package com.tourguide.modules.user.service;

import com.tourguide.common.exception.BusinessException;
import com.tourguide.modules.user.dto.GuidePhoneChangeTokenResponse;
import com.tourguide.modules.user.dto.GuideUserResponse;
import com.tourguide.modules.user.dto.SmsCodeResponse;
import com.tourguide.modules.user.entity.GuideUser;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import java.time.Duration;
import java.util.UUID;

/** 管理导游手机号更换流程，避免绕过旧手机号验证直接修改账号。 */
@Service
public class GuidePhoneChangeService {
    private static final String OLD_PHONE_SCENE = "change-old";
    private static final String NEW_PHONE_SCENE = "change-new";
    private static final String TOKEN_KEY_PREFIX = "tourguide:guide-phone-change:token:";
    private static final Duration TOKEN_TTL = Duration.ofMinutes(10);

    private final StringRedisTemplate redisTemplate;
    private final GuideVerificationCodeService verificationCodeService;
    private final GuideUserService userService;

    public GuidePhoneChangeService(StringRedisTemplate redisTemplate,
                                   GuideVerificationCodeService verificationCodeService,
                                   GuideUserService userService) {
        this.redisTemplate = redisTemplate;
        this.verificationCodeService = verificationCodeService;
        this.userService = userService;
    }

    public SmsCodeResponse sendOldPhoneCode(Long guideId, String phone) {
        requireCurrentPhone(guideId, phone);
        return verificationCodeService.send(phone, OLD_PHONE_SCENE);
    }

    public GuidePhoneChangeTokenResponse verifyOldPhone(Long guideId, String phone, String code) {
        requireCurrentPhone(guideId, phone);
        verificationCodeService.verifyAndConsume(phone, code, OLD_PHONE_SCENE);
        String token = UUID.randomUUID().toString().replace("-", "");
        redisTemplate.opsForValue().set(tokenKey(token), String.valueOf(guideId), TOKEN_TTL);
        return new GuidePhoneChangeTokenResponse(token, TOKEN_TTL.getSeconds());
    }

    public SmsCodeResponse sendNewPhoneCode(Long guideId, String changeToken, String newPhone) {
        requireValidToken(guideId, changeToken);
        requireNewPhone(guideId, newPhone);
        return verificationCodeService.send(newPhone, NEW_PHONE_SCENE);
    }

    public GuideUserResponse changePhone(Long guideId, String changeToken, String newPhone, String code) {
        requireValidToken(guideId, changeToken);
        requireNewPhone(guideId, newPhone);
        verificationCodeService.verifyAndConsume(newPhone, code, NEW_PHONE_SCENE);
        GuideUserResponse response = userService.changeMobile(guideId, newPhone);
        redisTemplate.delete(tokenKey(changeToken));
        return response;
    }

    private void requireCurrentPhone(Long guideId, String phone) {
        GuideUser user = userService.findEnabledById(guideId);
        if (user.getMobile() == null || !user.getMobile().equals(phone)) {
            throw new BusinessException(400, "旧手机号与当前账号不一致");
        }
    }

    private void requireValidToken(Long guideId, String changeToken) {
        String tokenGuideId = redisTemplate.opsForValue().get(tokenKey(changeToken));
        if (!String.valueOf(guideId).equals(tokenGuideId)) {
            throw new BusinessException(401, "换号验证已失效，请重新验证旧手机号");
        }
    }

    private void requireNewPhone(Long guideId, String newPhone) {
        GuideUser user = userService.findEnabledById(guideId);
        if (newPhone.equals(user.getMobile())) {
            throw new BusinessException(400, "新手机号不能与当前手机号相同");
        }
        userService.ensurePhoneAvailable(guideId, newPhone);
    }

    private String tokenKey(String token) {
        return TOKEN_KEY_PREFIX + token;
    }
}