisodes,
+        ) ?: return null
+
+        cacheMutex.withLock {
+            reverseMappingCache[reverseKey] = mapped
+        }
+        return mapped
+    }
+
+    suspend fun getCachedEpisodeMapping(
+        contentId: String?,
+        contentType: String?,
+        videoId: String?,
+        season: Int?,
+        episode: Int?,
+    ): EpisodeMappingEntry? {
+        val key = cacheKey(contentId, contentType, videoId, season, episode) ?: return null
+        return cacheMutex.withLock { mappingCache[key] }
+    }
+
+    suspend fun prefetchEpisodeMapping(
+        contentId: String?,
+        contentType: String?,
+        videoId: String?,
+        season: Int?,
+        episode: Int?,
+    ): EpisodeMappingEntry? {
+        return resolveEpisodeMapping(contentId, contentType, videoId, season, episode)
+    }
+
+    fun clearCache() {
+        mappingCache.clear()
+        reverseMappingCache.clear()
+        addonEpisodesCache.clear()
+        traktEpisodesCache.clear()
+    }
+
+    // ── Season structure comparison ───────────────────────────────────────
+
+    private fun hasSameSeasonStructure(
+        addonEpisodes: List<EpisodeMappingEntry>,
+        traktEpisodes: List<EpisodeMappingEntry>,
+    ): Boolean {
+        val addonSeasons = addonEpisodes.mapTo(mutableSetOf()) { it.season }
+        val traktSeasons = traktEpisodes.mapTo(mutableSetOf()) { it.season }
+        return addonSeasons == traktSeasons
+    }
+
+    // ── Forward mapping: addon → Trakt ──────────────────────────────────
+
+    private fun remapEpisodeByTitleOrIndex(
+        requestedSeason: Int,
+        requestedEpisode: Int,
+        requestedVideoId: String?,
+        requestedTitle: String?,
+        addonEpisodes: List<EpisodeMappingEntry>,
+        traktEpisodes: List<EpisodeMappingEntry>,
+    ): EpisodeMappingEntry? {
+        // Find the addon episode entry
+        val addonEntry = addonEpisodes.firstOrNull {
+            it.season == requestedSeason && it.episode == requestedEpisode
+        } ?: if (!requestedVideoId.isNullOrBlank()) {
+            addonEpisodes.firstOrNull { it.videoId == requestedVideoId }
+        } else null
+        ?: return null
+
+        // Try title match first
+        val titleToMatch = addonEntry.title?.takeIf { it.isNotBlank() } ?: requestedTitle
+        if (!titleToMatch.isNullOrBlank()) {
+            val titleMatch = traktEpisodes.firstOrNull { target ->
+                !target.title.isNullOrBlank() &&
+                    normalizeTitle(target.title) == normalizeTitle(titleToMatch)
+            }
+            if (titleMatch != null) {
+                return titleMatch
+            }
+        }
+
+        // Fallback: global index mapping
+        val addonIndex = addonEpisodes.indexOf(addonEntry)
+        if (addonIndex < 0 || addonIndex >= traktEpisodes.size) return null
+
+        return traktEpisodes[addonIndex]
+    }
+
+    // ── Reverse mapping: Trakt → addon ──────────────────────────────────
+
+    private fun reverseRemapEpisodeByTitleOrIndex(
+        requestedSeason: Int,
+        requestedEpisode: Int,
+        requestedTitle: String?,
+        addonEpisodes: List<EpisodeMappingEntry>,
+        traktEpisodes: List<EpisodeMappingEntry>,
+    ): EpisodeMappingEntry? {
+        // Find the Trakt episode entry
+        val traktEntry = traktEpisodes.firstOrNull {
+            it.season == requestedSeason && it.episode == requestedEpisode
+        } ?: return null
+
+        // Try title match first
+        val titleToMatch = traktEntry.title?.takeIf { it.isNotBlank() } ?: requestedTitle
+        if (!titleToMatch.isNullOrBlank()) {
+            val titleMatch = addonEpisodes.firstOrNull { target ->
+                !target.title.isNullOrBlank() &&
+                    normalizeTitle(target.title) == normalizeTitle(titleToMatch)
+            }
+            if (titleMatch != null) {
+                return titleMatch
+            }
+        }
+
+        // Fallback: global index mapping
+        val traktIndex = traktEpisodes.indexOf(traktEntry)
+        if (traktIndex < 0 || traktIndex >= addonEpisodes.size) return null
+
+        return addonEpisodes[traktIndex]
+    }
+
+    // ── Addon episodes fetching (with dedup) ───────────────────────────
+
+    private suspend fun getAddonEpisodes(
+        contentId: String,
+        contentType: String,
+    ): List<EpisodeMappingEntry> {
+        val cacheKey = addonEpisodesCacheKey(contentId, contentType)
+
+        // Fast path: cache hit
