import express from 'express';
import { ScreenshotCache } from './cache.js';
import { takeScreenshot, checkWebGL, closeBrowser, initialize } from './screenshot.js';

const PORT = parseInt(process.env.PORT || '8002', 10);
const APP_URL = process.env.APP_URL;
const CACHE_DIR = process.env.CACHE_DIR;

if (!APP_URL) {
  console.error('Error: APP_URL environment variable is required');
  process.exit(1);
}

if (!CACHE_DIR) {
  console.error('Error: CACHE_DIR environment variable is required');
  process.exit(1);
}

const cache = new ScreenshotCache(CACHE_DIR);
const app = express();

app.get('/health', (_req, res) => {
  res.status(200).send('ok');
});

app.get('/debug', async (_req, res) => {
  try {
    const info = await checkWebGL();
    res.json(info);
  } catch (err) {
    res.status(500).json({ error: String(err) });
  }
});

app.get('/screenshot', async (req, res) => {
  try {
    const qs = new URLSearchParams();
    for (const key of ['lat', 'lon', 'zoom', 'tab', 'og']) {
      const val = req.query[key];
      if (typeof val === 'string' && val) {
        qs.set(key, val);
      }
    }
    // Repeated params: filter, poi
    for (const key of ['filter', 'poi']) {
      const val = req.query[key];
      if (typeof val === 'string' && val) {
        qs.append(key, val);
      } else if (Array.isArray(val)) {
        for (const v of val) {
          if (typeof v === 'string' && v) qs.append(key, v);
        }
      }
    }

    // Extract path param (used for non-root pages like /invite/CODE)
    const pagePath = typeof req.query.path === 'string' && req.query.path ? req.query.path : '/';
    if (pagePath !== '/') qs.set('path', pagePath);

    const cacheKey = cache.buildKey(qs);
    qs.delete('path');

    // Check cache first
    const cached = cache.get(cacheKey);
    if (cached) {
      res.setHeader('Content-Type', 'image/jpeg');
      res.setHeader('Cache-Control', 'public, max-age=86400');
      res.setHeader('X-Cache', 'HIT');
      cached.pipe(res);
      return;
    }

    // Build the URL for the frontend in screenshot mode
    qs.set('screenshot', '1');
    const url = `${APP_URL}${pagePath}?${qs}`;

    console.log(`Taking screenshot: ${url}`);
    const jpeg = await takeScreenshot(url);

    // Cache it
    cache.set(cacheKey, jpeg);

    res.setHeader('Content-Type', 'image/jpeg');
    res.setHeader('Cache-Control', 'public, max-age=86400');
    res.setHeader('X-Cache', 'MISS');
    res.send(jpeg);
  } catch (err) {
    console.error('Screenshot failed:', err);
    res.status(500).json({ error: 'Screenshot failed' });
  }
});

const server = app.listen(PORT, () => {
  console.log(`Screenshot service listening on port ${PORT}`);
  console.log(`  APP_URL: ${APP_URL}`);
  console.log(`  CACHE_DIR: ${CACHE_DIR}`);

  // Pre-warm browser and populate network cache in background.
  // The health endpoint is available immediately; screenshot requests
  // during warm-up will still work (just slower on the first call).
  initialize(APP_URL).catch((err) => {
    console.error('Initialization failed:', err);
  });
});

// Graceful shutdown
for (const signal of ['SIGTERM', 'SIGINT']) {
  process.on(signal, async () => {
    console.log(`Received ${signal}, shutting down...`);
    server.close();
    await closeBrowser();
    process.exit(0);
  });
}