Implement token caching to avoid unnecessary refresh token calls

- Add expires_at timestamp to OAuth config
- Cache access_token in database to reuse across requests
- Only refresh token when it expires (after 1 hour)
- Use 60-second buffer to avoid using almost-expired tokens
- Auto-update cached token after refresh
- This fixes the invalid_grant error from excessive refresh calls

supabase/functions/create-google-meet-event/index.ts

@@ -10,6 +10,8 @@ interface GoogleOAuthConfig {
   client_id: string;
   client_secret: string;
   refresh_token: string;
+  access_token?: string;
+  expires_at?: number; // Timestamp when access_token expires
 }
 
 interface CreateMeetRequest {
@@ -24,22 +26,36 @@ interface CreateMeetRequest {
 }
 
 // Function to get access token from refresh token (OAuth2)
-async function getGoogleAccessToken(oauthConfig: GoogleOAuthConfig): Promise<string> {
+async function getGoogleAccessToken(oauthConfig: GoogleOAuthConfig): Promise<{ access_token: string; expires_in: number }> {
   try {
+    console.log("Attempting to exchange refresh token for access token...");
+    console.log("Client ID:", oauthConfig.client_id);
+
+    const tokenRequest = {
+      client_id: oauthConfig.client_id,
+      client_secret: oauthConfig.client_secret,
+      refresh_token: oauthConfig.refresh_token,
+      grant_type: "refresh_token",
+    };
+
+    console.log("Token request payload:", JSON.stringify({
+      ...tokenRequest,
+      client_secret: "***REDACTED***",
+      refresh_token: tokenRequest.refresh_token.substring(0, 20) + "..."
+    }));
+
     const response = await fetch("https://oauth2.googleapis.com/token", {
       method: "POST",
       headers: { "Content-Type": "application/x-www-form-urlencoded" },
-      body: new URLSearchParams({
-        client_id: oauthConfig.client_id,
-        client_secret: oauthConfig.client_secret,
-        refresh_token: oauthConfig.refresh_token,
-        grant_type: "refresh_token",
-      }),
+      body: new URLSearchParams(tokenRequest),
     });
 
+    const responseText = await response.text();
+    console.log("Token response status:", response.status);
+    console.log("Token response body:", responseText);
+
     if (!response.ok) {
-      const errorText = await response.text();
-      throw new Error(`Token exchange failed: ${errorText}`);
+      throw new Error(`Token exchange failed: ${responseText}`);
     }
 
     const data = await response.json();
@@ -48,7 +64,11 @@ async function getGoogleAccessToken(oauthConfig: GoogleOAuthConfig): Promise<str
       throw new Error("No access token in response");
     }
 
-    return data.access_token;
+    console.log("Successfully obtained access token");
+    return {
+      access_token: data.access_token,
+      expires_in: data.expires_in || 3600
+    };
   } catch (error: any) {
     console.error("Error getting Google access token:", error);
     throw error;
@@ -119,8 +139,36 @@ serve(async (req: Request): Promise<Response> => {
       );
     }
 
-    // Get access token using OAuth2 refresh token
-    const accessToken = await getGoogleAccessToken(oauthConfig);
+    // Check if we have a valid cached access_token
+    let accessToken: string;
+    const now = Math.floor(Date.now() / 1000); // Current time in seconds
+
+    if (oauthConfig.access_token && oauthConfig.expires_at && oauthConfig.expires_at > now + 60) {
+      // Token is still valid (with 60 second buffer)
+      console.log("Using cached access_token (expires at:", new Date(oauthConfig.expires_at * 1000).toISOString(), ")");
+      accessToken = oauthConfig.access_token;
+    } else {
+      // Need to refresh the token
+      console.log("Access token expired or missing, refreshing...");
+      const tokenData = await getGoogleAccessToken(oauthConfig);
+      accessToken = tokenData.access_token;
+
+      // Update the cached token in database with new expiry
+      const newExpiresAt = now + tokenData.expires_in;
+      const updatedConfig = {
+        ...oauthConfig,
+        access_token: accessToken,
+        expires_at: newExpiresAt
+      };
+
+      // Save updated config back to database
+      await supabase
+        .from("platform_settings")
+        .update({ google_oauth_config: JSON.stringify(updatedConfig) })
+        .eq("id", settings.id);
+
+      console.log("Updated cached access_token in database");
+    }
     console.log("Got access token");
 
     // Build event data