package com.tcm.training.admin.member.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.tcm.training.admin.app.notice.service.AppSystemNoticeDispatchCommand;
import com.tcm.training.admin.app.notice.service.AppSystemNoticeDispatchService;
import com.tcm.training.admin.app.notice.service.AppSystemNoticeType;
import com.tcm.training.admin.member.entity.AppUser;
import com.tcm.training.admin.member.mapper.UserMapper;
import com.tcm.training.admin.system.entity.SystemSettings;
import com.tcm.training.admin.system.mapper.SystemSettingsMapper;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

import java.time.LocalDateTime;
import java.time.temporal.ChronoUnit;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * 会员到期提醒分发服务。
 */
@Service
public class MemberExpireRemindDispatchService {

    private final UserMapper userMapper;
    private final SystemSettingsMapper systemSettingsMapper;
    private final AppSystemNoticeDispatchService appSystemNoticeDispatchService;

    /**
     * 注入会员到期提醒分发所需依赖。
     */
    public MemberExpireRemindDispatchService(UserMapper userMapper,
                                             SystemSettingsMapper systemSettingsMapper,
                                             AppSystemNoticeDispatchService appSystemNoticeDispatchService) {
        this.userMapper = userMapper;
        this.systemSettingsMapper = systemSettingsMapper;
        this.appSystemNoticeDispatchService = appSystemNoticeDispatchService;
    }

    /**
     * 定时扫描即将到期的会员，并按系统设置发放提醒通知。
     */
    @Scheduled(fixedDelayString = "${app.member.expire-remind-interval-ms:3600000}")
    public void dispatchMemberExpireReminds() {
        Integer remindDays = resolveRemindDays();
        if (remindDays == null || remindDays.intValue() < 0) {
            return;
        }
        LocalDateTime now = LocalDateTime.now();
        LocalDateTime deadline = now.plusDays(remindDays.longValue());
        List<AppUser> users = userMapper.selectList(new LambdaQueryWrapper<AppUser>()
                .eq(AppUser::getDeleted, 0)
                .eq(AppUser::getStatus, 1)
                .isNotNull(AppUser::getMemberExpireAt)
                .ge(AppUser::getMemberExpireAt, now)
                .le(AppUser::getMemberExpireAt, deadline)
                .orderByAsc(AppUser::getMemberExpireAt)
                .orderByAsc(AppUser::getId));
        for (AppUser user : users) {
            dispatchMemberExpireNotice(user, now);
        }
    }

    /**
     * 为单个即将到期会员发放系统通知。
     */
    private void dispatchMemberExpireNotice(AppUser user, LocalDateTime now) {
        if (user == null || user.getId() == null || user.getMemberExpireAt() == null) {
            return;
        }
        long days = ChronoUnit.DAYS.between(now.toLocalDate(), user.getMemberExpireAt().toLocalDate());
        AppSystemNoticeDispatchCommand command = new AppSystemNoticeDispatchCommand();
        command.setAppUserId(user.getId());
        command.setNoticeTypeCode(AppSystemNoticeType.MEMBER_EXPIRE_REMIND);
        command.setTitle("会员到期提醒");
        command.setContent("您的会员有效期将于" + user.getMemberExpireAt().toLocalDate() + "到期");
        // 这里把到期时间编码进引用类型，保证同一到期批次只提醒一次。
        command.setReferenceType("MEMBER_EXPIRE_" + user.getMemberExpireAt().toLocalDate());
        command.setReferenceId(user.getId());
        command.setRequireUserSetting(Boolean.FALSE);
        Map<String, String> payload = new LinkedHashMap<String, String>();
        payload.put("expireAt", String.valueOf(user.getMemberExpireAt()));
        payload.put("remainingDays", String.valueOf(days));
        command.setPayload(payload);
        appSystemNoticeDispatchService.createAndPush(command);
    }

    /**
     * 获取系统配置的会员到期提醒天数。
     */
    private Integer resolveRemindDays() {
        SystemSettings settings = systemSettingsMapper.selectOne(new LambdaQueryWrapper<SystemSettings>()
                .eq(SystemSettings::getDeleted, 0)
                .orderByDesc(SystemSettings::getId)
                .last("limit 1"));
        return settings == null ? null : settings.getMemberExpireRemindDays();
    }
}