<?php
namespace Zadex\WooCommerce;

defined('ABSPATH') || exit;

/**
 * WP_Query arguments of the `products` grid widget (T152), built from its settings (pure, testable).
 *
 * Sources: latest | sale | featured | category | tag | ids | best_selling | top_rated | current (archive mode:
 * the main query as it is). Hidden products (catalog visibility "hidden" / "search only") are excluded, and out of
 * stock products too when WooCommerce hides them. Pagination reads `?product-page=N` (like WooCommerce's
 * shortcodes), so several grids on a page page together.
 *
 * Filter `zadex/woocommerce/products_query` (array $args, array $settings) can change the result.
 */
final class ProductsQuery
{
    public const SOURCES = ['latest', 'sale', 'featured', 'category', 'tag', 'ids', 'best_selling', 'top_rated', 'current'];
    public const ORDERBY = ['date', 'title', 'price', 'popularity', 'rating', 'rand', 'menu_order'];
    public const PAGE_VAR = 'product-page';

    /** @var null|callable(array): object test seam replacing WP_Query (returns an object with posts + max_num_pages) */
    public static $runner = null;

    /** Runs the query: a WP_Query (or the test runner); null when neither is available. */
    public static function run(array $args): ?object
    {
        if (is_callable(self::$runner)) {
            return (self::$runner)($args);
        }
        return class_exists('\WP_Query') ? new \WP_Query($args) : null;
    }

    /**
     * @param array<string, mixed> $settings widget settings
     * @param array<string, mixed> $env      { page, on_sale_ids, visibility_ids: {exclude-from-catalog, featured, outofstock}, hide_out_of_stock }
     */
    public static function args(array $settings, array $env = []): array
    {
        $source = in_array($settings['source'] ?? '', self::SOURCES, true) ? (string) $settings['source'] : 'latest';
        $columns = self::clamp($settings['columns'] ?? 4, 1, 8, 4);
        $rows = self::clamp($settings['rows'] ?? 1, 1, 20, 1);
        $per_page = $columns * $rows;
        $order = strtoupper((string) ($settings['order'] ?? 'DESC')) === 'ASC' ? 'ASC' : 'DESC';
        $orderby = in_array($settings['orderby'] ?? '', self::ORDERBY, true) ? (string) $settings['orderby'] : 'date';
        $page = max(1, (int) ($env['page'] ?? 1));
        $vis = is_array($env['visibility_ids'] ?? null) ? $env['visibility_ids'] : [];

        $args = [
            'post_type'           => 'product',
            'post_status'         => 'publish',
            'ignore_sticky_posts' => true,
            'posts_per_page'      => $per_page,
            'paged'               => !empty($settings['pagination']) ? $page : 1,
            'no_found_rows'       => empty($settings['pagination']),
            // phpcs:disable WordPress.DB.SlowDBQuery.slow_db_query_tax_query, WordPress.DB.SlowDBQuery.slow_db_query_meta_query -- product visibility / category filters, as WooCommerce itself queries them.
            'tax_query'           => [],
            'meta_query'          => [],
            // phpcs:enable WordPress.DB.SlowDBQuery.slow_db_query_tax_query, WordPress.DB.SlowDBQuery.slow_db_query_meta_query
        ];
        $hidden = array_filter([(int) ($vis['exclude-from-catalog'] ?? 0)]);
        if (!empty($env['hide_out_of_stock']) && !empty($vis['outofstock'])) {
            $hidden[] = (int) $vis['outofstock'];
        }
        if ($hidden) {
            $args['tax_query'][] = ['taxonomy' => 'product_visibility', 'field' => 'term_taxonomy_id', 'terms' => array_values($hidden), 'operator' => 'NOT IN'];
        }

