package roomescape.reservation.business

import org.springframework.data.jpa.domain.Specification
import org.springframework.data.repository.findByIdOrNull
import org.springframework.http.HttpStatus
import org.springframework.stereotype.Service
import org.springframework.transaction.annotation.Transactional
import roomescape.common.exception.ErrorType
import roomescape.common.exception.RoomescapeException
import roomescape.member.business.MemberService
import roomescape.reservation.infrastructure.persistence.*
import roomescape.reservation.web.*
import roomescape.theme.business.ThemeService
import java.time.LocalDate
import java.time.LocalDateTime

@Service
@Transactional
class ReservationService(
        private val reservationRepository: ReservationRepository,
        private val reservationTimeService: ReservationTimeService,
        private val memberService: MemberService,
        private val themeService: ThemeService,
) {

    @Transactional(readOnly = true)
    fun findAllReservations(): ReservationsResponse {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
                .confirmed()
                .build()


        return ReservationsResponse(findAllReservationByStatus(spec))
    }

    @Transactional(readOnly = true)
    fun findAllWaiting(): ReservationsResponse {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
                .waiting()
                .build()

        return ReservationsResponse(findAllReservationByStatus(spec))
    }

    private fun findAllReservationByStatus(spec: Specification<ReservationEntity>): List<ReservationResponse> {
        return reservationRepository.findAll(spec).map { it.toResponse() }
    }

    fun removeReservationById(reservationId: Long, memberId: Long) {
        validateIsMemberAdmin(memberId)
        reservationRepository.deleteById(reservationId)
    }

    fun addReservation(request: ReservationRequest, memberId: Long): ReservationEntity {
        validateIsReservationExist(request.themeId, request.timeId, request.date)
        return getReservationForSave(
                request.timeId,
                request.themeId,
                request.date,
                memberId,
                ReservationStatus.CONFIRMED
        ).also {
            reservationRepository.save(it)
        }
    }

    fun addReservationByAdmin(request: AdminReservationRequest): ReservationResponse {
        validateIsReservationExist(request.themeId, request.timeId, request.date)

        return addReservationWithoutPayment(
                request.themeId,
                request.timeId,
                request.date,
                request.memberId,
                ReservationStatus.CONFIRMED_PAYMENT_REQUIRED
        )
    }

    fun addWaiting(request: WaitingRequest, memberId: Long): ReservationResponse {
        validateMemberAlreadyReserve(request.themeId, request.timeId, request.date, memberId)
        return addReservationWithoutPayment(
                request.themeId,
                request.timeId,
                request.date,
                memberId,
                ReservationStatus.WAITING
        )
    }

    private fun addReservationWithoutPayment(
            themeId: Long,
            timeId: Long,
            date: LocalDate,
            memberId: Long,
            status: ReservationStatus
    ): ReservationResponse = getReservationForSave(timeId, themeId, date, memberId, status)
            .also {
                reservationRepository.save(it)
            }.toResponse()


    private fun validateMemberAlreadyReserve(themeId: Long?, timeId: Long?, date: LocalDate?, memberId: Long?) {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
                .sameMemberId(memberId)
                .sameThemeId(themeId)
                .sameTimeId(timeId)
                .sameDate(date)
                .build()

        if (reservationRepository.exists(spec)) {
            throw RoomescapeException(ErrorType.HAS_RESERVATION_OR_WAITING, HttpStatus.BAD_REQUEST)
        }
    }

    private fun validateIsReservationExist(themeId: Long, timeId: Long, date: LocalDate) {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
                .confirmed()
                .sameThemeId(themeId)
                .sameTimeId(timeId)
                .sameDate(date)
                .build()

        if (reservationRepository.exists(spec)) {
            throw RoomescapeException(ErrorType.RESERVATION_DUPLICATED, HttpStatus.CONFLICT)
        }
    }

    private fun validateDateAndTime(
            requestDate: LocalDate,
            requestReservationTime: ReservationTimeEntity
    ) {
        val now = LocalDateTime.now()
        val request = LocalDateTime.of(requestDate, requestReservationTime.startAt)

        if (request.isBefore(now)) {
            throw RoomescapeException(
                    ErrorType.RESERVATION_PERIOD_IN_PAST,
                    "[now: $now | request: $request]",
                    HttpStatus.BAD_REQUEST
            )
        }
    }

    private fun getReservationForSave(
            timeId: Long,
            themeId: Long,
            date: LocalDate,
            memberId: Long,
            status: ReservationStatus
    ): ReservationEntity {
        val time = reservationTimeService.findTimeById(timeId)
        val theme = themeService.findById(themeId)
        val member = memberService.findById(memberId)

        validateDateAndTime(date, time)

        return ReservationEntity(
                date = date,
                reservationTime = time,
                theme = theme,
                member = member,
                reservationStatus = status
        )
    }

    @Transactional(readOnly = true)
    fun findFilteredReservations(
            themeId: Long?,
            memberId: Long?,
            dateFrom: LocalDate?,
            dateTo: LocalDate?
    ): ReservationsResponse {
        validateDateForSearch(dateFrom, dateTo)
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
                .confirmed()
                .sameThemeId(themeId)
                .sameMemberId(memberId)
                .dateStartFrom(dateFrom)
                .dateEndAt(dateTo)
                .build()

        return ReservationsResponse(findAllReservationByStatus(spec))
    }

    private fun validateDateForSearch(startFrom: LocalDate?, endAt: LocalDate?) {
        if (startFrom == null || endAt == null) {
            return
        }
        if (startFrom.isAfter(endAt)) {
            throw RoomescapeException(
                    ErrorType.INVALID_DATE_RANGE,
                    "[startFrom: $startFrom, endAt: $endAt", HttpStatus.BAD_REQUEST
            )
        }
    }

    @Transactional(readOnly = true)
    fun findMemberReservations(memberId: Long): MyReservationsResponse {
        return MyReservationsResponse(reservationRepository.findMyReservations(memberId))
    }

    fun approveWaiting(reservationId: Long, memberId: Long) {
        validateIsMemberAdmin(memberId)
        if (reservationRepository.isExistConfirmedReservation(reservationId)) {
            throw RoomescapeException(ErrorType.RESERVATION_DUPLICATED, HttpStatus.CONFLICT)
        }
        reservationRepository.updateStatusByReservationId(reservationId, ReservationStatus.CONFIRMED_PAYMENT_REQUIRED)
    }

    fun cancelWaiting(reservationId: Long, memberId: Long) {
        reservationRepository.findByIdOrNull(reservationId)?.takeIf {
            it.isWaiting() && it.isSameMember(memberId)
        }?.let {
            reservationRepository.delete(it)
        } ?: throw throwReservationNotFound(reservationId)
    }

    fun denyWaiting(reservationId: Long, memberId: Long) {
        validateIsMemberAdmin(memberId)
        reservationRepository.findByIdOrNull(reservationId)?.takeIf {
            it.isWaiting()
        }?.let {
            reservationRepository.delete(it)
        } ?: throw throwReservationNotFound(reservationId)
    }

    private fun validateIsMemberAdmin(memberId: Long) {
        memberService.findById(memberId).takeIf {
            it.isAdmin()
        } ?: throw RoomescapeException(
                ErrorType.PERMISSION_DOES_NOT_EXIST,
                "[memberId: $memberId]",
                HttpStatus.FORBIDDEN
        )
    }

    private fun throwReservationNotFound(reservationId: Long?): RoomescapeException {
        return RoomescapeException(
                ErrorType.RESERVATION_NOT_FOUND,
                "[reservationId: $reservationId]",
                HttpStatus.NOT_FOUND
        )
    }
}