package core

import (
	"context"
	"fmt"
	"sort"
	"strings"
	"sync"
	"time"

	"github.com/Masterminds/squirrel"
	"github.com/deluan/navidrome/core/lastfm"
	"github.com/deluan/navidrome/core/spotify"
	"github.com/deluan/navidrome/log"
	"github.com/deluan/navidrome/model"
	"github.com/microcosm-cc/bluemonday"
	"github.com/xrash/smetrics"
)

const placeholderArtistImageSmallUrl = "https://lastfm.freetls.fastly.net/i/u/64s/2a96cbd8b46e442fc41c2b86b821562f.png"
const placeholderArtistImageMediumUrl = "https://lastfm.freetls.fastly.net/i/u/174s/2a96cbd8b46e442fc41c2b86b821562f.png"
const placeholderArtistImageLargeUrl = "https://lastfm.freetls.fastly.net/i/u/300x300/2a96cbd8b46e442fc41c2b86b821562f.png"

type ExternalInfo interface {
	ArtistInfo(ctx context.Context, id string, count int, includeNotPresent bool) (*model.ArtistInfo, error)
	SimilarSongs(ctx context.Context, id string, count int) (model.MediaFiles, error)
	TopSongs(ctx context.Context, artist string, count int) (model.MediaFiles, error)
}

func NewExternalInfo(ds model.DataStore, lfm *lastfm.Client, spf *spotify.Client) ExternalInfo {
	return &externalInfo{ds: ds, lfm: lfm, spf: spf}
}

type externalInfo struct {
	ds  model.DataStore
	lfm *lastfm.Client
	spf *spotify.Client
}

func (e *externalInfo) getArtist(ctx context.Context, id string) (artist *model.Artist, err error) {
	var entity interface{}
	entity, err = GetEntityByID(ctx, e.ds, id)
	if err != nil {
		return nil, err
	}

	switch v := entity.(type) {
	case *model.Artist:
		artist = v
	case *model.MediaFile:
		artist = &model.Artist{
			ID:   v.ArtistID,
			Name: v.Artist,
		}
	case *model.Album:
		artist = &model.Artist{
			ID:   v.AlbumArtistID,
			Name: v.Artist,
		}
	default:
		err = model.ErrNotFound
		return
	}
	artist.Name = clearName(artist.Name)
	return
}

// Replace some Unicode chars with their equivalent ASCII
func clearName(name string) string {
	name = strings.ReplaceAll(name, "–", "-")
	name = strings.ReplaceAll(name, "‐", "-")
	name = strings.ReplaceAll(name, "“", `"`)
	name = strings.ReplaceAll(name, "”", `"`)
	name = strings.ReplaceAll(name, "‘", `'`)
	name = strings.ReplaceAll(name, "’", `'`)
	return name
}

func (e *externalInfo) SimilarSongs(ctx context.Context, id string, count int) (model.MediaFiles, error) {
	if e.lfm == nil {
		log.Warn(ctx, "Last.FM client not configured")
		return nil, model.ErrNotAvailable
	}

	artist, err := e.getArtist(ctx, id)
	if err != nil {
		return nil, err
	}

	artists, err := e.similarArtists(ctx, artist, count, false)
	if err != nil {
		return nil, err
	}
	ids := make([]string, len(artists)+1)
	ids[0] = artist.ID
	for i, a := range artists {
		ids[i+1] = a.ID
	}

	return e.ds.MediaFile(ctx).GetAll(model.QueryOptions{
		Filters: squirrel.Eq{"artist_id": ids},
		Max:     count,
		Sort:    "random()",
	})
}

func (e *externalInfo) similarArtists(ctx context.Context, artist *model.Artist, count int, includeNotPresent bool) (model.Artists, error) {
	var result model.Artists
	var notPresent []string

	log.Debug(ctx, "Calling Last.FM ArtistGetSimilar", "artist", artist.Name)
	similar, err := e.lfm.ArtistGetSimilar(ctx, artist.Name, count)
	if err != nil {
		return nil, err
	}

	// First select artists that are present.
	for _, s := range similar {
		sa, err := e.ds.Artist(ctx).FindByName(s.Name)
		if err != nil {
			notPresent = append(notPresent, s.Name)
			continue
		}
		result = append(result, *sa)
	}

