import { ParsedStream, UserData } from '../db/schemas.js';
import { MetadataService } from '../metadata/service.js';
import { Metadata } from '../metadata/utils.js';
import { ReleaseDate, TMDBMetadata } from '../metadata/tmdb.js';
import {
  AnimeDatabase,
  AnimeEntry,
  IdParser,
  ParsedId,
  createLogger,
  getSeaDexInfoHashes,
  enrichParsedIdWithAnimeEntry,
} from '../utils/index.js';
import { SeaDexResult } from '../utils/seadex.js';
import { calculateAbsoluteEpisode } from '../builtins/utils/general.js';
import { iso6391ToLanguage } from '../utils/languages.js';

const logger = createLogger('stream-context');

/**
 * Extended metadata that includes additional fields computed during context build
 */
export interface ExtendedMetadata extends Metadata {
  absoluteEpisode?: number;
  relativeAbsoluteEpisode?: number; // Episode number within current AniDB entry (for split entries)
  seasonYear?: number; // For anime, the year of the season (e.g., 2021 for "Winter 2021")
}

export interface ExpressionContext {
  type?: string;
  id?: string;
  isAnime?: boolean;
  queryType?: string;
  season?: number;
  episode?: number;
  // Metadata fields
  title?: string;
  titles?: string[];
  year?: number;
  yearEnd?: number;
  genres?: string[];
  runtime?: number;
  absoluteEpisode?: number;
  relativeAbsoluteEpisode?: number; // Episode number within current AniDB entry (for split entries)
  originalLanguage?: string;
  daysSinceRelease?: number; // age in days of the movie / **episode**
  hasNextEpisode?: boolean;
  daysUntilNextEpisode?: number;
  daysSinceFirstAired?: number;
  daysSinceLastAired?: number;
  latestSeason?: number;
  // Anime entry data
  anilistId?: number;
  malId?: number;
  // SeaDex availability
  hasSeaDex?: boolean;
}
/**
 * StreamContext encapsulates all request-specific data that can be shared
 * across filtering, sorting, precomputing, and expression evaluation.
 *
 */
export class StreamContext {
  // Core request info
  public readonly type: string;
  public readonly id: string;
  public readonly parsedId: ParsedId | null;

  // Anime-related data (cached from AnimeDatabase)
  public readonly isAnime: boolean;
  public readonly animeEntry: AnimeEntry | null;
  public readonly queryType: string; // 'anime.movie', 'anime.series', 'movie', 'series'

  // Metadata (fetched from TMDB/TVDB/IMDB)
  private _metadata: ExtendedMetadata | undefined;
  private _metadataPromise: Promise<ExtendedMetadata | undefined> | undefined;
  private _metadataFetched: boolean = false;

  // Release dates for digital release filter (movie only)
  private _releaseDates: ReleaseDate[] | undefined;
  private _releaseDatesPromise: Promise<ReleaseDate[] | undefined> | undefined;

  // Episode details for series digital release filter and bitrate calculation
  private _episodeDetails: { airDate?: string; runtime?: number } | undefined;
  private _episodeDetailsPromise:
    | Promise<{ airDate?: string; runtime?: number } | undefined>
    | undefined;

  // SeaDex data (for anime)
  private _seadex: SeaDexResult | undefined;
  private _seadexPromise: Promise<SeaDexResult | undefined> | undefined;
  private _seadexFetched: boolean = false;

  // Year within title (for year matching)
  // public readonly yearWithinTitle: string | undefined;
  // public readonly yearWithinTitleRegex: RegExp | undefined;

  // User data reference
  private readonly userData: UserData;

  private constructor(
    type: string,
    id: string,
    userData: UserData,
    options: {
      parsedId: ParsedId | null;
      isAnime: boolean;
      animeEntry: AnimeEntry | null;
      queryType: string;
    }
  ) {
    this.type = type;
    this.id = id;
    this.userData = userData;
    this.parsedId = options.parsedId;
    this.isAnime = options.isAnime;
    this.animeEntry = options.animeEntry;
    this.queryType = options.queryType;
  }

