<?php
declare(strict_types=1);

require_once __DIR__ . '/includes/layout.php';

$errors = [];
$flash = null;

$id = (int)($_GET['id'] ?? 0);
if (!$id) {
    header('Location: admin_shipments.php'); exit;
}

$stmt = db()->prepare("SELECT * FROM shipments WHERE id = ?");
$stmt->execute([$id]);
$shipment = $stmt->fetch();

if (!$shipment) {
    header('Location: admin_shipments.php'); exit;
}

// Fetch all countries for dropdowns
$countries = [];
try {
    $countries = db()->query("SELECT * FROM countries ORDER BY name_en ASC")->fetchAll();
} catch (Throwable $e) {}

// Helper to find country_id by city name
function find_country_id_by_city_name($cityName) {
    if (!$cityName) return null;
    $stmt = db()->prepare("SELECT country_id FROM cities WHERE name_en = ? LIMIT 1");
    $stmt->execute([$cityName]);
    return $stmt->fetchColumn() ?: null;
}

// Pre-fetch country IDs for existing cities
$origin_country_id = find_country_id_by_city_name($shipment['origin_city']);
$destination_country_id = find_country_id_by_city_name($shipment['destination_city']);

// Fetch initial city lists for the pre-selected countries
$origin_cities_list = [];
if ($origin_country_id) {
    $stmt = db()->prepare("SELECT * FROM cities WHERE country_id = ? ORDER BY name_en ASC");
    $stmt->execute([$origin_country_id]);
    $origin_cities_list = $stmt->fetchAll();
}

$destination_cities_list = [];
if ($destination_country_id) {
    $stmt = db()->prepare("SELECT * FROM cities WHERE country_id = ? ORDER BY name_en ASC");
    $stmt->execute([$destination_country_id]);
    $destination_cities_list = $stmt->fetchAll();
}


if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $shipper_name = trim($_POST['shipper_name'] ?? '');
    $shipper_company = trim($_POST['shipper_company'] ?? '');
    // These are now selected from dropdowns, but the value is still the city name
    $origin_city = trim($_POST['origin_city'] ?? '');
    $destination_city = trim($_POST['destination_city'] ?? '');
    $cargo_description = trim($_POST['cargo_description'] ?? '');
    $weight_tons = (float)($_POST['weight_tons'] ?? 0);
    $pickup_date = trim($_POST['pickup_date'] ?? '');
    $delivery_date = trim($_POST['delivery_date'] ?? '');
    $payment_method = trim($_POST['payment_method'] ?? 'thawani');
    $status = trim($_POST['status'] ?? 'posted');
    
    if ($shipper_name === '') $errors[] = "Shipper name is required.";
    if ($origin_city === '') $errors[] = "Origin city is required.";
    if ($destination_city === '') $errors[] = "Destination city is required.";
    
    if (empty($errors)) {
        $updateSql = "
            UPDATE shipments 
            SET shipper_name = ?, shipper_company = ?, origin_city = ?, destination_city = ?,
                cargo_description = ?, weight_tons = ?, pickup_date = ?, delivery_date = ?,
                payment_method = ?, status = ?
            WHERE id = ?
        ";
        db()->prepare($updateSql)->execute([
            $shipper_name, $shipper_company, $origin_city, $destination_city,
            $cargo_description, $weight_tons, $pickup_date, $delivery_date,
            $payment_method, $status, $id
        ]);
        $flash = "Shipment updated successfully.";
        
        // Refresh data
        $stmt->execute([$id]);
        $shipment = $stmt->fetch();
        
        // Re-fetch derived data for the form
        $origin_country_id = find_country_id_by_city_name($shipment['origin_city']);
        $destination_country_id = find_country_id_by_city_name($shipment['destination_city']);
        
        $origin_cities_list = [];
        if ($origin_country_id) {
            $stmt = db()->prepare("SELECT * FROM cities WHERE country_id = ? ORDER BY name_en ASC");
            $stmt->execute([$origin_country_id]);
            $origin_cities_list = $stmt->fetchAll();
        }