+        cacheMutex.withLock {
+            addonEpisodesCache[cacheKey]?.let { return it }
+        }
+
+        // Dedup: if another coroutine is already fetching this show, await its result.
+        val existingDeferred = cacheMutex.withLock { addonEpisodesInFlight[cacheKey] }
+        if (existingDeferred != null) {
+            return try { existingDeferred.await() } catch (_: Exception) { emptyList() }
+        }
+
+        // Register ourselves as the in-flight fetcher.
+        val deferred = CompletableDeferred<List<EpisodeMappingEntry>>()
+        val weOwn = cacheMutex.withLock {
+            // Double-check: cache or another flight may have appeared while we waited.
+            addonEpisodesCache[cacheKey]?.let { return it }
+            if (addonEpisodesInFlight.containsKey(cacheKey)) {
+                false
+            } else {
+                addonEpisodesInFlight[cacheKey] = deferred
+                true
+            }
+        }
+        if (!weOwn) {
+            val other = cacheMutex.withLock { addonEpisodesInFlight[cacheKey] }
+            return try { other?.await() ?: emptyList() } catch (_: Exception) { emptyList() }
+        }
+
+        return try {
+            val addonEpisodes = fetchAddonEpisodes(contentId, contentType)
+            if (addonEpisodes.isNotEmpty()) {
+                cacheMutex.withLock { addonEpisodesCache[cacheKey] = addonEpisodes }
+            }
+            deferred.complete(addonEpisodes)
+            addonEpisodes
+        } catch (e: Exception) {
+            if (e is CancellationException) throw e
+            deferred.completeExceptionally(e)
+            emptyList()
+        } finally {
+            cacheMutex.withLock { addonEpisodesInFlight.remove(cacheKey) }
+        }
+    }
+
+    private suspend fun fetchAddonEpisodes(
+        contentId: String,
+        contentType: String,
+    ): List<EpisodeMappingEntry> {
+        val typeCandidates = buildList {
+            val normalized = contentType.lowercase()
+            if (normalized.isNotBlank()) add(normalized)
+            if (normalized in listOf("series", "tv")) {
+                add("series")
+                add("tv")
+            }
+        }.distinct()
+        if (typeCandidates.isEmpty()) return emptyList()
+
+        val idCandidates = buildList {
+            add(contentId)
+            if (contentId.startsWith("tmdb:")) add(contentId.substringAfter(':'))
+            if (contentId.startsWith("trakt:")) add(contentId.substringAfter(':'))
+        }.distinct()
+
+        for (type in typeCandidates) {
+            for (candidateId in idCandidates) {
+                val meta = withTimeoutOrNull(3_500L) {
+                    MetaDetailsRepository.fetch(type = type, id = candidateId)
+                } ?: continue
+                val episodes = meta.videos.toEpisodeMappingEntries()
+                if (episodes.isNotEmpty()) return episodes
+            }
+        }
+        return emptyList()
+    }
+
+    // ── Trakt episodes fetching ─────────────────────────────────────────
+
+    private suspend fun getTraktEpisodes(showLookupId: String): List<EpisodeMappingEntry> {
+        cacheMutex.withLock {
+            traktEpisodesCache[showLookupId]?.let { return it }
+        }
+
+        val headers = TraktAuthRepository.authorizedHeaders() ?: return emptyList()
+
+        // Trakt API: GET /shows/{id}/seasons?extended=episodes
+        val url = "$BASE_URL/shows/$showLookupId/seasons?extended=episodes"
+        val payload = runCatching {
+            httpGetTextWithHeaders(url = url, headers = headers)
+        }.onFailure { e ->
+            if (e is CancellationException) throw e
+            log.w { "getTraktEpisodes: seasons request failed id=$showLookupId: ${e.message}" }
+        }.getOrNull() ?: return emptyList()
+
+        val traktEpisodes = parseTraktSeasonsPayload(payload)
+        if (traktEpisodes.isNotEmpty()) {
+            cacheMutex.withLock {
+                traktEpisodesCache[showLookupId] = traktEpisodes
+            }
+        }
+        return traktEpisodes
+    }
+
+    private fun parseTraktSeasonsPayload(payload: String): List<EpisodeMappingEntry> {
+        val seasons = runCatching {
+            json.decodeFromString<List<TraktSeasonDto>>(payload)
+        }.getOrNull() ?: return emptyList()
+
+        return seasons
+            .asSequence()
+            .filter { (it.number ?: 0) > 0 } // Skip specials (season 0)
+            .sortedBy { it.number }