  /**
   * Create a StreamContext for a request.
   * This performs initial synchronous lookups from the AnimeDatabase.
   */
  public static create(
    type: string,
    id: string,
    userData: UserData
  ): StreamContext {
    const start = Date.now();
    const parsedId = IdParser.parse(id, type);
    let isAnime = id.startsWith('kitsu');

    const animeDb = AnimeDatabase.getInstance();
    if (animeDb.isAnime(id)) {
      isAnime = true;
    }

    let animeEntry: AnimeEntry | null = null;
    if (parsedId) {
      animeEntry = animeDb.getEntryById(
        parsedId.type,
        parsedId.value,
        parsedId.season ? Number(parsedId.season) : undefined,
        parsedId.episode ? Number(parsedId.episode) : undefined
      );

      // Enrich parsedId with anime entry data if available and no season specified
      if (animeEntry && !parsedId.season) {
        enrichParsedIdWithAnimeEntry(parsedId, animeEntry);
      }
    }

    const queryType = isAnime ? `anime.${type}` : type;

    logger.debug(
      {
        id,
        type,
        isAnime,
        hasAnimeEntry: !!animeEntry,
        queryType,
        took: Date.now() - start,
      },
      'stream context created'
    );

    return new StreamContext(type, id, userData, {
      parsedId,
      isAnime,
      animeEntry,
      queryType,
    });
  }

  /**
   * Start fetching metadata asynchronously.
   * Call this early (e.g., when starting addon fetches) to parallelize.
   */
  public startMetadataFetch(): void {
    if (this._metadataPromise || this._metadataFetched) {
      return;
    }

    this._metadataPromise = (async () => {
      try {
        const service = new MetadataService({
          tmdbAccessToken: this.userData.tmdbAccessToken,
          tmdbApiKey: this.userData.tmdbApiKey,
          tvdbApiKey: this.userData.tvdbApiKey,
        });

        const metadata = await service.getMetadata(
          this.parsedId!,
          this.type as any
        );

        // Calculate absolute episode for anime
        let absoluteEpisode: number | undefined;
        let relativeAbsoluteEpisode: number | undefined;
        if (
          this.isAnime &&
          this.parsedId!.season &&
          this.parsedId!.episode &&
          metadata.seasons
        ) {
          const seasons = metadata.seasons.map(
            ({ season_number, episode_count }) => ({
              number: season_number.toString(),
              episodes: episode_count,
            })
          );
          absoluteEpisode = Number(
            calculateAbsoluteEpisode(
              this.parsedId!.season,
              this.parsedId!.episode,
              seasons
            )
          );

          // Calculate relative absolute episode (within current AniDB entry)
          const startingSeason =
            this.animeEntry?.imdb?.seasonNumber ??
            this.animeEntry?.tvdb?.seasonNumber ??
            this.animeEntry?.trakt?.seasonNumber ??
            this.animeEntry?.tmdb?.seasonNumber;

          if (startingSeason) {
            // Calculate absolute episode from the starting season (AniDB episode number)
            const episodeNum = Number(this.parsedId!.episode);
            let totalEpisodesBeforeCurrentSeason = 0;

            for (const s of seasons.filter((s) => s.number !== '0')) {
              const seasonNum = Number(s.number);
              if (seasonNum < startingSeason) continue; // Skip seasons before this AniDB entry
              if (s.number === this.parsedId!.season) break;
              totalEpisodesBeforeCurrentSeason += s.episodes;
            }

            const calculated = totalEpisodesBeforeCurrentSeason + episodeNum;
            // Only set if different from regular episode number
            if (calculated !== episodeNum) {
              relativeAbsoluteEpisode = calculated;
            }
          }

          // Adjust for non-IMDB episodes if they exist.
          const parsedSeasonRecord = seasons.find(
            (s) => s.number === this.parsedId!.season
          );
          const isAlreadyAbsoluteForNonImdb =
            parsedSeasonRecord !== undefined &&
            Number(this.parsedId!.episode) > parsedSeasonRecord.episodes;

          if (
            this.animeEntry?.imdb?.nonImdbEpisodes &&
            absoluteEpisode &&
            !isAlreadyAbsoluteForNonImdb
          ) {
            const nonImdbEpisodesBefore =
              this.animeEntry.imdb.nonImdbEpisodes.filter(
                (ep: number) => ep < absoluteEpisode!
              ).length;
            if (nonImdbEpisodesBefore > 0) {
              absoluteEpisode += nonImdbEpisodesBefore;
            }

            if (relativeAbsoluteEpisode) {
              const nonImdbEpisodesBeforeRelative =
                this.animeEntry.imdb.nonImdbEpisodes.filter(
                  (ep: number) => ep < relativeAbsoluteEpisode!
                ).length;
              if (nonImdbEpisodesBeforeRelative > 0) {
                relativeAbsoluteEpisode += nonImdbEpisodesBeforeRelative;
              }
            }
          }
        }

