Implements mp3 copy when source is mp3

There's no need to transcode to mp3 if the source file is already an MP3
file. This copies the file to the destination.

find_and_transcode_files.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -19,27 +20,61 @@ type FileToRender struct {
 // findFiles traverses the specified directory and transcodes all .m4a files to .mp3 format.
 func findFiles(sourceDir, destinationDir string) {
 	fmt.Printf("🔍 Finding files in source directory %s\n", sourceDir)
-	// TODO: Needs to either look for existence of .m4a or compareDirectories() should be rewritten to return source file name
-	// TODO: But if .mp3 exists as source, then it should be copied to the destination as-is
 	filesThatNeedToBeRendered, err := compareDirectories(sourceDir, destinationDir)
-
 	if err != nil {
 		fmt.Println("Error:", err)
 	}
+
 	for _, file := range filesThatNeedToBeRendered {
-		if strings.HasSuffix(file.sourcePath, ".m4a") {
+		sourcePath := filepath.Join(sourceDir, file.sourcePath)
+
+		if strings.HasSuffix(sourcePath, ".m4a") {
 			// TODO: Extract to transcodeFileAtPath with sourcePath and destinationDir
-			sourcePath := filepath.Join(sourceDir, file.sourcePath)
 			destinationPath := filepath.Join(destinationDir, strings.TrimSuffix(file.sourcePath, filepath.Ext(file.sourcePath))+".mp3")
-
 			err := transcodeFileAtPath(sourcePath, destinationPath)
 			if err != nil {
 				fmt.Println("Error:", err)
 			}
+		} else {
+			// Copy mp3 from source to destination
+			destinationPath := filepath.Join(destinationDir, file.sourcePath)
+			fmt.Printf("📂 Copy MP3: %s\n", destinationPath)
+			if err := copyFile(sourcePath, destinationPath); err != nil {
+				fmt.Println("Error:", err)
+			}
 		}
+	}
+}
 
+func copyFile(source, destination string) error {
+	if err := os.MkdirAll(filepath.Dir(destination), 0755); err != nil {
+		return fmt.Errorf("❗️Failed to create directories: %v", err)
 	}
 
+	// Open the source file for reading
+	sourceFile, err := os.Open(source)
+	if err != nil {
+		return err
+	}
+	defer sourceFile.Close()
+
+	// Create the destination file
+	destinationFile, err := os.Create(destination)
+	if err != nil {
+		return err
+	}
+	defer destinationFile.Close()
+
+	// Copy the contents of the source file into the destination file
+	_, err = io.Copy(destinationFile, sourceFile)
+	if err != nil {
+		return err
+	}
+
+	// Call Sync to flush writes to stable storage
+	destinationFile.Sync()
+
+	return nil
 }
 
 // transcodeFileAtPath transcodes the file at the specified path from .m4a to .mp3 format.
@@ -118,11 +153,12 @@ func getExclusiveFiles(filesA, filesB []string) []FileToRender {
 	// Generate destination filenames so they can be compared to rendered output filenames
 	var sourceFileOutputNameList []FileToRender
 	for _, file := range filesA {
-		// TODO: This needs to be a struct with source and destination filenames (so that they can be rendered properly)
+
 		destinationFilename := ""
 		if strings.HasSuffix(file, ".mp3") {
 			destinationFilename = file
 		} else {
+			// TODO: Use func to get file ext instead of hard coding .m4a
 			destinationFilename = strings.TrimSuffix(file, ".m4a") + ".mp3"
 		}
 		fileToRender := FileToRender{

sync_and_transcode_music_files_test.go

@@ -54,11 +54,12 @@ func setupFixtureFilesInDirectory(tempDir string, numberOfFiles int) error {
 		"source/file4.m4a",
 		"source/a-band/file5.m4a",
 		"source/Whitespace Band/file6.m4a",
+		"source/the-band/file7.mp3",
 	}
 	for _, file := range testFiles[0:numberOfFiles] {
 		filePath := filepath.Join(tempDir, file)
 		if err := generateM4aFixtureFileAtPath(filePath); err != nil {
-			return fmt.Errorf("failed to create test file: %v", err)
+			return fmt.Errorf("Failed to create test file: %v", err)
 		}
 	}
 
@@ -87,23 +88,25 @@ func setup(t *testing.T, numberOfFiles int) (string, error) {
 }
 
 func TestFindFiles(t *testing.T) {
-	tempDir, err := setup(t, 5)
-	defer os.RemoveAll(tempDir)
-
-	findFiles(filepath.Join(tempDir, "source"), filepath.Join(tempDir, "destination"))
-
 	transcodedFiles := []string{
 		"destination/file1.mp3",
 		"destination/file2.mp3",
 		"destination/file4.mp3",
 		"destination/a-band/file5.mp3",
 		"destination/Whitespace Band/file6.mp3",
+		"destination/the-band/file7.mp3",
 	}
+
+	tempDir, err := setup(t, len(transcodedFiles))
+	defer os.RemoveAll(tempDir)
+
+	findFiles(filepath.Join(tempDir, "source"), filepath.Join(tempDir, "destination"))
+
 	for _, file := range transcodedFiles {
 		t.Run(fmt.Sprintf("File %s should be rendered", file), func(t *testing.T) {
 			filePath := filepath.Join(tempDir, file)
 			_, err = os.Stat(filePath)
-			assert.False(t, os.IsNotExist(err), fmt.Sprintf("transcoded file not found: %s", file))
+			assert.False(t, os.IsNotExist(err), fmt.Sprintf("Transcoded file not found: %s", file))
 		})
 	}