<?php
/**
 * Tom's Java Jive - Stripe Integration (cURL-based for vanilla PHP)
 * Works without Composer - uses direct API calls
 */

class StripeAPI {
    private $secretKey;
    private $apiBase = 'https://api.stripe.com/v1';
    
    public function __construct($secretKey = null) {
        $this->secretKey = $secretKey ?: STRIPE_SECRET_KEY;
    }
    
    /**
     * Make a cURL request to Stripe API
     */
    private function request($method, $endpoint, $data = []) {
        $url = $this->apiBase . $endpoint;
        
        $ch = curl_init();
        
        $headers = [
            'Authorization: Bearer ' . $this->secretKey,
            'Content-Type: application/x-www-form-urlencoded'
        ];
        
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        curl_setopt($ch, CURLOPT_TIMEOUT, 30);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
        
        if ($method === 'POST') {
            curl_setopt($ch, CURLOPT_POST, true);
            curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($data));
        } elseif ($method === 'GET' && !empty($data)) {
            $url .= '?' . http_build_query($data);
            curl_setopt($ch, CURLOPT_URL, $url);
        }
        
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $error = curl_error($ch);
        curl_close($ch);
        
        if ($error) {
            throw new Exception('Stripe API Error: ' . $error);
        }
        
        $decoded = json_decode($response, true);
        
        if ($httpCode >= 400) {
            $errorMsg = $decoded['error']['message'] ?? 'Unknown Stripe error';
            throw new Exception($errorMsg);
        }
        
        return $decoded;
    }
    
    /**
     * Create a Payment Intent
     */
    public function createPaymentIntent($amount, $currency = 'usd', $options = []) {
        $data = [
            'amount' => (int)($amount * 100), // Convert to cents
            'currency' => strtolower($currency),
            'automatic_payment_methods' => ['enabled' => 'true']
        ];
        
        if (!empty($options['metadata'])) {
            foreach ($options['metadata'] as $key => $value) {
                $data["metadata[$key]"] = $value;
            }
        }
        
        if (!empty($options['receipt_email'])) {
            $data['receipt_email'] = $options['receipt_email'];
        }
        
        if (!empty($options['description'])) {
            $data['description'] = $options['description'];
        }
        
        return $this->request('POST', '/payment_intents', $data);
    }
    
    /**
     * Retrieve a Payment Intent
     */
    public function getPaymentIntent($paymentIntentId) {
        return $this->request('GET', '/payment_intents/' . $paymentIntentId);
    }
    
    /**
     * Create a Checkout Session (hosted payment page)
     */
    public function createCheckoutSession($lineItems, $successUrl, $cancelUrl, $options = []) {
        $data = [
            'mode' => $options['mode'] ?? 'payment',
            'success_url' => $successUrl,
            'cancel_url' => $cancelUrl
        ];
        
        // Add line items
        foreach ($lineItems as $i => $item) {
            $data["line_items[$i][price_data][currency]"] = $item['currency'] ?? 'usd';
            $data["line_items[$i][price_data][product_data][name]"] = $item['name'];
            $data["line_items[$i][price_data][unit_amount]"] = (int)($item['price'] * 100);
            $data["line_items[$i][quantity]"] = $item['quantity'] ?? 1;
            
            if (!empty($item['description'])) {
                $data["line_items[$i][price_data][product_data][description]"] = $item['description'];
            }
        }
        
        if (!empty($options['customer_email'])) {
            $data['customer_email'] = $options['customer_email'];
        }
        
        if (!empty($options['metadata'])) {
            foreach ($options['metadata'] as $key => $value) {
                $data["metadata[$key]"] = $value;
            }
        }
        
        return $this->request('POST', '/checkout/sessions', $data);
    }
    
    /**
     * Retrieve a Checkout Session
     */
    public function getCheckoutSession($sessionId) {
        return $this->request('GET', '/checkout/sessions/' . $sessionId);
    }
    
    /**
     * Verify webhook signature
     */
    public function verifyWebhookSignature($payload, $sigHeader, $webhookSecret) {
        if (empty($webhookSecret)) {
            return true; // Skip verification if secret not configured
        }
        
        $elements = explode(',', $sigHeader);
        $timestamp = null;
        $signatures = [];
        
        foreach ($elements as $element) {
            $parts = explode('=', $element, 2);
            if (count($parts) === 2) {
                if ($parts[0] === 't') {
                    $timestamp = $parts[1];
                } elseif ($parts[0] === 'v1') {
                    $signatures[] = $parts[1];
                }
            }
        }
        
        if (empty($timestamp) || empty($signatures)) {
            throw new Exception('Invalid signature format');
        }
        
        // Check timestamp tolerance (5 minutes)
        if (abs(time() - $timestamp) > 300) {
            throw new Exception('Timestamp outside tolerance');
        }
        
        $signedPayload = $timestamp . '.' . $payload;
        $expectedSignature = hash_hmac('sha256', $signedPayload, $webhookSecret);
        
        foreach ($signatures as $sig) {
            if (hash_equals($expectedSignature, $sig)) {
                return true;
            }
        }
        
        throw new Exception('Signature verification failed');
    }
    
    /**
     * Create a refund
     */
    public function createRefund($paymentIntentId, $amount = null) {
        $data = ['payment_intent' => $paymentIntentId];
        
        if ($amount !== null) {
            $data['amount'] = (int)($amount * 100);
        }
        
        return $this->request('POST', '/refunds', $data);
    }
}

/**
 * Get Stripe instance
 */
function stripe() {
    static $stripe = null;
    if ($stripe === null) {
        $stripe = new StripeAPI();
    }
    return $stripe;
}

/**
 * Check if Stripe is properly configured
 */
function isStripeConfigured() {
    return !empty(STRIPE_SECRET_KEY) && 
           STRIPE_SECRET_KEY !== 'sk_test_your_stripe_key' &&
           !empty(STRIPE_PUBLISHABLE_KEY) && 
           STRIPE_PUBLISHABLE_KEY !== 'pk_test_your_stripe_key';
}