        $destination_cities_list = [];
        if ($destination_country_id) {
            $stmt = db()->prepare("SELECT * FROM cities WHERE country_id = ? ORDER BY name_en ASC");
            $stmt->execute([$destination_country_id]);
            $destination_cities_list = $stmt->fetchAll();
        }
    }
}

render_header('Edit Shipment', 'admin', true);
?>

<div class="row g-0">
    <div class="col-md-2 bg-white border-end min-vh-100">
        <?php render_admin_sidebar('shipments'); ?>
    </div>
    <div class="col-md-10 p-4">
        <div class="d-flex align-items-center gap-3 mb-4">
            <a href="admin_shipments.php" class="btn btn-light border text-secondary" title="Back">
                <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" fill="currentColor" class="bi bi-arrow-left" viewBox="0 0 16 16">
                  <path fill-rule="evenodd" d="M15 8a.5.5 0 0 0-.5-.5H2.707l3.147-3.146a.5.5 0 1 0-.708-.708l-4 4a.5.5 0 0 0 0 .708l4 4a.5.5 0 0 0 .708-.708L2.707 8.5H14.5A.5.5 0 0 0 15 8z"/>
                </svg>
            </a>
            <div>
                <h1 class="section-title mb-1">Edit Shipment #<?= e((string)$shipment['id']) ?></h1>
                <p class="muted mb-0">Update shipment details and status.</p>
            </div>
        </div>

        <?php if ($flash): ?>
            <div class="alert alert-success" data-auto-dismiss="true"><?= e($flash) ?></div>
        <?php endif; ?>

        <?php if ($errors): ?>
            <div class="alert alert-danger">
                <ul class="mb-0">
                    <?php foreach ($errors as $error): ?>
                        <li><?= e($error) ?></li>
                    <?php endforeach; ?>
                </ul>
            </div>
        <?php endif; ?>

        <div class="panel p-4">
            <form method="post">
                <div class="row g-3">
                    <div class="col-md-6">
                        <label class="form-label">Shipper Name</label>
                        <input type="text" name="shipper_name" class="form-control" value="<?= e($shipment['shipper_name']) ?>" required>
                    </div>
                    <div class="col-md-6">
                        <label class="form-label">Shipper Company</label>
                        <input type="text" name="shipper_company" class="form-control" value="<?= e((string)$shipment['shipper_company']) ?>">
                    </div>

                    <!-- Origin Selection -->
                    <div class="col-md-6">
                        <label class="form-label">Origin Country</label>
                        <select class="form-select" id="origin_country">
                            <option value="">Select Country</option>
                            <?php foreach ($countries as $c): ?>
                                <option value="<?= e($c['id']) ?>" <?= $c['id'] == $origin_country_id ? 'selected' : '' ?>>
                                    <?= e($c['name_en']) ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                    </div>
                    <div class="col-md-6">
                        <label class="form-label">Origin City</label>
                        <select class="form-select" name="origin_city" id="origin_city" required>
                            <option value="">Select City</option>
                            <!-- If shipment has a city but we couldn't match a country, preserve the value as a fallback option -->
                            <?php if (!$origin_country_id && $shipment['origin_city']): ?>
                                <option value="<?= e($shipment['origin_city']) ?>" selected><?= e($shipment['origin_city']) ?></option>
                            <?php endif; ?>
                            
                            <?php foreach ($origin_cities_list as $city): ?>
                                <option value="<?= e($city['name_en']) ?>" <?= $city['name_en'] === $shipment['origin_city'] ? 'selected' : '' ?>>
                                    <?= e($city['name_en']) ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                    </div>

                    <!-- Destination Selection -->
                    <div class="col-md-6">
                        <label class="form-label">Destination Country</label>
                         <select class="form-select" id="destination_country">
                            <option value="">Select Country</option>
                            <?php foreach ($countries as $c): ?>
                                <option value="<?= e($c['id']) ?>" <?= $c['id'] == $destination_country_id ? 'selected' : '' ?>>
                                    <?= e($c['name_en']) ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                    </div>
                    <div class="col-md-6">
                        <label class="form-label">Destination City</label>
                         <select class="form-select" name="destination_city" id="destination_city" required>
                            <option value="">Select City</option>
                             <!-- Fallback for unmapped city -->
                            <?php if (!$destination_country_id && $shipment['destination_city']): ?>
                                <option value="<?= e($shipment['destination_city']) ?>" selected><?= e($shipment['destination_city']) ?></option>
                            <?php endif; ?>

