<?php

class WPI_Product_Validator
{
    /**
     * Validate product data after mapping
     *
     * @return array [bool $is_valid, array $errors]
     */
    public static function validate(array $data): array
    {
        $errors = [];

        // Required fields
        if (empty($data['sku'])) {
            $errors[] = 'SKU is required';
        }

        if (empty($data['name'])) {
            $errors[] = 'Product name is required';
        }

        // Price
        if (!isset($data['price']) || !is_numeric($data['price'])) {
            $errors[] = 'Price must be numeric';
        } elseif ($data['price'] < 0) {
            $errors[] = 'Price must be >= 0';
        }

        // Stock
        if (!isset($data['stock']) || !is_numeric($data['stock'])) {
            $errors[] = 'Stock must be numeric';
        }

        // Images
        if (!empty($data['images']) && !is_array($data['images'])) {
            $errors[] = 'Images must be an array';
        }

        // Categories
        if (!empty($data['categories']) && !is_array($data['categories'])) {
            $errors[] = 'Categories must be an array';
        }

        return [
            'valid'  => empty($errors),
            'errors' => $errors
        ];
    }
}