	// Then fill up with non-present artists
	if includeNotPresent {
		for _, s := range notPresent {
			sa := model.Artist{ID: "-1", Name: s}
			result = append(result, sa)
		}
	}

	return result, nil
}

func (e *externalInfo) TopSongs(ctx context.Context, artistName string, count int) (model.MediaFiles, error) {
	if e.lfm == nil {
		log.Warn(ctx, "Last.FM client not configured")
		return nil, model.ErrNotAvailable
	}
	artist, err := e.ds.Artist(ctx).FindByName(artistName)
	if err != nil {
		log.Error(ctx, "Artist not found", "name", artistName, err)
		return nil, nil
	}
	artistName = clearName(artistName)

	log.Debug(ctx, "Calling Last.FM ArtistGetTopTracks", "artist", artistName, "id", artist.ID)
	tracks, err := e.lfm.ArtistGetTopTracks(ctx, artistName, count)
	if err != nil {
		return nil, err
	}
	var songs model.MediaFiles
	for _, t := range tracks {
		mf, err := e.findMatchingTrack(ctx, t.MBID, artist.ID, t.Name)
		if err != nil {
			continue
		}
		songs = append(songs, *mf)
	}
	return songs, nil
}

func (e *externalInfo) findMatchingTrack(ctx context.Context, mbid string, artistID, title string) (*model.MediaFile, error) {
	if mbid != "" {
		mfs, err := e.ds.MediaFile(ctx).GetAll(model.QueryOptions{
			Filters: squirrel.Eq{"mbz_track_id": mbid},
		})
		if err == nil && len(mfs) > 0 {
			return &mfs[0], nil
		}
	}
	mfs, err := e.ds.MediaFile(ctx).GetAll(model.QueryOptions{
		Filters: squirrel.And{
			squirrel.Or{
				squirrel.Eq{"artist_id": artistID},
				squirrel.Eq{"album_artist_id": artistID},
			},
			squirrel.Like{"title": title},
		},
		Sort: "starred desc, rating desc, year asc",
	})
	if err != nil || len(mfs) == 0 {
		return nil, model.ErrNotFound
	}
	return &mfs[0], nil
}

func (e *externalInfo) ArtistInfo(ctx context.Context, id string, count int, includeNotPresent bool) (*model.ArtistInfo, error) {
	artist, err := e.getArtist(ctx, id)
	if err != nil {
		return nil, err
	}

	info := model.ArtistInfo{ID: artist.ID, Name: artist.Name}

	// TODO Load from local: artist.jpg/png/webp, artist.json (with the remaining info)

	var wg sync.WaitGroup
	e.callArtistInfo(ctx, artist, &wg, &info)
	e.callArtistImages(ctx, artist, &wg, &info)
	e.callSimilarArtists(ctx, artist, count, includeNotPresent, &wg, &info)
	wg.Wait()

	// Use placeholders if could not get from external sources
	e.setBio(&info, "Biography not available")
	e.setSmallImageUrl(&info, placeholderArtistImageSmallUrl)
	e.setMediumImageUrl(&info, placeholderArtistImageMediumUrl)
	e.setLargeImageUrl(&info, placeholderArtistImageLargeUrl)

	log.Trace(ctx, "ArtistInfo collected", "artist", artist.Name, "info", info)

	return &info, nil
}

func (e *externalInfo) callArtistInfo(ctx context.Context, artist *model.Artist, wg *sync.WaitGroup, info *model.ArtistInfo) {
	if e.lfm != nil {
		log.Debug(ctx, "Calling Last.FM ArtistGetInfo", "artist", artist.Name)
		wg.Add(1)
		go func() {
			start := time.Now()
			defer wg.Done()
			lfmArtist, err := e.lfm.ArtistGetInfo(ctx, artist.Name)
			if err != nil {
				log.Error(ctx, "Error calling Last.FM", "artist", artist.Name, err)
			} else {
				log.Debug(ctx, "Got info from Last.FM", "artist", artist.Name, "info", lfmArtist.Bio.Summary, "elapsed", time.Since(start))
			}
			e.setBio(info, lfmArtist.Bio.Summary)
			e.setLastFMUrl(info, lfmArtist.URL)
			e.setMbzID(info, lfmArtist.MBID)
		}()
	}
}

func (e *externalInfo) findArtist(ctx context.Context, name string) (*spotify.Artist, error) {
	artists, err := e.spf.SearchArtists(ctx, name, 40)
	if err != nil || len(artists) == 0 {
		return nil, model.ErrNotFound
	}
	name = strings.ToLower(name)

