<?php

declare(strict_types=1);

namespace App\Service;

use App\Exception\BookingSessionNotFoundException;
use App\Exception\HotelNotInTravelException;
use App\Exception\TravelNotFoundException;
use App\Form\Model\BookingDto;
use Symfony\Component\HttpFoundation\Request;

/**
 * Owns booking-flow session state.
 *
 * This service keeps the HTTP session concerns separate from booking
 * orchestration and pricing logic. It handles DTO persistence, baseline
 * room snapshots, and return URL storage for the booking create/edit flows.
 */
class BookingSessionManager
{
    public const BOOKING_CREATE_KEY = 'booking_create';
    public const BOOKING_CREATE_BASELINE_KEY = 'booking_create_baseline_snapshot';
    public const BOOKING_CREATE_AVAILABILITY_REFRESHED_AT_KEY = 'booking_create_availability_refreshed_at';
    public const BOOKING_EDIT_KEY = 'booking_edit';
    public const RETURN_URL_KEY = 'booking_return_url';
    public const DEFAULT_RETURN_URL = 'https://www.ep-reisen.de';
    private const CREATE_AVAILABILITY_REFRESH_INTERVAL = 600;

    public function __construct(
        private readonly TravelDataProvider $travelDataService,
    ) {
    }

    /**
     * Retrieves the booking creation DTO from the session.
     *
     * @throws BookingSessionNotFoundException
     * @throws TravelNotFoundException
     * @throws HotelNotInTravelException
     */
    public function getOrCreateBookingCreateDto(Request $request): BookingDto
    {
        $bookingDto = $this->getBookingDto($request, BookingDto::MODE_CREATE);

        if (null !== $bookingDto) {
            return $bookingDto;
        }

        throw new BookingSessionNotFoundException();
    }

    /**
     * Gets or creates the baseline room selection snapshot for change detection.
     *
     * @return array<int, array{int, int, float}>
     */
    public function getOrCreateBaselineSnapshot(Request $request, BookingDto $bookingCreateDto): array
    {
        $baselineKey = self::BOOKING_CREATE_BASELINE_KEY;

        if (!$request->getSession()->has($baselineKey) || $request->query->has('reset_baseline')) {
            return $this->saveBaselineSnapshot($request, $bookingCreateDto);
        }

        return $request->getSession()->get($baselineKey);
    }

    /**
     * Stores the current room selection snapshot in the session.
     *
     * @return array<int, array{int, int, float}>
     */
    public function saveBaselineSnapshot(Request $request, BookingDto $bookingCreateDto): array
    {
        $baseline = $bookingCreateDto->createRoomSelectionSnapshot();
        $request->getSession()->set(self::BOOKING_CREATE_BASELINE_KEY, $baseline);

        return $baseline;
    }

    /**
     * Clears the baseline snapshot from the session.
     */
    public function clearBaselineSnapshot(Request $request): void
    {
        $request->getSession()->remove(self::BOOKING_CREATE_BASELINE_KEY);
    }

    /**
     * Saves the booking DTO to the session.
     */
    public function saveBookingDto(Request $request, BookingDto $bookingDto, string $mode): void
    {
        $sessionKey = $this->getSessionKey($mode);
        $request->getSession()->set($sessionKey, $bookingDto);
    }

    /**
     * Retrieves the booking DTO from the session and restores the Travel object.
     */
    public function getBookingDto(Request $request, string $mode): ?BookingDto
    {
        $sessionKey = $this->getSessionKey($mode);
        $session = $request->getSession();

        if (false === $session->has($sessionKey)) {
            return null;
        }

        $bookingDto = $session->get($sessionKey);
        $shouldCheck = BookingDto::MODE_CREATE === $mode && $this->shouldRefreshCreateAvailability($request);
        $hydrated = $this->hydrate($bookingDto, $shouldCheck);

        if (BookingDto::MODE_CREATE === $mode && true === $shouldCheck && true === $hydrated) {
            $this->markCreateAvailabilityRefreshed($request);
        }

        return $bookingDto;
    }

    /**
     * Clears the booking DTO from the session.
     */
    public function clearBookingDto(Request $request, string $mode): void
    {
        $sessionKey = $this->getSessionKey($mode);
        $request->getSession()->remove($sessionKey);
    }

