package ripsort

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"regexp"
	"strings"
)

func sortSong(src, dst string) error {
	m, err := ReadAudioTags(src)
	if err != nil {
		return err
	}

	dstPath := pathForFile(src, *m)
	finalPath := filepath.Join(dst, dstPath)

	err = copyFile(src, finalPath)
	if err != nil {
		return err
	}

	return nil
}

func sanitizeName(name string) *string {
	if name == "" {
		return nil
	}

	re := regexp.MustCompile(`[<>:"/\\|?*\x00-\x1F]`)
	name = re.ReplaceAllString(name, "_")

	name = strings.Trim(name, " .")

	if name == "" {
		return nil
	}

	return &name
}

func getArtistName(m metadata) string {
	var artist *string

	if len(m.Artist) > 0 {
		artist = sanitizeName(m.Artist[0])
	}

	if artist == nil && len(m.AlbumArtist) > 0 {
		if aa := m.AlbumArtist[0]; aa != "" {
			artist = sanitizeName(aa)
		}
	}

	if artist == nil {
		return "Unknown Artist"
	}

	return *artist
}

func getAlbumName(m metadata) string {
	album := sanitizeName(m.Album)
	if album == nil {
		return "Unknown Album"
	}
	return *album
}

func getTitle(src string, m metadata) string {
	title := sanitizeName(m.Title)
	if title == nil {
		return *sanitizeName(strings.TrimSuffix(filepath.Base(src), filepath.Ext(src)))
	}
	return *title
}

func pathForFile(src string, m metadata) string {
	ext := strings.ToLower(filepath.Ext(src))

	artist := getArtistName(m)
	album := getAlbumName(m)
	title := getTitle(src, m)

	filename := title + ext

	return filepath.Join(artist, album, filename)
}

func copyFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("open source file: %w", err)
	}
	defer in.Close()

	dir := filepath.Dir(dst)
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return fmt.Errorf("create destination directory: %w", err)
	}

	out, err := os.Create(dst)
	if err != nil {
		return fmt.Errorf("create destination file: %w", err)
	}
	defer func() {
		if cerr := out.Close(); err == nil && cerr != nil {
			err = cerr
		}
	}()

	if _, err = io.Copy(out, in); err != nil {
		return fmt.Errorf("copy file contents: %w", err)
	}

	if err = out.Sync(); err != nil {
		return fmt.Errorf("sync destination file: %w", err)
	}

	return nil
}