const express = require('express');
const jwt = require('jsonwebtoken');
const fs = require('fs');
const path = require('path');

const app = express();
const PORT = process.env.PORT || 3000;
const JWT_SECRET = process.env.JWT_SECRET || 'fallback-secret-key';
const APPS_FILE = path.join(__dirname, 'data', 'apps.json');

app.use(express.json());
app.use((req, res, next) => {
  res.setHeader('Access-Control-Allow-Origin', '*');
  res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
  res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');
  if (req.method === 'OPTIONS') {
    return res.status(200).end();
  }
  next();
});

// Health check
app.get('/health', (req, res) => {
  res.json({ status: 'ok', timestamp: new Date().toISOString() });
});

function verifyToken(req, res, next) {
  const authHeader = req.headers.authorization;
  if (!authHeader) {
    return res.status(401).json({ error: 'Authorization header required' });
  }
  
  try {
    const token = authHeader.split(' ')[1];
    const decoded = jwt.verify(token, JWT_SECRET);
    req.auth = decoded;
    next();
  } catch (err) {
    return res.status(401).json({ error: 'Invalid or expired token' });
  }
}

function readAppsFile() {
  try {
    if (fs.existsSync(APPS_FILE)) {
      const data = fs.readFileSync(APPS_FILE, 'utf8');
      return JSON.parse(data);
    }
  } catch (err) {
    console.error('Error reading apps file:', err);
  }
  return [];
}

function writeAppsFile(apps) {
  try {
    const tempFile = `${APPS_FILE}.tmp`;
    fs.writeFileSync(tempFile, JSON.stringify(apps, null, 2));
    fs.renameSync(tempFile, APPS_FILE);
    return true;
  } catch (err) {
    console.error('Error writing apps file:', err);
    return false;
  }
}

app.post('/api/admin/login', (req, res) => {
  const { token } = req.body;
  const adminToken = process.env.ADMIN_TOKEN;

  if (!adminToken) {
    return res.status(500).json({ error: 'ADMIN_TOKEN not configured' });
  }

  if (token === adminToken) {
    const payload = {
      admin: true,
      iat: Math.floor(Date.now() / 1000),
      exp: Math.floor(Date.now() / 1000) + (60 * 60 * 24)
    };
    const secret = process.env.JWT_SECRET || 'fallback-secret-key';
    const apiKey = jwt.sign(payload, secret);
    return res.json({ apiKey });
  }

  return res.status(401).json({ error: 'Invalid token' });
});

app.get('/api/apps', (req, res) => {
  const apps = readAppsFile();
  return res.json(apps);
});

app.post('/api/admin/apps', verifyToken, (req, res) => {
  if (!req.auth || !req.auth.admin) {
    return res.status(403).json({ error: 'Admin access required' });
  }
  const { name, description, icon, colors, packages } = req.body;

  if (!name || !description) {
    return res.status(400).json({ error: 'Name and description are required' });
  }

  let apps = readAppsFile();
  const newId = apps.length > 0 ? Math.max(...apps.map(a => a.id)) + 1 : 1;

  const newApp = {
    id: newId,
    name,
    description,
    icon: icon || '',
    colors: colors || { background: '', text: '' },
    packages: packages || { apt: '', appstream: '', flatpak: '' }
  };

  apps.push(newApp);

  if (writeAppsFile(apps)) {
    return res.status(201).json(newApp);
  }

  return res.status(500).json({ error: 'Failed to save app' });
});

app.put('/api/admin/apps/:id', verifyToken, (req, res) => {
  if (!req.auth || !req.auth.admin) {
    return res.status(403).json({ error: 'Admin access required' });
  }
  const { id } = req.params;
  const updates = req.body;

  let apps = readAppsFile();
  const appIndex = apps.findIndex(a => a.id === parseInt(id));

  if (appIndex === -1) {
    return res.status(404).json({ error: 'App not found' });
  }

  const updatedApp = { ...apps[appIndex], ...updates, id: parseInt(id) };
  apps[appIndex] = updatedApp;

  if (writeAppsFile(apps)) {
    return res.json(updatedApp);
  }

  return res.status(500).json({ error: 'Failed to update app' });
});

app.delete('/api/admin/apps/:id', verifyToken, (req, res) => {
  if (!req.auth || !req.auth.admin) {
    return res.status(403).json({ error: 'Admin access required' });
  }
  const { id } = req.params;

  let apps = readAppsFile();
  const appIndex = apps.findIndex(a => a.id === parseInt(id));

  if (appIndex === -1) {
    return res.status(404).json({ error: 'App not found' });
  }

  apps.splice(appIndex, 1);

  if (writeAppsFile(apps)) {
    return res.json({ message: 'App deleted successfully' });
  }

  return res.status(500).json({ error: 'Failed to delete app' });
});

app.listen(PORT, () => {
  console.log(`Admin API running on port ${PORT}`);
});