package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"
)

type FileQuality struct {
	Path     string
	Bitrate  int
	Bitdepth int
	Size     int64
}

var (
	logFile    *os.File
	armed      bool
	dryRun     bool
	logWriter  *bufio.Writer
	version    = "1.0.0"
	dateFormat = "2006-01-02 15:04:05"
)

func init() {
	flag.BoolVar(&armed, "armed", false, "Enable actual file operations (rename/delete)")
	flag.BoolVar(&dryRun, "dry-run", false, "Simulate operations without making changes")
	flag.Usage = func() {
		fmt.Fprintf(flag.CommandLine.Output(), "FLAC Duplicate Cleaner v%s\n", version)
		fmt.Fprintf(flag.CommandLine.Output(), "Usage: %s [options] [directory]\n", os.Args[0])
		flag.PrintDefaults()
		fmt.Println("\nBy default, runs in dry-run mode showing what would be done")
		fmt.Println("Specify -armed to actually perform operations")
	}
}

func initLogging(logFilename string) error {
	var err error
	logFile, err = os.OpenFile(logFilename, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		return fmt.Errorf("failed to open log file: %w", err)
	}
	logWriter = bufio.NewWriter(logFile)
	log.SetOutput(io.MultiWriter(os.Stdout, logWriter))
	return nil
}

func closeLogging() {
	logWriter.Flush()
	logFile.Close()
}

func writeLog(message string) {
	log.Println(message)
}

func getCurrentTime() string {
	return time.Now().Format(dateFormat)
}

func getMediaInfo(filePath string) (int, int, error) {
	// Get bitrate
	bitrateCmd := exec.Command("mediainfo", "--Output=Audio;%BitRate%", filePath)
	bitrateOut, err := bitrateCmd.Output()
	if err != nil {
		return 0, 0, fmt.Errorf("mediainfo bitrate failed: %w", err)
	}
	bitrateStr := strings.TrimSpace(string(bitrateOut))
	bitrate, err := strconv.Atoi(bitrateStr)
	if err != nil {
		bitrate = 0
	}

	// Get bitdepth
	bitdepthCmd := exec.Command("mediainfo", "--Output=Audio;%BitDepth%", filePath)
	bitdepthOut, err := bitdepthCmd.Output()
	if err != nil {
		return 0, 0, fmt.Errorf("mediainfo bitdepth failed: %w", err)
	}
	bitdepthStr := strings.TrimSpace(string(bitdepthOut))
	bitdepth, err := strconv.Atoi(bitdepthStr)
	if err != nil {
		bitdepth = 0
	}

	return bitrate, bitdepth, nil
}

func findDuplicateFiles(rootDir string) (map[string][]FileQuality, error) {
	dupePattern := regexp.MustCompile(`(?i)(.+)( \(\d+\))\.flac$`)
	fileGroups := make(map[string][]FileQuality)

	err := filepath.Walk(rootDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return fmt.Errorf("access error %q: %w", path, err)
		}

		if info.IsDir() {
			return nil
		}

		baseName := strings.ToLower(filepath.Base(path))
		if !strings.HasSuffix(baseName, ".flac") {
			return nil
		}

		// Check if file matches the duplicate pattern
		matches := dupePattern.FindStringSubmatch(path)
		if len(matches) > 1 {
			baseFile := matches[1] + ".flac"
			fileInfo, err := os.Stat(path)
			if err != nil {
				return fmt.Errorf("stat failed for %q: %w", path, err)
			}
			fileGroups[baseFile] = append(fileGroups[baseFile], FileQuality{Path: path, Size: fileInfo.Size()})
		} else {
			// Include the original file in the group
			baseFile := strings.TrimSuffix(path, ".flac") + ".flac"
			fileInfo, err := os.Stat(path)
			if err != nil {
				return fmt.Errorf("stat failed for %q: %w", path, err)
			}
			fileGroups[baseFile] = append(fileGroups[baseFile], FileQuality{Path: path, Size: fileInfo.Size()})
		}

		return nil
	})

	if err != nil {
		return nil, fmt.Errorf("error walking directory: %w", err)
	}

	// Filter out groups that don't have duplicates
	for key, group := range fileGroups {
		if len(group) <= 1 {
			delete(fileGroups, key)
		}
	}

	return fileGroups, nil
}

func bytesToHumanReadable(bytes int64) string {
	const unit = 1024
	if bytes < unit {
		return fmt.Sprintf("%d B", bytes)
	}
	div, exp := int64(unit), 0
	for n := bytes / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}
	return fmt.Sprintf("%.1f %ciB", float64(bytes)/float64(div), "KMGTPE"[exp])
}

func processFileGroup(baseFile string, files []FileQuality) {
	writeLog(fmt.Sprintf("Processing group for: %s", baseFile))