+            .flatMap { seasonDto ->
+                seasonDto.episodes.orEmpty().asSequence().mapNotNull { episodeDto ->
+                    val seasonNumber = episodeDto.season ?: seasonDto.number ?: return@mapNotNull null
+                    val episodeNumber = episodeDto.number ?: return@mapNotNull null
+                    EpisodeMappingEntry(
+                        season = seasonNumber,
+                        episode = episodeNumber,
+                        title = episodeDto.title,
+                    )
+                }
+            }
+            .toList()
+    }
+
+    // ── Helpers ───────────────────────────────────────────────────────────
+
+    private fun resolveShowLookupId(contentId: String?, videoId: String?): String? {
+        val contentIds = parseTraktContentIds(contentId)
+        if (contentIds.hasAnyId()) {
+            return when {
+                !contentIds.imdb.isNullOrBlank() -> contentIds.imdb
+                contentIds.trakt != null -> contentIds.trakt.toString()
+                contentIds.tmdb != null -> contentIds.tmdb.toString()
+                else -> null
+            }
+        }
+
+        val videoIds = parseTraktContentIds(videoId)
+        return when {
+            !videoIds.imdb.isNullOrBlank() -> videoIds.imdb
+            videoIds.trakt != null -> videoIds.trakt.toString()
+            videoIds.tmdb != null -> videoIds.tmdb.toString()
+            else -> null
+        }
+    }
+
+    private fun TraktExternalIds.hasAnyId(): Boolean =
+        !imdb.isNullOrBlank() || trakt != null || tmdb != null
+
+    private fun cacheKey(
+        contentId: String?,
+        contentType: String?,
+        videoId: String?,
+        season: Int?,
+        episode: Int?,
+    ): String? {
+        val resolvedContentId = contentId?.trim()?.takeIf { it.isNotBlank() } ?: return null
+        val resolvedContentType = contentType?.trim()?.lowercase()?.takeIf { it.isNotBlank() } ?: return null
+        val resolvedSeason = season ?: return null
+        val resolvedEpisode = episode ?: return null
+        val resolvedVideoId = videoId?.trim().orEmpty()
+        return "$resolvedContentType|$resolvedContentId|$resolvedVideoId|$resolvedSeason|$resolvedEpisode"
+    }
+
+    private fun reverseCacheKey(
+        contentId: String,
+        contentType: String,
+        season: Int,
+        episode: Int,
+        title: String?,
+    ): String {
+        val normalizedTitle = title?.trim()?.lowercase().orEmpty()
+        return "reverse|${contentType.trim().lowercase()}|${contentId.trim()}|$season|$episode|$normalizedTitle"
+    }
+
+    private fun addonEpisodesCacheKey(contentId: String, contentType: String): String {
+        return "${contentType.trim().lowercase()}|${contentId.trim()}"
+    }
+
+    private fun List<MetaVideo>.toEpisodeMappingEntries(): List<EpisodeMappingEntry> {
+        return asSequence()
+            .mapNotNull { video ->
+                val season = video.season ?: return@mapNotNull null
+                val episode = video.episode ?: return@mapNotNull null
+                if (season <= 0) return@mapNotNull null
+                EpisodeMappingEntry(
+                    season = season,
+                    episode = episode,
+                    title = video.title.takeIf { it.isNotBlank() },
+                    videoId = video.id.takeIf { it.isNotBlank() },
+                )
+            }
+            .distinctBy { it.videoId ?: "${it.season}:${it.episode}" }
+            .sortedWith(compareBy(EpisodeMappingEntry::season, EpisodeMappingEntry::episode))
+            .toList()
+    }
+
+    private fun normalizeTitle(title: String?): String =
+        title.orEmpty().trim().lowercase()
+            .replace(Regex("[^a-z0-9]"), "")
+}
+
+// ── Data classes ────────────────────────────────────────────────────────
+
+data class EpisodeMappingEntry(
+    val season: Int,
+    val episode: Int,
+    val title: String? = null,
+    val videoId: String? = null,
+)
+
+// ── Trakt API DTOs for seasons endpoint ─────────────────────────────────
+
+@Serializable
+private data class TraktSeasonDto(
+    @SerialName("number") val number: Int? = null,
+    @SerialName("episodes") val episodes: List<TraktSeasonEpisodeDto>? = null,
+)
+
+@Serializable
+private data class TraktSeasonEpisodeDto(
+    @SerialName("number") val number: Int? = null,
+    @SerialName("season") val season: Int? = null,
+    @SerialName("title") val title: String? = null,
+)

