<?php
// Start session
session_start();

// Check if user is logged in
if (!isset($_SESSION['user_id']) || $_SESSION['role'] !== 'student') {
    header('Location: ../login.php');
    exit();
}

// Include database connection
require_once('database/db_config.php');

// Include Razorpay configuration
require_once('../enroll/includes/razorpay_config.php');

// Get student ID from session
$student_id = $_SESSION['user_id'];

// Check if this is a Razorpay callback
if (!isset($_GET['razorpay_payment_id']) || !isset($_GET['razorpay_order_id'])) {
    $_SESSION['error_message'] = "Invalid payment callback.";
    header('Location: payments.php');
    exit();
}

// Get callback parameters
$razorpay_payment_id = $_GET['razorpay_payment_id'];
$razorpay_order_id = $_GET['razorpay_order_id'];
$razorpay_signature = $_GET['razorpay_signature'] ?? '';
$course_id = isset($_GET['course_id']) ? intval($_GET['course_id']) : 0;
$amount = isset($_GET['amount']) ? floatval($_GET['amount']) : 0;
$payment_for = isset($_GET['payment_for']) ? $_GET['payment_for'] : 'Course Fee';
$payment_plan = isset($_GET['payment_plan']) ? $_GET['payment_plan'] : 'full';
$receipt_id = isset($_GET['receipt']) ? $_GET['receipt'] : 'rcpt_' . time() . '_' . $student_id;
$cert_id = isset($_GET['cert_id']) ? intval($_GET['cert_id']) : 0;

// Get site settings for institute information
$settings_query = "SELECT * FROM site_settings WHERE setting_key IN ('site_name', 'site_address', 'contact_phone', 'contact_email', 'site_logo', 'site_url')";
$settings_result = $conn->query($settings_query);
$settings = [];

if ($settings_result) {
    while ($row = $settings_result->fetch_assoc()) {
        $settings[$row['setting_key']] = $row['setting_value'];
    }
}

// School/Institute information for receipt
$school = [
    'site_name' => $settings['site_name'] ?? $razorpay_company_name,
    'site_address' => $settings['site_address'] ?? '',
    'contact_phone' => $settings['contact_phone'] ?? '',
    'contact_email' => $settings['contact_email'] ?? '',
    'site_logo' => $settings['site_logo'] ?? $razorpay_company_logo,
    'site_url' => $settings['site_url'] ?? ''
];

$success = false;
$error = null;

try {
    // Log the payment data
    error_log("Received payment callback: PaymentID=$razorpay_payment_id, OrderID=$razorpay_order_id");
    
    // Get enrollment information
    $stmt = $conn->prepare("
        SELECT e.id as enrollment_id, e.payment_plan, e.status,
               c.title as course_title, c.duration, c.price, c.discount_price,
               CONCAT(u.first_name, ' ', u.last_name) as student_name, u.email, u.phone
        FROM enrollments e
        JOIN courses c ON e.course_id = c.id
        JOIN users u ON e.user_id = u.id
        WHERE e.user_id = ? AND e.course_id = ?
    ");
    $stmt->bind_param('ii', $student_id, $course_id);
    $stmt->execute();
    $result = $stmt->get_result();
    
    if ($result->num_rows > 0) {
        $enrollment = $result->fetch_assoc();
        $enrollment_id = $enrollment['enrollment_id'];
        
        // Insert payment record - removing enrollment_id from the query
        $stmt = $conn->prepare("
            INSERT INTO payments (
                user_id, course_id, amount, payment_method,
                transaction_id, status
            ) VALUES (?, ?, ?, 'razorpay', ?, 'completed')
        ");
        
        $stmt->bind_param('iids', $student_id, $course_id, $amount, 
                        $razorpay_payment_id);
        
        if ($stmt->execute()) {
            $payment_id = $conn->insert_id;
            $success = true;
            $_SESSION['success_message'] = "Payment completed successfully.";
            
            error_log("Payment record inserted successfully: ID=$payment_id");
            
            // Update certificate payment status if this was a certificate payment
            if ($payment_for == 'Certificate Fee' && $cert_id > 0) {
                $cert_update = $conn->prepare("UPDATE unified_certificates SET payment_status = 'completed' WHERE id = ?");
                $cert_update->bind_param('i', $cert_id);
                $cert_update->execute();
                error_log("Certificate payment status updated for cert_id=$cert_id");
            }
            
            // Generate receipt data
            $receipt_data = [
                'payment_id' => $payment_id,
                'receipt_id' => $receipt_id,
                'transaction_id' => $razorpay_payment_id,
                'order_id' => $razorpay_order_id,
                'student_id' => $student_id,
                'student_name' => $enrollment['student_name'],
                'email' => $enrollment['email'],
                'phone' => $enrollment['phone'],
                'course_id' => $course_id,
                'course_title' => $enrollment['course_title'],
                'amount' => $amount,
                'payment_date' => date('Y-m-d H:i:s'),
                'payment_method' => 'Razorpay',
                'payment_status' => 'Completed',
                'payment_for' => $payment_for,
                'payment_plan' => $payment_plan,
                'institute_name' => $school['site_name'],
                'institute_address' => $school['site_address'],
                'institute_email' => $school['contact_email'],
                'institute_phone' => $school['contact_phone'],
                'institute_logo' => $school['site_logo']
            ];
            
