From e773d1dc5201d906f9892cf2ceda5a3a45f0978c Mon Sep 17 00:00:00 2001
From: "Builder.io" <builder-bot@builder.io>
Date: Mon, 10 Nov 2025 00:29:51 +0000
Subject: [PATCH] completionId: cgen-f56c2e4ea4844e18ad901fce69459562

cgen-f56c2e4ea4844e18ad901fce69459562
---
 api/discord/oauth/callback.ts | 39 +++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/api/discord/oauth/callback.ts b/api/discord/oauth/callback.ts
index 62a5e6d2..1a17ee10 100644
--- a/api/discord/oauth/callback.ts
+++ b/api/discord/oauth/callback.ts
@@ -142,6 +142,45 @@ export default async function handler(req: any, res: any) {
     // Initialize Supabase client with service role
     const supabase = createClient(supabaseUrl, supabaseServiceRole);
 
+    // LINKING FLOW: Link Discord to authenticated user
+    if (isLinkingFlow && authenticatedUserId) {
+      console.log("[Discord OAuth] Linking Discord to user:", authenticatedUserId);
+
+      // Check if Discord ID is already linked to someone else
+      const { data: existingLink } = await supabase
+        .from("discord_links")
+        .select("user_id")
+        .eq("discord_id", discordUser.id)
+        .single();
+
+      if (existingLink && existingLink.user_id !== authenticatedUserId) {
+        console.error("[Discord OAuth] Discord ID already linked to different user");
+        return res.redirect(
+          `/dashboard?error=already_linked&message=${encodeURIComponent("This Discord account is already linked to another AeThex account")}`,
+        );
+      }
+
+      // Create or update Discord link
+      const { error: linkError } = await supabase
+        .from("discord_links")
+        .upsert({
+          discord_id: discordUser.id,
+          user_id: authenticatedUserId,
+          linked_at: new Date().toISOString(),
+        });
+
+      if (linkError) {
+        console.error("[Discord OAuth] Link creation failed:", linkError);
+        return res.redirect(
+          `/dashboard?error=link_failed&message=${encodeURIComponent("Failed to link Discord account")}`,
+        );
+      }
+
+      console.log("[Discord OAuth] Successfully linked Discord:", discordUser.id);
+      return res.redirect(redirectTo);
+    }
+
+    // LOGIN/SIGNUP FLOW: Standard OAuth login
     // Check if Discord user already exists
     const { data: existingLink } = await supabase
       .from("discord_links")