package torrent

import (
	"cmp"
	"context"
	"fmt"
	"seanime/internal/api/anilist"
	"seanime/internal/api/metadata"
	"seanime/internal/debrid/debrid"
	"seanime/internal/extension"
	hibiketorrent "seanime/internal/extension/hibike/torrent"
	"seanime/internal/library/anime"
	"seanime/internal/util"
	"seanime/internal/util/comparison"
	"seanime/internal/util/result"
	"slices"
	"strconv"
	"sync"

	"github.com/5rahim/habari"
	"github.com/samber/lo"
	"github.com/samber/mo"
)

const (
	AnimeSearchTypeSmart  AnimeSearchType = "smart"
	AnimeSearchTypeSimple AnimeSearchType = "simple"
)

var (
	metadataCache = result.NewResultMap[string, *TorrentMetadata]()
)

type (
	AnimeSearchType string

	AnimeSearchOptions struct {
		// Provider extension ID
		Provider string
		Type     AnimeSearchType
		Media    *anilist.BaseAnime
		// Search options
		Query string
		// Filter options
		Batch         bool
		EpisodeNumber int
		BestReleases  bool
		Resolution    string
	}

	// Preview contains the torrent and episode information
	Preview struct {
		Episode *anime.Episode              `json:"episode"` // nil if batch
		Torrent *hibiketorrent.AnimeTorrent `json:"torrent"`
	}

	TorrentMetadata struct {
		Distance int              `json:"distance"`
		Metadata *habari.Metadata `json:"metadata"`
	}

	// SearchData is the struct returned by NewSmartSearch
	SearchData struct {
		Torrents                  []*hibiketorrent.AnimeTorrent                    `json:"torrents"`                  // Torrents found
		Previews                  []*Preview                                       `json:"previews"`                  // TorrentPreview for each torrent
		TorrentMetadata           map[string]*TorrentMetadata                      `json:"torrentMetadata"`           // Torrent metadata
		DebridInstantAvailability map[string]debrid.TorrentItemInstantAvailability `json:"debridInstantAvailability"` // Debrid instant availability
		AnimeMetadata             *metadata.AnimeMetadata                          `json:"animeMetadata"`             // Animap media
	}
)

func (r *Repository) SearchAnime(ctx context.Context, opts AnimeSearchOptions) (ret *SearchData, err error) {
	defer util.HandlePanicInModuleWithError("torrents/torrent/SearchAnime", &err)

	r.logger.Debug().Str("provider", opts.Provider).Str("type", string(opts.Type)).Str("query", opts.Query).Msg("torrent repo: Searching for anime torrents")

	// Find the provider by ID
	providerExtension, ok := extension.GetExtension[extension.AnimeTorrentProviderExtension](r.extensionBank, opts.Provider)
	if !ok {
		// Get the default provider
		providerExtension, ok = r.GetDefaultAnimeProviderExtension()
		if !ok {
			return nil, fmt.Errorf("torrent provider not found")
		}
	}

	if opts.Type == AnimeSearchTypeSmart && !providerExtension.GetProvider().GetSettings().CanSmartSearch {
		return nil, fmt.Errorf("provider does not support smart search")
	}

	var torrents []*hibiketorrent.AnimeTorrent

	// Fetch Animap media
	animeMetadata := mo.None[*metadata.AnimeMetadata]()
	animeMetadataF, err := r.metadataProvider.GetAnimeMetadata(metadata.AnilistPlatform, opts.Media.GetID())
	if err == nil {
		animeMetadata = mo.Some(animeMetadataF)
	}

	queryMedia := hibiketorrent.Media{
		ID:                   opts.Media.GetID(),
		IDMal:                opts.Media.GetIDMal(),
		Status:               string(*opts.Media.GetStatus()),
		Format:               string(*opts.Media.GetFormat()),
		EnglishTitle:         opts.Media.GetTitle().GetEnglish(),
		RomajiTitle:          opts.Media.GetRomajiTitleSafe(),
		EpisodeCount:         opts.Media.GetTotalEpisodeCount(),
		AbsoluteSeasonOffset: 0,
		Synonyms:             opts.Media.GetSynonymsContainingSeason(),
		IsAdult:              *opts.Media.GetIsAdult(),
		StartDate: &hibiketorrent.FuzzyDate{
			Year:  *opts.Media.GetStartDate().GetYear(),
			Month: opts.Media.GetStartDate().GetMonth(),
			Day:   opts.Media.GetStartDate().GetDay(),
		},
	}

