package com.tourguide.modules.system.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.tourguide.common.exception.BusinessException;
import com.tourguide.modules.system.dto.GuideNotificationResponse;
import com.tourguide.modules.system.entity.GuideNoticeRead;
import com.tourguide.modules.system.entity.GuideNotification;
import com.tourguide.modules.system.entity.SystemNotice;
import com.tourguide.modules.system.mapper.GuideNotificationMapper;
import com.tourguide.modules.system.mapper.GuideNoticeReadMapper;
import com.tourguide.modules.system.mapper.SystemNoticeMapper;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

@Service
public class GuideNotificationService {
    private final SystemNoticeMapper noticeMapper;
    private final GuideNoticeReadMapper readMapper;
    private final GuideNotificationMapper guideNotificationMapper;

    public GuideNotificationService(SystemNoticeMapper noticeMapper, GuideNoticeReadMapper readMapper,
                                    GuideNotificationMapper guideNotificationMapper) {
        this.noticeMapper = noticeMapper;
        this.readMapper = readMapper;
        this.guideNotificationMapper = guideNotificationMapper;
    }

    public long unreadCount(Long guideId) {
        List<SystemNotice> notices = publishedNotices();
        if (notices.isEmpty()) return 0L;
        Set<Long> readIds = readNoticeIds(guideId, notices);
        long systemUnread = notices.stream().filter(notice -> !readIds.contains(notice.getId())).count();
        Long personalUnread = guideNotificationMapper.selectCount(new LambdaQueryWrapper<GuideNotification>()
                .eq(GuideNotification::getGuideId, guideId)
                .isNull(GuideNotification::getReadAt));
        return systemUnread + personalUnread;
    }

    public List<GuideNotificationResponse> list(Long guideId) {
        List<SystemNotice> notices = publishedNotices();
        Set<Long> readIds = readNoticeIds(guideId, notices);
        List<GuideNotificationResponse> responses = notices.stream()
                .map(notice -> new GuideNotificationResponse(notice, readIds.contains(notice.getId())))
                .collect(Collectors.toList());
        responses.addAll(guideNotificationMapper.selectList(new LambdaQueryWrapper<GuideNotification>()
                        .eq(GuideNotification::getGuideId, guideId)
                        .orderByDesc(GuideNotification::getCreatedAt))
                .stream().map(GuideNotificationResponse::new).collect(Collectors.toList()));
        responses.sort(Comparator.comparing(GuideNotificationResponse::getTime,
                Comparator.nullsLast(Comparator.reverseOrder())));
        return responses;
    }

    public void markRead(Long guideId, String notificationId) {
        if (notificationId != null && notificationId.startsWith("guide:")) {
            markPersonalRead(guideId, parseId(notificationId, "guide:"));
            return;
        }
        Long noticeId = parseId(notificationId, "system:");
        SystemNotice notice = noticeMapper.selectOne(new LambdaQueryWrapper<SystemNotice>()
                .eq(SystemNotice::getId, noticeId)
                .eq(SystemNotice::getStatus, 1)
                .last("LIMIT 1"));
        if (notice == null) throw new BusinessException(404, "Notification not found");
        Long count = readMapper.selectCount(new LambdaQueryWrapper<GuideNoticeRead>()
                .eq(GuideNoticeRead::getGuideId, guideId)
                .eq(GuideNoticeRead::getNoticeId, noticeId));
        if (count > 0) return;
        GuideNoticeRead read = new GuideNoticeRead();
        read.setGuideId(guideId);
        read.setNoticeId(noticeId);
        read.setReadAt(LocalDateTime.now());
        readMapper.insert(read);
    }

    public void notifyOrderAssigned(com.tourguide.modules.order.entity.TourOrder order) {
        if (order == null || order.getGuideId() == null) return;
        create(order.getGuideId(), "ORDER_ASSIGNED", "接单提醒", "您有一个新的讲解订单，请查看",
                order.getId(), "/pages/order-detail/index?id=" + order.getId());
    }

    public void notifyOrderCancelled(com.tourguide.modules.order.entity.TourOrder order) {
        if (order == null || order.getGuideId() == null) return;
        create(order.getGuideId(), "ORDER_CANCELLED", "取消提醒", "您有一个被取消的讲解订单，请查看",
                order.getId(), "/pages/order-detail/index?id=" + order.getId());
    }

    public void notifyAuditResult(Long guideId, boolean approved) {
        create(guideId, approved ? "AUDIT_APPROVED" : "AUDIT_REJECTED", "【名导精讲】",
                approved ? "您的资料审核已通过，请前往应用查看。" : "您的资料审核未通过，请前往应用更新提交。",
                null, null);
    }

    private void create(Long guideId, String type, String title, String content, Long orderId, String targetUrl) {
        if (guideId == null) return;
        GuideNotification notification = new GuideNotification();
        notification.setGuideId(guideId);
        notification.setNotificationType(type);
        notification.setTitle(title);
        notification.setContent(content);
        notification.setOrderId(orderId);
        notification.setTargetUrl(targetUrl);
        notification.setCreatedAt(LocalDateTime.now());
        guideNotificationMapper.insert(notification);
    }

    private void markPersonalRead(Long guideId, Long notificationId) {
        GuideNotification notification = guideNotificationMapper.selectOne(new LambdaQueryWrapper<GuideNotification>()
                .eq(GuideNotification::getId, notificationId)
                .eq(GuideNotification::getGuideId, guideId)
                .last("LIMIT 1"));
        if (notification == null) throw new BusinessException(404, "Notification not found");
        if (notification.getReadAt() != null) return;
        notification.setReadAt(LocalDateTime.now());
        guideNotificationMapper.updateById(notification);
    }

    private Long parseId(String value, String prefix) {
        String raw = value == null ? "" : value;
        if (raw.startsWith(prefix)) raw = raw.substring(prefix.length());
        try {
            return Long.valueOf(raw);
        } catch (NumberFormatException exception) {
            throw new BusinessException(400, "Notification id is invalid");
        }
    }

    private List<SystemNotice> publishedNotices() {
        return noticeMapper.selectList(new LambdaQueryWrapper<SystemNotice>()
                .eq(SystemNotice::getStatus, 1)
                .isNotNull(SystemNotice::getPublishTime)
                .le(SystemNotice::getPublishTime, LocalDateTime.now())
                .orderByDesc(SystemNotice::getPublishTime));
    }

    private Set<Long> readNoticeIds(Long guideId, List<SystemNotice> notices) {
        if (notices.isEmpty()) return Collections.emptySet();
        List<Long> noticeIds = notices.stream().map(SystemNotice::getId).collect(Collectors.toList());
        return readMapper.selectList(new LambdaQueryWrapper<GuideNoticeRead>()
                        .eq(GuideNoticeRead::getGuideId, guideId)
                        .in(GuideNoticeRead::getNoticeId, noticeIds))
                .stream().map(GuideNoticeRead::getNoticeId).collect(Collectors.toSet());
    }
}