package com.xuekairui.user.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.xuekairui.common.BusinessException;
import com.xuekairui.common.ErrorCode;
import com.xuekairui.user.dto.GrantMembershipRequest;
import com.xuekairui.user.dto.MembershipBenefitResponse;
import com.xuekairui.user.dto.MembershipResponse;
import com.xuekairui.user.entity.MembershipBenefit;
import com.xuekairui.user.entity.User;
import com.xuekairui.user.entity.UserMembership;
import com.xuekairui.user.enums.MembershipLevel;
import com.xuekairui.user.enums.OperationType;
import com.xuekairui.user.mapper.MembershipBenefitMapper;
import com.xuekairui.user.mapper.UserMapper;
import com.xuekairui.user.mapper.UserMembershipMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.LocalDateTime;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * 会员体系服务
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class MembershipService {

    private final UserMembershipMapper userMembershipMapper;
    private final MembershipBenefitMapper membershipBenefitMapper;
    private final UserMapper userMapper;
    private final OperationAuditLogService auditLogService;

    /**
     * 获取用户当前生效的会员信息
     * <p>无活跃会员记录时，回退到用户表的当前等级（默认PLUS普通会员）
     */
    public MembershipResponse getMyMembership(Long userId) {
        UserMembership membership = userMembershipMapper.selectActiveByUserId(userId);
        if (membership != null) {
            return toResponse(membership);
        }
        // 无活跃会员记录，默认为免费普通会员(PLUS)
        return MembershipResponse.builder()
                .userId(userId)
                .level(MembershipLevel.PLUS.getCode())
                .levelName(MembershipLevel.PLUS.getDescription())
                .source("SYSTEM")
                .effectiveFrom(null)
                .effectiveTo(null)
                .status(1)
                .remark("免费会员")
                .build();
    }

    /**
     * 查询用户会员历史记录
     */
    public List<MembershipResponse> getUserMembershipHistory(Long userId) {
        List<UserMembership> list = userMembershipMapper.selectListByUserId(userId);
        return list.stream()
                .map(this::toResponse)
                .collect(Collectors.toList());
    }

    /**
     * 查询指定会员等级的权益列表
     */
    public List<MembershipBenefitResponse> getBenefits(String levelCode) {
        MembershipLevel level = MembershipLevel.fromCode(levelCode);
        if (level == null) {
            throw new BusinessException(ErrorCode.PARAM_ERROR, "会员等级无效");
        }
        List<MembershipBenefit> benefits = membershipBenefitMapper.selectEnabledByLevel(level);
        return benefits.stream()
                .map(this::toBenefitResponse)
                .collect(Collectors.toList());
    }

    /**
     * 发放/调整用户会员等级（运营/超管）
     */
    @Transactional
    public MembershipResponse grantMembership(GrantMembershipRequest request, Long operatorId, String operatorRole) {
        User user = userMapper.selectById(request.getUserId());
        if (user == null) {
            throw new BusinessException(ErrorCode.USER_NOT_FOUND);
        }

        MembershipLevel level = MembershipLevel.fromCode(request.getLevel());
        if (level == null) {
            throw new BusinessException(ErrorCode.PARAM_ERROR, "会员等级无效");
        }

        // 停用该用户其他有效会员记录
        List<UserMembership> activeList = userMembershipMapper.selectList(
                new LambdaQueryWrapper<UserMembership>()
                        .eq(UserMembership::getUserId, request.getUserId())
                        .eq(UserMembership::getStatus, 1));
        for (UserMembership active : activeList) {
            active.setStatus(0);
            userMembershipMapper.updateById(active);
        }

        // 创建新会员记录
        UserMembership membership = UserMembership.builder()
                .userId(request.getUserId())
                .level(level)
                .source(request.getSource() != null ? request.getSource() : "ADMIN_GRANT")
                .effectiveFrom(request.getEffectiveFrom() != null ? request.getEffectiveFrom() : LocalDateTime.now())
                .effectiveTo(request.getEffectiveTo())
                .status(1)
                .remark(request.getRemark())
                .build();
        userMembershipMapper.insert(membership);

        // 同步到用户表当前会员等级与过期时间
        user.setMembershipLevel(level);
        user.setMembershipExpireAt(membership.getEffectiveTo());
        userMapper.updateById(user);

        // 审计日志
        auditLogService.logSuccess(operatorId, "管理员", operatorRole,
                OperationType.USER_UPDATE,
                "MEMBERSHIP:" + request.getUserId() + "->" + level.getCode(), request.getUserId());

        log.info("运营人员{}为用户{}发放会员等级{}", operatorId, request.getUserId(), level.getCode());
        return toResponse(membership);
    }

    /**
     * 统一发放或续期会员（互斥模式）
     * <p>
     * 如果用户已有同等级活跃会员，续期（叠加天数）；
     * 否则停用所有旧会员，创建新记录。
     */
    @Transactional
    public void grantOrExtendMembership(Long userId, MembershipLevel level, int days,
                                         String source, String remark) {
        User user = userMapper.selectById(userId);
        if (user == null) {
            return;
        }

