<?php

namespace App\Domains\Catalog\Services;

use App\Domains\Catalog\Models\CatalogItem;
use App\Domains\Purchase\Services\UserPurchaseLimitService;
use Illuminate\Support\Collection;

class CatalogItemAllowanceService
{
    private const USER_QUOTA_REACHED_MESSAGE = 'Alcanzaste el cupo máximo permitido para este producto.';

    private const OUT_OF_STOCK_MESSAGE = 'Este producto no tiene stock disponible.';

    public function __construct(
        private readonly UserPurchaseLimitService $purchaseLimits,
    ) {}

    /** @param Collection<int, CatalogItem> $catalogItems */
    public function attach(Collection $catalogItems, ?int $userId): void
    {
        $remaining = $this->purchaseLimits->remainingByCatalogItem($catalogItems, $userId);

        foreach ($catalogItems as $catalogItem) {
            $catalogItem->setAttribute(
                'remaining_user_quota',
                $remaining->get($catalogItem->getKey()),
            );
        }
    }

    public function maximumAddableQuantity(?int $availableStock, ?int $remainingUserQuota): ?int
    {
        if ($availableStock === null) {
            return $remainingUserQuota;
        }

        if ($remainingUserQuota === null) {
            return $availableStock;
        }

        return min($availableStock, $remainingUserQuota);
    }

    /**
     * @return array{
     *     maximum_quantity: int|null,
     *     restrictions: list<array{code: string, message: string, scope: string}>,
     *     capabilities: array{select_variant: bool, change_quantity: bool, add_to_cart: bool, buy_now: bool}
     * }
     */
    public function availability(
        ?int $availableStock,
        ?int $remainingUserQuota,
        string $scope = 'product',
    ): array {
        $restrictions = [];

        if ($remainingUserQuota !== null && $remainingUserQuota <= 0) {
            $restrictions[] = [
                'code' => 'user_quota_reached',
                'message' => self::USER_QUOTA_REACHED_MESSAGE,
                'scope' => $scope,
            ];
        }

        if ($availableStock !== null && $availableStock <= 0) {
            $restrictions[] = [
                'code' => 'out_of_stock',
                'message' => self::OUT_OF_STOCK_MESSAGE,
                'scope' => $scope,
            ];
        }

        $capabilities = [
            'select_variant' => true,
            'change_quantity' => true,
            'add_to_cart' => true,
            'buy_now' => true,
        ];

        foreach ($restrictions as $restriction) {
            /** @var array<string, bool> $policy */
            $policy = config("catalog.availability_policies.{$restriction['code']}", []);

            foreach ($capabilities as $capability => $allowed) {
                $capabilities[$capability] = $allowed && ($policy[$capability] ?? true);
            }
        }

        return [
            'maximum_quantity' => $this->maximumAddableQuantity(
                $availableStock,
                $remainingUserQuota,
            ),
            'restrictions' => $restrictions,
            'capabilities' => $capabilities,
        ];
    }

    /** @return array<string, mixed> */
    public function purchaseLimitExceededAvailability(int $maximumQuantity, string $message): array
    {
        $availability = $this->availability(null, $maximumQuantity);

        if ($maximumQuantity > 0) {
            $availability['restrictions'][] = [
                'code' => 'requested_quantity_exceeds_user_quota',
                'message' => $message,
                'scope' => 'product',
            ];
        }

        return $availability;
    }
}