vibn-frontend/app/api/chat/route.ts

/**
 * POST /api/chat
 *
 * Streaming chat endpoint. Accepts a thread_id + user message,
 * loads history, calls Gemini 3.1 Pro, runs the tool loop,
 * persists messages, and streams SSE back to the client.
 *
 * SSE event shapes:
 *   data: {"type":"text","text":"..."}
 *   data: {"type":"tool_start","name":"...","args":{}}
 *   data: {"type":"tool_result","name":"...","result":"..."}
 *   data: {"type":"done"}
 *   data: {"type":"error","error":"..."}
 */
import { NextResponse } from 'next/server';
import { authSession } from '@/lib/auth/session-server';
import { query } from '@/lib/db-postgres';
import { callGeminiChat, streamGeminiChat } from '@/lib/ai/gemini-chat';
import { VIBN_TOOL_DEFINITIONS, executeMcpTool } from '@/lib/ai/vibn-tools';
import type { ChatMessage, ToolCall } from '@/lib/ai/gemini-chat';

const MAX_TOOL_ROUNDS = 6;

let chatTablesReady = false;
async function ensureChatTables() {
  if (chatTablesReady) return;
  await query(`
    CREATE TABLE IF NOT EXISTS fs_chat_threads (
      id         TEXT PRIMARY KEY DEFAULT gen_random_uuid()::text,
      user_id    TEXT NOT NULL,
      workspace  TEXT NOT NULL DEFAULT '',
      data       JSONB NOT NULL DEFAULT '{}',
      created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
      updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
    );
    CREATE INDEX IF NOT EXISTS fs_chat_threads_user_ws_idx
      ON fs_chat_threads (user_id, workspace, updated_at DESC);

    CREATE TABLE IF NOT EXISTS fs_chat_messages (
      id         BIGSERIAL PRIMARY KEY,
      thread_id  TEXT NOT NULL REFERENCES fs_chat_threads(id) ON DELETE CASCADE,
      user_id    TEXT NOT NULL,
      data       JSONB NOT NULL DEFAULT '{}',
      created_at TIMESTAMPTZ NOT NULL DEFAULT now()
    );
    CREATE INDEX IF NOT EXISTS fs_chat_messages_thread_idx
      ON fs_chat_messages (thread_id, created_at ASC);
  `, []);
  chatTablesReady = true;
}

function buildSystemPrompt(projects: any[], workspace: string): string {
  const projectsText = projects.length
    ? projects
        .map(
          (p: any) =>
            `- "${p.productName || p.name}" (id: ${p.id}, status: ${p.status || 'defining'})${p.productVision ? ': ' + p.productVision.slice(0, 120) : ''}`,
        )
        .join('\n')
    : '(no projects yet)';

  return `You are Vibn AI, an expert product and infrastructure assistant embedded in the Vibn platform.
You are talking to the owner of the "${workspace}" workspace.

## How Vibn is structured
- **Workspace** ("${workspace}") — the tenant boundary. One per user. Owns the Gitea org and a fleet of Coolify projects.
- **Project** — an initiative the user is building (e.g. "Twenty CRM", "My Blog"). Each project has its OWN isolated Coolify project so all its apps + databases + services are grouped together. A project has both:
  - Planning side: name, vision/objectives, requirements (from \`projects_get\`)
  - Live side: deployed apps + services (in \`projects_get → possibleDeployments[]\` and \`apps_list { projectId }\`)
  These are facets of ONE thing — never describe them as separate.

When the user asks about a project, call \`projects_get\` first — it returns both the planning details and the linked deployments. Use \`apps_list { projectId }\` to drill into running services for a specific project, or \`apps_list\` (no args) to see everything in the workspace.

When deploying with \`apps_create\`, ALWAYS pass \`projectId\` so the new app/service lands inside the right project's isolated Coolify namespace. If the user hasn't specified a project, ask them which one.

## Current workspace projects
${projectsText}

## Your capabilities
You have full access to the Vibn platform. You can:
- **Apps**: list, create, update, delete, deploy, get logs, exec commands, manage domains, manage env vars, manage volumes, repair broken deploys
- **Databases**: provision Postgres/MySQL/Redis/MongoDB and 5 other flavors, get connection URLs
- **Auth providers**: deploy Pocketbase, Authentik, Keycloak, Logto, SuperTokens, and others
- **Domains**: search availability, register, attach to apps with full DNS wiring
- **Storage**: provision GCS buckets, inject S3-compatible credentials into apps
- **Templates**: search and deploy from 320+ one-click app templates (n8n, Ghost, Supabase, etc.)
- **GitHub**: search open-source repos, read any file from a public repo
- **Web**: fetch any public URL or documentation page

