package roomescape.reservation.business

import com.github.f4b6a3.tsid.TsidFactory
import io.github.oshai.kotlinlogging.KotlinLogging
import org.springframework.data.jpa.domain.Specification
import org.springframework.data.repository.findByIdOrNull
import org.springframework.stereotype.Service
import org.springframework.transaction.annotation.Transactional
import roomescape.common.config.next
import roomescape.member.business.MemberService
import roomescape.member.infrastructure.persistence.MemberEntity
import roomescape.reservation.exception.ReservationErrorCode
import roomescape.reservation.exception.ReservationException
import roomescape.reservation.infrastructure.persistence.ReservationEntity
import roomescape.reservation.infrastructure.persistence.ReservationRepository
import roomescape.reservation.infrastructure.persistence.ReservationSearchSpecification
import roomescape.reservation.infrastructure.persistence.ReservationStatus
import roomescape.reservation.web.*
import roomescape.theme.business.ThemeService
import roomescape.theme.infrastructure.persistence.ThemeEntity
import roomescape.time.business.TimeService
import roomescape.time.infrastructure.persistence.TimeEntity
import java.time.LocalDate
import java.time.LocalDateTime

private val log = KotlinLogging.logger {}

@Service
@Transactional
class ReservationService(
    private val tsidFactory: TsidFactory,
    private val reservationRepository: ReservationRepository,
    private val timeService: TimeService,
    private val memberService: MemberService,
    private val themeService: ThemeService,
) {

    @Transactional(readOnly = true)
    fun findReservations(): ReservationRetrieveListResponse {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
            .confirmed()
            .build()
        val reservations = findAllReservationByStatus(spec)
        log.info { "[ReservationService.findReservations] ${reservations.size} 개의 확정 예약 조회 완료" }

        return ReservationRetrieveListResponse(reservations)
    }

    @Transactional(readOnly = true)
    fun findAllWaiting(): ReservationRetrieveListResponse {
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
            .waiting()
            .build()
        val reservations = findAllReservationByStatus(spec)
        log.info { "[ReservationService.findAllWaiting] ${reservations.size} 개의 대기 예약 조회 완료" }

        return ReservationRetrieveListResponse(reservations)
    }

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

    fun deleteReservation(reservationId: Long, memberId: Long) {
        validateIsMemberAdmin(memberId, "deleteReservation")
        log.debug { "[ReservationService.deleteReservation] 예약 삭제 시작: reservationId=$reservationId, memberId=$memberId" }
        reservationRepository.deleteById(reservationId)
        log.info { "[ReservationService.deleteReservation] 예약 삭제 완료: reservationId=$reservationId" }
    }

    fun createConfirmedReservation(
        request: ReservationCreateWithPaymentRequest,
        memberId: Long,
    ): ReservationEntity {
        val themeId = request.themeId
        val timeId = request.timeId
        val date: LocalDate = request.date
        validateIsReservationExist(themeId, timeId, date, "createConfirmedReservation")

        log.debug { "[ReservationService.createConfirmedReservation] 예약 추가 시작: memberId=$memberId, themeId=${request.themeId}, timeId=${request.timeId}, date=${request.date}" }
        val reservation: ReservationEntity =
            createEntity(timeId, themeId, date, memberId, ReservationStatus.CONFIRMED)

        return reservationRepository.save(reservation)
            .also { log.info { "[ReservationService.createConfirmedReservation] 예약 추가 완료: reservationId=${it.id}, status=${it.status}" } }
    }

    fun createReservationByAdmin(request: AdminReservationCreateRequest): ReservationRetrieveResponse {
        validateIsReservationExist(request.themeId, request.timeId, request.date)

        log.debug { "[ReservationService.createReservationByAdmin] 관리자의 예약 추가: memberId=${request.memberId}, themeId=${request.themeId}, timeId=${request.timeId}, date=${request.date}" }
        return addReservationWithoutPayment(
            request.themeId,
            request.timeId,
            request.date,
            request.memberId,
            ReservationStatus.CONFIRMED_PAYMENT_REQUIRED
        ).also {
            log.info { "[ReservationService.createReservationByAdmin] 관리자 예약 추가 완료: reservationId=${it.id}" }
        }
    }

    fun createWaiting(request: WaitingCreateRequest, memberId: Long): ReservationRetrieveResponse {
        validateMemberAlreadyReserve(request.themeId, request.timeId, request.date, memberId)
        log.debug { "[ReservationService.createWaiting] 예약 대기 추가 시작: memberId=$memberId, themeId=${request.themeId}, timeId=${request.timeId}, date=${request.date}" }
        return addReservationWithoutPayment(
            request.themeId,
            request.timeId,
            request.date,
            memberId,
            ReservationStatus.WAITING
        ).also {
            log.info { "[ReservationService.createWaiting] 예약 대기 추가 완료: reservationId=${it.id}, status=${it.status}" }
        }
    }

