<?php
// PayPal Webhook for software upgrade payments
// Based on webhook_mollie.php structure
// Handles PayPal IPN/webhook notifications for payment status updates

require_once 'settings/config_redirector.php';
require_once 'assets/functions.php';
include dirname(__FILE__).'/settings/settings_redirector.php';

// DEBUG: Log webhook call
debuglog("PAYPAL WEBHOOK CALLED - POST data: " . print_r($_POST, true));
debuglog("PAYPAL WEBHOOK CALLED - RAW input: " . file_get_contents('php://input'));

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
//LOGIN TO API (same as webhook_mollie.php)
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
debuglog("WEBHOOK: Attempting API authorization...");
debuglog("WEBHOOK: Interface user: " . interface_user);
$data = json_encode(array("clientID" => interface_user, "clientsecret" => interface_pw), JSON_UNESCAPED_UNICODE);
$responses = ioAPIv2('/v2/authorization', $data,'');
debuglog("WEBHOOK: Authorization response: " . $responses);
if (!empty($responses)){$responses = json_decode($responses,true);}else{$responses = '400';}
$clientsecret = $responses['token'];
debuglog("WEBHOOK: Token obtained: " . ($clientsecret ? 'YES' : 'NO'));

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
// BASEURL is required for invoice template
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
$base_url = 'https://'.$_SERVER['SERVER_NAME'].'/';
define('base_url', $base_url);

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
// Initialize DomPDF for invoice generation
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
use Dompdf\Dompdf;
use Dompdf\Options;
$options = new Options();
$options->set('isRemoteEnabled', true);
$dompdf = new Dompdf($options);

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
// Language mapping for invoices
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
$available_languages = [
    'NL' => 'NL',
    'BE' => 'NL',
    'US' => 'US',
    'GB' => 'US',
    'DE' => 'DE',
    'FR' => 'FR',
    'ES' => 'ES'
];

try {
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    // Get the webhook event data from PayPal
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    $raw_input = file_get_contents('php://input');
    $webhook_event = json_decode($raw_input, true);

    debuglog("PAYPAL WEBHOOK: Decoded event: " . print_r($webhook_event, true));

    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    // Verify webhook signature (recommended for production)
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    if (!debug && PAYPAL_WEBHOOK_ID) {
        $verified = verifyPayPalWebhookSignature($raw_input, $_SERVER);
        if (!$verified) {
            debuglog("PAYPAL WEBHOOK ERROR: Signature verification failed");
            http_response_code(401);
            exit;
        }
        debuglog("PAYPAL WEBHOOK: Signature verified successfully");
    }

    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    // Extract event type and resource
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    $event_type = $webhook_event['event_type'] ?? '';
    $resource = $webhook_event['resource'] ?? [];

    debuglog("PAYPAL WEBHOOK: Event type: {$event_type}");

    // Get order ID from custom_id in the payment resource
    $orderId = $resource['custom_id'] ?? $resource['purchase_units'][0]['custom_id'] ?? null;

    if (!$orderId) {
        debuglog("PAYPAL WEBHOOK ERROR: No custom_id (order_id) in webhook event");
        http_response_code(400);
        exit;
    }

    debuglog("PAYPAL WEBHOOK: Order ID: {$orderId}");

    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    // Map PayPal event types to payment status
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    $payment_status = null;

    switch ($event_type) {
        case 'PAYMENT.CAPTURE.COMPLETED':
        case 'CHECKOUT.ORDER.APPROVED':
            $payment_status = 1; // Paid
            debuglog("PAYPAL WEBHOOK: Payment completed/approved");
            break;

        case 'PAYMENT.CAPTURE.PENDING':
        case 'CHECKOUT.ORDER.PROCESSED':
            $payment_status = 101; // Pending
            debuglog("PAYPAL WEBHOOK: Payment pending");
            break;

        case 'PAYMENT.CAPTURE.DECLINED':
        case 'PAYMENT.CAPTURE.FAILED':
            $payment_status = 102; // Failed
            debuglog("PAYPAL WEBHOOK: Payment failed/declined");
            break;

        case 'PAYMENT.CAPTURE.REFUNDED':
            $payment_status = 104; // Refunded
            debuglog("PAYPAL WEBHOOK: Payment refunded");
            break;

        case 'CHECKOUT.ORDER.VOIDED':
            $payment_status = 999; // Canceled
            debuglog("PAYPAL WEBHOOK: Payment voided/canceled");
            break;

        default:
            debuglog("PAYPAL WEBHOOK: Unhandled event type: {$event_type}");
            http_response_code(200);
            echo "OK - Event type not handled";
            exit;
    }

