dttt/cmd/convert.go

package cmd

import (
	"fmt"
	"image"
	"image/jpeg"
	"image/png"
	"log"
	"os"
	"path/filepath"
	"strings"

	"github.com/chai2010/webp"
	"github.com/spf13/cobra"
)

// convertCmd represents the convert command
var convertCmd = &cobra.Command{
	Use:   "convert [input] [output]",
	Short: "Convert images between different formats",
	Long: `Convert images between different formats including JPG, PNG, and WebP.
The output format is determined by the output file extension or the --format flag.

Examples:
  # Convert a single file
  dttt convert input.jpg output.webp
  
  # Batch convert all images in a directory
  dttt convert ./input_dir ./output_dir --batch --format webp
  
  # Batch convert with specific extensions and quality
  dttt convert ./photos ./webp_photos --batch --format webp --quality 85 --extensions jpg,png`,
	Args: cobra.RangeArgs(1, 2),
	Run: func(cmd *cobra.Command, args []string) {
		isBatch, _ := cmd.Flags().GetBool("batch")
		quality, _ := cmd.Flags().GetInt("quality")
		format, _ := cmd.Flags().GetString("format")
		extensions, _ := cmd.Flags().GetString("extensions")

		if isBatch {
			if len(args) != 2 {
				log.Fatal("Batch mode requires input and output directories")
			}

			inputDir := args[0]
			outputDir := args[1]

			if format == "" {
				log.Fatal("Batch mode requires specifying an output format with --format")
			}

			batchConvert(inputDir, outputDir, format, extensions, quality)
		} else {
			if len(args) != 2 {
				log.Fatal("Single file mode requires input and output file paths")
			}

			inputFile := args[0]
			outputFile := args[1]

			convertImage(inputFile, outputFile, quality)
		}
	},
}

func init() {
	rootCmd.AddCommand(convertCmd)

	// Add flags
	convertCmd.Flags().IntP("quality", "q", 90, "Quality for lossy formats (1-100)")
	convertCmd.Flags().BoolP("batch", "b", false, "Enable batch conversion mode")
	convertCmd.Flags().StringP("format", "f", "", "Output format for batch conversion (jpg, jpeg, png, webp)")
	convertCmd.Flags().StringP("extensions", "e", "jpg,jpeg,png,webp", "Comma-separated list of file extensions to process in batch mode")
}

func batchConvert(inputDir, outputDir, format, extensions string, quality int) {
	// Ensure output directory exists
	if err := os.MkdirAll(outputDir, 0755); err != nil {
		log.Fatal("Failed to create output directory:", err)
	}

	// Parse extensions
	validExts := strings.Split(extensions, ",")
	for i, ext := range validExts {
		validExts[i] = strings.ToLower(strings.TrimSpace(ext))
		if !strings.HasPrefix(validExts[i], ".") {
			validExts[i] = "." + validExts[i]
		}
	}

	// Ensure format has a dot prefix and is lowercase
	format = strings.ToLower(format)
	if !strings.HasPrefix(format, ".") {
		format = "." + format
	}

	// Get all files from input directory
	files, err := os.ReadDir(inputDir)
	if err != nil {
		log.Fatal("Error reading input directory:", err)
	}

	// Track conversion statistics
	successCount := 0
	errorCount := 0

	for _, file := range files {
		if file.IsDir() {
			continue
		}

		// Check if file has a valid extension
		fileExt := strings.ToLower(filepath.Ext(file.Name()))
		isValidExt := false
		for _, ext := range validExts {
			if ext == fileExt {
				isValidExt = true
				break
			}
		}

		if !isValidExt {
			continue
		}

		// Generate input and output file paths
		inputPath := filepath.Join(inputDir, file.Name())
		baseName := strings.TrimSuffix(file.Name(), fileExt)
		outputPath := filepath.Join(outputDir, baseName+format)

		// Convert the file
		err := convertImageWithError(inputPath, outputPath, quality)
		if err != nil {
			fmt.Printf("Error converting %s: %v\n", file.Name(), err)
			errorCount++
		} else {
			successCount++
		}
	}

	fmt.Printf("Batch conversion complete: %d files converted successfully, %d failed\n", successCount, errorCount)
}

func convertImageWithError(inputFile, outputFile string, quality int) error {
	// Open input file
	input, err := os.Open(inputFile)
	if err != nil {
		return fmt.Errorf("error opening input file: %w", err)
	}
	defer input.Close()

	// Decode input image
	img, format, err := image.Decode(input)
	if err != nil {
		return fmt.Errorf("error decoding input image: %w", err)
	}

	// Create output file
	output, err := os.Create(outputFile)
	if err != nil {
		return fmt.Errorf("error creating output file: %w", err)
	}
	defer output.Close()

	// Determine output format based on file extension and encode
	outFormat := getOutputFormat(outputFile)

	switch strings.ToLower(filepath.Ext(outputFile)) {
	case ".jpg", ".jpeg":
		err = jpeg.Encode(output, img, &jpeg.Options{Quality: quality})
	case ".png":
		err = png.Encode(output, img)
	case ".webp":
		err = webp.Encode(output, img, &webp.Options{Lossless: quality == 100, Quality: float32(quality)})
	default:
		return fmt.Errorf("unsupported output format: %s", filepath.Ext(outputFile))
	}

	if err != nil {
		return fmt.Errorf("error encoding output image: %w", err)
	}

	fmt.Printf("Converted %s (%s) to %s\n", filepath.Base(inputFile), format, outFormat)
	return nil
}

func convertImage(inputFile, outputFile string, quality int) {
	err := convertImageWithError(inputFile, outputFile, quality)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println("Image converted successfully!")
}

func getOutputFormat(filename string) string {
	ext := strings.ToLower(filepath.Ext(filename))
	switch ext {
	case ".jpg", ".jpeg":
		return "JPEG"
	case ".png":
		return "PNG"
	case ".webp":
		return "WebP"
	default:
		return ext
	}
}