// Claude Chat API — Express + WebSocket Server
//
// Exponiert die Claude Bridge als HTTP-REST-API und WebSocket fuer Streaming.
// Port: 3100 (ENV: PORT)

import express from 'express';
import cors from 'cors';
import { createServer } from 'node:http';
import { WebSocketServer } from 'ws';
import { authMiddleware, verifyWsToken } from './auth.js';
import {
  sendMessage,
  stopAll,
  getStatus,
  listModels,
  setModel,
  setMode,
  createSession,
  listSessions,
  getSession,
} from './bridge.js';

const PORT = parseInt(process.env.PORT || '3100', 10);
const app = express();
const server = createServer(app);

// ============ Middleware ============

app.use(cors());
app.use(express.json());

// ============ REST Endpoints ============

// Status — oeffentlich fuer Health-Checks (optional: mit Auth schuetzen)
app.get('/api/status', authMiddleware, (req, res) => {
  const status = getStatus();
  res.json(status);
});

// Modelle auflisten
app.get('/api/models', authMiddleware, (req, res) => {
  res.json(listModels());
});

// Modell setzen
app.post('/api/model', authMiddleware, (req, res) => {
  const { model } = req.body;
  if (!model) {
    return res.status(400).json({ error: 'Feld "model" fehlt' });
  }
  try {
    const result = setModel(model);
    res.json(result);
  } catch (err) {
    res.status(400).json({ error: err.message });
  }
});

// Modus setzen
app.post('/api/mode', authMiddleware, (req, res) => {
  const { mode } = req.body;
  if (!mode) {
    return res.status(400).json({ error: 'Feld "mode" fehlt' });
  }
  try {
    const result = setMode(mode);
    res.json(result);
  } catch (err) {
    res.status(400).json({ error: err.message });
  }
});

// Sessions auflisten
app.get('/api/sessions', authMiddleware, (req, res) => {
  res.json(listSessions());
});

// Neue Session erstellen
app.post('/api/sessions', authMiddleware, (req, res) => {
  const { title } = req.body || {};
  const session = createSession(title);
  res.status(201).json(session);
});

// Einzelne Session abrufen
app.get('/api/sessions/:id', authMiddleware, (req, res) => {
  const session = getSession(req.params.id);
  if (!session) {
    return res.status(404).json({ error: 'Session nicht gefunden' });
  }
  res.json(session);
});

// Stopp-Endpoint (auch ueber REST erreichbar)
app.post('/api/stop', authMiddleware, (req, res) => {
  const stopped = stopAll();
  res.json({ stopped });
});

// ============ WebSocket ============

const wss = new WebSocketServer({ noServer: true });

// Upgrade-Handler: Token aus Query-Parameter pruefen
server.on('upgrade', (request, socket, head) => {
  // Nur /ws akzeptieren
  const url = new URL(request.url, `http://${request.headers.host}`);
  if (url.pathname !== '/ws') {
    socket.write('HTTP/1.1 404 Not Found\r\n\r\n');
    socket.destroy();
    return;
  }

  // Token pruefen
  if (!verifyWsToken(request.url)) {
    socket.write('HTTP/1.1 401 Unauthorized\r\n\r\n');
    socket.destroy();
    return;
  }

  wss.handleUpgrade(request, socket, head, (ws) => {
    wss.emit('connection', ws, request);
  });
});

wss.on('connection', (ws) => {
  console.log('[ws] Client verbunden');

  ws.on('message', (data) => {
    let msg;
    try {
      msg = JSON.parse(data.toString());
    } catch {
      ws.send(JSON.stringify({ type: 'error', message: 'Ungueltiges JSON' }));
      return;
    }

    switch (msg.type) {
      case 'message': {
        if (!msg.content) {
          ws.send(JSON.stringify({ type: 'error', message: 'Feld "content" fehlt' }));
          return;
        }

        const emitter = sendMessage(msg.content, msg.model, msg.mode, msg.sessionId);

        // Alle Events an den WebSocket-Client weiterleiten
        emitter.on('text', (payload) => {
          safeSend(ws, { type: 'text', content: payload.content });
        });

        emitter.on('tool_call', (payload) => {
          safeSend(ws, {
            type: 'tool_call',
            name: payload.name,
            args: payload.args,
            id: payload.id,
            summary: payload.summary,
          });
        });

        emitter.on('tool_result', (payload) => {
          safeSend(ws, {
            type: 'tool_result',
            id: payload.id,
            success: payload.success,
          });
        });

        emitter.on('agent_started', (payload) => {
          safeSend(ws, {
            type: 'agent_started',
            id: payload.id,
            name: payload.name || payload.type,
          });
        });

        emitter.on('agent_stopped', (payload) => {
          safeSend(ws, {
            type: 'agent_stopped',
            id: payload.id,
            success: payload.success,
          });
        });

        emitter.on('result', (payload) => {
          safeSend(ws, {
            type: 'result',
            content: payload.content,
            cost: payload.cost,
            tokens: payload.tokens,
            session_id: payload.session_id,
            duration_ms: payload.duration_ms,
            model: payload.model,
          });
        });

        emitter.on('error', (payload) => {
          safeSend(ws, { type: 'error', message: payload.message });
        });

        break;
      }

      case 'stop': {
        const stopped = stopAll();
        safeSend(ws, { type: 'stopped', success: stopped });
        break;
      }

      default:
        safeSend(ws, { type: 'error', message: `Unbekannter Nachrichtentyp: ${msg.type}` });
    }
  });

  ws.on('close', () => {
    console.log('[ws] Client getrennt');
  });

  ws.on('error', (err) => {
    console.error('[ws] Fehler:', err.message);
  });

  // Willkommens-Nachricht
  safeSend(ws, {
    type: 'connected',
    status: getStatus(),
    models: listModels(),
  });
});

/** Sicher an WebSocket senden (nur wenn offen) */
function safeSend(ws, data) {
  if (ws.readyState === ws.OPEN) {
    ws.send(JSON.stringify(data));
  }
}

// ============ Server starten ============

server.listen(PORT, () => {
  console.log(`[claude-chat-api] Server laeuft auf Port ${PORT}`);
  console.log(`  REST:      http://localhost:${PORT}/api/status`);
  console.log(`  WebSocket: ws://localhost:${PORT}/ws?token=<TOKEN>`);
});

// Graceful Shutdown
process.on('SIGTERM', () => {
  console.log('[server] SIGTERM empfangen, fahre herunter...');
  stopAll();
  wss.close();
  server.close(() => process.exit(0));
});

process.on('SIGINT', () => {
  console.log('[server] SIGINT empfangen, fahre herunter...');
  stopAll();
  wss.close();
  server.close(() => process.exit(0));
});