package analysis

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	"github.com/rs/zerolog/log"

	"homelab.lan/music-agregator/internal/audio"
	"homelab.lan/music-agregator/internal/database"
)

var audioExtensions = map[string]bool{
	".flac": true, ".mp3": true, ".aac": true, ".m4a": true,
	".ape": true, ".wv": true, ".ogg": true, ".wav": true, ".alac": true,
}

var trackNumberRegex = regexp.MustCompile(`^(\d+)[\s\-._]+`)

type ReleaseAnalyzer struct {
	downloads     *database.DownloadRepository
	downloadFiles *database.DownloadFileRepository
	albumReleases *database.AlbumReleaseRepository
	trackReleases *database.TrackReleaseRepository
}

func NewReleaseAnalyzer(db *database.DB) *ReleaseAnalyzer {
	return &ReleaseAnalyzer{
		downloads:     database.NewDownloadRepository(db.Pool),
		downloadFiles: database.NewDownloadFileRepository(db.Pool),
		albumReleases: database.NewAlbumReleaseRepository(db.Pool),
		trackReleases: database.NewTrackReleaseRepository(db.Pool),
	}
}

func (a *ReleaseAnalyzer) Analyze(ctx context.Context, downloadID string, contentPath string) (*database.AlbumRelease, []*database.TrackRelease, error) {
	download, err := a.downloads.GetByID(ctx, downloadID)
	if err != nil {
		return nil, nil, fmt.Errorf("getting download: %w", err)
	}

	files, err := a.downloadFiles.GetByDownloadID(ctx, downloadID)
	if err != nil || len(files) == 0 {
		log.Info().Str("download_id", downloadID).Msg("no download files in DB, scanning filesystem")
		scanned, scanErr := ScanAndHashFiles(contentPath)
		if scanErr != nil {
			return nil, nil, fmt.Errorf("scanning files: %w", scanErr)
		}
		for _, f := range scanned {
			f.DownloadID = downloadID
		}
		if err := a.downloadFiles.CreateBatch(ctx, scanned); err != nil {
			return nil, nil, fmt.Errorf("persisting scanned files: %w", err)
		}
		files = scanned
	}

	var audioFiles []*database.DownloadFile
	var hasCoverArt, hasCueSheet, hasRipLog bool
	for _, f := range files {
		if audioExtensions["."+f.FileType] {
			audioFiles = append(audioFiles, f)
		}
		switch f.FileType {
		case "jpg", "jpeg", "png", "gif", "webp":
			hasCoverArt = true
		case "cue":
			hasCueSheet = true
		case "log":
			hasRipLog = true
		}
	}

	if len(audioFiles) == 0 {
		return nil, nil, fmt.Errorf("no audio files found for download %s", downloadID)
	}

	var trackReleases []*database.TrackRelease
	var totalSize int64
	var totalDuration int
	formatCounts := make(map[string]int)
	var firstBitDepth, firstSampleRate, firstChannels int
	var firstIsLossless bool

	for i, f := range audioFiles {
		fullPath := filepath.Join(contentPath, f.FilePath)
		info, err := audio.Analyze(fullPath)
		if err != nil {
			log.Warn().Err(err).Str("path", f.FilePath).Msg("failed to analyze audio file")
			info = &audio.TrackInfo{
				Format: strings.ToUpper(f.FileType),
			}
		}

		if i == 0 {
			firstBitDepth = info.BitDepth
			firstSampleRate = info.SampleRate
			firstChannels = info.Channels
			firstIsLossless = info.IsLossless
		}

		formatCounts[info.Format]++
		totalSize += f.FileSize
		totalDuration += info.DurationMs

		trackNum := extractTrackNumber(f.FilePath)
		title := extractTitle(f.FilePath)

		tr := &database.TrackRelease{
			Title:       title,
			TrackNumber: trackNum,
			DiscNumber:  1,
			Format:      info.Format,
			Channels:    info.Channels,
			FileSize:    f.FileSize,
			FilePath:    f.FilePath,
		}
		if info.DurationMs > 0 {
			dur := info.DurationMs
			tr.DurationMs = &dur
		}
		if info.BitDepth > 0 {
			bd := info.BitDepth
			tr.BitDepth = &bd
		}
		if info.SampleRate > 0 {
			sr := info.SampleRate
			tr.SampleRate = &sr
		}
		if info.BitrateKbps > 0 {
			br := info.BitrateKbps
			tr.BitrateKbps = &br
		}
		trackReleases = append(trackReleases, tr)
	}

