<?php
// Include database configuration
require_once '../database/db_config.php';

// Check if admin is logged in
session_start();
if (!isset($_SESSION['user_id']) || ($_SESSION['role'] !== 'admin' && $_SESSION['role'] !== 'director')) {
    echo json_encode(['success' => false, 'message' => 'Access denied. Please log in as an administrator.']);
    exit;
}

// Check if all required data is provided
if (!isset($_POST['payment_id']) || !isset($_POST['amount']) || !isset($_POST['reason'])) {
    echo json_encode(['success' => false, 'message' => 'Missing required data.']);
    exit;
}

$payment_id = intval($_POST['payment_id']);
$amount = floatval($_POST['amount']);
$reason = trim($_POST['reason']);
$enrollment_id = isset($_POST['enrollment_id']) ? intval($_POST['enrollment_id']) : 0;

// Validate data
if ($payment_id <= 0) {
    echo json_encode(['success' => false, 'message' => 'Invalid payment ID.']);
    exit;
}

if ($amount <= 0) {
    echo json_encode(['success' => false, 'message' => 'Refund amount must be greater than zero.']);
    exit;
}

if (empty($reason)) {
    echo json_encode(['success' => false, 'message' => 'Refund reason is required.']);
    exit;
}

// Begin transaction
$conn->begin_transaction();

try {
    // Get payment details
    $query = "SELECT * FROM payments WHERE id = ? AND status = 'completed'";
    $stmt = $conn->prepare($query);
    $stmt->bind_param("i", $payment_id);
    $stmt->execute();
    $payment = $stmt->get_result()->fetch_assoc();
    
    if (!$payment) {
        throw new Exception("Payment not found or already refunded.");
    }
    
    // Update payment status
    $update_query = "UPDATE payments SET status = 'refunded', updated_at = NOW() WHERE id = ?";
    $stmt = $conn->prepare($update_query);
    $stmt->bind_param("i", $payment_id);
    
    if (!$stmt->execute()) {
        throw new Exception("Failed to update payment status: " . $conn->error);
    }
    
    // Create refund record
    $insert_query = "INSERT INTO refunds (payment_id, amount, reason, refunded_by, refund_date) 
                    VALUES (?, ?, ?, ?, NOW())";
    $stmt = $conn->prepare($insert_query);
    $stmt->bind_param("idsi", $payment_id, $amount, $reason, $_SESSION['user_id']);
    
    if (!$stmt->execute()) {
        throw new Exception("Failed to create refund record: " . $conn->error);
    }
    
    // Log the refund
    $log_message = "Payment ID #{$payment_id} refunded. Amount: ₹" . number_format($amount, 2) . ". Reason: " . $reason;
    
    // Check if logger function exists
    if (function_exists('logger')) {
        logger($_SESSION['user_id'], 'payment_refunded', $log_message);
    } else {
        // Basic logging fallback
        error_log($log_message);
    }
    
    // Commit the transaction
    $conn->commit();
    
    // Return success response
    echo json_encode([
        'success' => true, 
        'message' => 'Payment refunded successfully.',
        'payment_id' => $payment_id,
        'amount' => $amount,
        'enrollment_id' => $enrollment_id
    ]);
    
} catch (Exception $e) {
    // Rollback the transaction on error
    $conn->rollback();
    
    // Return error response
    echo json_encode(['success' => false, 'message' => $e->getMessage()]);
}
?>