    public function refreshCreateAvailability(
        Request $request,
        BookingDto $bookingDto,
        bool $forceRefresh = false,
    ): BookingAvailabilityRefreshResult {
        $beforeSnapshot = $bookingDto->createRoomSelectionSnapshot();
        $availabilityRefreshed = $this->travelDataService->enrichWithFreshAvailabilities(
            $bookingDto->travel,
            true,
            $forceRefresh,
            refreshRooms: true,
        );
        $roomSelectionQuantityReset = $bookingDto->syncRoomSelectionsWithAvailableRooms();
        $afterSnapshot = $bookingDto->createRoomSelectionSnapshot();

        if (true === $roomSelectionQuantityReset) {
            $bookingDto->resetParticipantAssignments();
        }

        $this->saveBookingDto($request, $bookingDto, BookingDto::MODE_CREATE);

        if (true === $forceRefresh && true === $availabilityRefreshed) {
            $this->markCreateAvailabilityRefreshed($request);
        }

        return new BookingAvailabilityRefreshResult(
            availabilityRefreshed: $availabilityRefreshed,
            roomSelectionQuantityReset: $roomSelectionQuantityReset,
            roomSelectionSnapshotChanged: $beforeSnapshot !== $afterSnapshot,
            hasAvailableRooms: [] !== $bookingDto->travel->getAvailableRooms(),
        );
    }

    /**
     * Clears all booking-related session data except the return URL.
     */
    public function clearBookingSession(Request $request): void
    {
        $session = $request->getSession();
        $session->remove(self::BOOKING_CREATE_KEY);
        $session->remove(self::BOOKING_CREATE_BASELINE_KEY);
        $session->remove(self::BOOKING_CREATE_AVAILABILITY_REFRESHED_AT_KEY);
    }

    /**
     * Stores the return URL in the session.
     */
    public function storeReturnUrl(Request $request, ?string $returnUrl): void
    {
        $url = self::DEFAULT_RETURN_URL;

        if (null !== $returnUrl && '' !== trim($returnUrl)) {
            if (false !== filter_var($returnUrl, \FILTER_VALIDATE_URL)
                && 1 === preg_match('#^https?://#i', $returnUrl)) {
                $url = $returnUrl;
            }
        }

        $request->getSession()->set(self::RETURN_URL_KEY, $url);
    }

    /**
     * Retrieves the return URL from the session.
     */
    public function getReturnUrl(Request $request): string
    {
        return $request->getSession()->get(self::RETURN_URL_KEY, self::DEFAULT_RETURN_URL);
    }

    private function getSessionKey(string $mode): string
    {
        return BookingDto::MODE_EDIT === $mode ? self::BOOKING_EDIT_KEY : self::BOOKING_CREATE_KEY;
    }

    /**
     * Restores the full Travel object after session deserialization.
     */
    public function markCreateAvailabilityRefreshed(Request $request): void
    {
        $request->getSession()->set(self::BOOKING_CREATE_AVAILABILITY_REFRESHED_AT_KEY, time());
    }

    private function shouldRefreshCreateAvailability(Request $request): bool
    {
        $lastRefreshedAt = (int) $request->getSession()->get(self::BOOKING_CREATE_AVAILABILITY_REFRESHED_AT_KEY, 0);

        return 0 === $lastRefreshedAt
            || (time() - $lastRefreshedAt) >= self::CREATE_AVAILABILITY_REFRESH_INTERVAL;
    }

    private function hydrate(BookingDto $bookingDto, bool $forceRefresh = false): bool
    {
        $travel = $this->travelDataService->getTravelData(
            $bookingDto->travel->id,
            $bookingDto->hotelId
        );

        if (null === $travel) {
            return false;
        }

        $availabilityRefreshed = $this->travelDataService->enrichWithFreshAvailabilities($travel, true, $forceRefresh, refreshRooms: true);
        $bookingDto->travel = $travel;

        if (null !== $bookingDto->booking) {
            $bookingDto->booking->travelData = $travel;
        }

        return $availabilityRefreshed;
    }
}