    private fun addReservationWithoutPayment(
        themeId: Long,
        timeId: Long,
        date: LocalDate,
        memberId: Long,
        status: ReservationStatus,
    ): ReservationRetrieveResponse = createEntity(timeId, themeId, date, memberId, status)
        .also {
            reservationRepository.save(it)
        }.toRetrieveResponse()

    private fun validateMemberAlreadyReserve(themeId: Long, timeId: Long, date: LocalDate, memberId: Long) {
        log.debug {
            "[ReservationService.validateMemberAlreadyReserve] 회원의 중복 예약 여부 확인: themeId=$themeId, timeId=$timeId, date=$date, memberId=$memberId"
        }
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
            .sameMemberId(memberId)
            .sameThemeId(themeId)
            .sameTimeId(timeId)
            .sameDate(date)
            .build()

        if (reservationRepository.exists(spec)) {
            log.warn { "[ReservationService.validateMemberAlreadyReserve] 중복된 예약 존재: themeId=$themeId, timeId=$timeId, date=$date" }
            throw ReservationException(ReservationErrorCode.ALREADY_RESERVE)
        }
    }

    private fun validateIsReservationExist(
        themeId: Long,
        timeId: Long,
        date: LocalDate,
        calledBy: String = "validateIsReservationExist"
    ) {
        log.debug {
            "[ReservationService.$calledBy] 예약 존재 여부 확인: themeId=$themeId, timeId=$timeId, date=$date"
        }
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
            .confirmed()
            .sameThemeId(themeId)
            .sameTimeId(timeId)
            .sameDate(date)
            .build()

        if (reservationRepository.exists(spec)) {
            log.warn { "[ReservationService.$calledBy] 중복된 예약 존재: themeId=$themeId, timeId=$timeId, date=$date" }
            throw ReservationException(ReservationErrorCode.RESERVATION_DUPLICATED)
        }
    }

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

        if (request.isBefore(now)) {
            log.info { "[ReservationService.validateDateAndTime] 날짜 범위 오류. request=$request, now=$now" }
            throw ReservationException(ReservationErrorCode.PAST_REQUEST_DATETIME)
        }
    }

    private fun createEntity(
        timeId: Long,
        themeId: Long,
        date: LocalDate,
        memberId: Long,
        status: ReservationStatus,
    ): ReservationEntity {
        val time: TimeEntity = timeService.findById(timeId)
        val theme: ThemeEntity = themeService.findById(themeId)
        val member: MemberEntity = memberService.findById(memberId)

        validateDateAndTime(date, time)

        return ReservationEntity(
            _id = tsidFactory.next(),
            date = date,
            time = time,
            theme = theme,
            member = member,
            status = status
        )
    }

    @Transactional(readOnly = true)
    fun searchReservations(
        themeId: Long?,
        memberId: Long?,
        dateFrom: LocalDate?,
        dateTo: LocalDate?,
    ): ReservationRetrieveListResponse {
        log.debug { "[ReservationService.searchReservations] 예약 검색 시작: themeId=$themeId, memberId=$memberId, dateFrom=$dateFrom, dateTo=$dateTo" }
        validateSearchDateRange(dateFrom, dateTo)
        val spec: Specification<ReservationEntity> = ReservationSearchSpecification()
            .confirmed()
            .sameThemeId(themeId)
            .sameMemberId(memberId)
            .dateStartFrom(dateFrom)
            .dateEndAt(dateTo)
            .build()
        val reservations = findAllReservationByStatus(spec)

        return ReservationRetrieveListResponse(reservations)
            .also { log.info { "[ReservationService.searchReservations] 예약 ${reservations.size}개 조회 완료: themeId=$themeId, memberId=$memberId, dateFrom=$dateFrom, dateTo=$dateTo" } }
    }

    private fun validateSearchDateRange(startFrom: LocalDate?, endAt: LocalDate?) {
        if (startFrom == null || endAt == null) {
            return
        }
        if (startFrom.isAfter(endAt)) {
            log.info { "[ReservationService.validateSearchDateRange] 조회 범위 오류: startFrom=$startFrom, endAt=$endAt" }
            throw ReservationException(ReservationErrorCode.INVALID_SEARCH_DATE_RANGE)
        }
    }