	dominantFormat := ""
	maxCount := 0
	for format, count := range formatCounts {
		if count > maxCount {
			dominantFormat = format
			maxCount = count
		}
	}

	var source *string
	if hasRipLog {
		s := "CD"
		source = &s
	}

	release := &database.AlbumRelease{
		AlbumID:         download.AlbumID,
		DownloadID:      downloadID,
		Format:          dominantFormat,
		Channels:        firstChannels,
		IsLossless:      firstIsLossless,
		Source:          source,
		TotalSize:       totalSize,
		TotalDurationMs: totalDuration,
		TrackCount:      len(audioFiles),
		HasCoverArt:     hasCoverArt,
		HasCueSheet:     hasCueSheet,
		HasRipLog:       hasRipLog,
		Path:            contentPath,
	}
	if firstBitDepth > 0 {
		release.BitDepth = &firstBitDepth
	}
	if firstSampleRate > 0 {
		release.SampleRate = &firstSampleRate
	}

	return release, trackReleases, nil
}

func (a *ReleaseAnalyzer) AnalyzeAndPersist(ctx context.Context, downloadID string, contentPath string) (*database.AlbumRelease, []*database.TrackRelease, error) {
	release, trackReleases, err := a.Analyze(ctx, downloadID, contentPath)
	if err != nil {
		return nil, nil, err
	}

	if err := a.albumReleases.DeleteByDownloadID(ctx, downloadID); err != nil {
		log.Warn().Err(err).Str("download_id", downloadID).Msg("failed to delete existing album release")
	}

	if err := a.albumReleases.Create(ctx, release); err != nil {
		return nil, nil, fmt.Errorf("creating album release: %w", err)
	}

	for _, tr := range trackReleases {
		tr.AlbumReleaseID = release.ID
	}
	if err := a.trackReleases.CreateBatch(ctx, trackReleases); err != nil {
		return nil, nil, fmt.Errorf("creating track releases: %w", err)
	}

	return release, trackReleases, nil
}

func extractTrackNumber(filePath string) int {
	base := filepath.Base(filePath)
	matches := trackNumberRegex.FindStringSubmatch(base)
	if len(matches) >= 2 {
		var num int
		fmt.Sscanf(matches[1], "%d", &num)
		return num
	}
	return 0
}

func extractTitle(filePath string) string {
	base := filepath.Base(filePath)
	ext := filepath.Ext(base)
	name := strings.TrimSuffix(base, ext)
	name = trackNumberRegex.ReplaceAllString(name, "")
	return strings.TrimSpace(name)
}

func IsAudioExtension(ext string) bool {
	return audioExtensions[ext]
}

func ScanAndHashFiles(rootPath string) ([]*database.DownloadFile, error) {
	var files []*database.DownloadFile

	err := filepath.Walk(rootPath, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() {
			return err
		}

		ext := strings.ToLower(filepath.Ext(path))
		relPath, _ := filepath.Rel(rootPath, path)

		fileType := strings.TrimPrefix(ext, ".")
		if fileType == "" {
			return nil
		}

		df := &database.DownloadFile{
			FilePath: relPath,
			FileSize: info.Size(),
			FileType: fileType,
		}

		if IsAudioExtension(ext) || ext == ".cue" || ext == ".log" {
			hash, err := hashFile(path)
			if err != nil {
				log.Warn().Err(err).Str("path", path).Msg("failed to hash file")
			} else {
				df.SHA256Hash = hash
				now := time.Now()
				df.VerifiedAt = &now
			}
		}

		files = append(files, df)
		return nil
	})

	return files, err
}

func hashFile(path string) (string, error) {
	f, err := os.Open(path)
	if err != nil {
		return "", fmt.Errorf("opening file: %w", err)
	}
	defer f.Close()

	h := sha256.New()
	if _, err := io.Copy(h, f); err != nil {
		return "", fmt.Errorf("hashing file: %w", err)
	}

	return hex.EncodeToString(h.Sum(nil)), nil
}