boms_save.php

<?php
require_once 'includes/auth.php';
require_login();
require_csrf();
require_once 'includes/db.php';

$product_id = (int)$_POST['product_id'];
$material_id = (int)$_POST['material_id'];
$quantity = (float)$_POST['quantity'];
$unit = trim($_POST['unit'] ?? '');
$version = $_POST['version'] ?? 'standard';

// There can be no duplicate rows: same product_id, material_id, version!
$stmt = $pdo->prepare("SELECT id FROM boms WHERE product_id=? AND material_id=? AND version=?");
$stmt->execute([$product_id, $material_id, $version]);
if ($stmt->fetch()) {
    echo json_encode(['success'=>false, 'message'=>'This material is already in the bill of materials!']);
    exit;
}

$stmt = $pdo->prepare("INSERT INTO boms (product_id, material_id, quantity, unit, version) VALUES (?, ?, ?, ?, ?)");
$res = $stmt->execute([$product_id, $material_id, $quantity, $unit, $version]);
echo json_encode(['success'=>$res]);