    @Transactional(readOnly = true)
    fun findReservationsByMemberId(memberId: Long): MyReservationRetrieveListResponse {
        val reservations = reservationRepository.findAllByMemberId(memberId)
        log.info { "[ReservationService.findReservationsByMemberId] memberId=${memberId}인  ${reservations.size}개의 예약 조회 완료" }
        return MyReservationRetrieveListResponse(reservations)
    }

    fun confirmWaiting(reservationId: Long, memberId: Long) {
        log.debug { "[ReservationService.confirmWaiting] 대기 예약 승인 시작: reservationId=$reservationId (by adminId=$memberId)" }
        validateIsMemberAdmin(memberId, "confirmWaiting")

        log.debug { "[ReservationService.confirmWaiting] 대기 여부 확인 시작: reservationId=$reservationId" }
        if (reservationRepository.isExistConfirmedReservation(reservationId)) {
            log.warn { "[ReservationService.confirmWaiting] 승인 실패(이미 확정된 예약 존재): reservationId=$reservationId" }
            throw ReservationException(ReservationErrorCode.CONFIRMED_RESERVATION_ALREADY_EXISTS)
        }

        log.debug { "[ReservationService.confirmWaiting] 대기 예약 상태 변경 시작: reservationId=$reservationId" }
        reservationRepository.updateStatusByReservationId(reservationId, ReservationStatus.CONFIRMED_PAYMENT_REQUIRED)
        log.debug { "[ReservationService.confirmWaiting] 대기 예약 상태 변경 완료: reservationId=$reservationId, status=${ReservationStatus.CONFIRMED_PAYMENT_REQUIRED}" }

        log.info { "[ReservationService.confirmWaiting] 대기 예약 승인 완료: reservationId=$reservationId" }
    }

    fun deleteWaiting(reservationId: Long, memberId: Long) {
        log.debug { "[ReservationService.deleteWaiting] 대기 취소 시작: reservationId=$reservationId, memberId=$memberId" }

        val reservation: ReservationEntity = findReservationOrThrow(reservationId, "deleteWaiting")
        if (!reservation.isWaiting()) {
            log.warn {
                "[ReservationService.deleteWaiting] 대기 취소 실패(대기 예약이 아님): reservationId=$reservationId" +
                        ", currentStatus=${reservation.status} memberId=$memberId"
            }
            throw ReservationException(ReservationErrorCode.ALREADY_CONFIRMED)
        }
        if (!reservation.isReservedBy(memberId)) {
            log.error {
                "[ReservationService.deleteWaiting] 대기 취소 실패(예약자 본인의 취소 요청이 아님): reservationId=$reservationId" +
                        ", memberId=$memberId "
            }
            throw ReservationException(ReservationErrorCode.NOT_RESERVATION_OWNER)
        }
        log.debug { "[ReservationService.deleteWaiting] 대기 예약 삭제 시작: reservationId=$reservationId" }
        reservationRepository.delete(reservation)

        log.info { "[ReservationService.deleteWaiting] 대기 취소 완료: reservationId=$reservationId, memberId=$memberId" }
    }

    fun rejectWaiting(reservationId: Long, memberId: Long) {
        validateIsMemberAdmin(memberId, "rejectWaiting")
        log.debug { "[ReservationService.rejectWaiting] 대기 예약 삭제 시작: reservationId=$reservationId (by adminId=$memberId)" }
        val reservation: ReservationEntity = findReservationOrThrow(reservationId, "rejectWaiting")

        if (!reservation.isWaiting()) {
            log.warn {
                "[ReservationService.rejectWaiting] 대기 예약 삭제 실패(이미 확정 상태): reservationId=$reservationId" +
                        ", status=${reservation.status}"
            }
            throw ReservationException(ReservationErrorCode.ALREADY_CONFIRMED)
        }
        reservationRepository.delete(reservation)
        log.info { "[ReservationService.rejectWaiting] 대기 예약 삭제 완료: reservationId=$reservationId" }
    }

    private fun validateIsMemberAdmin(memberId: Long, calledBy: String = "validateIsMemberAdmin") {
        log.debug { "[ReservationService.$calledBy] 관리자 여부 확인: memberId=$memberId" }
        val member: MemberEntity = memberService.findById(memberId)
        if (member.isAdmin()) {
            return
        }
        log.warn { "[ReservationService.$calledBy] 관리자가 아님: memberId=$memberId, role=${member.role}" }
        throw ReservationException(ReservationErrorCode.NO_PERMISSION)
    }

    private fun findReservationOrThrow(
        reservationId: Long,
        calledBy: String = "findReservationOrThrow"
    ): ReservationEntity {
        log.debug { "[ReservationService.$calledBy] 예약 조회: reservationId=$reservationId" }
        return reservationRepository.findByIdOrNull(reservationId)
            ?.also { log.info { "[ReservationService.$calledBy] 예약 조회 완료: reservationId=$reservationId" } }
            ?: run {
                log.warn { "[ReservationService.$calledBy] 예약 조회 실패: reservationId=$reservationId" }
                throw ReservationException(ReservationErrorCode.RESERVATION_NOT_FOUND)
            }

    }
}