package metadata

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"git.meatbag.se/varl/subsyt/internal/model"
)

type ShowAsset struct {
	Show     model.Show
	InfoPath string
	Dir      string
	Images   []string
}

type EpisodeAsset struct {
	Episode   model.Episode
	InfoPath  string
	Dir       string
	MediaPath string
	Sidecars  []string
}

func findFiles(root, ext string) ([]string, error) {
	if root == "" {
		return nil, fmt.Errorf("find files: empty root")
	}

	if _, err := os.Stat(root); errors.Is(err, os.ErrNotExist) {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("find files: %w", err)
	}

	var result []string
	walkErr := filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		if strings.HasSuffix(path, ext) {
			result = append(result, path)
		}
		return nil
	})
	if walkErr != nil {
		return nil, fmt.Errorf("walk %s: %w", root, walkErr)
	}
	return result, nil
}

func trimInfoSuffix(path string) string {
	return strings.TrimSuffix(path, ".info.json")
}

func globSidecars(base string) ([]string, error) {
	matches, err := filepath.Glob(base + ".*")
	if err != nil {
		return nil, fmt.Errorf("glob %s.*: %w", base, err)
	}

	var sidecars []string
	for _, match := range matches {
		if strings.HasSuffix(match, ".info.json") {
			continue
		}
		sidecars = append(sidecars, match)
	}
	return sidecars, nil
}

func resolveMediaPath(base string, episode model.Episode, sidecars []string) (string, []string) {
	if episode.Ext != "" {
		candidate := base + "." + episode.Ext
		if _, err := os.Stat(candidate); err == nil {
			var rest []string
			for _, path := range sidecars {
				if path != candidate {
					rest = append(rest, path)
				}
			}
			return candidate, rest
		}
	}

	for _, path := range sidecars {
		ext := strings.ToLower(filepath.Ext(path))
		switch ext {
		case ".mp4", ".mkv", ".webm", ".m4v", ".mov", ".avi":
			var rest []string
			for _, other := range sidecars {
				if other != path {
					rest = append(rest, other)
				}
			}
			return path, rest
		}
	}

	return "", sidecars
}

func ScanShows(root string) ([]ShowAsset, error) {
	infoFiles, err := findFiles(root, ".info.json")
	if err != nil {
		return nil, err
	}

	var assets []ShowAsset
	for _, infoPath := range infoFiles {
		show := model.LoadShow(infoPath)
		dir := filepath.Dir(infoPath)
		base := trimInfoSuffix(infoPath)

		sidecars, sidecarErr := globSidecars(base)
		if sidecarErr != nil {
			return nil, sidecarErr
		}

		var images []string
		for _, path := range sidecars {
			ext := strings.ToLower(filepath.Ext(path))
			switch ext {
			case ".jpg", ".jpeg", ".png", ".webp":
				images = append(images, path)
			}
		}

		assets = append(assets, ShowAsset{
			Show:     show,
			InfoPath: infoPath,
			Dir:      dir,
			Images:   images,
		})
	}

	return assets, nil
}

func ScanEpisodes(root string) ([]EpisodeAsset, error) {
	infoFiles, err := findFiles(root, ".info.json")
	if err != nil {
		return nil, err
	}

	var assets []EpisodeAsset
	for _, infoPath := range infoFiles {
		episode := model.LoadEpisode(infoPath)
		base := trimInfoSuffix(infoPath)
		dir := filepath.Dir(infoPath)

		sidecars, sidecarErr := globSidecars(base)
		if sidecarErr != nil {
			return nil, sidecarErr
		}

		mediaPath, remaining := resolveMediaPath(base, episode, sidecars)
		assets = append(assets, EpisodeAsset{
			Episode:   episode,
			InfoPath:  infoPath,
			Dir:       dir,
			MediaPath: mediaPath,
			Sidecars:  remaining,
		})
	}

	return assets, nil
}