	// Sort results, prioritizing artists with images, with similar names and with high popularity, in this order
	sort.Slice(artists, func(i, j int) bool {
		ai := fmt.Sprintf("%-5t-%03d-%04d", len(artists[i].Images) == 0, smetrics.WagnerFischer(name, strings.ToLower(artists[i].Name), 1, 1, 2), 1000-artists[i].Popularity)
		aj := fmt.Sprintf("%-5t-%03d-%04d", len(artists[j].Images) == 0, smetrics.WagnerFischer(name, strings.ToLower(artists[j].Name), 1, 1, 2), 1000-artists[j].Popularity)
		return strings.Compare(ai, aj) < 0
	})

	// If the first one has the same name, that's the one
	if strings.ToLower(artists[0].Name) != name {
		return nil, model.ErrNotFound
	}
	return &artists[0], err
}

func (e *externalInfo) callSimilarArtists(ctx context.Context, artist *model.Artist, count int, includeNotPresent bool,
	wg *sync.WaitGroup, info *model.ArtistInfo) {
	if e.lfm != nil {
		wg.Add(1)
		go func() {
			start := time.Now()
			defer wg.Done()
			similar, err := e.similarArtists(ctx, artist, count, includeNotPresent)
			if err != nil {
				log.Error(ctx, "Error calling Last.FM", "artist", artist.Name, err)
				return
			}
			log.Debug(ctx, "Got similar artists from Last.FM", "artist", artist.Name, "info", "elapsed", time.Since(start))
			info.SimilarArtists = similar
		}()
	}
}

func (e *externalInfo) callArtistImages(ctx context.Context, artist *model.Artist, wg *sync.WaitGroup, info *model.ArtistInfo) {
	if e.spf != nil {
		log.Debug(ctx, "Calling Spotify SearchArtist", "artist", artist.Name)
		wg.Add(1)
		go func() {
			start := time.Now()
			defer wg.Done()

			a, err := e.findArtist(ctx, artist.Name)
			if err != nil {
				log.Error(ctx, "Error calling Spotify", "artist", artist.Name, err)
				return
			}
			spfImages := a.Images
			log.Debug(ctx, "Got images from Spotify", "artist", artist.Name, "images", spfImages, "elapsed", time.Since(start))

			sort.Slice(spfImages, func(i, j int) bool { return spfImages[i].Width > spfImages[j].Width })
			if len(spfImages) >= 1 {
				e.setLargeImageUrl(info, spfImages[0].URL)
			}
			if len(spfImages) >= 2 {
				e.setMediumImageUrl(info, spfImages[1].URL)
			}
			if len(spfImages) >= 3 {
				e.setSmallImageUrl(info, spfImages[2].URL)
			}
		}()
	}
}

func (e *externalInfo) setBio(info *model.ArtistInfo, bio string) {
	policy := bluemonday.UGCPolicy()
	if info.Biography == "" {
		bio = policy.Sanitize(bio)
		bio = strings.ReplaceAll(bio, "\n", " ")
		info.Biography = strings.ReplaceAll(bio, "<a ", "<a target='_blank' ")
	}
}

func (e *externalInfo) setLastFMUrl(info *model.ArtistInfo, url string) {
	if info.LastFMUrl == "" {
		info.LastFMUrl = url
	}
}

func (e *externalInfo) setMbzID(info *model.ArtistInfo, mbID string) {
	if info.MBID == "" {
		info.MBID = mbID
	}
}

func (e *externalInfo) setSmallImageUrl(info *model.ArtistInfo, url string) {
	if info.SmallImageUrl == "" {
		info.SmallImageUrl = url
	}
}

func (e *externalInfo) setMediumImageUrl(info *model.ArtistInfo, url string) {
	if info.MediumImageUrl == "" {
		info.MediumImageUrl = url
	}
}

func (e *externalInfo) setLargeImageUrl(info *model.ArtistInfo, url string) {
	if info.LargeImageUrl == "" {
		info.LargeImageUrl = url
	}
}