const http = require('http');
const net = require('net');

const port = 8080;
const fulcrumTimeoutMs = 3000;

function checkFulcrum(fulcrumUrl) {
  return new Promise((resolve) => {
    if (!fulcrumUrl) {
      resolve({
        configured: false,
        connected: false,
        url: null,
      });
      return;
    }

    let parsed;

    try {
      parsed = new URL(fulcrumUrl);
    } catch {
      resolve({
        configured: true,
        connected: false,
        url: fulcrumUrl,
      });
      return;
    }

    if (parsed.protocol !== 'tcp:') {
      resolve({
        configured: true,
        connected: false,
        url: fulcrumUrl,
      });
      return;
    }

    const host = parsed.hostname;
    const port = Number(parsed.port);

    if (!host || !port) {
      resolve({
        configured: true,
        connected: false,
        url: fulcrumUrl,
      });
      return;
    }

    const socket = net.createConnection({
      host,
      port,
    });

    let response = '';
    let settled = false;

    const finish = (connected) => {
      if (settled) return;
      settled = true;

      socket.destroy();

      resolve({
        configured: true,
        connected,
        url: fulcrumUrl,
      });
    };

    socket.setTimeout(fulcrumTimeoutMs);

    socket.on('connect', () => {
      socket.write(
        `${JSON.stringify({
          jsonrpc: '2.0',
          id: 1,
          method: 'server.version',
          params: ['Munin Bitcoin', '1.4'],
        })}\n`,
      );
    });

    socket.on('data', (data) => {
      response += data.toString();

      if (response.includes('"result"')) {
        finish(true);
      } else if (response.includes('"error"')) {
        finish(false);
      }
    });

    socket.on('timeout', () => finish(false));
    socket.on('error', () => finish(false));
    socket.on('close', () => finish(false));
  });
}

async function getStatus() {
  const fulcrumUrl = process.env.MUNIN_FULCRUM_URL || null;
  const fulcrum = await checkFulcrum(fulcrumUrl);

  return {
    service: 'running',
    fulcrum,
    wallet: 'not configured',
    labels: 0,
    transactions: 0,
    lastScan: 'never',
  };
}

const server = http.createServer(async (req, res) => {
  if (req.url === '/api/status') {
    try {
      const status = await getStatus();

      res.writeHead(200, {
        'Content-Type': 'application/json',
      });

      res.end(JSON.stringify(status));
    } catch (error) {
      console.error('Failed to get service status:', error);

      res.writeHead(500, {
        'Content-Type': 'application/json',
      });

      res.end(
        JSON.stringify({
          service: 'running',
          error: 'Failed to determine service status',
        }),
      );
    }

    return;
  }

  res.writeHead(404);
  res.end('Not found');
});

server.listen(port, () => {
  console.log(`Status API listening on port ${port}`);
});