fix(validation): prevent overwriting files with same artist and title by generating unique filenames

- Implement generateUniqueFilename to ensure each file is saved with a unique name

These changes address the issue when two or more different songs by the same artist and with the same title overwrite each other

src/utils/generateUniqueFileName.js

@@ -0,0 +1,28 @@
+import fs from 'fs/promises';
+import path from 'path';
+
+/**
+ * Generates a unique filename based on the original filename, ensuring it doesn't overwrite existing files.
+ * @param {string} directory - The directory to save the downloaded image.
+ * @param {string} filename - The original filename.
+ * @returns {Promise<string>} - A promise that resolves to a unique filename.
+ */
+const generateUniqueFilename = async (directory, filename) => {
+  const extension = path.extname(filename);
+  const basename = path.basename(filename, extension);
+  let counter = 1;
+
+  let uniqueFilename = filename;
+  let filePath = path.join(directory, uniqueFilename);
+
+  // Check if the file exists and append a counter to make it unique
+  while (await fs.stat(filePath).catch(() => false)) {
+    uniqueFilename = `${basename} (${counter})${extension}`;
+    filePath = path.join(directory, uniqueFilename);
+    counter += 1;
+  }
+
+  return filePath;
+};
+
+export default generateUniqueFilename;

src/utils/renameAudioFileTitle.js

@@ -1,5 +1,6 @@
 import path from 'path';
 import fs from 'fs/promises';
+import generateUniqueFilename from '../utils/generateUniqueFilename.js';
 
 /**
  * Renames an audio file by its metadata properties: artist and title.
@@ -13,13 +14,15 @@ import fs from 'fs/promises';
 export default async function renameFile(artist, title, filePath) {
   // Ensure file path, artist, and title are provided
   if (!filePath || !artist || !title) {
-    throw new Error('File path, artist, and title must be provided.');
+    throw new Error('File path, artist, and title must be provided when renaming file.');
   }
 
   const ext = path.extname(filePath);
   const dir = path.dirname(filePath);
-  const newFileName = `${artist} - ${title}${ext}`;
-  const newFilePath = path.join(dir, newFileName);
+  const proposedFileName = `${artist} - ${title}${ext}`;
+
+  // Generate a unique filename to avoid overwriting
+  const newFilePath = await generateUniqueFilename(dir, proposedFileName);
 
   try {
     await fs.rename(filePath, newFilePath);