Add cross-platform path handling (#89)

Add cross-platform path handling support

- Add sanitizePath, joinPath, buildOutputPath utilities
- Add operatingSystem to Settings interface
- Replace hardcoded Windows paths with dynamic path handling
- Support Windows, Linux, and macOS

frontend/src/App.tsx

@@ -36,6 +36,7 @@ import {
   TooltipTrigger,
 } from "@/components/ui/tooltip";
 import { Spinner } from "@/components/ui/spinner";
+import { joinPath, sanitizePath } from "./lib/utils";
 
 function App() {
   const [spotifyUrl, setSpotifyUrl] = useState("");
@@ -125,32 +126,30 @@ function App() {
     const query = trackName && artistName ? `${trackName} ${artistName}` : undefined;
     
     // Build output directory based on settings
+    const os = settings.operatingSystem;
+
+    // Base download path
     let outputDir = settings.downloadPath;
 
     // For playlist or artist discography downloads
-    if (playlistName) {
-      const sanitizedPlaylist = playlistName.replace(/[<>:"/\\|?*]/g, '_').trim();
-      outputDir = `${settings.downloadPath}\\${sanitizedPlaylist}`;
 
-      // For artist discography: only use album subfolder (artist is redundant)
+    // Playlist or discography
+    if (playlistName) {
+      outputDir = joinPath(os, outputDir, sanitizePath(playlistName, os));
+
       if (isArtistDiscography) {
-        // Only add album subfolder if enabled
+        // Only album subfolder
         if (settings.albumSubfolder && albumName) {
-          const sanitizedAlbum = albumName.replace(/[<>:"/\\|?*]/g, '_').trim();
-          outputDir = `${outputDir}\\${sanitizedAlbum}`;
+          outputDir = joinPath(os, outputDir, sanitizePath(albumName, os));
         }
       } else {
-        // For playlist: use both artist and album subfolders if enabled
-        // Add artist subfolder if enabled
+        // Playlist rules:
         if (settings.artistSubfolder && artistName) {
-          const sanitizedArtist = artistName.replace(/[<>:"/\\|?*]/g, '_').trim();
-          outputDir = `${outputDir}\\${sanitizedArtist}`;
+          outputDir = joinPath(os, outputDir, sanitizePath(artistName, os));
         }
 
-        // Add album subfolder if enabled
         if (settings.albumSubfolder && albumName) {
-          const sanitizedAlbum = albumName.replace(/[<>:"/\\|?*]/g, '_').trim();
-          outputDir = `${outputDir}\\${sanitizedAlbum}`;
+          outputDir = joinPath(os, outputDir, sanitizePath(albumName, os));
         }
       }
     }

frontend/src/lib/settings.ts

@@ -9,6 +9,7 @@ export interface Settings {
   artistSubfolder: boolean;
   albumSubfolder: boolean;
   trackNumber: boolean;
+  operatingSystem: "Windows" | "linux/MacOS"
 }
 
 export const DEFAULT_SETTINGS: Settings = {
@@ -20,16 +21,20 @@ export const DEFAULT_SETTINGS: Settings = {
   artistSubfolder: false,
   albumSubfolder: false,
   trackNumber: false,
+  operatingSystem: "Windows"
 };
 
+// TODO: add mac/linux defaults
+const DEFAULT_PATH : string = "C:\\Users\\Public\\Music"; 
+
 async function fetchDefaultPath(): Promise<string> {
   try {
     const data = await GetDefaults();
-    return data.downloadPath || "C:\\Users\\Public\\Music";
+    return data.downloadPath || DEFAULT_PATH;
   } catch (error) {
     console.error("Failed to fetch default path:", error);
   }
-  return "C:\\Users\\Public\\Music";
+  return DEFAULT_PATH;
 }
 
 const SETTINGS_KEY = "spotiflac-settings";

frontend/src/lib/utils.ts

@@ -1,6 +1,35 @@
 import { clsx, type ClassValue } from "clsx"
 import { twMerge } from "tailwind-merge"
+import type { Settings } from "./settings";
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+
+export function sanitizePath(input: string, os: string): string {
+  if (os === "Windows") {
+    return input.replace(/[<>:"/\\|?*]/g, "_");
+  }
+
+  // unix-based OS
+  return input.replace(/\//g, "_");
+}
+
+export function joinPath(os: string, ...parts: string[]): string {
+  const sep = os === "Windows" ? "\\" : "/";
+
+  return parts
+    .filter(Boolean)
+    .map(p => p.replace(/^[/\\]+|[/\\]+$/g, ""))
+    .join(sep);
+}
+
+export function buildOutputPath(settings: Settings, folder?: string) {
+  const os = settings.operatingSystem;
+
+  const base = settings.downloadPath || "";
+  const sanitized = folder ? sanitizePath(folder, os) : undefined;
+
+  return sanitized ? joinPath(os, base, sanitized) : base;
+}