🔑 Add OAuth token exchange endpoint with support for Discord and error handling

code/websites/pokedex.online/server/routes/auth.js

@@ -176,5 +176,108 @@ export function createAuthRouter({ secret, adminPassword } = {}) {
     });
   });
 
+  /**
+   * POST /oauth/token
+   * Exchange OAuth authorization code for access token
+   * Supports multiple providers (Discord, Challonge, etc.)
+   */
+  router.post('/oauth/token', async (req, res) => {
+    const { code, provider } = req.body;
+
+    if (!code) {
+      return res.status(400).json({
+        error: 'Authorization code is required',
+        code: 'MISSING_CODE'
+      });
+    }
+
+    if (!provider) {
+      return res.status(400).json({
+        error: 'Provider is required',
+        code: 'MISSING_PROVIDER'
+      });
+    }
+
+    try {
+      // Handle Discord OAuth
+      if (provider === 'discord') {
+        const clientId = process.env.VITE_DISCORD_CLIENT_ID;
+        const clientSecret = process.env.DISCORD_CLIENT_SECRET;
+        const redirectUri = process.env.VITE_DISCORD_REDIRECT_URI;
+
+        if (!clientId || !clientSecret) {
+          console.error('Discord OAuth not configured:', {
+            hasClientId: !!clientId,
+            hasClientSecret: !!clientSecret
+          });
+          return res.status(500).json({
+            error: 'Discord OAuth not configured on server',
+            code: 'OAUTH_NOT_CONFIGURED'
+          });
+        }
+
+        // Exchange code for token with Discord
+        const tokenResponse = await fetch(
+          'https://discord.com/api/oauth2/token',
+          {
+            method: 'POST',
+            headers: {
+              'Content-Type': 'application/x-www-form-urlencoded'
+            },
+            body: new URLSearchParams({
+              client_id: clientId,
+              client_secret: clientSecret,
+              grant_type: 'authorization_code',
+              code: code,
+              redirect_uri: redirectUri
+            })
+          }
+        );
+
+        if (!tokenResponse.ok) {
+          const errorData = await tokenResponse.text();
+          console.error('Discord token exchange failed:', errorData);
+          return res.status(tokenResponse.status).json({
+            error: 'Failed to exchange code with Discord',
+            code: 'DISCORD_TOKEN_EXCHANGE_FAILED',
+            details: errorData
+          });
+        }
+
+        const tokenData = await tokenResponse.json();
+
+        // Return tokens to client
+        return res.json({
+          access_token: tokenData.access_token,
+          refresh_token: tokenData.refresh_token,
+          token_type: tokenData.token_type,
+          expires_in: tokenData.expires_in,
+          scope: tokenData.scope
+        });
+      }
+
+      // Handle Challonge OAuth (if needed in the future)
+      if (provider === 'challonge') {
+        // Challonge uses the existing /api/oauth/token endpoint via oauth-proxy.js
+        return res.status(400).json({
+          error: 'Use /api/oauth/token for Challonge OAuth',
+          code: 'WRONG_ENDPOINT'
+        });
+      }
+
+      // Unknown provider
+      return res.status(400).json({
+        error: `Unknown provider: ${provider}`,
+        code: 'UNKNOWN_PROVIDER'
+      });
+    } catch (err) {
+      console.error('OAuth token exchange error:', err);
+      return res.status(500).json({
+        error: err.message || 'Failed to exchange OAuth code',
+        code: 'TOKEN_EXCHANGE_ERROR'
+      });
+    }
+  });
+
   return router;
 }