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require_once __DIR__ . '/admin_header.php';

$error = '';
$success = '';
$product = null;
$categories = [];

if (!isset($_GET['id'])) {
    header("Location: products.php");
    exit;
}

$prod_id = intval($_GET['id']);

// Fetch categories for dropdown
try {
    $stmt_cats = $pdo->query("SELECT id, name FROM categories ORDER BY name ASC");
    $categories = $stmt_cats->fetchAll();
} catch (Exception $e) {
    $error = 'Failed to load categories: ' . $e->getMessage();
}

// Fetch active colors and sizes for checkboxes
$colors = [];
$sizes = [];
$assigned_colors = [];
$assigned_sizes = [];
try {
    $colors = $pdo->query("SELECT * FROM colors ORDER BY name ASC")->fetchAll();
    $sizes = $pdo->query("SELECT * FROM sizes ORDER BY id ASC")->fetchAll();

    // Fetch assigned colors for current product
    $stmt_assigned_colors = $pdo->prepare("SELECT color_id FROM product_colors WHERE product_id = ?");
    $stmt_assigned_colors->execute([$prod_id]);
    $assigned_colors = $stmt_assigned_colors->fetchAll(PDO::FETCH_COLUMN);

    // Fetch assigned sizes for current product
    $stmt_assigned_sizes = $pdo->prepare("SELECT size_id FROM product_sizes WHERE product_id = ?");
    $stmt_assigned_sizes->execute([$prod_id]);
    $assigned_sizes = $stmt_assigned_sizes->fetchAll(PDO::FETCH_COLUMN);
} catch (Exception $e) {
    $error = 'Failed to load custom attributes: ' . $e->getMessage();
}

// Fetch existing product details
try {
    $stmt = $pdo->prepare("SELECT * FROM products WHERE id = ?");
    $stmt->execute([$prod_id]);
    $product = $stmt->fetch();
    
    if (!$product) {
        header("Location: products.php");
        exit;
    }
} catch (Exception $e) {
    $error = 'Error loading product: ' . $e->getMessage();
}

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $name = isset($_POST['name']) ? trim($_POST['name']) : '';
    $description = isset($_POST['description']) ? trim($_POST['description']) : '';
    $price = isset($_POST['price']) ? floatval($_POST['price']) : 0.00;
    $category_id = isset($_POST['category_id']) ? intval($_POST['category_id']) : 0;
    $stock = isset($_POST['stock']) ? intval($_POST['stock']) : 0;
    $is_featured = isset($_POST['is_featured']) ? 1 : 0;
    $selected_colors = isset($_POST['colors']) ? $_POST['colors'] : [];
    $selected_sizes = isset($_POST['sizes']) ? $_POST['sizes'] : [];

    if (empty($name) || empty($description) || $price <= 0 || $category_id <= 0) {
        $error = 'Please fill out all required fields: Name, Description, Category, and a valid Price.';
    } else {
        try {
            $image_filename = $product['image']; // Default to current image

            // Handle Image Upload if selected
            if (isset($_FILES['image']) && $_FILES['image']['error'] === UPLOAD_ERR_OK) {
                $file_tmp = $_FILES['image']['tmp_name'];
                $file_name = $_FILES['image']['name'];
                $file_size = $_FILES['image']['size'];
                $file_ext = strtolower(pathinfo($file_name, PATHINFO_EXTENSION));
                
                $allowed_exts = ['png', 'jpg', 'jpeg', 'webp'];
                
                if (!in_array($file_ext, $allowed_exts)) {
                    $error = 'Invalid image type. Only PNG, JPG, JPEG, and WEBP formats are accepted.';
                } elseif ($file_size > 5 * 1024 * 1024) {
                    $error = 'Image file size is too large. Keep uploads under 5 megabytes.';
                } else {
                    // Create unique target filename
                    $new_image_filename = 'prod_' . time() . '_' . uniqid() . '.' . $file_ext;
                    $upload_dir = __DIR__ . '/../assets/images/';
                    
                    if (move_uploaded_file($file_tmp, $upload_dir . $new_image_filename)) {
                        // Delete old custom product image if exists
                        if (!empty($product['image']) && file_exists($upload_dir . $product['image']) && strpos($product['image'], 'prod_') !== false) {
                            @unlink($upload_dir . $product['image']);
                        }
                        $image_filename = $new_image_filename;
                    } else {
                        $error = 'Failed to save product image to local storage.';
                    }
                }
            }

            if (empty($error)) {
                $pdo->beginTransaction();

