<?php
session_start();
require_once 'includes/auth.php';
requireAdmin();
require_once 'config/db.php';

$success = '';
$error   = '';

// Sticky form values
$form = [
    'name'          => '',
    'description'   => '',
    'unit'          => 'pcs',
    'initial_stock' => '0',
];

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // Collect & sanitize inputs
    $form['name']          = trim($_POST['name'] ?? '');
    $form['description']   = trim($_POST['description'] ?? '');
    $form['unit']          = trim($_POST['unit'] ?? 'pcs');
    $form['initial_stock'] = $_POST['initial_stock'] ?? '0';

    $initial_stock = (int) $form['initial_stock'];

    if ($form['name'] === '') {
        $error = 'Product name is required.';
    } elseif ($initial_stock < 0) {
        $error = 'Initial stock cannot be negative.';
    } else {
        // Check for duplicate name
        $dup = $pdo->prepare("SELECT id FROM products WHERE name = ?");
        $dup->execute([$form['name']]);

        if ($dup->fetch()) {
            $error = "A product named \"{$form['name']}\" already exists.";
        } else {
            // Insert product
            $ins = $pdo->prepare(
                "INSERT INTO products (name, description, unit, current_stock) VALUES (?, ?, ?, ?)"
            );
            $ins->execute([$form['name'], $form['description'], $form['unit'], $initial_stock]);
            $new_id = (int) $pdo->lastInsertId();

            // Log initial stock as a transaction
            if ($initial_stock > 0) {
                $pdo->prepare(
                    "INSERT INTO stock_transactions (product_id, quantity, type, notes) VALUES (?, ?, 'added', 'Initial stock')"
                )->execute([$new_id, $initial_stock]);
            }

            $success = "Product \"{$form['name']}\" added successfully!";
            // Reset form after success
            $form = ['name' => '', 'description' => '', 'unit' => 'pcs', 'initial_stock' => '0'];
        }
    }
}

$units = ['pcs', 'meter', 'roll', 'pack', 'box', 'set', 'unit'];

include 'includes/header.php';
?>

<div class="row mb-3">
    <div class="col">
        <h4 class="page-title"><i class="bi bi-plus-circle me-2 text-primary"></i>Add New Product</h4>
        <nav aria-label="breadcrumb">
            <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href="dashboard.php">Dashboard</a></li>
                <li class="breadcrumb-item active">Add Product</li>
            </ol>
        </nav>
    </div>
</div>

<div class="row justify-content-center">
    <div class="col-md-7 col-lg-6">
        <div class="card">
            <div class="card-header bg-primary text-white">
                <i class="bi bi-box me-1"></i> Product Details
            </div>
            <div class="card-body">

                <?php if ($success !== ''): ?>
                <div class="alert alert-success d-flex align-items-center gap-2">
                    <i class="bi bi-check-circle-fill"></i>
                    <div>
                        <?= htmlspecialchars($success) ?>
                        <div class="mt-2 d-flex gap-2">
                            <a href="add_product.php"  class="btn btn-sm btn-success">Add Another</a>
                            <a href="product_list.php" class="btn btn-sm btn-outline-secondary">View All Products</a>
                        </div>
                    </div>
                </div>
                <?php endif; ?>

                <?php if ($error !== ''): ?>
                <div class="alert alert-danger d-flex align-items-center gap-2">
                    <i class="bi bi-exclamation-triangle-fill"></i>
                    <?= htmlspecialchars($error) ?>
                </div>
                <?php endif; ?>

                <form method="POST" action="" novalidate>

                    <div class="mb-3">
                        <label for="name" class="form-label fw-semibold">
                            Product Name <span class="text-danger">*</span>
                        </label>
                        <input type="text"
                               class="form-control"
                               id="name"
                               name="name"
                               value="<?= htmlspecialchars($form['name']) ?>"
                               placeholder="e.g., ONU, Cable, TJ Box"
                               maxlength="100"
                               required>
                    </div>

                    <div class="mb-3">
                        <label for="description" class="form-label fw-semibold">Description</label>
                        <textarea class="form-control"
                                  id="description"
                                  name="description"
                                  rows="3"
                                  placeholder="Optional — short description of the product"><?= htmlspecialchars($form['description']) ?></textarea>
                    </div>

                    <div class="row g-3 mb-3">
                        <div class="col-6">
                            <label for="unit" class="form-label fw-semibold">Unit of Measure</label>
                            <select class="form-select" id="unit" name="unit">
                                <?php foreach ($units as $u): ?>
                                <option value="<?= $u ?>" <?= $form['unit'] === $u ? 'selected' : '' ?>>
                                    <?= ucfirst($u) ?>
                                </option>
                                <?php endforeach; ?>
                            </select>
                        </div>
                        <div class="col-6">
                            <label for="initial_stock" class="form-label fw-semibold">Initial Stock</label>
                            <input type="number"
                                   class="form-control"
                                   id="initial_stock"
                                   name="initial_stock"
                                   value="<?= (int) $form['initial_stock'] ?>"
                                   min="0"
                                   placeholder="0">
                        </div>
                    </div>

                    <div class="d-grid gap-2 mt-4">
                        <button type="submit" class="btn btn-primary fw-semibold">
                            <i class="bi bi-plus-circle me-1"></i> Add Product
                        </button>
                        <a href="product_list.php" class="btn btn-outline-secondary">Cancel</a>
                    </div>

                </form>
            </div>
        </div>
    </div>
</div>

<?php include 'includes/footer.php'; ?>