    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    // Update transaction status directly in database
    //+++++++++++++++++++++++++++++++++++++++++++++++++++++
    if ($payment_status !== null) {
        debuglog("PAYPAL WEBHOOK: Order ID: $orderId, Payment Status: $payment_status");

        $pdo = dbConnect($dbname);

        // Update transaction status
        $sql = 'UPDATE transactions SET payment_status = ? WHERE txn_id = ?';
        $stmt = $pdo->prepare($sql);
        $stmt->execute([$payment_status, $orderId]);

        debuglog("PAYPAL WEBHOOK: Transaction status updated in database");

        // Fetch transaction data for license creation
        $sql = 'SELECT * FROM transactions WHERE txn_id = ?';
        $stmt = $pdo->prepare($sql);
        $stmt->execute([$orderId]);
        $transaction = $stmt->fetch(PDO::FETCH_ASSOC);

        debuglog("PAYPAL WEBHOOK: Transaction data: " . print_r($transaction, true));

        //+++++++++++++++++++++++++++++++++++++++++++++++++++++
        // Only create license and invoice if payment is PAID
        //+++++++++++++++++++++++++++++++++++++++++++++++++++++
        if ($payment_status == 1 && $transaction !== null && !empty($transaction)) {
            debuglog("PAYPAL WEBHOOK: Payment is PAID, processing license...");
            debuglog("PAYPAL WEBHOOK: Transaction ID (auto-increment): " . $transaction['id']);
            debuglog("PAYPAL WEBHOOK: Transaction txn_id: " . $transaction['txn_id']);

            //+++++++++++++++++++++++++++++++++++++++++++++++++++++
            // CREATE LICENSE for software upgrade
            //+++++++++++++++++++++++++++++++++++++++++++++++++++++
            $pdo = dbConnect($dbname);

            // Fetch transaction items to find software upgrade
            $sql = 'SELECT * FROM transactions_items WHERE txn_id = ?';
            $stmt = $pdo->prepare($sql);
            $stmt->execute([$transaction['id']]);
            $items = $stmt->fetchAll(PDO::FETCH_ASSOC);
            
            debuglog("PAYPAL WEBHOOK: Found " . count($items) . " transaction items");
            debuglog("PAYPAL WEBHOOK: Items data: " . print_r($items, true));

            foreach ($items as $item) {
                debuglog("PAYPAL WEBHOOK: Processing item: " . print_r($item, true));
                
                if (!empty($item['item_options'])) {
                    $options = json_decode($item['item_options'], true);
                    debuglog("PAYPAL WEBHOOK: Item options: " . print_r($options, true));

                    // Check if this is a software upgrade (has serial_number and equipment_id)
                    if (isset($options['serial_number']) && isset($options['equipment_id'])) {
                        debuglog("PAYPAL WEBHOOK: This is a software upgrade item");

                        // Check if license already exists for this transaction
                        $sql = 'SELECT rowID FROM products_software_licenses WHERE transaction_id = ?';
                        $stmt = $pdo->prepare($sql);
                        $stmt->execute([$orderId]);
                        $existing_license = $stmt->fetch(PDO::FETCH_ASSOC);

                        if (!$existing_license) {
                            debuglog("PAYPAL WEBHOOK: No existing license, creating new one...");
                            
                            // Generate unique license key
                            $license_key = generateUniqueLicenseKey();

                            // Create license
                            $sql = 'INSERT INTO products_software_licenses
                                    (version_id, license_type, license_key, status, starts_at, expires_at, transaction_id, accounthierarchy,created, createdby)
                                    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)';
                            $stmt = $pdo->prepare($sql);
                            $stmt->execute([
                                $item['item_id'], // version_id
                                1, // license_type (1 = upgrade)
                                $license_key,
                                1, // status = active
                                date('Y-m-d H:i:s'),
                                '2099-12-31 23:59:59', // effectively permanent
                                $orderId,
                                '{"salesid":"21-Total Safety Solutions B.V.","soldto":""}',
                                date('Y-m-d H:i:s'),
                                'webhook_paypal' // created by PayPal webhook
                            ]);

                            debuglog("PAYPAL WEBHOOK: License created: $license_key");

