// Copyright (c) 2026 Gordon Bolton. MIT License.
const express = require('express');
const router = express.Router();
const logStreamAuth = require('../middleware/logStreamAuth');
const {
  logEmitter,
  logBuffer,
  clientLogBuffer,
  ingestClientLogs
} = require('../utils/logCapture');

// Public status check (no auth, no 403 block, returns standard config state)
router.get('/status', (req, res) => {
  res.json({ enabled: process.env.ENABLE_LOG_STREAM === 'true' });
});

// Global toggle check
router.use((req, res, next) => {
  if (process.env.ENABLE_LOG_STREAM !== 'true') {
    return res.status(403).json({ error: 'Log streaming feature is disabled' });
  }
  next();
});

// Enforce subnet and authentication validations on all debug routes
router.use(logStreamAuth);

/**
 * GET /api/debug/server-logs
 * Exposes a real-time SSE stream of intercepted server stdout/stderr logs.
 */
router.get('/server-logs', (req, res) => {
  res.writeHead(200, {
    'Content-Type': 'text/event-stream',
    'Cache-Control': 'no-cache',
    'Connection': 'keep-alive',
    'X-Accel-Buffering': 'no'
  });

  // Send historical server logs buffer first
  for (const line of logBuffer) {
    res.write(`data: ${line}\n\n`);
  }

  // Gracefully close for integration testing
  if (req.query.testClose === 'true') {
    res.end();
    return;
  }

  const sendLog = (line) => {
    try {
      res.write(`data: ${line}\n\n`);
    } catch (err) {
      console.error('[debugRoutes] Error sending server log line:', err.message);
    }
  };

  logEmitter.on('server-log', sendLog);

  // 25s heartbeat comment to prevent proxy timeouts
  const heartbeat = setInterval(() => {
    try {
      res.write(': heartbeat\n\n');
    } catch {
      // Ignore
    }
  }, 25000);

  req.on('close', () => {
    clearInterval(heartbeat);
    logEmitter.off('server-log', sendLog);
  });
});

/**
 * GET /api/debug/client-logs
 * Exposes a real-time SSE stream of ingested client-side console logs.
 */
router.get('/client-logs', (req, res) => {
  res.writeHead(200, {
    'Content-Type': 'text/event-stream',
    'Cache-Control': 'no-cache',
    'Connection': 'keep-alive',
    'X-Accel-Buffering': 'no'
  });

  // Send historical client logs buffer first
  for (const line of clientLogBuffer) {
    res.write(`data: ${line}\n\n`);
  }

  // Gracefully close for integration testing
  if (req.query.testClose === 'true') {
    res.end();
    return;
  }

  const sendClientLog = (line) => {
    try {
      res.write(`data: ${line}\n\n`);
    } catch (err) {
      console.error('[debugRoutes] Error sending client log line:', err.message);
    }
  };

  logEmitter.on('client-log', sendClientLog);

  // 25s heartbeat comment to prevent proxy timeouts
  const heartbeat = setInterval(() => {
    try {
      res.write(': heartbeat\n\n');
    } catch {
      // Ignore
    }
  }, 25000);

  req.on('close', () => {
    clearInterval(heartbeat);
    logEmitter.off('client-log', sendClientLog);
  });
});

/**
 * POST /api/debug/client-logs
 * Receives batches of frontend console logs to store in buffer and emit.
 */
router.post('/client-logs', (req, res) => {
  const logs = req.body;
  if (!Array.isArray(logs)) {
    return res.status(400).json({ error: 'Body must be a JSON array of log entries' });
  }

  try {
    ingestClientLogs(logs);
    return res.status(200).json({ success: true, count: logs.length });
  } catch (err) {
    console.error('[debugRoutes] Ingestion failed:', err.message);
    return res.status(500).json({ error: 'Internal server error during ingestion' });
  }
});

module.exports = router;