<?php

namespace Modules\Core\Order\Services;

use Lunar\Models\Order;
use Lunar\Shipping\Models\ShippingMethod;
use Modules\Core\Order\DTOs\OrderFulfillmentResult;
use Modules\Core\Order\Events\OrderPickedUp;
use Modules\Core\Order\Events\OrderReadyForDispatch;
use Modules\Core\Order\Events\OrderReadyForPickup;
use Modules\Core\Shipping\Contracts\CarrierFulfillmentInterface;
use Modules\Core\Shipping\DTOs\ShipmentRequest;
use Throwable;

/**
 * The staff-facing fulfillment/return/payment workflow behind the three
 * header actions in Modules\Core\Shipping\Extensions\OrderViewExtension
 * ("Create Shipment", "Update Status", "Mark Paid") — every guard check,
 * status write (via Modules\Core\Order\Services\OrderStatusWriter), and
 * event dispatch lives here, keeping this workflow usable and testable
 * independent of Filament.
 *
 * Every method re-validates its own precondition internally (not just
 * trusted from the caller's own visible()-equivalent check) — protects
 * against a stale page load racing a concurrent automatic transition
 * (e.g. a carrier tracking checkpoint advancing the same order between
 * page load and button click).
 */
class OrderFulfillmentService
{
    public function __construct(
        private readonly OrderStatusWriter $writer,
        private readonly OrderStatusFlow $flow,
    ) {}

    public function markReady(Order $order): OrderFulfillmentResult
    {
        if ($order->status !== 'processing') {
            return OrderFulfillmentResult::failure('This order must be in Processing before it can be marked ready.');
        }

        $target = $order->isStorePickupOrder() ? 'ready_for_pickup' : 'ready_for_dispatch';

        $this->writer->write($order, $target, self::class.'::markReady');

        if ($order->isStorePickupOrder()) {
            OrderReadyForPickup::dispatch($order);
        } else {
            OrderReadyForDispatch::dispatch($order);
        }

        return OrderFulfillmentResult::success('Order marked ready.');
    }

    public function createShipmentAndDispatch(Order $order, ShipmentRequest $request): OrderFulfillmentResult
    {
        if ($order->status !== 'ready_for_dispatch') {
            return OrderFulfillmentResult::failure('This order is not ready to be dispatched.');
        }

        $service = $this->resolveFulfillmentService($order);

        if (! $service) {
            return OrderFulfillmentResult::failure('No carrier fulfillment integration is configured for this order.');
        }

        try {
            $service->createShipment($order, $request);
        } catch (Throwable $e) {
            report($e);

            return OrderFulfillmentResult::failure('Failed to create shipment: '.$e->getMessage());
        }

        $this->writer->write($order, 'dispatched', self::class.'::createShipmentAndDispatch');

        return OrderFulfillmentResult::success('Shipment created and order dispatched.');
    }

    public function markPickedUp(Order $order): OrderFulfillmentResult
    {
        if ($order->status !== 'ready_for_pickup') {
            return OrderFulfillmentResult::failure('This order is not ready for pickup.');
        }

        $this->writer->write($order, 'picked_up', self::class.'::markPickedUp');

        OrderPickedUp::dispatch($order);

        return OrderFulfillmentResult::success('Order marked as picked up.');
    }

    /**
     * The general-purpose entry point for any transition with no special
     * side effect — a manual override, not restricted to the guided next
     * step(s), so staff can revert to an earlier status in the order's
     * own branch. Validates $to is actually a member of
     * OrderStatusFlow::allOptions() before writing (server-side
     * re-validation of whatever the Select offered) — still refuses a
     * status from the WRONG branch or an unknown value.
     */
    public function transitionTo(Order $order, string $to): OrderFulfillmentResult
    {
        if (! array_key_exists($to, $this->flow->allOptions($order))) {
            return OrderFulfillmentResult::failure('That status is not valid for this order.');
        }

        $this->writer->write($order, $to, self::class.'::transitionTo');

        return OrderFulfillmentResult::success('Order status updated.');
    }

    /**
     * Independent of `status` entirely — offered by the single "Update
     * Status" action regardless of current status (see
     * OrderStatusFlow::canMarkPaid()).
     */
    public function markPaid(Order $order): OrderFulfillmentResult
    {
        if (! $this->flow->canMarkPaid($order)) {
            return OrderFulfillmentResult::failure('This order cannot be marked paid right now.');
        }

        $this->writer->markPaid($order, self::class.'::markPaid');

        return OrderFulfillmentResult::success('Order marked as paid.');
    }

    public function canCreateShipment(Order $order): bool
    {
        return $order->status === 'ready_for_dispatch'
            && ! $order->isStorePickupOrder()
            && $order->shipments()->exists() === false
            && $this->resolveFulfillmentService($order) !== null;
    }

    /**
     * Public wrapper around resolveCarrier() — Modules\Core\Shipping\
     * Extensions\OrderViewExtension needs to know which carrier an order
     * uses to branch the "Create Shipment" form (Box Now's box-size
     * repeater vs. every other carrier's plain weight field).
     */
    public function carrierFor(Order $order): ?string
    {
        return $this->resolveCarrier($order);
    }

    private function resolveCarrier(Order $order): ?string
    {
        $code = $order->shippingAddress?->shipping_option;

        if (! $code) {
            return null;
        }

        return ShippingMethod::where('code', $code)->value('driver');
    }

    private function resolveFulfillmentService(Order $order): ?CarrierFulfillmentInterface
    {
        $carrier = $this->resolveCarrier($order);

        if (! $carrier) {
            return null;
        }

        return app(CarrierFulfillmentInterface::class, ['carrier' => $carrier]);
    }
}