        const extendedMetadata: ExtendedMetadata = {
          ...metadata,
          absoluteEpisode,
          relativeAbsoluteEpisode,
          seasonYear: this.animeEntry?.animeSeason?.year ?? undefined,
        };

        return extendedMetadata;
      } catch (error) {
        logger.warn(
          {
            id: this.id,
            err: error instanceof Error ? error.message : String(error),
          },
          'failed to fetch metadata'
        );
        return undefined;
      } finally {
        this._metadataFetched = true;
      }
    })();
  }

  /**
   * Start fetching release dates asynchronously (for digital release filter).
   */
  public startReleaseDatesFetch(): void {
    if (
      this._releaseDatesPromise ||
      !this.userData.digitalReleaseFilter?.enabled
    ) {
      return;
    }

    this._releaseDatesPromise = (async () => {
      const metadata = await this.getMetadata();
      if (!metadata?.tmdbId) {
        return undefined;
      }

      if (this.type === 'movie') {
        try {
          return await new TMDBMetadata({
            accessToken: this.userData.tmdbAccessToken,
            apiKey: this.userData.tmdbApiKey,
          }).getReleaseDates(metadata.tmdbId);
        } catch (error) {
          logger.warn(
            {
              id: this.id,
              err: error instanceof Error ? error.message : String(error),
            },
            'failed to fetch release dates'
          );
          return undefined;
        }
      }
      return undefined;
    })();
  }

  /**
   * Start fetching episode details asynchronously (for series digital release filter and bitrate).
   */
  public startEpisodeDetailsFetch(): void {
    const useMetadataRuntime =
      this.userData.bitrate?.useMetadataRuntime !== false;
    const digitalReleaseFilterEnabled =
      this.userData.digitalReleaseFilter?.enabled;

    if (
      this._episodeDetailsPromise ||
      (!digitalReleaseFilterEnabled && !useMetadataRuntime) ||
      (this.type !== 'series' && !this.isAnime)
    ) {
      return;
    }

    this._episodeDetailsPromise = (async () => {
      const metadata = await this.getMetadata();
      if (
        !metadata?.tmdbId ||
        !this.parsedId?.season ||
        !this.parsedId?.episode
      ) {
        return undefined;
      }

      try {
        const originalSeason = Number(this.parsedId.season);
        let seasonNumber = originalSeason;
        let episodeNumber = Number(this.parsedId.episode);
        if (this.isAnime && this.animeEntry) {
          seasonNumber = this.animeEntry.tmdb?.seasonNumber ?? seasonNumber;
          if (this.animeEntry.tmdb?.fromEpisode) {
            const fromEpisode = Number(this.animeEntry.tmdb.fromEpisode);
            if (
              seasonNumber !== originalSeason ||
              episodeNumber < fromEpisode
            ) {
              episodeNumber = fromEpisode + episodeNumber - 1;
            }
          }
          logger.debug(
            {
              originalSeason,
              originalEpisode: this.parsedId.episode,
              tmdbSeason: seasonNumber,
              tmdbEpisode: episodeNumber,
              fromEpisode: this.animeEntry.tmdb?.fromEpisode,
            },
            'resolved tmdb season/episode for episode details'
          );
        }
        return await new TMDBMetadata({
          accessToken: this.userData.tmdbAccessToken,
          apiKey: this.userData.tmdbApiKey,
        }).getEpisodeDetails(metadata.tmdbId, seasonNumber, episodeNumber);
      } catch (error) {
        logger.warn(
          {
            id: this.id,
            err: error instanceof Error ? error.message : String(error),
          },
          'failed to fetch episode details'
        );
        return undefined;
      }
    })();
  }