	//// Force simple search if Animap media is absent
	//if opts.Type == AnimeSearchTypeSmart && animeMetadata.IsAbsent() {
	//	opts.Type = AnimeSearchTypeSimple
	//}

	var queryKey string

	switch opts.Type {
	case AnimeSearchTypeSmart:
		anidbAID := 0
		anidbEID := 0

		// Get the AniDB Anime ID and Episode ID
		if animeMetadata.IsPresent() {
			// Override absolute offset value of queryMedia
			queryMedia.AbsoluteSeasonOffset = animeMetadata.MustGet().GetOffset()

			if animeMetadata.MustGet().GetMappings() != nil {

				anidbAID = animeMetadata.MustGet().GetMappings().AnidbId
				// Find Animap Episode based on inputted episode number
				episodeMetadata, found := animeMetadata.MustGet().FindEpisode(strconv.Itoa(opts.EpisodeNumber))
				if found {
					anidbEID = episodeMetadata.AnidbEid
				}
			}
		}

		queryKey = fmt.Sprintf("%d-%s-%d-%d-%d-%s-%t-%t", opts.Media.GetID(), opts.Query, opts.EpisodeNumber, anidbAID, anidbEID, opts.Resolution, opts.BestReleases, opts.Batch)
		if cache, found := r.animeProviderSmartSearchCaches.Get(opts.Provider); found {
			// Check the cache
			data, found := cache.Get(queryKey)
			if found {
				r.logger.Debug().Str("provider", opts.Provider).Str("type", string(opts.Type)).Msg("torrent repo: Cache HIT")
				return data, nil
			}
		}

		// Check for context cancellation before making the request
		select {
		case <-ctx.Done():
			return nil, ctx.Err()
		default:
		}

		torrents, err = providerExtension.GetProvider().SmartSearch(hibiketorrent.AnimeSmartSearchOptions{
			Media:         queryMedia,
			Query:         opts.Query,
			Batch:         opts.Batch,
			EpisodeNumber: opts.EpisodeNumber,
			Resolution:    opts.Resolution,
			AnidbAID:      anidbAID,
			AnidbEID:      anidbEID,
			BestReleases:  opts.BestReleases,
		})

		torrents = lo.UniqBy(torrents, func(t *hibiketorrent.AnimeTorrent) string {
			return t.InfoHash
		})

	case AnimeSearchTypeSimple:

		queryKey = fmt.Sprintf("%d-%s", opts.Media.GetID(), opts.Query)
		if cache, found := r.animeProviderSearchCaches.Get(opts.Provider); found {
			// Check the cache
			data, found := cache.Get(queryKey)
			if found {
				r.logger.Debug().Str("provider", opts.Provider).Str("type", string(opts.Type)).Msg("torrent repo: Cache HIT")
				return data, nil
			}
		}

		// Check for context cancellation before making the request
		select {
		case <-ctx.Done():
			return nil, ctx.Err()
		default:
		}

		torrents, err = providerExtension.GetProvider().Search(hibiketorrent.AnimeSearchOptions{
			Media: queryMedia,
			Query: opts.Query,
		})
	}
	if err != nil {
		return nil, err
	}

	//
	// Torrent metadata
	//
	torrentMetadata := make(map[string]*TorrentMetadata)
	mu := sync.Mutex{}
	wg := sync.WaitGroup{}
	wg.Add(len(torrents))
	for _, t := range torrents {
		go func(t *hibiketorrent.AnimeTorrent) {
			defer wg.Done()
			metadata, found := metadataCache.Get(t.Name)
			if !found {
				m := habari.Parse(t.Name)
				var distance *comparison.LevenshteinResult
				distance, ok := comparison.FindBestMatchWithLevenshtein(&m.Title, opts.Media.GetAllTitles())
				if !ok {
					distance = &comparison.LevenshteinResult{
						Distance: 1000,
					}
				}
				metadata = &TorrentMetadata{
					Distance: distance.Distance,
					Metadata: m,
				}
				metadataCache.Set(t.Name, metadata)
			}
			mu.Lock()
			torrentMetadata[t.InfoHash] = metadata
			mu.Unlock()
		}(t)
	}
	wg.Wait()