	// Get quality info for all files
	var bestFile FileQuality
	var totalSize int64

	for i := range files {
		bitrate, bitdepth, err := getMediaInfo(files[i].Path)
		if err != nil {
			writeLog(fmt.Sprintf("  - Error getting media info for %s: %v", files[i].Path, err))
			continue
		}
		files[i].Bitrate = bitrate
		files[i].Bitdepth = bitdepth
		totalSize += files[i].Size

		writeLog(fmt.Sprintf("  - Found: %s (Bitrate: %d, Bitdepth: %d, Size: %d bytes)",
			files[i].Path, files[i].Bitrate, files[i].Bitdepth, files[i].Size))

		// Determine the best file using quality then size as tiebreaker
		if files[i].Bitrate > bestFile.Bitrate ||
			(files[i].Bitrate == bestFile.Bitrate && files[i].Bitdepth > bestFile.Bitdepth) ||
			(files[i].Bitrate == bestFile.Bitrate && files[i].Bitdepth == bestFile.Bitdepth && files[i].Size > bestFile.Size) {
			bestFile = files[i]
		}
	}

	if bestFile.Path == "" {
		writeLog("  - No valid files found in group")
		return
	}

	writeLog(fmt.Sprintf("  -> Keeping: %s (Bitrate: %d, Bitdepth: %d, Size: %d bytes)",
		bestFile.Path, bestFile.Bitrate, bestFile.Bitdepth, bestFile.Size))

	// Rename best file to original name if it's not already
	if bestFile.Path != baseFile {
		action := "Would rename"
		if armed && !dryRun {
			action = "Renaming"
			err := os.Rename(bestFile.Path, baseFile)
			if err != nil {
				writeLog(fmt.Sprintf("    ! Rename failed: %v", err))
				return
			}
		}
		writeLog(fmt.Sprintf("  * %s: %s -> %s", action, bestFile.Path, baseFile))
		bestFile.Path = baseFile
	}

	// Delete other files
	for _, file := range files {
		if file.Path != bestFile.Path {
			action := "Would delete"
			if armed && !dryRun {
				action = "Deleting"
				err := os.Remove(file.Path)
				if err != nil {
					writeLog(fmt.Sprintf("    ! Delete failed for %s: %v", file.Path, err))
					continue
				}
			}
			writeLog(fmt.Sprintf("  * %s: %s (Recovering %s)", action, file.Path, bytesToHumanReadable(file.Size)))
		}
	}

	writeLog(fmt.Sprintf("  Total recoverable space: %s", bytesToHumanReadable(totalSize-bestFile.Size)))
}

func main() {
	flag.Parse()

	// Default to dry-run mode unless armed is explicitly set
	if !armed {
		dryRun = true
	}

	// Get working directory
	dir := "."
	if flag.NArg() > 0 {
		dir = flag.Arg(0)
	}

	// Initialize logging
	err := initLogging("dupe_cleanup.log")
	if err != nil {
		log.Fatalf("Error initializing logging: %v", err)
	}
	defer closeLogging()

	writeLog("===============================")
	writeLog(fmt.Sprintf("FLAC Duplicate Cleaner v%s", version))
	writeLog(fmt.Sprintf("Started at %s", getCurrentTime()))
	writeLog(fmt.Sprintf("Processing directory: %s", dir))
	if dryRun {
		writeLog("DRY-RUN MODE: No files will be renamed or deleted.")
	} else {
		writeLog("ARMED MODE: Files will be renamed and deleted!")
	}
	writeLog("===============================")

	// Check mediainfo is available
	_, err = exec.LookPath("mediainfo")
	if err != nil {
		writeLog("Error: 'mediainfo' command not found. Please install MediaInfo package.")
		os.Exit(1)
	}

	fileGroups, err := findDuplicateFiles(dir)
	if err != nil {
		writeLog(fmt.Sprintf("Error finding duplicate files: %v", err))
		os.Exit(1)
	}

	if len(fileGroups) == 0 {
		writeLog("No duplicate FLAC files found.")
	} else {
		writeLog(fmt.Sprintf("Found %d groups of duplicate files", len(fileGroups)))
		writeLog("")
	}

	var totalRecoverableSpace int64

	for baseFile, group := range fileGroups {
		processFileGroup(baseFile, group)
		for _, file := range group {
			if file.Path != baseFile {
				totalRecoverableSpace += file.Size
			}
		}
		writeLog("")
	}

	writeLog(fmt.Sprintf("Total recoverable space: %s", bytesToHumanReadable(totalRecoverableSpace)))
	writeLog(fmt.Sprintf("Cleanup completed at %s", getCurrentTime()))
	writeLog("===============================")
}