spotify controls

src/lib/spotify/auth.ts

@@ -0,0 +1,74 @@
+import type { PKCEState, SpotifyTokenResponse } from './types';
+
+const SPOTIFY_AUTH_BASE = 'https://accounts.spotify.com';
+const SPOTIFY_SCOPES = [
+  'user-read-playback-state',
+  'user-modify-playback-state',
+  'user-read-currently-playing',
+  'streaming',
+].join(' ');
+
+function generateRandomString(length: number): string {
+  const possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+  const values = crypto.getRandomValues(new Uint8Array(length));
+  return values.reduce((acc, x) => acc + possible[x % possible.length], '');
+}
+
+export class SpotifyAuth {
+  private clientId: string;
+  private redirectUri: string;
+
+  constructor(clientId: string, redirectUri: string) {
+    this.clientId = clientId;
+    this.redirectUri = redirectUri;
+  }
+
+  async startAuthFlow(returnPath: string = window.location.pathname): Promise<void> {
+    const randomState = generateRandomString(16);
+    
+    const stateWithPath = btoa(JSON.stringify({
+      state: randomState,
+      returnPath: returnPath
+    }));
+    
+    sessionStorage.setItem('spotify_state', randomState);
+    
+    const params = new URLSearchParams({
+      response_type: 'code',
+      client_id: this.clientId,
+      scope: SPOTIFY_SCOPES,
+      redirect_uri: this.redirectUri,
+      state: stateWithPath,
+    });
+
+    const authUrl = `${SPOTIFY_AUTH_BASE}/authorize?${params.toString()}`;
+    window.location.href = authUrl;
+  }
+
+  async refreshAccessToken(refreshToken: string): Promise<SpotifyTokenResponse> {
+    const response = await fetch('/api/spotify/token', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+      },
+      body: JSON.stringify({
+        refresh_token: refreshToken,
+      }),
+    });
+
+    if (!response.ok) {
+      const error = await response.json();
+      throw new Error(`Token refresh failed: ${error.error || 'Unknown error'}`);
+    }
+
+    return response.json();
+  }
+
+  getReturnPath(): string {
+    return '/';
+  }
+
+  clearStoredData(): void {
+    sessionStorage.removeItem('spotify_state');
+  }
+}