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

$id = isset($_POST['id']) ? (int)$_POST['id'] : 0;
$qty = isset($_POST['qty']) ? (float)$_POST['qty'] : null;

if ($id <= 0 || $qty === null) {
    echo json_encode(['success' => false, 'message' => 'Invalid input']);
    exit;
}

if ($qty < 0) {
    echo json_encode(['success' => false, 'message' => 'Quantity cannot be negative']);
    exit;
}

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

try {
    $stmt = $pdo->prepare("UPDATE mescole_supplier_lots SET qty = ? WHERE id = ?");
    $stmt->execute([$qty, $id]);

    if ($stmt->rowCount() === 0) {
        echo json_encode(['success' => false, 'message' => 'No rows updated (id not found?)']);
        exit;
    }

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