## Key rules
- Call \`apps_list\` (not \`projects_list\`) when the user asks what is running or what has a domain.
- Always call \`apps_templates_search\` before \`apps_create\` for any popular third-party app.
- Be concise and action-oriented — if the user wants to deploy something, do it, don't just describe how.
- Confirm app name and domain before deploying unless the user has been explicit.
- After tool calls, summarize in plain language what happened.
- Format code, URLs, and technical values in backticks.
- Today's date: ${new Date().toLocaleDateString('en-US', { weekday: 'long', year: 'numeric', month: 'long', day: 'numeric' })}.`;
}

export async function POST(request: Request) {
  await ensureChatTables();

  const session = await authSession();
  if (!session?.user?.email) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
  }

  let body: { thread_id: string; message: string; workspace: string; mcp_token?: string };
  try {
    body = await request.json();
  } catch {
    return NextResponse.json({ error: 'Invalid JSON' }, { status: 400 });
  }

  const { thread_id, message, workspace, mcp_token } = body;
  if (!thread_id || !message?.trim()) {
    return NextResponse.json({ error: 'thread_id and message are required' }, { status: 400 });
  }

  const email = session.user.email;

  // Verify thread belongs to user
  const threads = await query<any>(
    `SELECT id FROM fs_chat_threads WHERE id = $1 AND user_id = $2`,
    [thread_id, email],
  );
  if (!threads.length) {
    return NextResponse.json({ error: 'Thread not found' }, { status: 404 });
  }

  // Load message history (last 40 messages)
  const rows = await query<any>(
    `SELECT data FROM fs_chat_messages WHERE thread_id = $1 ORDER BY created_at DESC LIMIT 40`,
    [thread_id],
  );
  const history: ChatMessage[] = rows.reverse().map((r: any) => r.data);

  // Add user message
  const userMsg: ChatMessage = { role: 'user', content: message.trim() };
  history.push(userMsg);
  await query(
    `INSERT INTO fs_chat_messages (thread_id, user_id, data) VALUES ($1, $2, $3)`,
    [thread_id, email, JSON.stringify(userMsg)],
  );

  // Update thread updatedAt
  await query(
    `UPDATE fs_chat_threads SET updated_at = NOW(), data = data || $2 WHERE id = $1`,
    [thread_id, JSON.stringify({ updatedAt: new Date().toISOString() })],
  );

  // Load projects for system prompt context
  const projectRows = await query<any>(
    `SELECT p.data FROM fs_projects p
     JOIN fs_users u ON u.id = p.user_id
     WHERE u.data->>'email' = $1
     ORDER BY (p.data->>'updatedAt') DESC NULLS LAST LIMIT 20`,
    [email],
  );
  const projects = projectRows.map((r: any) => r.data);
  const systemPrompt = buildSystemPrompt(projects, workspace);

  // Base URL for internal MCP calls
  const host = request.headers.get('host') || 'vibnai.com';
  const proto = host.startsWith('localhost') ? 'http' : 'https';
  const baseUrl = `${proto}://${host}`;

  // Stream response
  const encoder = new TextEncoder();
  const stream = new ReadableStream({
    async start(controller) {
      function emit(chunk: object) {
        controller.enqueue(encoder.encode(`data: ${JSON.stringify(chunk)}\n\n`));
      }

      let messages = [...history];
      let round = 0;
      let assistantText = '';
      const assistantToolCalls: ToolCall[] = [];

      try {
        // Tool-calling loop: use non-streaming so thought_signature is
        // always present in the complete response (required by thinking models).
        while (round < MAX_TOOL_ROUNDS) {
          round++;

          const toolDefs = mcp_token ? VIBN_TOOL_DEFINITIONS : [];
          const resp = await callGeminiChat({ systemPrompt, messages, tools: toolDefs, temperature: 0.7 });

          if (resp.error) {
            emit({ type: 'error', error: resp.error });
            controller.close();
            return;
          }

          // Stream text to client
          if (resp.text) {
            assistantText += resp.text;
            emit({ type: 'text', text: resp.text });
          }

          // Announce tool calls
          for (const tc of resp.toolCalls) {
            assistantToolCalls.push(tc);
            emit({ type: 'tool_start', name: tc.name, args: tc.args });
          }

          // Save assistant turn
          messages.push({
            role: 'assistant',
            content: resp.text,
            toolCalls: resp.toolCalls.length ? resp.toolCalls : undefined,
          });

          if (!resp.toolCalls.length) break;

          // Execute tool calls and add results
          for (const tc of resp.toolCalls) {
            const result = mcp_token
              ? await executeMcpTool(tc.name, tc.args, mcp_token, baseUrl)
              : JSON.stringify({ error: 'No MCP token — read-only mode.' });

            emit({ type: 'tool_result', name: tc.name, result: result.slice(0, 500) });

            messages.push({
              role: 'tool',
              content: result,
              toolCallId: tc.id,
              toolName: tc.name,
              thoughtSignature: tc.thoughtSignature,
            });
          }
        }

        // Persist final assistant message
        const finalMsg: ChatMessage = {
          role: 'assistant',
          content: assistantText,
          toolCalls: assistantToolCalls.length ? assistantToolCalls : undefined,
        };
        await query(
          `INSERT INTO fs_chat_messages (thread_id, user_id, data) VALUES ($1, $2, $3)`,
          [thread_id, email, JSON.stringify(finalMsg)],
        );

        emit({ type: 'done' });
        controller.close();
      } catch (e) {
        emit({ type: 'error', error: e instanceof Error ? e.message : String(e) });
        controller.close();
      }
    },
  });

  return new Response(stream, {
    headers: {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      Connection: 'keep-alive',
    },
  });
}