Implement federated chat message sending and receiving

Adds /api/chat/receive endpoint to accept federated chat messages from remote nodes and store them for local users. Updates /api/chat/send to support sending messages to remote nodes by resolving recipient domains, posting to their /api/chat/receive endpoint, and storing a local copy of the sent message. Enables basic cross-node chat federation.

src/app/api/chat/receive/route.ts

@@ -0,0 +1,94 @@
+
+import { NextRequest, NextResponse } from 'next/server';
+import { db } from '@/db';
+import { chatConversations, chatMessages, users } from '@/db/schema';
+import { eq, and } from 'drizzle-orm';
+
+/**
+ * POST /api/chat/receive
+ * Endpoint for receiving federated chat messages from other nodes.
+ * 
+ * Body: {
+ *   senderDid: string,
+ *   senderHandle: string, // user@domain
+ *   senderDisplayName: string,
+ *   senderAvatarUrl: string,
+ *   senderNodeDomain: string,
+ *   recipientDid: string,
+ *   encryptedContent: string (base64 JSON of {senderPublicKey, ciphertext, nonce, recipientDid}),
+ *   sentAt: string (ISO date)
+ * }
+ */
+export async function POST(request: NextRequest) {
+    try {
+        const body = await request.json();
+        const {
+            senderDid,
+            senderHandle,
+            senderDisplayName,
+            senderAvatarUrl,
+            senderNodeDomain,
+            recipientDid,
+            encryptedContent
+        } = body;
+
+        // Basic validation
+        if (!senderDid || !senderHandle || !recipientDid || !encryptedContent || !senderNodeDomain) {
+            return NextResponse.json({ error: 'Missing required fields' }, { status: 400 });
+        }
+
+        // 1. Find local recipient
+        const recipientUser = await db.query.users.findFirst({
+            where: eq(users.did, recipientDid)
+        });
+
+        if (!recipientUser) {
+            return NextResponse.json({ error: 'Recipient not found' }, { status: 404 });
+        }
+
+        // 2. Find or Create Conversation
+        // For the RECIPIENT, the conversation is with the SENDER (Remote)
+        let conversation = await db.query.chatConversations.findFirst({
+            where: and(
+                eq(chatConversations.participant1Id, recipientUser.id),
+                eq(chatConversations.participant2Handle, senderHandle)
+            )
+        });
+
+        if (!conversation) {
+            const [newConv] = await db.insert(chatConversations).values({
+                participant1Id: recipientUser.id,
+                participant2Handle: senderHandle,
+                lastMessageAt: new Date(),
+                lastMessagePreview: '[Encrypted Message]'
+            }).returning();
+            conversation = newConv;
+        }
+
+        // 3. Store Message
+        await db.insert(chatMessages).values({
+            conversationId: conversation.id,
+            senderHandle: senderHandle,
+            senderDisplayName: senderDisplayName || senderHandle,
+            senderAvatarUrl: senderAvatarUrl,
+            senderNodeDomain: senderNodeDomain,
+            senderDid: senderDid,
+            encryptedContent: encryptedContent,
+            deliveredAt: new Date(),
+        });
+
+        // 4. Update conversation timestamp
+        await db.update(chatConversations)
+            .set({
+                lastMessageAt: new Date(),
+                lastMessagePreview: '[Encrypted Message]'
+            })
+            .where(eq(chatConversations.id, conversation.id));
+
+        return NextResponse.json({ success: true });
+
+    } catch (error: any) {
+        console.error('Federated Receive Failed:', error);
+        return NextResponse.json({ error: error.message }, { status: 500 });
+    }
+}

src/app/api/chat/send/route.ts

@@ -1,6 +1,6 @@
 import { NextRequest, NextResponse } from 'next/server';
 import { db } from '@/db';
-import { chatConversations, chatMessages, users } from '@/db/schema';
+import { chatConversations, chatMessages, users, handleRegistry } from '@/db/schema';
 import { requireAuth } from '@/lib/auth';
 import { eq, and } from 'drizzle-orm';
 
@@ -34,7 +34,7 @@ export async function POST(request: NextRequest) {
 
         if (recipientUser) {
             // LOCAL RECIPIENT
-            
+
             // Ensure conversations exist
             let recipientConv = await db.query.chatConversations.findFirst({
                 where: and(
@@ -105,8 +105,91 @@ export async function POST(request: NextRequest) {
 
             return NextResponse.json({ success: true });
         } else {
-            // REMOTE RECIPIENT - not implemented yet
+            // REMOTE RECIPIENT
-            return NextResponse.json({ error: 'Remote delivery not yet implemented' }, { status: 501 });
+            const { handleRegistry } = await import('@/db/schema'); // dynamic import or add to top
+
+            // 1. Resolve recipient node
+            const registryEntry = await db.query.handleRegistry.findFirst({
+                where: eq(handleRegistry.did, recipientDid)
+            });
+
+            if (!registryEntry) {
+                return NextResponse.json({ error: 'Recipient not found in registry' }, { status: 404 });
+            }
+
+            const targetDomain = registryEntry.nodeDomain;
+            const targetHandle = registryEntry.handle; // e.g. user@domain
+
+            // 2. Prepare Payload
+            const messageData = {
+                senderPublicKey,
+                recipientDid,
+                ciphertext,
+                nonce,
+            };
+            const encryptedContent = JSON.stringify(messageData);
+
+            const payload = {
+                senderDid: user.did,
+                senderHandle: user.handle,
+                senderDisplayName: user.displayName,
+                senderAvatarUrl: user.avatarUrl,
+                senderNodeDomain: process.env.NEXT_PUBLIC_NODE_DOMAIN || 'dev.syn.quest', // Current node domain
+                recipientDid,
+                encryptedContent,
+                sentAt: new Date().toISOString()
+            };
+
+            // 3. Send to Remote Node
+            try {
+                const protocol = targetDomain.includes('localhost') ? 'http' : 'https';
+                const res = await fetch(`${protocol}://${targetDomain}/api/chat/receive`, {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: JSON.stringify(payload)
+                });
+
+                if (!res.ok) {
+                    const errText = await res.text();
+                    console.error('Remote node rejected chat:', errText);
+                    return NextResponse.json({ error: `Remote delivery failed: ${res.statusText}` }, { status: 502 });
+                }
+            } catch (err: any) {
+                console.error('Failed to contact remote node:', err);
+                return NextResponse.json({ error: 'Failed to contact remote node' }, { status: 504 });
+            }
+
+            // 4. Store "Sent" copy locally
+            // Ensure conversation exists locally
+            let senderConv = await db.query.chatConversations.findFirst({
+                where: and(
+                    eq(chatConversations.participant1Id, user.id),
+                    eq(chatConversations.participant2Handle, targetHandle)
+                )
+            });
+
+            if (!senderConv) {
+                const [newConv] = await db.insert(chatConversations).values({
+                    participant1Id: user.id,
+                    participant2Handle: targetHandle,
+                    lastMessageAt: new Date(),
+                    lastMessagePreview: '[Encrypted]'
+                }).returning();
+                senderConv = newConv;
+            }
+
+            await db.insert(chatMessages).values({
+                conversationId: senderConv.id,
+                senderHandle: user.handle,
+                senderDisplayName: user.displayName,
+                senderAvatarUrl: user.avatarUrl,
+                senderNodeDomain: null, // It's ME, so null
+                senderDid: user.did,
+                encryptedContent: encryptedContent,
+                deliveredAt: new Date(),
+            });
+
+            return NextResponse.json({ success: true });
         }
 
     } catch (error: any) {