	//
	// Previews
	//
	previews := make([]*Preview, 0)

	if opts.Type == AnimeSearchTypeSmart {

		wg := sync.WaitGroup{}
		wg.Add(len(torrents))
		for _, t := range torrents {
			go func(t *hibiketorrent.AnimeTorrent) {
				defer wg.Done()

				// Check for context cancellation in each goroutine
				select {
				case <-ctx.Done():
					return
				default:
				}

				preview := r.createAnimeTorrentPreview(createAnimeTorrentPreviewOptions{
					torrent:       t,
					media:         opts.Media,
					animeMetadata: animeMetadata,
					searchOpts:    &opts,
				})
				if preview != nil {
					previews = append(previews, preview)
				}
			}(t)
		}
		wg.Wait()

		// Check if context was cancelled during preview creation
		select {
		case <-ctx.Done():
			return nil, ctx.Err()
		default:
		}
	}

	// sort both by seeders
	slices.SortFunc(torrents, func(i, j *hibiketorrent.AnimeTorrent) int {
		return cmp.Compare(j.Seeders, i.Seeders)
	})
	previews = lo.Filter(previews, func(p *Preview, _ int) bool {
		return p != nil && p.Torrent != nil
	})
	slices.SortFunc(previews, func(i, j *Preview) int {
		return cmp.Compare(j.Torrent.Seeders, i.Torrent.Seeders)
	})

	ret = &SearchData{
		Torrents:        torrents,
		Previews:        previews,
		TorrentMetadata: torrentMetadata,
	}

	if animeMetadata.IsPresent() {
		ret.AnimeMetadata = animeMetadata.MustGet()
	}

	// Store the data in the cache
	switch opts.Type {
	case AnimeSearchTypeSmart:
		if cache, found := r.animeProviderSmartSearchCaches.Get(opts.Provider); found {
			cache.Set(queryKey, ret)
		}
	case AnimeSearchTypeSimple:
		if cache, found := r.animeProviderSearchCaches.Get(opts.Provider); found {
			cache.Set(queryKey, ret)
		}
	}

	return
}

type createAnimeTorrentPreviewOptions struct {
	torrent       *hibiketorrent.AnimeTorrent
	media         *anilist.BaseAnime
	animeMetadata mo.Option[*metadata.AnimeMetadata]
	searchOpts    *AnimeSearchOptions
}

func (r *Repository) createAnimeTorrentPreview(opts createAnimeTorrentPreviewOptions) *Preview {

	var parsedData *habari.Metadata
	metadata, found := metadataCache.Get(opts.torrent.Name)
	if !found { // Should always be found
		parsedData = habari.Parse(opts.torrent.Name)
		metadataCache.Set(opts.torrent.Name, &TorrentMetadata{
			Distance: 1000,
			Metadata: parsedData,
		})
	}
	parsedData = metadata.Metadata

	isBatch := opts.torrent.IsBestRelease ||
		opts.torrent.IsBatch ||
		comparison.ValueContainsBatchKeywords(opts.torrent.Name) || // Contains batch keywords
		(!opts.media.IsMovieOrSingleEpisode() && len(parsedData.EpisodeNumber) > 1) // Multiple episodes parsed & not a movie

	if opts.torrent.ReleaseGroup == "" {
		opts.torrent.ReleaseGroup = parsedData.ReleaseGroup
	}

	if opts.torrent.Resolution == "" {
		opts.torrent.Resolution = parsedData.VideoResolution
	}

	if opts.torrent.FormattedSize == "" {
		opts.torrent.FormattedSize = util.Bytes(uint64(opts.torrent.Size))
	}

	if isBatch {
		return &Preview{
			Episode: nil, // Will be displayed as batch
			Torrent: opts.torrent,
		}
	}

