package com.ruoyi.app.user;

import com.ruoyi.common.constant.CacheConstants;
import com.ruoyi.common.core.redis.RedisCache;
import com.ruoyi.common.exception.ServiceException;
import com.ruoyi.common.utils.MessageUtils;
import com.ruoyi.system.domain.InfoUser;
import com.ruoyi.system.mapper.InfoUserMapper;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.Date;

/** 普通用户主动注销；调用登录恢复前必须已经完成短信或第三方身份验证。 */
@Service
public class UserCancellationService {
    private final InfoUserMapper users;
    private final RedisCache redis;
    private final int graceDays;
    public UserCancellationService(InfoUserMapper users, RedisCache redis,
            @Value("${user.cancellation.grace-days:7}") int graceDays) {
        this.users = users; this.redis = redis;
        this.graceDays = graceDays > 0 && graceDays <= 365 ? graceDays : 7;
    }
    public record CancellationView(
            @com.fasterxml.jackson.annotation.JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
            Date cancellationDeadlineAt, int graceDays) { }

    @Transactional(rollbackFor = Exception.class)
    public CancellationView request(Long userId) {
        // 与认证恢复共用数据库行锁；重复申请不能延长原截止时间。
        InfoUser user = users.selectCancellationUserForUpdate(userId);
        requireUser(user);
        if (!"0".equals(user.getDelFlag())) throw unavailable();
        Date deadline = Date.from(Instant.now().plus(graceDays, ChronoUnit.DAYS));
        if (users.requestUserCancellation(userId, deadline) != 1) throw unavailable();
        redis.deleteKeys(CacheConstants.USER_TOKEN_KEY + userId + ":*");
        return new CancellationView(deadline, graceDays);
    }

    @Transactional(rollbackFor = Exception.class)
    public InfoUser authenticatedLogin(Long userId) {
        // 登录入口的外层事务持有此锁至签发新会话完成，防止并发注销覆盖恢复。
        InfoUser user = users.selectCancellationUserForUpdate(userId);
        requireUser(user);
        if ("0".equals(user.getDelFlag())) return user;
        Date now = new Date();
        if (!canRecover(user, now) || users.restoreCancelledUser(userId, now) != 1) throw unavailable();
        user.setDelFlag("0"); user.setCancellationDeadlineAt(null);
        return user;
    }

    public static boolean canRecover(InfoUser user, Date now) {
        return user != null && "0".equals(user.getUserType()) && "0".equals(user.getStatus())
                && "1".equals(user.getDelFlag()) && user.getCancellationDeadlineAt() != null
                && user.getCancellationDeadlineAt().after(now);
    }
    private void requireUser(InfoUser user) {
        if (user == null || !"0".equals(user.getUserType()) || !"0".equals(user.getStatus())) throw unavailable();
    }
    private ServiceException unavailable() { return new ServiceException(MessageUtils.message("no.user.stop")); }
}