<?php
include('include/headscript.php');
header('Content-Type: application/json');

$id = isset($_POST['id']) ? (int)$_POST['id'] : 0;
$idpackaging_item = isset($_POST['idpackaging_item']) ? (int)$_POST['idpackaging_item'] : 0;
$idsupplier = isset($_POST['idsupplier']) ? (int)$_POST['idsupplier'] : 0;
$lot_code = trim($_POST['lot_code'] ?? '');
$expiry_date = trim($_POST['expiry_date'] ?? '');
$qty = isset($_POST['qty']) ? (float)$_POST['qty'] : 0;

if ($id <= 0 || $idpackaging_item <= 0 || $idsupplier <= 0) {
    echo json_encode(['success' => false, 'message' => 'Invalid input']);
    exit;
}
if ($qty < 0) {
    echo json_encode(['success' => false, 'message' => 'Quantity cannot be negative']);
    exit;
}
if ($expiry_date === '') $expiry_date = null;

$db = DBHandlerSelect::getInstance();
$pdo = $db->getConnection();

try {
    $stmt = $pdo->prepare("UPDATE packaging_stock_lots
        SET idsupplier=?, lot_code=?, expiry_date=?, qty=?
        WHERE id=? AND idpackaging_item=?");

    $stmt->execute([
        $idsupplier,
        ($lot_code !== '' ? $lot_code : null),
        $expiry_date,
        $qty,
        $id,
        $idpackaging_item
    ]);

    echo json_encode(['success' => true]);
} catch (PDOException $e) {
    echo json_encode(['success' => false, 'message' => $e->getMessage()]);
}