<?php

namespace App\Catalog;

use Illuminate\Http\Request;
use Modules\Core\Catalog\DTOs\ProductFilters;
use Modules\Core\Catalog\Enums\ProductSort;

/**
 * The parsed filter/sort/page state of a product-listing request — used by the
 * category page (scoped to a collection) and the all-products page. The query
 * string is the single source of truth; build one of these from the request,
 * read the applied values off it, and use query() to build links (sort options,
 * pagination, "clear filter") that carry the rest of the state along.
 *
 * A param is only ever emitted when it differs from its default, so a pristine
 * listing has no query string at all.
 */
final class ProductListing
{
    private function __construct(
        public readonly ?ProductSort $sort,
        public readonly ?float $minPrice,
        public readonly ?float $maxPrice,
        public readonly bool $inStockOnly,
        public readonly int $page,
    ) {}

    public static function fromRequest(Request $request): self
    {
        return new self(
            sort: ProductSort::tryFrom((string) $request->query('sort')),
            minPrice: self::floatOrNull($request->query('price_min')),
            maxPrice: self::floatOrNull($request->query('price_max')),
            inStockOnly: $request->boolean('in_stock'),
            page: max(1, (int) $request->query('page', 1)),
        );
    }

    /**
     * @param  ?int  $collectionId  scope to a collection (category page); null = every product
     */
    public function filters(?int $collectionId = null): ProductFilters
    {
        return new ProductFilters(
            collectionId: $collectionId,
            minPrice: $this->minPrice,
            maxPrice: $this->maxPrice,
            inStockOnly: $this->inStockOnly,
        );
    }

    /**
     * The applied params as a clean array (defaults omitted), with `$overrides`
     * merged on top — pass `['key' => null]` to drop one.
     *
     * @param  array<string, string|int|null>  $overrides
     * @return array<string, string|int>
     */
    public function query(array $overrides = []): array
    {
        return array_filter([
            'sort' => $this->sort?->value,
            'price_min' => $this->minPrice,
            'price_max' => $this->maxPrice,
            'in_stock' => $this->inStockOnly ? 1 : null,
            'page' => $this->page > 1 ? $this->page : null,
            ...$overrides,
        ], fn ($value) => $value !== null);
    }

    /**
     * Whether the listing is reordered/narrowed enough that it shouldn't be
     * indexed as its own page (the canonical still points at the bare listing
     * URL either way). A plain in-stock toggle is left indexable.
     */
    public function isRefined(): bool
    {
        return $this->sort !== null
            || $this->minPrice !== null
            || $this->maxPrice !== null
            || $this->page > 1;
    }

    private static function floatOrNull(mixed $value): ?float
    {
        return is_numeric($value) ? (float) $value : null;
    }
}