            // Store receipt data in session for displaying in receipt page
            $_SESSION['payment_receipt'] = $receipt_data;
            
            // Redirect to receipt page
            header('Location: payment_receipt.php');
            exit();
        } else {
            $error = "Failed to record payment: " . $stmt->error;
            error_log("Failed to insert payment record: " . $stmt->error);
        }
    } else {
        // If this is a certificate payment, we can proceed even without enrollment information
        if ($payment_for == 'Certificate Fee' && $cert_id > 0) {
            try {
                // Get student information
                $student_query = "SELECT CONCAT(first_name, ' ', last_name) as student_name, email, phone FROM users WHERE id = ?";
                $stmt = $conn->prepare($student_query);
                $stmt->bind_param('i', $student_id);
                $stmt->execute();
                $student_result = $stmt->get_result();
                
                if ($student_result->num_rows > 0) {
                    $student = $student_result->fetch_assoc();
                    
                    // Get course information
                    $course_query = "SELECT title FROM courses WHERE id = ?";
                    $stmt = $conn->prepare($course_query);
                    $stmt->bind_param('i', $course_id);
                    $stmt->execute();
                    $course_result = $stmt->get_result();
                    
                    if ($course_result->num_rows > 0) {
                        $course = $course_result->fetch_assoc();
                        
                        // Insert payment record
                        $stmt = $conn->prepare("
                            INSERT INTO payments (
                                user_id, course_id, amount, payment_method,
                                transaction_id, status
                            ) VALUES (?, ?, ?, 'razorpay', ?, 'completed')
                        ");
                        
                        $stmt->bind_param('iids', $student_id, $course_id, $amount, 
                                        $razorpay_payment_id);
                        
                        if ($stmt->execute()) {
                            $payment_id = $conn->insert_id;
                            $success = true;
                            $_SESSION['success_message'] = "Certificate payment completed successfully.";
                            
                            error_log("Certificate payment record inserted successfully: ID=$payment_id");
                            
                            // Update certificate payment status
                            $cert_update = $conn->prepare("UPDATE unified_certificates SET payment_status = 'completed', payment_date = NOW(), payment_reference = ? WHERE id = ?");
                            $cert_update->bind_param('si', $razorpay_payment_id, $cert_id);
                            $cert_update->execute();
                            
                            // Generate receipt data
                            $receipt_data = [
                                'payment_id' => $payment_id,
                                'receipt_id' => $receipt_id,
                                'transaction_id' => $razorpay_payment_id,
                                'order_id' => $razorpay_order_id,
                                'student_id' => $student_id,
                                'student_name' => $student['student_name'],
                                'email' => $student['email'],
                                'phone' => $student['phone'],
                                'course_id' => $course_id,
                                'course_title' => $course['title'],
                                'amount' => $amount,
                                'payment_date' => date('Y-m-d H:i:s'),
                                'payment_method' => 'Razorpay',
                                'payment_status' => 'Completed',
                                'payment_for' => $payment_for,
                                'payment_plan' => $payment_plan,
                                'institute_name' => $school['site_name'],
                                'institute_address' => $school['site_address'],
                                'institute_email' => $school['contact_email'],
                                'institute_phone' => $school['contact_phone'],
                                'institute_logo' => $school['site_logo']
                            ];
                            
                            // Store receipt data in session for displaying in receipt page
                            $_SESSION['payment_receipt'] = $receipt_data;
                            
                            // Redirect to receipt page
                            header('Location: payment_receipt.php');
                            exit();
                        } else {
                            $error = "Failed to record certificate payment: " . $stmt->error;
                        }
                    } else {
                        $error = "Course not found.";
                    }
                } else {
                    $error = "Student information not found.";
                }
            } catch (Exception $e) {
                $error = "Error processing certificate payment: " . $e->getMessage();
                error_log("Certificate payment processing error: " . $e->getMessage());
            }
        } else {
            $error = "Enrollment not found.";
            error_log("Enrollment not found for user_id=$student_id and course_id=$course_id");
        }
    }
} catch (Exception $e) {
    $error = "Error processing payment: " . $e->getMessage();
    error_log("Payment processing error: " . $e->getMessage());
}

// If there's an error, set error message
if (!$success && $error) {
    $_SESSION['error_message'] = $error;
    error_log("Payment error set in session: $error");
}

// Redirect based on payment type
if ($payment_for == 'Certificate Fee') {
    header('Location: certificates.php');
} else {
    header('Location: payments.php');
}
exit();