<?php
/**
 * For the full copyright and license information, please view the
 * docs/licenses/LICENSE.txt file that was distributed with this source code.
 */

namespace PrestaShop\PrestaShop\Adapter\Carrier\QueryHandler;

use Address;
use PrestaShop\Decimal\DecimalNumber;
use PrestaShop\PrestaShop\Adapter\Address\Repository\AddressRepository;
use PrestaShop\PrestaShop\Adapter\Carrier\Repository\CarrierRepository;
use PrestaShop\PrestaShop\Adapter\Product\Repository\ProductRepository;
use PrestaShop\PrestaShop\Adapter\Zone\Repository\ZoneRepository;
use PrestaShop\PrestaShop\Core\CommandBus\Attributes\AsQueryHandler;
use PrestaShop\PrestaShop\Core\Context\LanguageContext;
use PrestaShop\PrestaShop\Core\Context\ShopContext;
use PrestaShop\PrestaShop\Core\Domain\Carrier\Query\GetAvailableCarriers;
use PrestaShop\PrestaShop\Core\Domain\Carrier\QueryHandler\GetAvailableCarriersHandlerInterface;
use PrestaShop\PrestaShop\Core\Domain\Carrier\QueryResult\CarrierSummary;
use PrestaShop\PrestaShop\Core\Domain\Carrier\QueryResult\FilteredCarrier;
use PrestaShop\PrestaShop\Core\Domain\Carrier\QueryResult\GetCarriersResult;
use PrestaShop\PrestaShop\Core\Domain\Carrier\QueryResult\ProductSummary;
use PrestaShop\PrestaShop\Core\Domain\Carrier\ValueObject\CarrierId;
use PrestaShop\PrestaShop\Core\Domain\Country\ValueObject\CountryId;
use PrestaShop\PrestaShop\Core\Domain\Product\ValueObject\ProductQuantity;
use PrestaShop\PrestaShop\Core\Domain\Shop\ValueObject\ShopId;
use PrestaShop\PrestaShop\Core\Domain\Zone\ValueObject\ZoneId;
use Product;
use RuntimeException;
use Symfony\Component\DependencyInjection\Attribute\Autowire;

#[AsQueryHandler]
class GetAvailableCarriersHandler implements GetAvailableCarriersHandlerInterface
{
    public function __construct(
        private readonly CarrierRepository $carrierRepository,
        private readonly ProductRepository $productRepository,
        private readonly AddressRepository $addressRepository,
        private readonly ZoneRepository $zoneRepository,
        private readonly LanguageContext $languageContext,
        #[Autowire(service: 'prestashop.default.language.context')]
        private readonly LanguageContext $defaultLanguageContext,
        private readonly ShopContext $shopContext
    ) {
    }

    /**
     * Handle the query to retrieve available and filtered carriers based on products, delivery address and constraints.
     */
    public function handle(GetAvailableCarriers $query): GetCarriersResult
    {
        $shopId = new ShopId($this->shopContext->getId());
        $productQuantities = $query->getProductQuantities();
        $productIds = $query->getProductIds();

        // Load all products
        $products = $this->loadProducts($productQuantities);

        // Validate and resolve address
        $address = $this->addressRepository->get($query->getAddressId());
        $countryId = new CountryId($address->id_country);
        $zoneId = $this->zoneRepository->getZoneIdByCountryId($countryId);

        // Load carriers mapped per product
        $carriersMapping = $this->carrierRepository->findCarriersByProductIds($productIds, $shopId);

        // Compute common carriers shared by all products
        $commonCarriers = $this->getCommonCarriers($carriersMapping);

        $carriersIndex = $this->indexCarriers($carriersMapping);

        $eligibleCarrierIds = [];
        foreach ($commonCarriers as $carrierId) {
            $carrierData = $carriersIndex[$carrierId];

            if ($this->isCarrierEligible($carrierData, $zoneId, $products, $productQuantities)) {
                $eligibleCarrierIds[] = $carrierId;
            }
        }

        $availableCarriers = [];
        foreach ($eligibleCarrierIds as $carrierId) {
            $carrier = $carriersIndex[$carrierId];
            $availableCarriers[] = new CarrierSummary($carrier['id_carrier'], $carrier['name']);
        }

        $currentCarrierId = $query->getCurrentCarrierId();
        if ($currentCarrierId !== null && !in_array($currentCarrierId, $eligibleCarrierIds)) {
            $currentCarrier = $this->carrierRepository->get(new CarrierId($currentCarrierId));
            if ($currentCarrier !== null) {
                $availableCarriers[] = new CarrierSummary($currentCarrier->id, $currentCarrier->name);
            }
        }