composeApp/src/commonMain/kotlin/com/nuvio/app/features/trakt/TraktProgressRepository.kt

@@ -434,9 +434,31 @@ object TraktProgressRepository {
 
         entries.map { entry ->
             val meta = metadataByContent[entry.parentMetaType to entry.parentMetaId] ?: return@map entry
-            val episode = if (entry.seasonNumber != null && entry.episodeNumber != null) {
+            var resolvedSeason = entry.seasonNumber
-                meta.videos.firstOrNull { video ->
+            var resolvedEpisode = entry.episodeNumber
-                    video.season == entry.seasonNumber && video.episode == entry.episodeNumber
+
+            val episode = if (resolvedSeason != null && resolvedEpisode != null) {
+                // Try direct match first
+                val directMatch = meta.videos.firstOrNull { video ->
+                    video.season == resolvedSeason && video.episode == resolvedEpisode
+                }
+                if (directMatch != null) {
+                    directMatch
+                } else {
+                    // Fallback: reverse-remap from Trakt numbering to addon numbering
+                    val addonSeasons = meta.videos.mapTo(mutableSetOf()) { it.season }
+                    if (resolvedSeason == 1 && addonSeasons.size > 1 && resolvedEpisode!! > 0) {
+                        val sorted = meta.videos
+                            .filter { it.season != null && it.episode != null }
+                            .sortedWith(compareBy({ it.season }, { it.episode }))
+                        val globalIndex = resolvedEpisode!! - 1
+                        if (globalIndex in sorted.indices) {
+                            val remapped = sorted[globalIndex]
+                            resolvedSeason = remapped.season
+                            resolvedEpisode = remapped.episode
+                            remapped
+                        } else null
+                    } else null
                 }
             } else {
                 null
@@ -447,6 +469,8 @@ object TraktProgressRepository {
                 logo = entry.logo ?: meta.logo,
                 poster = entry.poster ?: meta.poster,
                 background = entry.background ?: meta.background,
+                seasonNumber = resolvedSeason ?: entry.seasonNumber,
+                episodeNumber = resolvedEpisode ?: entry.episodeNumber,
                 episodeTitle = entry.episodeTitle ?: episode?.title,
                 episodeThumbnail = entry.episodeThumbnail ?: episode?.thumbnail,
                 pauseDescription = entry.pauseDescription

composeApp/src/commonMain/kotlin/com/nuvio/app/features/watching/domain/SeriesContinuity.kt

@@ -46,12 +46,30 @@ fun nextReleasedEpisodeAfter(
         compareBy<WatchingReleasedEpisode>({ normalizeSeasonNumber(it.seasonNumber) }, { it.episodeNumber ?: 0 }),
     )
     val watchedVideoId = buildPlaybackVideoId(content, seasonNumber, episodeNumber)
+    var watchedIndex = sortedEpisodes.indexOfFirst { episode ->
+        buildPlaybackVideoId(content, episode.seasonNumber, episode.episodeNumber, episode.videoId) == watchedVideoId
+    }
+
+    // Fallback: if the seed wasn't found by season+episode (anime with absolute
+    // numbering on Trakt vs multi-season on addon), try global index matching.
+    if (watchedIndex < 0 && seasonNumber != null && episodeNumber != null) {
+        val addonSeasons = sortedEpisodes.mapTo(mutableSetOf()) { it.seasonNumber }
+        if (seasonNumber == 1 && addonSeasons.size > 1 && episodeNumber > 0) {
+            val globalIndex = episodeNumber - 1
+            if (globalIndex in sortedEpisodes.indices) {
+                watchedIndex = globalIndex
+            }
+        }
+    }
+
+    if (watchedIndex < 0) return null
+
+    val watchedEpisodeSeason = sortedEpisodes[watchedIndex].seasonNumber
     val candidates = sortedEpisodes
-        .dropWhile { episode -> buildPlaybackVideoId(content, episode.seasonNumber, episode.episodeNumber, episode.videoId) != watchedVideoId }
+        .drop(watchedIndex + 1)
-        .drop(1)
         .filter { episode ->
             shouldSurfaceNextEpisode(
-                watchedSeasonNumber = seasonNumber,
+                watchedSeasonNumber = watchedEpisodeSeason,
                 candidateSeasonNumber = episode.seasonNumber,
                 todayIsoDate = todayIsoDate,
                 releasedDate = episode.releasedDate,

composeApp/src/commonMain/kotlin/com/nuvio/app/features/watching/domain/WatchingPolicies.kt

