package main

import (
	"bufio"
	"fmt"
	"os"
	"os/exec"
	"strconv"
	"strings"
)

func readLine(reader *bufio.Reader) string {
	line, _ := reader.ReadString('\n')
	return strings.TrimSpace(line)
}

func promptChoice(reader *bufio.Reader, max int) int {
	for {
		s := readLine(reader)
		n, err := strconv.Atoi(s)
		if err == nil && n >= 0 && n <= max {
			return n
		}
		fmt.Printf("  请输入 0-%d: ", max)
	}
}

func promptReleaseSelection(reader *bufio.Reader, max int) []int {
	for {
		s := readLine(reader)
		if strings.ToLower(s) == "all" {
			result := make([]int, max)
			for i := range result {
				result[i] = i + 1
			}
			return result
		}

		parts := strings.Split(s, ",")
		var result []int
		valid := true
		for _, p := range parts {
			p = strings.TrimSpace(p)
			n, err := strconv.Atoi(p)
			if err != nil || n < 1 || n > max {
				valid = false
				break
			}
			result = append(result, n)
		}
		if valid && len(result) > 0 {
			return result
		}
		fmt.Printf("  请输入 1-%d (逗号分隔) 或 'all': ", max)
	}
}

func promptCategory(reader *bufio.Reader) string {
	fmt.Println("\n分类:")
	for i, cat := range cfg.Categories {
		fmt.Printf("  [%d] %s\n", i+1, cat)
	}
	fmt.Printf("\n> 选择分类 [1]: ")
	s := readLine(reader)
	if s == "" {
		return cfg.Categories[0]
	}
	n, err := strconv.Atoi(s)
	if err != nil || n < 1 || n > len(cfg.Categories) {
		return cfg.Categories[0]
	}
	return cfg.Categories[n-1]
}

func promptArtistFolder(reader *bufio.Reader, defaultName string) string {
	fmt.Printf("> 艺术家文件夹名 [%s]: ", defaultName)
	s := readLine(reader)
	if s == "" {
		return defaultName
	}
	return s
}

func printHelp() {
	fmt.Println(`YTM - YouTube Music Downloader
从 YouTube Music 搜索并下载音乐到 Navidrome 音乐库

使用方法:
  1. 输入关键词搜索艺术家或专辑
  2. 选择搜索模式（艺术家/专辑）
  3. 从列表中选择要下载的项目
  4. 选择音乐分类和文件夹名
  5. 等待下载完成

命令:
  help  显示此帮助信息
  q     退出程序

输入格式:
  数字        选择单项 (如: 1)
  逗号分隔    选择多项 (如: 1,3,5)
  all         选择全部
  回车        接受默认值 [方括号内]`)
	fmt.Printf("\n下载目录: %s{分类}/{艺术家}/{专辑}/\n", cfg.MusicRoot)
	fmt.Printf("分类: %s\n", strings.Join(cfg.Categories, " | "))
	fmt.Println("单曲保存到: {艺术家}/Singles/")
	fmt.Println()
}

func fetchTrackCounts(releases []Release) {
	fmt.Println("获取曲目信息...")
	for i := range releases {
		tracks, err := ListPlaylistTracks(releases[i].OLAKID)
		if err == nil {
			releases[i].TrackCount = len(tracks)
			releases[i].Tracks = tracks
		} else {
			releases[i].TrackCount = 0
		}
	}
}

func displayReleases(label string, releases []Release, showArtist bool) {
	fmt.Printf("\n%s:\n", label)
	for i, r := range releases {
		trackLabel := "track"
		if r.TrackCount != 1 {
			trackLabel = "tracks"
		}
		if showArtist && r.Artist != "" {
			fmt.Printf("  [%d] %s - %s (%d %s)\n", i+1, r.Artist, r.Title, r.TrackCount, trackLabel)
		} else {
			fmt.Printf("  [%d] %s (%d %s)\n", i+1, r.Title, r.TrackCount, trackLabel)
		}
	}
}

func downloadReleases(reader *bufio.Reader, releases []Release, defaultArtist string) {
	fmt.Printf("\n> 选择要下载的 (逗号分隔, 或 'all'): ")
	selections := promptReleaseSelection(reader, len(releases))