  /**
   * Start fetching SeaDex data asynchronously.
   * Call this early to parallelize with addon fetches.
   */
  public startSeaDexFetch(): void {
    if (
      this._seadexPromise ||
      this._seadexFetched ||
      !this.isAnime ||
      this.userData.enableSeadex === false
    ) {
      return;
    }

    const anilistIdRaw = this.animeEntry?.mappings?.anilistId;
    if (!anilistIdRaw) {
      logger.debug(
        { id: this.id },
        'no anilist id found, skipping seadex lookup'
      );
      this._seadexFetched = true;
      return;
    }

    const anilistId =
      typeof anilistIdRaw === 'string'
        ? parseInt(anilistIdRaw, 10)
        : anilistIdRaw;
    if (isNaN(anilistId)) {
      logger.debug(
        { id: this.id, anilistId: anilistIdRaw },
        'invalid anilist id, skipping seadex lookup'
      );
      this._seadexFetched = true;
      return;
    }

    this._seadexPromise = (async () => {
      try {
        return await getSeaDexInfoHashes(anilistId);
      } catch (error) {
        logger.warn(
          {
            id: this.id,
            err: error instanceof Error ? error.message : String(error),
          },
          'failed to fetch seadex data'
        );
        return undefined;
      } finally {
        this._seadexFetched = true;
      }
    })();
  }

  /**
   * Start all async fetches in parallel.
   * Call this when starting addon fetches to maximize parallelism.
   */
  public startAllFetches(): void {
    this.startMetadataFetch();
    this.startSeaDexFetch();
    this.startReleaseDatesFetch();
    this.startEpisodeDetailsFetch();
  }

  /**
   * Get metadata, waiting for fetch if needed.
   */
  public async getMetadata(): Promise<ExtendedMetadata | undefined> {
    if (this._metadata !== undefined) {
      return this._metadata;
    }

    if (!this._metadataPromise) {
      this.startMetadataFetch();
    }

    if (this._metadataPromise) {
      this._metadata = await this._metadataPromise;
    }

    return this._metadata;
  }

  /**
   * Get release dates, waiting for fetch if needed.
   */
  public async getReleaseDates(): Promise<ReleaseDate[] | undefined> {
    if (this._releaseDates !== undefined) {
      return this._releaseDates;
    }

    if (!this._releaseDatesPromise) {
      this.startReleaseDatesFetch();
    }

    if (this._releaseDatesPromise) {
      this._releaseDates = await this._releaseDatesPromise;
    }

    return this._releaseDates;
  }

  /**
   * Get episode air date, waiting for fetch if needed.
   */
  public async getEpisodeAirDate(): Promise<string | undefined> {
    if (this._episodeDetails !== undefined) {
      return this._episodeDetails.airDate;
    }

    if (!this._episodeDetailsPromise) {
      this.startEpisodeDetailsFetch();
    }

    if (this._episodeDetailsPromise) {
      this._episodeDetails = await this._episodeDetailsPromise;
    }

    return this._episodeDetails?.airDate;
  }

  public async getEpisodeRuntime(): Promise<number | undefined> {
    if (this._episodeDetails !== undefined) {
      return this._episodeDetails.runtime;
    }

    if (!this._episodeDetailsPromise) {
      this.startEpisodeDetailsFetch();
    }

    if (this._episodeDetailsPromise) {
      this._episodeDetails = await this._episodeDetailsPromise;
    }

    return this._episodeDetails?.runtime;
  }

  /**
   * Get SeaDex data, waiting for fetch if needed.
   */
  public async getSeaDex(): Promise<SeaDexResult | undefined> {
    if (this._seadex !== undefined) {
      return this._seadex;
    }

    if (!this._seadexPromise) {
      this.startSeaDexFetch();
    }

    if (this._seadexPromise) {
      this._seadex = await this._seadexPromise;
    }

    return this._seadex;
  }

  private getDaysSince(dateString: string): number {
    const date = new Date(dateString);
    const now = new Date();
    date.setHours(0, 0, 0, 0);
    now.setHours(0, 0, 0, 0);
    const diffTime = now.getTime() - date.getTime();
    return Math.floor(diffTime / (1000 * 60 * 60 * 24));
  }

  private computeAgeInDays(): number | undefined {
    if (this.type === 'series' && this._episodeDetails?.airDate) {
      return this.getDaysSince(this._episodeDetails.airDate);
    } else if (this._metadata?.releaseDate) {
      return this.getDaysSince(this._metadata.releaseDate);
    }
    return undefined;
  }

  private computeDaysUntilNextEpisode(): number | undefined {
    if (!this._metadata?.nextAirDate) {
      return undefined;
    }
    return -this.getDaysSince(this._metadata.nextAirDate);
  }

  private computeDaysSinceFirstAired(): number | undefined {
    if (this._metadata?.firstAiredDate) {
      return this.getDaysSince(this._metadata.firstAiredDate);
    }
    return undefined;
  }

  private computeDaysSinceLastAired(): number | undefined {
    if (this._metadata?.lastAiredDate) {
      return this.getDaysSince(this._metadata.lastAiredDate);
    }
    return undefined;
  }