                // Update product in database
                $stmt_update = $pdo->prepare("UPDATE products SET name = ?, description = ?, price = ?, category_id = ?, image = ?, stock = ?, is_featured = ? WHERE id = ?");
                $stmt_update->execute([$name, $description, $price, $category_id, $image_filename, $stock, $is_featured, $prod_id]);

                // Clear previous colors and sizes
                $stmt_clear_colors = $pdo->prepare("DELETE FROM product_colors WHERE product_id = ?");
                $stmt_clear_colors->execute([$prod_id]);
                $stmt_clear_sizes = $pdo->prepare("DELETE FROM product_sizes WHERE product_id = ?");
                $stmt_clear_sizes->execute([$prod_id]);

                // Re-insert selected colors
                if (!empty($selected_colors)) {
                    $stmt_prod_color = $pdo->prepare("INSERT INTO product_colors (product_id, color_id) VALUES (?, ?)");
                    foreach ($selected_colors as $cid) {
                        $stmt_prod_color->execute([$prod_id, intval($cid)]);
                    }
                }

                // Re-insert selected sizes
                if (!empty($selected_sizes)) {
                    $stmt_prod_size = $pdo->prepare("INSERT INTO product_sizes (product_id, size_id) VALUES (?, ?)");
                    foreach ($selected_sizes as $sid) {
                        $stmt_prod_size->execute([$prod_id, intval($sid)]);
                    }
                }

                $pdo->commit();

                // Refresh local variables for page rendering
                $assigned_colors = $selected_colors;
                $assigned_sizes = $selected_sizes;

                $success = 'Product updated successfully! Redirecting back...';
                
                // Refresh local product details
                $product['name'] = $name;
                $product['description'] = $description;
                $product['price'] = $price;
                $product['category_id'] = $category_id;
                $product['image'] = $image_filename;
                $product['stock'] = $stock;
                $product['is_featured'] = $is_featured;

                echo "<script>setTimeout(() => { window.location.href = 'products.php'; }, 1500);</script>";
            }
        } catch (Exception $e) {
            if ($pdo->inTransaction()) {
                $pdo->rollBack();
            }
            $error = 'Database update transaction failed: ' . $e->getMessage();
        }
    }
}
?>

<div class="row mb-4">
    <div class="col-12">
        <nav aria-label="breadcrumb">
            <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href="index.php">Dashboard</a></li>
                <li class="breadcrumb-item"><a href="products.php">Products</a></li>
                <li class="breadcrumb-item active" aria-current="page">Edit Product</li>
            </ol>
        </nav>
        <h2 class="text-white">Refine Product Details</h2>
        <p class="text-muted small">Update classifications, listings, and assets for "<?php echo htmlspecialchars($product['name'] ?? ''); ?>".</p>
    </div>
</div>

<div class="row justify-content-center">
    <div class="col-lg-10">
        <div class="admin-card">
            
            <?php if (!empty($error)): ?>
                <div class="alert alert-danger border-danger bg-dark text-danger rounded-3 py-2 px-3 small mb-4" role="alert">
                    <i class="fa-solid fa-circle-exclamation me-2"></i> <?php echo htmlspecialchars($error); ?>
                </div>
            <?php endif; ?>

            <?php if (!empty($success)): ?>
                <div class="alert alert-success border-success bg-dark text-success rounded-3 py-2 px-3 small mb-4" role="alert">
                    <i class="fa-solid fa-circle-check me-2"></i> <?php echo htmlspecialchars($success); ?>
                </div>
            <?php endif; ?>