                            <?php foreach ($destination_cities_list as $city): ?>
                                <option value="<?= e($city['name_en']) ?>" <?= $city['name_en'] === $shipment['destination_city'] ? 'selected' : '' ?>>
                                    <?= e($city['name_en']) ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                    </div>

                    <div class="col-md-12">
                        <label class="form-label">Cargo Description</label>
                        <input type="text" name="cargo_description" class="form-control" value="<?= e((string)$shipment['cargo_description']) ?>">
                    </div>

                    <div class="col-md-4">
                        <label class="form-label">Weight (Tons)</label>
                        <input type="number" step="0.1" name="weight_tons" class="form-control" value="<?= e((string)$shipment['weight_tons']) ?>">
                    </div>
                    <div class="col-md-4">
                        <label class="form-label">Pickup Date</label>
                        <input type="date" name="pickup_date" class="form-control" value="<?= e((string)$shipment['pickup_date']) ?>">
                    </div>
                    <div class="col-md-4">
                        <label class="form-label">Delivery Date</label>
                        <input type="date" name="delivery_date" class="form-control" value="<?= e((string)$shipment['delivery_date']) ?>">
                    </div>
                    
                    <div class="col-md-6">
                        <label class="form-label">Payment Method</label>
                        <select name="payment_method" class="form-select">
                            <option value="thawani" <?= $shipment['payment_method'] === 'thawani' ? 'selected' : '' ?>>Thawani</option>
                            <option value="bank_transfer" <?= $shipment['payment_method'] === 'bank_transfer' ? 'selected' : '' ?>>Bank Transfer</option>
                        </select>
                    </div>
                    <div class="col-md-6">
                        <label class="form-label">Status</label>
                        <select name="status" class="form-select">
                            <option value="posted" <?= $shipment['status'] === 'posted' ? 'selected' : '' ?>>Posted</option>
                            <option value="offered" <?= $shipment['status'] === 'offered' ? 'selected' : '' ?>>Offered</option>
                            <option value="confirmed" <?= $shipment['status'] === 'confirmed' ? 'selected' : '' ?>>Confirmed</option>
                            <option value="in_transit" <?= $shipment['status'] === 'in_transit' ? 'selected' : '' ?>>In Transit</option>
                            <option value="delivered" <?= $shipment['status'] === 'delivered' ? 'selected' : '' ?>>Delivered</option>
                        </select>
                    </div>
                </div>
                
                <div class="mt-4 pt-3 border-top d-flex justify-content-end">
                    <button type="submit" class="btn btn-primary">Save Changes</button>
                </div>
            </form>
        </div>
    </div>
</div>

<script>
document.addEventListener('DOMContentLoaded', function() {
    function setupCityLoader(countrySelectId, citySelectId) {
        const countrySelect = document.getElementById(countrySelectId);
        const citySelect = document.getElementById(citySelectId);
        
        countrySelect.addEventListener('change', function() {
            const countryId = this.value;
            citySelect.innerHTML = '<option value="">Loading...</option>';
            citySelect.disabled = true;
            
            if (countryId) {
                fetch('api/get_cities.php?country_id=' + countryId)
                    .then(response => response.json())
                    .then(data => {
                        citySelect.innerHTML = '<option value="">Select City</option>';
                        data.forEach(city => {
                            const option = document.createElement('option');
                            option.value = city.name_en; // Using name as value for DB compatibility
                            option.textContent = city.name_en;
                            citySelect.appendChild(option);
                        });
                        citySelect.disabled = false;
                    })
                    .catch(error => {
                        console.error('Error fetching cities:', error);
                        citySelect.innerHTML = '<option value="">Error loading cities</option>';
                    });
            } else {
                citySelect.innerHTML = '<option value="">Select City</option>';
                citySelect.disabled = true;
            }
        });
    }

    setupCityLoader('origin_country', 'origin_city');
    setupCityLoader('destination_country', 'destination_city');
});
</script>

<?php render_footer(); ?>