#!/usr/bin/env node

import Fastify from 'fastify';
import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { StreamableHTTPServerTransport } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
import { JsonStore } from './storage/json-store.js';
import { Collections } from './storage/collections.js';
import { requireAuth } from './middleware/auth.js';
import { registerRoutes } from './routes/api.js';
import { registerMcpTools } from './mcp/tools.js';

const HOST = process.env['HOST'] ?? '0.0.0.0';
const PORT = Number(process.env['PORT'] ?? 8100);
const DATA_DIR = process.env['MOSAIC_BRAIN_DATA_DIR'] ?? './data';

/**
 * Create a fresh MCP server instance with all tools registered.
 * Each HTTP request gets its own instance to avoid state leaks.
 */
function createMcpServer(collections: Collections): McpServer {
  const mcp = new McpServer({
    name: 'mosaic-brain',
    version: '0.1.0',
  });
  registerMcpTools(mcp, collections);
  return mcp;
}

async function main(): Promise<void> {
  // --- Storage ---
  const store = new JsonStore({ dataDir: DATA_DIR });
  await store.init();
  const collections = new Collections(store);

  // --- Fastify ---
  const app = Fastify({ logger: true });

  // Auth on all /v1 and /mcp routes
  app.addHook('onRequest', async (req, reply) => {
    if (req.url.startsWith('/v1/') || req.url === '/mcp') {
      await requireAuth(req, reply);
    }
  });

  // REST API
  registerRoutes(app, collections);

  // MCP over HTTP (Streamable HTTP transport)
  // Each request gets a fresh McpServer + transport to avoid state leaks
  app.all('/mcp', async (req, reply) => {
    const mcp = createMcpServer(collections);
    const transport = new StreamableHTTPServerTransport({
      sessionIdGenerator: undefined, // stateless
    });
    await mcp.connect(transport);

    if (req.method === 'POST') {
      await transport.handleRequest(
        req.raw,
        reply.raw,
        req.body as Record<string, unknown>,
      );
    } else if (req.method === 'GET') {
      await transport.handleRequest(req.raw, reply.raw);
    } else if (req.method === 'DELETE') {
      await transport.handleRequest(req.raw, reply.raw);
    } else {
      reply.code(405).send({ error: 'Method not allowed' });
    }
  });

  // --- Start ---
  await app.listen({ host: HOST, port: PORT });
  console.log(`mosaic-brain listening on ${HOST}:${PORT}`);
  console.log(`  REST API: http://${HOST}:${PORT}/v1/`);
  console.log(`  MCP:      http://${HOST}:${PORT}/mcp`);
  console.log(`  Data dir: ${DATA_DIR}`);
}

main().catch((err) => {
  console.error('Failed to start mosaic-brain:', err);
  process.exit(1);
});