            <form action="product_edit.php?id=<?php echo $prod_id; ?>" method="POST" enctype="multipart/form-data">
                <div class="row g-4">
                    <!-- Product Title -->
                    <div class="col-md-8">
                        <label for="name" class="form-label text-muted small text-uppercase fw-bold">Product Name *</label>
                        <input type="text" class="form-control" id="name" name="name" required value="<?php echo htmlspecialchars($product['name']); ?>" placeholder="e.g. Classic Trench Coat">
                    </div>

                    <!-- Category selection -->
                    <div class="col-md-4">
                        <label for="category_id" class="form-label text-muted small text-uppercase fw-bold">Category Classification *</label>
                        <select class="form-select" id="category_id" name="category_id" required>
                            <option value="" disabled>Select Category</option>
                            <?php foreach ($categories as $cat): ?>
                                <option value="<?php echo $cat['id']; ?>" <?php echo ($cat['id'] == $product['category_id']) ? 'selected' : ''; ?>>
                                    <?php echo htmlspecialchars($cat['name']); ?>
                                </option>
                            <?php endforeach; ?>
                        </select>
                    </div>

                    <!-- Pricing & Inventory -->
                    <div class="col-md-4">
                        <label for="price" class="form-label text-muted small text-uppercase fw-bold">Boutique Price (LKR) *</label>
                        <div class="input-group">
                            <span class="input-group-text bg-dark border-secondary text-warning fw-bold">LKR</span>
                            <input type="number" class="form-control" id="price" name="price" step="0.01" min="0" required value="<?php echo htmlspecialchars($product['price']); ?>" placeholder="4250.00">
                        </div>
                    </div>

                    <div class="col-md-4">
                        <label for="stock" class="form-label text-muted small text-uppercase fw-bold">Inventory Stock Level</label>
                        <input type="number" class="form-control" id="stock" name="stock" min="0" required value="<?php echo htmlspecialchars($product['stock']); ?>" placeholder="10">
                    </div>

                    <!-- Spotlight -->
                    <div class="col-md-4 d-flex align-items-center">
                        <div class="form-check form-switch mt-3 mt-md-4">
                            <input class="form-check-input bg-dark border-secondary" type="checkbox" id="is_featured" name="is_featured" value="1" <?php echo ($product['is_featured'] == 1) ? 'checked' : ''; ?>>
                            <label class="form-check-input-label text-white ms-2" for="is_featured" style="cursor: pointer;">
                                <i class="fa-solid fa-star text-warning me-1"></i> Spotlight on Homepage
                            </label>
                        </div>
                    </div>

                    <!-- Product Description -->
                    <div class="col-12">
                        <label for="description" class="form-label text-muted small text-uppercase fw-bold">Description Details *</label>
                        <textarea class="form-control" id="description" name="description" rows="5" required placeholder="Describe details..."><?php echo htmlspecialchars($product['description']); ?></textarea>
                    </div>

                    <!-- Couture Attributes (Colors & Sizes) -->
                    <div class="col-md-6">
                        <label class="form-label text-muted small text-uppercase fw-bold d-block mb-3">Available Couture Colors</label>
                        <div class="d-flex flex-wrap gap-3 p-3 rounded bg-dark border border-secondary" style="min-height: 100px;">
                            <?php if (empty($colors)): ?>
                                <span class="text-white small">No colors defined. Add them in <a href="colors.php" class="text-warning">Colors Settings</a>.</span>
                            <?php else: ?>
                                <?php foreach ($colors as $c): ?>
                                    <?php $checked = in_array($c['id'], $assigned_colors) ? 'checked' : ''; ?>
                                    <div class="form-check d-flex align-items-center gap-2">
                                        <input class="form-check-input bg-dark border-secondary" type="checkbox" name="colors[]" value="<?php echo $c['id']; ?>" id="color-<?php echo $c['id']; ?>" <?php echo $checked; ?>>
                                        <label class="form-check-label text-white d-flex align-items-center gap-2" for="color-<?php echo $c['id']; ?>" style="cursor: pointer;">
                                            <span class="rounded-circle d-inline-block" style="width: 18px; height: 18px; background-color: <?php echo $c['hex']; ?>; border: 1px solid <?php echo $c['border']; ?>;"></span>
                                            <span class="small"><?php echo htmlspecialchars($c['name']); ?></span>
                                        </label>
                                    </div>
                                <?php endforeach; ?>
                            <?php endif; ?>
                        </div>
                    </div>

