const express = require('express');
const fs = require('fs').promises;
const path = require('path');

const app = express();
const PORT = process.env.PORT || 3000;
const DATA_DIR = process.env.DATA_DIR || './data';
const REGISTRATIONS_FILE = path.join(DATA_DIR, 'registrations.json');

// Middleware
app.use(express.json());
app.use(express.static('.'));

// Ensure data directory exists
async function ensureDataDir() {
    try {
        await fs.mkdir(DATA_DIR, { recursive: true });
        try {
            await fs.access(REGISTRATIONS_FILE);
        } catch {
            await fs.writeFile(REGISTRATIONS_FILE, '[]');
        }
    } catch (error) {
        console.error('Error creating data directory:', error);
    }
}

// Load registrations
async function loadRegistrations() {
    try {
        const data = await fs.readFile(REGISTRATIONS_FILE, 'utf8');
        return JSON.parse(data);
    } catch {
        return [];
    }
}

// Save registrations
async function saveRegistrations(registrations) {
    await fs.writeFile(REGISTRATIONS_FILE, JSON.stringify(registrations, null, 2));
}

// Registration endpoint
app.post('/api/register', async (req, res) => {
    try {
        const { firstName, lastName, email, location, role, interests, contribute, message } = req.body;

        // Validation
        if (!firstName || !lastName || !email) {
            return res.status(400).json({ error: 'First name, last name, and email are required' });
        }

        if (!email.match(/^[^\s@]+@[^\s@]+\.[^\s@]+$/)) {
            return res.status(400).json({ error: 'Please provide a valid email address' });
        }

        // Load existing registrations
        const registrations = await loadRegistrations();

        // Check for duplicate email
        if (registrations.some(r => r.email.toLowerCase() === email.toLowerCase())) {
            return res.status(400).json({ error: 'This email is already registered' });
        }

        // Create new registration
        const registration = {
            id: Date.now().toString(36) + Math.random().toString(36).substr(2),
            firstName: firstName.trim(),
            lastName: lastName.trim(),
            email: email.toLowerCase().trim(),
            location: location?.trim() || '',
            role: role || '',
            interests: interests || [],
            contribute: contribute || '',
            message: message?.trim() || '',
            registeredAt: new Date().toISOString(),
            ipAddress: req.ip || req.connection.remoteAddress
        };

        // Save registration
        registrations.push(registration);
        await saveRegistrations(registrations);

        console.log(`New registration: ${registration.firstName} ${registration.lastName} <${registration.email}>`);

        res.json({
            success: true,
            message: 'Registration successful',
            id: registration.id
        });

    } catch (error) {
        console.error('Registration error:', error);
        res.status(500).json({ error: 'An error occurred. Please try again.' });
    }
});

// Admin endpoint to view registrations (protected by simple token)
app.get('/api/registrations', async (req, res) => {
    const token = req.headers['x-admin-token'] || req.query.token;
    const adminToken = process.env.ADMIN_TOKEN || 'worldplay-admin-2026';

    if (token !== adminToken) {
        return res.status(401).json({ error: 'Unauthorized' });
    }

    try {
        const registrations = await loadRegistrations();
        res.json({
            count: registrations.length,
            registrations: registrations.map(r => ({
                ...r,
                ipAddress: undefined // Don't expose IP in admin view
            }))
        });
    } catch (error) {
        res.status(500).json({ error: 'Failed to load registrations' });
    }
});

// Export registrations as CSV
app.get('/api/registrations/export', async (req, res) => {
    const token = req.headers['x-admin-token'] || req.query.token;
    const adminToken = process.env.ADMIN_TOKEN || 'worldplay-admin-2026';

    if (token !== adminToken) {
        return res.status(401).json({ error: 'Unauthorized' });
    }

    try {
        const registrations = await loadRegistrations();

        const headers = ['ID', 'First Name', 'Last Name', 'Email', 'Location', 'Role', 'Interests', 'Contribute', 'Message', 'Registered At'];
        const rows = registrations.map(r => [
            r.id,
            r.firstName,
            r.lastName,
            r.email,
            r.location,
            r.role,
            Array.isArray(r.interests) ? r.interests.join('; ') : r.interests,
            r.contribute,
            r.message.replace(/"/g, '""'),
            r.registeredAt
        ]);

        const csv = [
            headers.join(','),
            ...rows.map(row => row.map(cell => `"${cell}"`).join(','))
        ].join('\n');

        res.setHeader('Content-Type', 'text/csv');
        res.setHeader('Content-Disposition', 'attachment; filename=worldplay-registrations.csv');
        res.send(csv);
    } catch (error) {
        res.status(500).json({ error: 'Failed to export registrations' });
    }
});

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

// Stats endpoint
app.get('/api/stats', async (req, res) => {
    try {
        const registrations = await loadRegistrations();

        const stats = {
            totalRegistrations: registrations.length,
            byRole: {},
            byInterest: {},
            byContribute: {}
        };

        registrations.forEach(r => {
            // Count by role
            if (r.role) {
                stats.byRole[r.role] = (stats.byRole[r.role] || 0) + 1;
            }

            // Count by interest
            if (Array.isArray(r.interests)) {
                r.interests.forEach(interest => {
                    stats.byInterest[interest] = (stats.byInterest[interest] || 0) + 1;
                });
            }

            // Count by contribute
            if (r.contribute) {
                stats.byContribute[r.contribute] = (stats.byContribute[r.contribute] || 0) + 1;
            }
        });

        res.json(stats);
    } catch (error) {
        res.status(500).json({ error: 'Failed to calculate stats' });
    }
});

// Start server
ensureDataDir().then(() => {
    app.listen(PORT, '0.0.0.0', () => {
        console.log(`WORLDPLAY server running on port ${PORT}`);
        console.log(`Admin token: ${process.env.ADMIN_TOKEN || 'worldplay-admin-2026'}`);
    });
});