                            // Update equipment.sw_version_license
                            $sql = 'UPDATE equipment SET sw_version_license = ? WHERE rowID = ?';
                            $stmt = $pdo->prepare($sql);
                            $stmt->execute([$license_key, $options['equipment_id']]);

                            debuglog("PAYPAL WEBHOOK: Equipment updated with license: {$options['equipment_id']}");
                        } else {
                            debuglog("PAYPAL WEBHOOK: License already exists for order: $orderId");
                        }
                    } else {
                        debuglog("PAYPAL WEBHOOK: Not a software upgrade item (no serial_number/equipment_id)");
                    }
                } else {
                    debuglog("PAYPAL WEBHOOK: No item_options found");
                }
            }

            //+++++++++++++++++++++++++++++++++++++++++++++++++++++
            // Generate INVOICE directly in database
            //+++++++++++++++++++++++++++++++++++++++++++++++++++++

            // Check if invoice already exists for this transaction
            $sql = 'SELECT id FROM invoice WHERE txn_id = ?';
            $stmt = $pdo->prepare($sql);
            $stmt->execute([$transaction['txn_id']]);
            $existing_invoice = $stmt->fetch(PDO::FETCH_ASSOC);

            if (!$existing_invoice) {
                // Create invoice
                $sql = 'INSERT INTO invoice (txn_id, payment_status, payment_amount, shipping_amount, discount_amount, tax_amount, created,accounthierarchy)
                        VALUES (?, ?, ?, ?, ?, ?, ?,?)';
                $stmt = $pdo->prepare($sql);
                $stmt->execute([
                    $transaction['txn_id'],
                    $transaction['payment_status'],
                    $transaction['payment_amount'],
                    $transaction['shipping_amount'] ?? 0.00,
                    $transaction['discount_amount'] ?? 0.00,
                    $transaction['tax_amount'] ?? 0.00,
                    date('Y-m-d H:i:s'),
                    '{"salesid":"21-Total Safety Solutions B.V.","soldto":""}'
                ]);
                $invoice_id = $pdo->lastInsertId();
            } else {
                $invoice_id = $existing_invoice['id'];
            }

            // Fetch full invoice data with customer details for email
            $sql = 'SELECT tx.*, txi.item_id, txi.item_price, txi.item_quantity, txi.item_options,
                           p.productcode, p.productname, inv.id as invoice, inv.created as invoice_created,
                           i.language as user_language
                    FROM invoice inv
                    LEFT JOIN transactions tx ON tx.txn_id = inv.txn_id
                    LEFT JOIN transactions_items txi ON txi.txn_id = tx.id
                    LEFT JOIN products p ON p.rowID = txi.item_id
                    LEFT JOIN identity i ON i.userkey = tx.account_id
                    WHERE inv.id = ?';
            $stmt = $pdo->prepare($sql);
            $stmt->execute([$invoice_id]);
            $invoice_data = $stmt->fetchAll(PDO::FETCH_ASSOC);

            if (!empty($invoice_data)) {
                // Transform the data (group items like the API does)
                $invoice_cust = transformOrderData($invoice_data);

                // Determine invoice language
                if (!empty($invoice_cust['customer']['language'])) {
                    $invoice_language = strtoupper($invoice_cust['customer']['language']);
                } elseif (!empty($invoice_cust['customer']['country']) && isset($available_languages[strtoupper($invoice_cust['customer']['country'])])) {
                    $invoice_language = $available_languages[strtoupper($invoice_cust['customer']['country'])];
                } else {
                    $invoice_language = 'US'; // Default fallback
                }

                // Generate invoice HTML (using custom template for software upgrades)
                list($message,$pdf,$customer_email,$order_id) = generateSoftwareInvoice($invoice_cust,$orderId,$invoice_language);

                //+++++++++++++++++++++++++++++++++++++++++++++++++++++
                //CREATE PDF using DomPDF
                //+++++++++++++++++++++++++++++++++++++++++++++++++++++
                $dompdf->loadHtml($pdf);
                $dompdf->setPaper('A4', 'portrait');
                $dompdf->render();
                $subject = 'Software Upgrade - Invoice: '.$order_id;
                $attachment = $dompdf->output();

                //+++++++++++++++++++++++++++++++++++++++++++++++++++++
                //Send email via PHPMailer
                //+++++++++++++++++++++++++++++++++++++++++++++++++++++
                $mail_result = send_mail($customer_email, $subject, $message, $attachment, $subject);

