const express = require('express');
const cors = require('cors');
const dotenv = require('dotenv');
const path = require('path');

// Import models
const News = require('./models/News');
const Dataset = require('./models/Dataset');

dotenv.config();

const app = express();
// Use port 8501 for Hugging Face Spaces, or 3001 for local development
const isHuggingFaceSpaces = process.env.HF_SPACES === 'true' || process.env.HF_SPACES === true || !!process.env.HF_SPACES;
const PORT = isHuggingFaceSpaces ? 8501 : (process.env.PORT || 3001);

// Enable CORS for all origins in development, specific origins in production
if (process.env.NODE_ENV === 'development') {
  app.use(cors());
} else {
  // In production (like Hugging Face Spaces), be more specific about CORS
  app.use(cors({
    origin: function (origin, callback) {
      // Allow requests with no origin (like mobile apps or curl requests)
      if (!origin) return callback(null, true);
      
      // Allow localhost in development
      if (origin.startsWith('http://localhost') || 
          origin.startsWith('https://localhost') ||
          origin.includes('huggingface.co') ||
          origin.includes('hf.space') ||
          origin === 'http://localhost:80' ||
          origin === 'http://localhost:5173') {
        return callback(null, true);
      }
      
      // Allow same origin requests
      if (origin === `http://localhost:${PORT}`) {
        return callback(null, true);
      }
      
      callback(null, true); // Allow all in production for now
    }
  }));
}

app.use(express.json());

// Serve static files from the public directory in production
if (process.env.NODE_ENV === 'production') {
  app.use(express.static(path.join(__dirname, 'public')));
}

// Health check endpoint
app.get('/health', (req, res) => {
  res.status(200).json({ 
    status: 'OK', 
    timestamp: new Date().toISOString(),
    uptime: process.uptime()
  });
});

// API routes
app.get('/api/news', async (req, res) => {
  try {
    const news = await News.getAll();
    res.json(news);
  } catch (error) {
    console.error('Error fetching news:', error);
    res.status(500).json({ error: 'Failed to fetch news' });
  }
});

app.get('/api/news/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const newsItem = await News.getById(id);
    if (!newsItem) {
      return res.status(404).json({ error: 'News item not found' });
    }
    res.json(newsItem);
  } catch (error) {
    console.error('Error fetching news item:', error);
    res.status(500).json({ error: 'Failed to fetch news item' });
  }
});

app.get('/api/datasets', async (req, res) => {
  try {
    const datasets = await Dataset.getAll();
    res.json(datasets);
  } catch (error) {
    console.error('Error fetching datasets:', error);
    res.status(500).json({ error: 'Failed to fetch datasets' });
  }
});

app.get('/api/datasets/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const dataset = await Dataset.getById(id);
    if (!dataset) {
      return res.status(404).json({ error: 'Dataset not found' });
    }
    res.json(dataset);
  } catch (error) {
    console.error('Error fetching dataset:', error);
    res.status(500).json({ error: 'Failed to fetch dataset' });
  }
});

// Serve the React app for all non-API routes in production
if (process.env.NODE_ENV === 'production') {
  // For any non-API routes, serve the React app
  app.get('*', (req, res) => {
    // Don't serve the React app for API routes or health check
    if (req.path.startsWith('/api/') || req.path === '/health') {
      // For API routes that don't exist, return 404
      if (req.path.startsWith('/api/')) {
        return res.status(404).json({ error: 'API endpoint not found' });
      }
      // For health check, it's already handled above
      return res.status(404).json({ error: 'Not found' });
    }
    
    // Serve the React app for all other routes
    res.sendFile(path.resolve(__dirname, 'public', 'index.html'));
  });
} else {
  // In development, serve API info at root
  app.get('/', (req, res) => {
    res.json({ 
      message: 'BioNexus Hub API', 
      version: '1.0.0',
      timestamp: new Date().toISOString()
    });
  });
}

app.listen(PORT, '0.0.0.0', () => {
  console.log(`BioNexus Hub server running on port ${PORT}`);
});