        switch ($source) {
            case 'sale':
                $ids = array_map('intval', (array) ($env['on_sale_ids'] ?? []));
                $args['post__in'] = $ids ?: [0];
                break;
            case 'featured':
                $args['tax_query'][] = ['taxonomy' => 'product_visibility', 'field' => 'term_taxonomy_id', 'terms' => [(int) ($vis['featured'] ?? 0)], 'operator' => 'IN'];
                break;
            case 'category':
            case 'tag':
                $terms = self::ids($settings[$source === 'category' ? 'categories' : 'tags'] ?? []);
                if ($terms) {
                    $args['tax_query'][] = ['taxonomy' => $source === 'category' ? 'product_cat' : 'product_tag', 'field' => 'term_id', 'terms' => $terms, 'operator' => 'IN'];
                }
                break;
            case 'ids':
                $ids = self::ids($settings['ids'] ?? '');
                $args['post__in'] = $ids ?: [0];
                if ($orderby === 'menu_order' || empty($settings['orderby'])) {
                    $args['orderby'] = 'post__in';
                }
                break;
            case 'best_selling':
                $orderby = 'popularity';
                $order = 'DESC';
                break;
            case 'top_rated':
                $orderby = 'rating';
                $order = 'DESC';
                break;
        }
        $excluded = self::ids($settings['exclude'] ?? '');
        if ($excluded) {
            // phpcs:ignore WordPressVIPMinimum.Performance.WPQueryParams.PostNotIn_post__not_in -- user-chosen product exclusions, a short id list.
            $args['post__not_in'] = $excluded;
        }
        if (!isset($args['orderby'])) {
            $args = array_merge($args, self::ordering($orderby, $order));
        }
        if (!$args['tax_query']) {
            unset($args['tax_query']);
        } elseif (count($args['tax_query']) > 1) {
            $args['tax_query']['relation'] = 'AND';
        }
        if (!$args['meta_query']) {
            unset($args['meta_query']);
        }
        return (array) apply_filters('zadex/woocommerce/products_query', $args, $settings);
    }

    /** orderby / order (+ meta_key) for a WooCommerce ordering. */
    public static function ordering(string $orderby, string $order): array
    {
        switch ($orderby) {
            case 'price':
                // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key -- WooCommerce price ordering needs its meta key.
                return ['orderby' => 'meta_value_num', 'meta_key' => '_price', 'order' => $order];
            case 'popularity':
                // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key -- WooCommerce popularity ordering needs its meta key.
                return ['orderby' => ['meta_value_num' => 'DESC', 'ID' => 'DESC'], 'meta_key' => 'total_sales', 'order' => 'DESC'];
            case 'rating':
                // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key -- WooCommerce rating ordering needs its meta key.
                return ['orderby' => ['meta_value_num' => 'DESC', 'ID' => 'DESC'], 'meta_key' => '_wc_average_rating', 'order' => 'DESC'];
            case 'rand':
                return ['orderby' => 'rand', 'order' => $order];
            case 'title':
                return ['orderby' => 'title', 'order' => $order];
            case 'menu_order':
                return ['orderby' => 'menu_order title', 'order' => $order];
        }
        return ['orderby' => 'date ID', 'order' => $order];
    }

    /** Environment from WooCommerce (current page, sale ids, visibility term ids). */
    public static function env(): array
    {
        // Public pagination link of the Products widget: read-only page number, no nonce.
        $page = isset($_GET[self::PAGE_VAR]) ? absint(wp_unslash($_GET[self::PAGE_VAR])) : 1; // phpcs:ignore WordPress.Security.NonceVerification.Recommended
        return [
            'page'              => max(1, $page),
            'on_sale_ids'       => function_exists('wc_get_product_ids_on_sale') ? wc_get_product_ids_on_sale() : [],
            'visibility_ids'    => function_exists('wc_get_product_visibility_term_ids') ? wc_get_product_visibility_term_ids() : [],
            'hide_out_of_stock' => get_option('woocommerce_hide_out_of_stock_items') === 'yes',
        ];
    }

    /** @return int[] from "1, 2,3", [1, "2"] or a term-id select value */
    public static function ids($value): array
    {
        if (is_string($value) || is_int($value)) {
            $value = preg_split('/[\s,]+/', (string) $value) ?: [];
        }
        if (!is_array($value)) {
            return [];
        }
        return array_values(array_unique(array_filter(array_map('intval', $value), static fn(int $i): bool => $i > 0)));
    }

    private static function clamp($value, int $min, int $max, int $default): int
    {
        if (is_array($value)) {
            $value = $value['size'] ?? $default;
        }
        $n = is_numeric($value) ? (int) $value : $default;
        return max($min, min($max, $n));
    }
}