        LocalDateTime newExpireAt;
        MembershipLevel effectiveLevel = level;

        UserMembership existing = userMembershipMapper.selectActiveByUserId(userId);
        if (existing != null) {
            if (existing.getLevel() == level) {
                // 同等级续期：在原到期时间基础上追加
                LocalDateTime base = existing.getEffectiveTo() != null
                        && existing.getEffectiveTo().isAfter(LocalDateTime.now())
                        ? existing.getEffectiveTo()
                        : LocalDateTime.now();
                existing.setEffectiveTo(base.plusDays(days));
                userMembershipMapper.updateById(existing);
                newExpireAt = existing.getEffectiveTo();
            } else if (existing.getLevel().getWeight() > level.getWeight()) {
                // 已有更高等级：不降级，直接续期更高等级（如ULTRA用户邀请奖励仍保持ULTRA）
                LocalDateTime base = existing.getEffectiveTo() != null
                        && existing.getEffectiveTo().isAfter(LocalDateTime.now())
                        ? existing.getEffectiveTo()
                        : LocalDateTime.now();
                existing.setEffectiveTo(base.plusDays(days));
                userMembershipMapper.updateById(existing);
                newExpireAt = existing.getEffectiveTo();
                effectiveLevel = existing.getLevel();
            } else {
                // 升级：停用所有低等级旧会员，创建新记录
                deactivateAllActive(userId);
                LocalDateTime now = LocalDateTime.now();
                UserMembership membership = UserMembership.builder()
                        .userId(userId)
                        .level(level)
                        .source(source)
                        .effectiveFrom(now)
                        .effectiveTo(now.plusDays(days))
                        .status(1)
                        .remark(remark)
                        .build();
                userMembershipMapper.insert(membership);
                newExpireAt = membership.getEffectiveTo();
            }
        } else {
            // 无活跃会员：创建新记录
            deactivateAllActive(userId);
            LocalDateTime now = LocalDateTime.now();
            UserMembership membership = UserMembership.builder()
                    .userId(userId)
                    .level(level)
                    .source(source)
                    .effectiveFrom(now)
                    .effectiveTo(now.plusDays(days))
                    .status(1)
                    .remark(remark)
                    .build();
            userMembershipMapper.insert(membership);
            newExpireAt = membership.getEffectiveTo();
        }

        // 同步用户表：等级 + 过期时间（仅当等级变化或过期时间变化时更新）
        boolean needUpdate = false;
        if (user.getMembershipLevel() == null
                || user.getMembershipLevel().getWeight() < effectiveLevel.getWeight()) {
            user.setMembershipLevel(effectiveLevel);
            needUpdate = true;
        }
        if (user.getMembershipExpireAt() == null
                || !user.getMembershipExpireAt().equals(newExpireAt)) {
            user.setMembershipExpireAt(newExpireAt);
            needUpdate = true;
        }
        if (needUpdate) {
            userMapper.updateById(user);
        }
    }

    /**
     * 邀请人奖励：赠送1个月（30天）高级会员(PRO)
     * <p>
     * 无论邀请人当前是什么等级，统一赠送高级会员时长。
     * 同等级续期叠加，不同等级则停用旧会员并启用新的PRO会员。
     */
    @Transactional
    public void grantInviteRewardMembership(Long inviterId, Long inviteeId) {
        grantOrExtendMembership(inviterId, MembershipLevel.PRO, 30,
                "INVITE", "邀请奖励：邀请用户" + inviteeId + "注册");
        log.info("邀请奖励：用户{}获得30天高级会员(PRO)", inviterId);
    }

    /**
     * 支付购买激活会员（互斥模式：同等级续期，不同等级替换）
     * @param userId       用户ID
     * @param level        会员等级
     * @param durationDays 有效期天数（月卡30天，年卡365天）
     * @param orderNo      关联支付订单号
     * @return 创建或续期的会员记录
     */
    @Transactional
    public UserMembership activateFromPayment(Long userId, MembershipLevel level,
                                               int durationDays, String orderNo) {
        User user = userMapper.selectById(userId);
        if (user == null) {
            throw new BusinessException(ErrorCode.USER_NOT_FOUND);
        }

        grantOrExtendMembership(userId, level, durationDays, "RECHARGE", "支付购买: " + orderNo);

        // 审计日志
        auditLogService.logSuccess(userId, user.getNickname(), "USER",
                OperationType.USER_UPDATE,
                "PAY:" + orderNo + "->" + level.getCode(), userId);

        log.info("用户{}通过支付{}激活会员等级{}, 有效期{}天", userId, orderNo, level.getCode(), durationDays);

        // 返回当前活跃会员记录
        return userMembershipMapper.selectActiveByUserId(userId);
    }