@@ -166,7 +166,11 @@ fun latestCompletedSeriesEpisode(
             { it.markedAtEpochMs },
         )
     } else {
-        compareBy<WatchingCompletedEpisode> { it.markedAtEpochMs }
+        compareBy<WatchingCompletedEpisode>(
+            { it.markedAtEpochMs },
+            { normalizeSeasonNumber(it.seasonNumber) },
+            { it.episodeNumber },
+        )
     }
     val allMarkers = buildList {
         progressRecords

composeApp/src/commonMain/kotlin/com/nuvio/app/features/watching/sync/TraktWatchedSyncAdapter.kt

@@ -4,6 +4,7 @@ import co.touchlab.kermit.Logger
 import com.nuvio.app.features.addons.httpGetTextWithHeaders
 import com.nuvio.app.features.addons.httpPostJsonWithHeaders
 import com.nuvio.app.features.trakt.TraktAuthRepository
+import com.nuvio.app.features.trakt.TraktEpisodeMappingService
 import com.nuvio.app.features.watched.WatchedItem
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.async
@@ -92,7 +93,30 @@ object TraktWatchedSyncAdapter : WatchedSyncAdapter {
             }
         }
 
-        return result
+        // Apply reverse mapping for anime: if Trakt uses absolute numbering (S1E1..S1EN)
+        // but addon uses multi-season, remap pulled episodes to addon numbering.
+        val remappedResult = mutableListOf<WatchedItem>()
+        for (item in result) {
+            if (item.season == null || item.episode == null || item.type != "series") {
+                remappedResult += item
+                continue
+            }
+            val mapped = runCatching {
+                TraktEpisodeMappingService.resolveAddonEpisodeMapping(
+                    contentId = item.id,
+                    contentType = item.type,
+                    season = item.season,
+                    episode = item.episode,
+                )
+            }.getOrNull()
+            if (mapped != null && (mapped.season != item.season || mapped.episode != item.episode)) {
+                remappedResult += item.copy(season = mapped.season, episode = mapped.episode)
+            } else {
+                remappedResult += item
+            }
+        }
+
+        return remappedResult
     }
 
     // ── push (add to history) ───────────────────────────────────────────
@@ -178,7 +202,7 @@ object TraktWatchedSyncAdapter : WatchedSyncAdapter {
             ),
         )
 