                // Send to bookkeeping if configured
                if(invoice_bookkeeping){
                    debuglog("PAYPAL WEBHOOK: Sending to bookkeeping: " . email_bookkeeping);
                    send_mail(email_bookkeeping, $subject, $message, $attachment, $subject);
                }
            } else {
                debuglog("PAYPAL WEBHOOK: No invoice data found for invoice_id: $invoice_id");
            }
        }
    }

    // Return 200 OK to PayPal
    http_response_code(200);
    echo "OK";

} catch (Exception $e) {
    debuglog("PAYPAL WEBHOOK ERROR: " . $e->getMessage());
    debuglog("PAYPAL WEBHOOK ERROR TRACE: " . $e->getTraceAsString());
    error_log("PayPal webhook error: " . htmlspecialchars($e->getMessage()));
    http_response_code(500);
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
// Helper function to verify PayPal webhook signature
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
function verifyPayPalWebhookSignature($raw_body, $headers) {
    if (!PAYPAL_WEBHOOK_ID || !PAYPAL_CLIENT_ID || !PAYPAL_CLIENT_SECRET) {
        debuglog("PAYPAL WEBHOOK: Signature verification skipped - credentials not configured");
        return true; // Skip verification if not configured
    }

    // Get required headers
    $transmission_id = $headers['HTTP_PAYPAL_TRANSMISSION_ID'] ?? '';
    $transmission_time = $headers['HTTP_PAYPAL_TRANSMISSION_TIME'] ?? '';
    $cert_url = $headers['HTTP_PAYPAL_CERT_URL'] ?? '';
    $auth_algo = $headers['HTTP_PAYPAL_AUTH_ALGO'] ?? '';
    $transmission_sig = $headers['HTTP_PAYPAL_TRANSMISSION_SIG'] ?? '';

    debuglog("PAYPAL WEBHOOK: Headers - transmission_id: $transmission_id, cert_url: $cert_url");

    if (!$transmission_id || !$transmission_sig) {
        debuglog("PAYPAL WEBHOOK: Missing signature headers");
        return false;
    }

    try {
        // Get PayPal access token
        $access_token = getPayPalAccessToken();

        // Prepare verification request
        $verify_url = PAYPAL_URL . '/v1/notifications/verify-webhook-signature';
        $verify_data = [
            'transmission_id' => $transmission_id,
            'transmission_time' => $transmission_time,
            'cert_url' => $cert_url,
            'auth_algo' => $auth_algo,
            'transmission_sig' => $transmission_sig,
            'webhook_id' => PAYPAL_WEBHOOK_ID,
            'webhook_event' => json_decode($raw_body, true)
        ];

        debuglog("PAYPAL WEBHOOK: Verification request - webhook_id: " . PAYPAL_WEBHOOK_ID);
        debuglog("PAYPAL WEBHOOK: Verification URL: " . $verify_url);

        $ch = curl_init($verify_url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($verify_data));
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Content-Type: application/json',
            'Authorization: Bearer ' . $access_token
        ]);

        $response = curl_exec($ch);
        $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        debuglog("PAYPAL WEBHOOK: Verification response (HTTP $http_code): " . $response);

        $result = json_decode($response, true);
        $verified = ($http_code == 200 && isset($result['verification_status']) && $result['verification_status'] === 'SUCCESS');

        debuglog("PAYPAL WEBHOOK: Signature verification result: " . ($verified ? 'SUCCESS' : 'FAILED'));
        return $verified;

    } catch (Exception $e) {
        debuglog("PAYPAL WEBHOOK: Signature verification error: " . $e->getMessage());
        return false;
    }
}

//+++++++++++++++++++++++++++++++++++++++++++++++++++++
// Helper function to get PayPal access token
//+++++++++++++++++++++++++++++++++++++++++++++++++++++
function getPayPalAccessToken() {
    $ch = curl_init(PAYPAL_URL . '/v1/oauth2/token');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, 'grant_type=client_credentials');
    curl_setopt($ch, CURLOPT_USERPWD, PAYPAL_CLIENT_ID . ':' . PAYPAL_CLIENT_SECRET);
    curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/x-www-form-urlencoded']);

    $response = curl_exec($ch);
    $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    if ($http_code != 200) {
        throw new Exception("Failed to get PayPal access token: HTTP $http_code");
    }

    $result = json_decode($response, true);
    return $result['access_token'] ?? '';
}

?>