    /**
     * 分页查询会员记录
     */
    public Page<MembershipResponse> listMemberships(Integer pageNum, Integer pageSize, Long userId, String level) {
        Page<UserMembership> page = new Page<>(pageNum, pageSize);
        LambdaQueryWrapper<UserMembership> wrapper = new LambdaQueryWrapper<>();
        if (userId != null) {
            wrapper.eq(UserMembership::getUserId, userId);
        }
        if (level != null && !level.isBlank()) {
            MembershipLevel membershipLevel = MembershipLevel.fromCode(level);
            if (membershipLevel != null) {
                wrapper.eq(UserMembership::getLevel, membershipLevel);
            }
        }
        wrapper.orderByDesc(UserMembership::getCreateTime);

        Page<UserMembership> result = userMembershipMapper.selectPage(page, wrapper);
        Page<MembershipResponse> responsePage = new Page<>(result.getCurrent(), result.getSize(), result.getTotal());

        // 批量查询用户，避免N+1
        List<Long> userIds = result.getRecords().stream()
                .map(UserMembership::getUserId)
                .distinct()
                .collect(Collectors.toList());
        Map<Long, User> userMap = userIds.isEmpty() ? new HashMap<>()
                : userMapper.selectBatchIds(userIds).stream()
                        .collect(Collectors.toMap(User::getId, u -> u));

        responsePage.setRecords(result.getRecords().stream()
                .map(m -> toResponse(m, userMap.get(m.getUserId())))
                .collect(Collectors.toList()));
        return responsePage;
    }

    private MembershipResponse toResponse(UserMembership membership) {
        if (membership == null) {
            return null;
        }
        User user = membership.getUserId() != null ? userMapper.selectById(membership.getUserId()) : null;
        return toResponse(membership, user);
    }

    /**
     * 停用用户所有活跃会员记录
     */
    private void deactivateAllActive(Long userId) {
        List<UserMembership> activeList = userMembershipMapper.selectList(
                new LambdaQueryWrapper<UserMembership>()
                        .eq(UserMembership::getUserId, userId)
                        .eq(UserMembership::getStatus, 1));
        for (UserMembership active : activeList) {
            active.setStatus(0);
            userMembershipMapper.updateById(active);
        }
    }

    private MembershipResponse toResponse(UserMembership membership, User user) {
        if (membership == null) {
            return null;
        }
        MembershipLevel level = membership.getLevel();
        return MembershipResponse.builder()
                .id(membership.getId())
                .userId(membership.getUserId())
                .phone(user != null ? user.getPhone() : null)
                .nickname(user != null ? user.getNickname() : null)
                .level(level != null ? level.getCode() : null)
                .levelName(level != null ? level.getDescription() : null)
                .source(membership.getSource())
                .effectiveFrom(membership.getEffectiveFrom())
                .effectiveTo(membership.getEffectiveTo())
                .membershipExpireAt(membership.getEffectiveTo())
                .status(membership.getStatus())
                .remark(membership.getRemark())
                .createTime(membership.getCreateTime())
                .build();
    }

    private MembershipBenefitResponse toBenefitResponse(MembershipBenefit benefit) {
        return MembershipBenefitResponse.builder()
                .benefitType(benefit.getBenefitType())
                .benefitTypeName(toBenefitTypeName(benefit.getBenefitType()))
                .benefitValue(benefit.getBenefitValue())
                .description(benefit.getDescription())
                .build();
    }

    private String toBenefitTypeName(String type) {
        return switch (type) {
            case "DAILY_QUOTA" -> "每日查询配额";
            case "MONTHLY_QUOTA" -> "每月爬虫加成";
            case "MAX_CONCURRENT" -> "最大并发加成";
            default -> type;
        };
    }

    /**
     * 定时任务：每5分钟检查过期会员，自动降级
     * <p>
     * 高级会员全部时长到期后，账号降级为免费普通会员(PLUS)。
     */
    @Scheduled(cron = "0 */5 * * * ?")
    @Transactional
    public void expireMemberships() {
        // 查找所有已过期但仍标记为有效的会员记录
        List<UserMembership> expired = userMembershipMapper.selectList(
                new LambdaQueryWrapper<UserMembership>()
                        .eq(UserMembership::getStatus, 1)
                        .isNotNull(UserMembership::getEffectiveTo)
                        .lt(UserMembership::getEffectiveTo, LocalDateTime.now()));

        if (expired.isEmpty()) {
            return;
        }

        Set<Long> affectedUserIds = new HashSet<>();
        for (UserMembership m : expired) {
            m.setStatus(0);
            userMembershipMapper.updateById(m);
            affectedUserIds.add(m.getUserId());
        }

        // 对每个受影响的用户，检查是否还有其他有效会员
        for (Long userId : affectedUserIds) {
            UserMembership active = userMembershipMapper.selectActiveByUserId(userId);
            if (active == null) {
                // 无有效会员，降级为普通会员
                User user = userMapper.selectById(userId);
                if (user != null && user.getMembershipLevel() != MembershipLevel.PLUS) {
                    user.setMembershipLevel(MembershipLevel.PLUS);
                    user.setMembershipExpireAt(null);
                    userMapper.updateById(user);
                    log.info("用户{}会员已到期，降级为普通会员", userId);
                }
            }
        }

        log.info("处理过期会员记录: {}条，涉及用户: {}个", expired.size(), affectedUserIds.size());
    }
}