        // Compute filtered carriers (carriers not available for all products)
        $removedCarriers = [];
        $allCarrierIds = $this->mapCarrierToProducts($carriersMapping);
        foreach ($allCarrierIds as $carrierId => $productIds) {
            if (!in_array($carrierId, $eligibleCarrierIds, true)) {
                $carrier = $carriersIndex[$carrierId];
                $productPreviews = array_map(function (int $pid) use ($products) {
                    $product = $products[$pid];

                    return new ProductSummary($product->id, $this->getProductName($product));
                }, array_keys($productIds));

                $removedCarriers[] = new FilteredCarrier(
                    $productPreviews,
                    new CarrierSummary($carrier['id_carrier'], $carrier['name'])
                );
            }
        }

        return new GetCarriersResult($availableCarriers, $removedCarriers);
    }

    /**
     * @param ProductQuantity[] $productQuantities
     *
     * @return Product[]
     */
    private function loadProducts(array $productQuantities): array
    {
        $products = [];
        foreach ($productQuantities as $productQuantity) {
            $productId = $productQuantity->getProductId();
            $products[$productId->getValue()] = $this->productRepository->get(
                $productId,
                new ShopId($this->shopContext->getId())
            );
        }

        return $products;
    }

    /**
     * Compute intersection of carriers for all products.
     *
     * @param array<int, array<int, array{id_carrier: int, name: string}>> $carriersMapping
     *
     * @return int[] List of carrier IDs
     */
    private function getCommonCarriers(array $carriersMapping): array
    {
        $common = null;

        foreach ($carriersMapping as $carriers) {
            $ids = array_column($carriers, 'id_carrier');
            $common = is_null($common) ? $ids : array_intersect($common, $ids);
        }

        return $common ?? [];
    }

    /**
     * Index carriers by ID for quick lookup.
     *
     * @param array<int, array<int, array{id_carrier: int, name: string}>> $carriersMapping
     *
     * @return array<int, array{id_carrier: int, name: string}>
     */
    private function indexCarriers(array $carriersMapping): array
    {
        $index = [];

        foreach ($carriersMapping as $carriers) {
            foreach ($carriers as $carrier) {
                $index[$carrier['id_carrier']] = $carrier;
            }
        }

        return $index;
    }

    /**
     * Map carriers to products they apply to.
     *
     * @param array<int, array<int, array{id_carrier: int, name: string}>> $carriersMapping
     *
     * @return array<int, array<int, true>> [carrierId => [productId => true]]
     */
    private function mapCarrierToProducts(array $carriersMapping): array
    {
        $map = [];
        foreach ($carriersMapping as $productId => $carriers) {
            foreach ($carriers as $carrier) {
                $map[$carrier['id_carrier']][$productId] = true;
            }
        }

        return $map;
    }

    /**
     * Checks if a carrier is eligible for the current zone and constraints.
     *
     * @param array{id_carrier: int, name: string} $carrier
     * @param Product[] $products
     * @param ProductQuantity[] $quantities
     */
    private function isCarrierEligible(array $carrier, ZoneId $zoneId, array $products, array $quantities): bool
    {
        // Check if carrier supports the zone
        if (!$this->carrierRepository->checkCarrierZone(new CarrierId($carrier['id_carrier']), $zoneId)) {
            return false;
        }

        // Compute total weight and max dimensions
        $totalWeight = 0;
        $maxWidth = $maxHeight = $maxDepth = 0;

        foreach ($quantities as $productQuantity) {
            $product = $products[$productQuantity->getProductId()->getValue()];
            $quantity = $productQuantity->getQuantity();

            $totalWeight += $product->weight * $quantity;
            $maxWidth = max($maxWidth, $product->width);
            $maxHeight = max($maxHeight, $product->height);
            $maxDepth = max($maxDepth, $product->depth);
        }

        $limits = $this->carrierRepository->getCarrierConstraints(new CarrierId($carrier['id_carrier']));

        $check = fn ($value, $limit) => $limit === 0 || $value <= $limit;

        $weightOk = $limits->maxWeight->equalsZero() || $limits->maxWeight->isGreaterOrEqualThan(new DecimalNumber((string) $totalWeight));
        $widthOk = $check($maxWidth, $limits->maxWidth);
        $heightOk = $check($maxHeight, $limits->maxHeight);
        $depthOk = $check($maxDepth, $limits->maxDepth);

        return $weightOk && $widthOk && $heightOk && $depthOk;
    }

    /**
     * Get translated product name from current or fallback language.
     */
    private function getProductName(Product $product): string
    {
        $name = $product->name;
        if (!is_array($name)) {
            return $name;
        }

        $langId = $this->languageContext->getId();
        $fallbackId = $this->defaultLanguageContext->getId();

        if (isset($name[$langId])) {
            return $name[$langId];
        }

        if (isset($name[$fallbackId])) {
            return $name[$fallbackId];
        }

        throw new RuntimeException(sprintf(
            'Product name not found for product ID %d in current (%d) or default (%d) language.',
            $product->id,
            $langId,
            $fallbackId
        ));
    }
}