  /**
   * Convert context to FormatterContext for formatter initialization.
   * Requires streams to calculate maxRseScore and maxRegexScore.
   */
  public toFormatterContext(
    streams?: ParsedStream[]
  ): import('../formatters/base.js').FormatterContext {
    let maxSeScore: number | undefined;
    let maxRegexScore: number | undefined;

    if (streams && streams.length > 0) {
      // Calculate max scores from streams
      const seScores = streams
        .map((s) => s.streamExpressionScore)
        .filter((score): score is number => typeof score === 'number');
      const regexScores = streams
        .map((s) => s.regexScore)
        .filter((score): score is number => typeof score === 'number');

      maxSeScore = seScores.length > 0 ? Math.max(...seScores) : undefined;
      maxRegexScore =
        regexScores.length > 0 ? Math.max(...regexScores) : undefined;
    }

    return {
      userData: this.userData,
      type: this.type,
      isAnime: this.isAnime,
      queryType: this.queryType,
      season: this.parsedId?.season ? Number(this.parsedId.season) : undefined,
      episode: this.parsedId?.episode
        ? Number(this.parsedId.episode)
        : undefined,
      title: this._metadata?.title,
      titles: this._metadata?.titles?.map((t) => t.title),
      year: this._metadata?.year,
      yearEnd: this._metadata?.yearEnd,
      genres: this._metadata?.genres,
      runtime: this._metadata?.runtime,
      episodeRuntime: this._episodeDetails?.runtime,
      absoluteEpisode: this._metadata?.absoluteEpisode,
      relativeAbsoluteEpisode: this._metadata?.relativeAbsoluteEpisode,
      originalLanguage: iso6391ToLanguage(
        this._metadata?.originalLanguage || ''
      ),
      daysSinceRelease: this.computeAgeInDays(),
      hasNextEpisode: !!this._metadata?.nextAirDate,
      daysUntilNextEpisode: this.computeDaysUntilNextEpisode(),
      daysSinceFirstAired: this.computeDaysSinceFirstAired(),
      daysSinceLastAired: this.computeDaysSinceLastAired(),
      latestSeason: this._metadata?.seasons
        ? Math.max(...this._metadata.seasons.map((s) => s.season_number))
        : undefined,
      anilistId: this.animeEntry?.mappings?.anilistId,
      malId: this.animeEntry?.mappings?.malId,
      hasSeaDex: !!this._seadex?.allHashes?.size,
      maxSeScore,
      maxRegexScore,
    };
  }

  /**
   * Convert context to a plain object for expression evaluation.
   */
  public toExpressionContext(): Record<string, any> {
    return {
      type: this.type,
      id: this.id,
      isAnime: this.isAnime,
      queryType: this.queryType,
      season: this.parsedId?.season ? Number(this.parsedId.season) : undefined,
      episode: this.parsedId?.episode
        ? Number(this.parsedId.episode)
        : undefined,
      // Metadata fields
      title: this._metadata?.title,
      titles: this._metadata?.titles?.map((t) => t.title),
      year: this._metadata?.year,
      yearEnd: this._metadata?.yearEnd,
      genres: this._metadata?.genres ?? [],
      runtime: this._metadata?.runtime,
      originalLanguage: iso6391ToLanguage(
        this._metadata?.originalLanguage || ''
      ),
      daysSinceRelease: this.computeAgeInDays(),
      absoluteEpisode: this._metadata?.absoluteEpisode,
      relativeAbsoluteEpisode: this._metadata?.relativeAbsoluteEpisode,
      hasNextEpisode: !!this._metadata?.nextAirDate,
      daysUntilNextEpisode: this.computeDaysUntilNextEpisode(),
      daysSinceFirstAired: this.computeDaysSinceFirstAired(),
      daysSinceLastAired: this.computeDaysSinceLastAired(),
      latestSeason: this._metadata?.seasons
        ? Math.max(...this._metadata.seasons.map((s) => s.season_number))
        : undefined,
      // Anime entry data
      anilistId: this.animeEntry?.mappings?.anilistId,
      malId: this.animeEntry?.mappings?.malId,
      // SeaDex availability
      hasSeaDex: !!this._seadex?.allHashes?.size,
    };
  }
}