package com.tourguide.modules.order.service;

import com.tourguide.modules.order.mapper.TourOrderMapper;
import com.tourguide.modules.order.entity.TourOrder;
import com.tourguide.modules.user.entity.GuideReceivingSession;
import com.tourguide.modules.user.mapper.GuideRealtimeStatusMapper;
import com.tourguide.modules.user.mapper.GuideReceivingSessionMapper;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.time.LocalDateTime;

@Service
public class GuideSessionTransitionService {
    private final GuideReceivingSessionMapper sessionMapper;
    private final TourOrderMapper orderMapper;
    private final GuideRealtimeStatusMapper realtimeStatusMapper;

    public GuideSessionTransitionService(GuideReceivingSessionMapper sessionMapper,
                                         TourOrderMapper orderMapper,
                                         GuideRealtimeStatusMapper realtimeStatusMapper) {
        this.sessionMapper = sessionMapper;
        this.orderMapper = orderMapper;
        this.realtimeStatusMapper = realtimeStatusMapper;
    }

    @Transactional
    public void startIfDue(GuideReceivingSession session) {
        if (sessionMapper.startDueSession(session.getId()) != 1) return;
        orderMapper.startSessionOrders(session.getId(), LocalDateTime.now());
        realtimeStatusMapper.disableReceiving(session.getGuideId());
    }

    @Transactional
    public void restoreAfterOrderCancellation(TourOrder order) {
        if (order == null || order.getGuideId() == null || order.getReceivingSessionId() == null) return;

        GuideReceivingSession session = sessionMapper.selectForUpdate(
                order.getReceivingSessionId(), order.getGuideId());
        if (session == null) return;

        long remainingOrders = orderMapper.countPendingMeetingBySession(session.getId(), order.getGuideId());
        if ("PRIVATE".equals(session.getReceivingMode())
                || ("ALL".equals(session.getReceivingMode()) && isPrivateOrder(order))) {
            if (remainingOrders == 0
                    && sessionMapper.reopenPrivateAfterOrderCancellation(session.getId(), order.getGuideId()) == 1) {
                realtimeStatusMapper.enableReceiving(order.getGuideId());
            }
            return;
        }

        if (!("GROUP".equals(session.getReceivingMode())
                || ("ALL".equals(session.getReceivingMode()) && !isPrivateOrder(order)))
                || !"RECEIVING".equals(session.getStatus())) return;
        if (remainingOrders == 0) {
            sessionMapper.resetGroupAfterOrderCancellation(session.getId(), order.getGuideId());
            return;
        }
        int peopleCount = order.getPeopleCount() == null ? 0 : Math.max(0, order.getPeopleCount());
        if (peopleCount > 0) {
            sessionMapper.releaseGroupCapacity(session.getId(), order.getGuideId(), peopleCount);
        }
    }

    private boolean isPrivateOrder(TourOrder order) {
        return order.getOrderType() != null && order.getOrderType().startsWith("PRIVATE_");
    }
}