-        runCatching {
+        val responseText = runCatching {
             httpPostJsonWithHeaders(
                 url = "$BASE_URL/sync/history",
                 body = body,
@@ -187,6 +211,101 @@ object TraktWatchedSyncAdapter : WatchedSyncAdapter {
         }.onFailure { e ->
             if (e is CancellationException) throw e
             log.w { "Failed to push watched items to Trakt: ${e.message}" }
+        }.getOrNull()
+
+        // Retry with remapped numbering for episodes that Trakt didn't recognize
+        // (anime with different season structures between addon and Trakt).
+        if (responseText != null && shows.isNotEmpty()) {
+            val episodeItems = items.filter {
+                it.season != null && it.episode != null &&
+                    it.type.trim().lowercase() !in listOf("movie", "film")
+            }
+            if (episodeItems.isNotEmpty()) {
+                retryWithRemappedEpisodes(headers, episodeItems)
+            }
+        }
+    }
+
+    private suspend fun retryWithRemappedEpisodes(
+        headers: Map<String, String>,
+        items: Collection<WatchedItem>,
+    ) {
+        val remappedShows = mutableListOf<TraktHistoryShowRequestDto>()
+
+        for (item in items) {
+            val season = item.season ?: continue
+            val episode = item.episode ?: continue
+            val mapped = TraktEpisodeMappingService.resolveEpisodeMapping(
+                contentId = item.id,
+                contentType = item.type,
+                videoId = null,
+                season = season,
+                episode = episode,
+            ) ?: continue
+            if (mapped.season == season && mapped.episode == episode) continue
+
+            val ids = parseIds(item.id) ?: continue
+            val existing = remappedShows.firstOrNull { it.ids == ids }
+            if (existing != null) {
+                val seasonDto = existing.seasons?.firstOrNull { it.number == mapped.season }
+                if (seasonDto != null) {
+                    (seasonDto.episodes as? MutableList)?.add(
+                        TraktHistoryEpisodeRequestDto(
+                            number = mapped.episode,
+                            watchedAt = if (item.markedAtEpochMs > 0) epochMsToIso(item.markedAtEpochMs) else null,
+                        ),
+                    )
+                } else {
+                    (existing.seasons as? MutableList)?.add(
+                        TraktHistorySeasonRequestDto(
+                            number = mapped.season,
+                            episodes = mutableListOf(
+                                TraktHistoryEpisodeRequestDto(
+                                    number = mapped.episode,
+                                    watchedAt = if (item.markedAtEpochMs > 0) epochMsToIso(item.markedAtEpochMs) else null,
+                                ),
+                            ),
+                        ),
+                    )
+                }
+            } else {
+                remappedShows += TraktHistoryShowRequestDto(
+                    title = item.name.takeIf { it.isNotBlank() },
+                    year = parseYear(item.releaseInfo),
+                    ids = ids,
+                    seasons = mutableListOf(
+                        TraktHistorySeasonRequestDto(
+                            number = mapped.season,
+                            episodes = mutableListOf(
+                                TraktHistoryEpisodeRequestDto(
+                                    number = mapped.episode,
+                                    watchedAt = if (item.markedAtEpochMs > 0) epochMsToIso(item.markedAtEpochMs) else null,
+                                ),
+                            ),
+                        ),
+                    ),
+                )
+            }
+        }
+
+        if (remappedShows.isEmpty()) return
+
+        val retryBody = json.encodeToString(
+            TraktHistoryAddRequestDto(
+                movies = null,
+                shows = remappedShows,
+            ),
+        )
+
+        runCatching {
+            httpPostJsonWithHeaders(
+                url = "$BASE_URL/sync/history",
+                body = retryBody,
+                headers = headers,
+            )
+        }.onFailure { e ->
+            if (e is CancellationException) throw e
+            log.w { "Failed to push remapped episodes to Trakt: ${e.message}" }
         }
     }
 
@@ -251,6 +370,70 @@ object TraktWatchedSyncAdapter : WatchedSyncAdapter {
             if (e is CancellationException) throw e
             log.w { "Failed to remove watched items from Trakt: ${e.message}" }
         }
+
+        // Retry removal with remapped numbering for anime cases
+        val episodeItems = items.filter {
+            it.season != null && it.episode != null &&
+                it.type.trim().lowercase() !in listOf("movie", "film")
+        }
+        if (episodeItems.isNotEmpty()) {
+            retryDeleteWithRemappedEpisodes(headers, episodeItems)
+        }
+    }
+
+    private suspend fun retryDeleteWithRemappedEpisodes(
+        headers: Map<String, String>,
+        items: Collection<WatchedItem>,
+    ) {
+        val remappedShowDtos = mutableListOf<TraktHistoryShowRequestDto>()
+
+        for (item in items) {
+            val season = item.season ?: continue
+            val episode = item.episode ?: continue
+            val mapped = TraktEpisodeMappingService.resolveEpisodeMapping(
+                contentId = item.id,
+                contentType = item.type,
+                videoId = null,
+                season = season,
+                episode = episode,
+            ) ?: continue
+            if (mapped.season == season && mapped.episode == episode) continue
+
+            val ids = parseIds(item.id) ?: continue
+            remappedShowDtos += TraktHistoryShowRequestDto(
+                title = item.name.takeIf { it.isNotBlank() },
+                year = parseYear(item.releaseInfo),
+                ids = ids,
+                seasons = listOf(
+                    TraktHistorySeasonRequestDto(
+                        number = mapped.season,
+                        episodes = listOf(
+                            TraktHistoryEpisodeRequestDto(number = mapped.episode),
+                        ),
+                    ),
+                ),
+            )
+        }
+
+        if (remappedShowDtos.isEmpty()) return
+
+        val retryBody = json.encodeToString(
+            TraktHistoryRemoveRequestDto(
+                movies = null,
+                shows = remappedShowDtos,
+            ),
+        )
+
+        runCatching {
+            httpPostJsonWithHeaders(
+                url = "$BASE_URL/sync/history/remove",
+                body = retryBody,
+                headers = headers,
+            )
+        }.onFailure { e ->
+            if (e is CancellationException) throw e
+            log.w { "Failed to remove remapped episodes from Trakt: ${e.message}" }
+        }
     }
 
     // ── helpers ─────────────────────────────────────────────────────────