	category := promptCategory(reader)
	artistFolder := promptArtistFolder(reader, defaultArtist)
	artistFolder = sanitizePath(artistFolder)

	basePath := cfg.MusicRoot + category + "/" + artistFolder

	fmt.Printf("\n开始下载到 %s/ ...\n", basePath)

	totalTracks := 0
	for idx, sel := range selections {
		r := releases[sel-1]
		fmt.Printf("  [%d/%d] %s (%d tracks) ", idx+1, len(selections), r.Title, r.TrackCount)

		var dlErr error
		if r.TrackCount == 1 && len(r.Tracks) == 1 {
			singlesDir := basePath + "/Singles"
			os.MkdirAll(singlesDir, 0755)
			dlErr = DownloadSingle(r.Tracks[0].VideoID, singlesDir)
		} else {
			albumDir := basePath + "/" + sanitizePath(r.Title)
			os.MkdirAll(albumDir, 0755)
			dlErr = DownloadPlaylist(r.OLAKID, albumDir)
		}

		if dlErr != nil {
			fmt.Printf("x\n    错误: %v\n", dlErr)
		} else {
			fmt.Println("OK")
			totalTracks += r.TrackCount
		}
	}

	fmt.Printf("\n下载完成! 共 %d 首曲目\n\n", totalTracks)
}

func main() {
	// Set Windows console to UTF-8
	exec.Command("cmd", "/C", "chcp", "65001").Run()

	cfg = loadConfig()
	initHTTPClient()

	printHelp()

	reader := bufio.NewReader(os.Stdin)

	for {
		fmt.Print("> 输入搜索关键词 (q 退出): ")
		query := readLine(reader)
		if query == "" {
			continue
		}
		if query == "q" || query == "Q" {
			fmt.Println("再见!")
			return
		}
		if strings.ToLower(query) == "help" {
			printHelp()
			continue
		}

		// Choose search mode
		fmt.Println("\n搜索模式:")
		fmt.Println("  [1] 按艺术家搜索")
		fmt.Println("  [2] 按专辑搜索")
		fmt.Printf("\n> 选择模式 [1]: ")
		modeStr := readLine(reader)
		mode := 1
		if modeStr == "2" {
			mode = 2
		}

		if mode == 2 {
			// Album search
			fmt.Printf("\n搜索专辑 \"%s\" ...\n", query)
			releases, err := SearchAlbums(query)
			if err != nil {
				fmt.Printf("搜索失败: %v\n\n", err)
				continue
			}
			if len(releases) == 0 {
				fmt.Println("未找到专辑\n")
				continue
			}

			fetchTrackCounts(releases)
			displayReleases("搜索结果", releases, true)

			// Use artist from first release as default
			defaultArtist := ""
			if len(releases) > 0 {
				defaultArtist = releases[0].Artist
			}
			downloadReleases(reader, releases, defaultArtist)
		} else {
			// Artist search
			fmt.Printf("\n搜索艺术家 \"%s\" ...\n", query)
			artists, err := SearchArtists(query)
			if err != nil {
				fmt.Printf("搜索失败: %v\n\n", err)
				continue
			}
			if len(artists) == 0 {
				fmt.Println("未找到艺术家\n")
				continue
			}

			fmt.Println("\n搜索结果:")
			for i, a := range artists {
				fmt.Printf("  [%d] %s (%s) - %d releases\n", i+1, a.Name, a.ID, a.ReleaseCount)
			}
			fmt.Println("  [0] 重新搜索")
			fmt.Printf("\n> 选择艺术家 [1]: ")

			choice := promptChoice(reader, len(artists))
			if choice == 0 {
				continue
			}
			artist := artists[choice-1]

			// Browse channel to get MPRE IDs
			fmt.Printf("\n获取 %s 的发行列表...\n", artist.Name)
			_, mpreIDs, err := BrowseChannel(artist.ID)
			if err != nil {
				fmt.Printf("获取发行列表失败: %v\n\n", err)
				continue
			}

			releases := ResolveAllReleases(mpreIDs)
			if len(releases) == 0 {
				fmt.Println("未找到可用发行\n")
				continue
			}

			fetchTrackCounts(releases)
			displayReleases(artist.Name+" 的发行列表", releases, false)
			downloadReleases(reader, releases, artist.Name)
		}
	}
}