                    <div class="col-md-6">
                        <label class="form-label text-muted small text-uppercase fw-bold d-block mb-3">Available Couture Sizes</label>
                        <div class="d-flex flex-wrap gap-3 p-3 rounded bg-dark border border-secondary" style="min-height: 100px;">
                            <?php if (empty($sizes)): ?>
                                <span class="text-white small">No sizes defined. Add them in <a href="sizes.php" class="text-warning">Sizes Settings</a>.</span>
                            <?php else: ?>
                                <?php foreach ($sizes as $s): ?>
                                    <?php $checked = in_array($s['id'], $assigned_sizes) ? 'checked' : ''; ?>
                                    <div class="form-check d-flex align-items-center gap-2">
                                        <input class="form-check-input bg-dark border-secondary" type="checkbox" name="sizes[]" value="<?php echo $s['id']; ?>" id="size-<?php echo $s['id']; ?>" <?php echo $checked; ?>>
                                        <label class="form-check-label text-white fw-bold small" for="size-<?php echo $s['id']; ?>" style="cursor: pointer;">
                                            <?php echo htmlspecialchars($s['name']); ?>
                                        </label>
                                    </div>
                                <?php endforeach; ?>
                            <?php endif; ?>
                        </div>
                    </div>

                    <!-- Product image -->
                    <div class="col-12">
                        <label for="image" class="form-label text-muted small text-uppercase fw-bold">Update Showcase Image</label>
                        <input type="file" class="form-control" id="image" name="image" accept="image/*" onchange="previewFile()">
                        <div class="form-text text-muted mb-3" style="font-size: 0.7rem;">Leave empty to retain the current image asset. PNG, JPG, JPEG, WEBP. Max 5MB.</div>
                        
                        <!-- Previews Grid -->
                        <div class="row g-3">
                            <!-- Current Image -->
                            <?php if (!empty($product['image'])): ?>
                                <div class="col-6 col-sm-3">
                                    <span class="d-block text-muted small mb-2 text-uppercase fw-bold" style="font-size: 0.65rem;">Active Image Asset:</span>
                                    <img src="../assets/images/<?php echo htmlspecialchars($product['image']); ?>" alt="Current Image" class="rounded" style="max-width: 100%; height: 180px; object-fit: cover; border: 1px solid var(--border-gray);">
                                </div>
                            <?php endif; ?>

                            <!-- Live New Image Preview -->
                            <div id="preview-container" class="col-6 col-sm-3 d-none">
                                <span class="d-block text-muted small mb-2 text-uppercase fw-bold" style="font-size: 0.65rem;">Newly Selected Image:</span>
                                <img id="image-preview" src="#" alt="New Preview" class="rounded" style="max-width: 100%; height: 180px; object-fit: cover; border: 1px solid var(--accent-gold);">
                            </div>
                        </div>
                    </div>

                    <!-- Action buttons -->
                    <div class="col-12 mt-5 border-top border-dark pt-4 d-flex gap-3 justify-content-end">
                        <a href="products.php" class="btn btn-outline-secondary rounded-pill px-4 py-2 text-uppercase tracking-wider fw-bold" style="font-size: 0.75rem; border-color: var(--border-gray);">
                            Cancel
                        </a>
                        <button type="submit" class="btn-luxury px-4 py-2">
                            Save Changes <i class="fa-solid fa-check-double ms-2"></i>
                        </button>
                    </div>
                </div>
            </form>
        </div>
    </div>
</div>

<script>
function previewFile() {
    const preview = document.getElementById('image-preview');
    const container = document.getElementById('preview-container');
    const file = document.getElementById('image').files[0];
    const reader = new FileReader();

    reader.addEventListener("load", function () {
        preview.src = reader.result;
        container.classList.remove('d-none');
    }, false);

    if (file) {
        reader.readAsDataURL(file);
    }
}
</script>

<?php
require_once __DIR__ . '/admin_footer.php';
?>