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

date_default_timezone_set('Asia/Dhaka');

// Fetch product names only — NO stock quantity shown to technicians
$all_products = $pdo->query(
    "SELECT id, name, unit FROM products ORDER BY name ASC"
)->fetchAll();

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

$form = ['product_id' => '', 'quantity' => '', 'notes' => ''];

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $form['product_id'] = (int) ($_POST['product_id'] ?? 0);
    $form['quantity']   = trim($_POST['quantity'] ?? '');
    $form['notes']      = trim($_POST['notes'] ?? '');

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

    if ($form['product_id'] <= 0) {
        $error = 'Please select a product.';
    } elseif ($quantity <= 0) {
        $error = 'Quantity must be a positive number.';
    } else {
        // Fetch product (validate it exists and has enough stock)
        $prod_stmt = $pdo->prepare("SELECT id, name, unit, current_stock FROM products WHERE id = ?");
        $prod_stmt->execute([$form['product_id']]);
        $product = $prod_stmt->fetch();

        if (!$product) {
            $error = 'Selected product not found.';
        } elseif ($quantity > $product['current_stock']) {
            // Stock too low — tell tech to contact admin, but don't reveal exact stock number
            $error = 'Not enough stock available for this quantity. Please contact your admin.';
        } else {
            // Deduct stock
            $pdo->prepare("UPDATE products SET current_stock = current_stock - ? WHERE id = ?")
                ->execute([$quantity, $product['id']]);

            // Log transaction with user_id
            $pdo->prepare(
                "INSERT INTO stock_transactions (product_id, user_id, quantity, type, notes)
                 VALUES (?, ?, ?, 'deducted', ?)"
            )->execute([$product['id'], $_SESSION['user_id'], $quantity, $form['notes']]);

            $success = "Usage submitted: {$quantity} {$product['unit']}(s) of \"{$product['name']}\".";
            $form    = ['product_id' => '', 'quantity' => '', 'notes' => ''];
        }
    }
}

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>Submit Usage</h4>
        <nav aria-label="breadcrumb">
            <ol class="breadcrumb">
                <li class="breadcrumb-item"><a href="tech_dashboard.php">My Dashboard</a></li>
                <li class="breadcrumb-item active">Submit Usage</li>
            </ol>
        </nav>
    </div>
</div>

<div class="row justify-content-center">
    <div class="col-md-7 col-lg-6">

        <!-- Info box for technicians -->
        <div class="alert alert-info d-flex align-items-start gap-2 mb-4">
            <i class="bi bi-info-circle-fill mt-1"></i>
            <div>
                <strong>How to use:</strong> Select the product you used, enter the quantity, and optionally
                add a note (e.g., customer name, job location). You can edit a mistaken entry from your dashboard.
            </div>
        </div>

        <div class="card">
            <div class="card-header bg-primary text-white">
                <i class="bi bi-clipboard-plus me-1"></i> Log Product Usage
            </div>
            <div class="card-body">

                <?php if ($success !== ''): ?>
                <div class="alert alert-success d-flex align-items-start gap-2">
                    <i class="bi bi-check-circle-fill mt-1"></i>
                    <div>
                        <?= htmlspecialchars($success) ?>
                        <div class="mt-2 d-flex gap-2 flex-wrap">
                            <a href="tech_usage.php"     class="btn btn-sm btn-success">Submit Another</a>
                            <a href="tech_dashboard.php" class="btn btn-sm btn-outline-secondary">My Dashboard</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; ?>

                <?php if (empty($all_products)): ?>
                <div class="alert alert-warning">No products are available yet. Contact your admin.</div>
                <?php else: ?>

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

                    <div class="mb-3">
                        <label for="product_id" class="form-label fw-semibold">
                            Product Used <span class="text-danger">*</span>
                        </label>
                        <select class="form-select" id="product_id" name="product_id" required>
                            <option value="">-- Select Product --</option>
                            <?php foreach ($all_products as $p): ?>
                            <option value="<?= $p['id'] ?>"
                                    data-unit="<?= htmlspecialchars($p['unit']) ?>"
                                    <?= (int) $form['product_id'] === (int) $p['id'] ? 'selected' : '' ?>>
                                <?= htmlspecialchars($p['name']) ?>
                            </option>
                            <?php endforeach; ?>
                        </select>
                    </div>

                    <div class="mb-3">
                        <label for="quantity" class="form-label fw-semibold">
                            Quantity Used <span class="text-danger">*</span>
                        </label>
                        <div class="input-group">
                            <input type="number"
                                   class="form-control"
                                   id="quantity"
                                   name="quantity"
                                   value="<?= htmlspecialchars($form['quantity']) ?>"
                                   min="1"
                                   placeholder="e.g., 2"
                                   required>
                            <span class="input-group-text" id="unit-label">unit(s)</span>
                        </div>
                    </div>

                    <div class="mb-4">
                        <label for="notes" class="form-label fw-semibold">Notes / Reason</label>
                        <input type="text"
                               class="form-control"
                               id="notes"
                               name="notes"
                               value="<?= htmlspecialchars($form['notes']) ?>"
                               placeholder="e.g., House #5 Mirpur, Customer: Rahim">
                        <div class="form-text">Optional — helps identify the job this was used for.</div>
                    </div>

                    <div class="d-grid gap-2">
                        <button type="submit" class="btn btn-primary fw-semibold py-2">
                            <i class="bi bi-send me-1"></i> Submit Usage
                        </button>
                        <a href="tech_dashboard.php" class="btn btn-outline-secondary">Cancel</a>
                    </div>

                </form>

                <?php endif; ?>
            </div>
        </div>

    </div>
</div>

<script>
(function () {
    const select    = document.getElementById('product_id');
    const unitLabel = document.getElementById('unit-label');
    if (!select || !unitLabel) return;

    select.addEventListener('change', function () {
        const opt = this.options[this.selectedIndex];
        unitLabel.textContent = opt.dataset.unit ? opt.dataset.unit + '(s)' : 'unit(s)';
    });
}());
</script>

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