const rateLimit = require('express-rate-limit');
const config = require('../config');

// Helper to extract real IP with Cloudflare support
const keyGenerator = (req) => {
    return req.headers['cf-connecting-ip'] || 
           req.headers['x-forwarded-for']?.split(',')[0] || 
           req.ip;
};

// General API rate limiter
const apiLimiter = rateLimit({
    windowMs: 15 * 60 * 1000, // 15 minutes
    max: 100,
    keyGenerator,
    standardHeaders: true,
    legacyHeaders: false,
    trustProxy: true, // Explicitly trust proxy
    message: 'Too many requests, please try again later.'
});

// Strict limiter for write operations
const strictLimiter = rateLimit({
    windowMs: 15 * 60 * 1000,
    max: 20,
    keyGenerator,
    trustProxy: true, // Explicitly trust proxy
    message: 'Too many write operations, please try again later.'
});

// Auth-specific limiter with admin bypass capability
const authLimiter = rateLimit({
    windowMs: 15 * 60 * 1000,
    max: config.isProduction ? 30 : 50, // Increased from 10 to 30 for production
    keyGenerator,
    standardHeaders: true,
    legacyHeaders: false,
    trustProxy: true, // Explicitly trust proxy
    message: 'Too many login attempts, please try again later.',
    skipSuccessfulRequests: true,
    skip: (req, res) => {
        // Skip rate limiting for authenticated admin users on certain admin endpoints
        return req.session?.isAdmin && req.path?.includes('/admin');
    }
});

// Temp user rate limiter - stricter but allows for auto-refresh
const tempUserLimiter = rateLimit({
    windowMs: 15 * 60 * 1000, // 15 minutes
    max: 50, // Allow more requests to accommodate auto-refresh (every 30 seconds = ~30 requests per 15 min)
    keyGenerator,
    standardHeaders: true,
    legacyHeaders: false,
    trustProxy: true,
    message: JSON.stringify({
        success: false,
        error: 'Rate limit exceeded for temporary account. Please contact an administrator for full access.',
        isRateLimit: true
    })
});

// Conditional rate limiter that applies stricter limits to temp users
const conditionalTempLimiter = (req, res, next) => {
    if (req.session?.userType === 'temp') {
        return tempUserLimiter(req, res, next);
    }
    return apiLimiter(req, res, next);
};

// Admin-friendly limiter for admin operations
const adminLimiter = rateLimit({
    windowMs: 15 * 60 * 1000, // 15 minutes
    max: 200, // High limit for admin operations
    keyGenerator,
    standardHeaders: true,
    legacyHeaders: false,
    trustProxy: true,
    message: 'Rate limit exceeded for admin operations. Please try again later.'
});

module.exports = {
    apiLimiter,
    strictLimiter,
    authLimiter,
    tempUserLimiter,
    conditionalTempLimiter,
    adminLimiter
};