	// If past this point we haven't detected a batch but the episode number returned from the provider is -1
	// we will parse it from the torrent name
	if opts.torrent.EpisodeNumber == -1 && len(parsedData.EpisodeNumber) == 1 {
		opts.torrent.EpisodeNumber = util.StringToIntMust(parsedData.EpisodeNumber[0])
	}

	// If the torrent is confirmed, use the episode number from the search options
	// because it could be absolute
	if opts.torrent.Confirmed {
		opts.torrent.EpisodeNumber = opts.searchOpts.EpisodeNumber
	}

	// If there was no single episode number parsed but the media is movie, set the episode number to 1
	if opts.torrent.EpisodeNumber == -1 && opts.media.IsMovieOrSingleEpisode() {
		opts.torrent.EpisodeNumber = 1
	}

	if opts.animeMetadata.IsPresent() {

		// normalize episode number
		if opts.torrent.EpisodeNumber >= 0 && opts.torrent.EpisodeNumber > opts.media.GetCurrentEpisodeCount() {
			opts.torrent.EpisodeNumber = opts.torrent.EpisodeNumber - opts.animeMetadata.MustGet().GetOffset()
		}

		animeMetadata := opts.animeMetadata.MustGet()
		_, foundEp := animeMetadata.FindEpisode(strconv.Itoa(opts.searchOpts.EpisodeNumber))

		if foundEp {
			var episode *anime.Episode

			// Remove the episode if the parsed episode number is not the same as the search option
			if isProbablySameEpisode(parsedData.EpisodeNumber, opts.searchOpts.EpisodeNumber, opts.animeMetadata.MustGet().GetOffset()) {
				ep := opts.searchOpts.EpisodeNumber
				episode = anime.NewEpisode(&anime.NewEpisodeOptions{
					LocalFile:            nil,
					OptionalAniDBEpisode: strconv.Itoa(ep),
					AnimeMetadata:        animeMetadata,
					Media:                opts.media,
					ProgressOffset:       0,
					IsDownloaded:         false,
					MetadataProvider:     r.metadataProvider,
				})
				episode.IsInvalid = false

				if episode.DisplayTitle == "" {
					episode.DisplayTitle = parsedData.Title
				}
			}

			return &Preview{
				Episode: episode,
				Torrent: opts.torrent,
			}
		}

		var episode *anime.Episode

		// Remove the episode if the parsed episode number is not the same as the search option
		if isProbablySameEpisode(parsedData.EpisodeNumber, opts.searchOpts.EpisodeNumber, opts.animeMetadata.MustGet().GetOffset()) {
			displayTitle := ""
			if len(parsedData.EpisodeNumber) == 1 && parsedData.EpisodeNumber[0] != strconv.Itoa(opts.searchOpts.EpisodeNumber) {
				displayTitle = fmt.Sprintf("Episode %s", parsedData.EpisodeNumber[0])
			}
			// If the episode number could not be found in the Animap media, create a new episode
			episode = &anime.Episode{
				Type:                  anime.LocalFileTypeMain,
				DisplayTitle:          displayTitle,
				EpisodeTitle:          "",
				EpisodeNumber:         opts.searchOpts.EpisodeNumber,
				ProgressNumber:        opts.searchOpts.EpisodeNumber,
				AniDBEpisode:          "",
				AbsoluteEpisodeNumber: 0,
				LocalFile:             nil,
				IsDownloaded:          false,
				EpisodeMetadata:       anime.NewEpisodeMetadata(opts.animeMetadata.MustGet(), nil, opts.media, r.metadataProvider),
				FileMetadata:          nil,
				IsInvalid:             false,
				MetadataIssue:         "",
				BaseAnime:             opts.media,
			}
		}

		return &Preview{
			Episode: episode,
			Torrent: opts.torrent,
		}

	}

	return &Preview{
		Episode: nil,
		Torrent: opts.torrent,
	}
}

func isProbablySameEpisode(parsedEpisode []string, searchEpisode int, absoluteOffset int) bool {
	if len(parsedEpisode) == 1 {
		if util.StringToIntMust(parsedEpisode[0]) == searchEpisode || util.StringToIntMust(parsedEpisode[0]) == searchEpisode+absoluteOffset {
			return true
		}
	}

	return false
}