package com.ruoyi.auth.service;

import java.security.SecureRandom;
import java.util.concurrent.TimeUnit;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.ruoyi.auth.config.UniversalCodeProperties;
import com.ruoyi.auth.constant.SmsConstants;
import com.ruoyi.auth.enums.SmsSceneEnum;
import com.ruoyi.auth.service.sms.SmsSender;
import com.ruoyi.common.core.constant.CacheConstants;
import com.ruoyi.common.core.constant.SecurityConstants;
import com.ruoyi.common.core.domain.R;
import com.ruoyi.common.core.exception.ServiceException;
import com.ruoyi.common.core.text.Convert;
import com.ruoyi.common.core.utils.StringUtils;
import com.ruoyi.common.redis.service.RedisService;
import com.ruoyi.system.api.RemoteAccountUserService;
import com.ruoyi.system.api.domain.AccountMember;

/**
 * 短信验证码服务
 *
 * 负责验证码的下发（含频率控制）与校验消费（一次性、错误次数限制）。
 *
 * @author hugray
 */
@Service
public class SmsCodeService
{
    private static final Logger log = LoggerFactory.getLogger(SmsCodeService.class);

    /** 手机号正则 */
    private static final Pattern PHONE_PATTERN = Pattern.compile("^1[3-9]\\d{9}$");

    /** 安全随机数生成器（避免在方法内重复创建） */
    private static final SecureRandom RANDOM = new SecureRandom();

    @Autowired
    private RedisService redisService;

    @Autowired
    private SmsSender smsSender;

    @Autowired
    private RemoteAccountUserService remoteAccountUserService;

    @Autowired
    private UniversalCodeProperties universalCodeProperties;

    /**
     * 下发短信验证码
     *
     * @param phone 手机号
     * @param scene 场景编码（register=注册 / login=登录 / reset=重置密码 / 其它=通用下发）
     */
    public void sendCode(String phone, String scene)
    {
        // STEP 1: 手机号非空 + 格式校验（Controller 已校验，此处做服务层兜底）
        if (StringUtils.isEmpty(phone) || !PHONE_PATTERN.matcher(phone).matches())
        {
            throw new ServiceException("请输入正确手机号");
        }

        SmsSceneEnum sceneEnum = SmsSceneEnum.getByCode(scene);

        // STEP 2: 场景化手机号状态校验：注册需手机号未注册，登录/重置密码需手机号已注册
        if (SmsSceneEnum.REGISTER == sceneEnum)
        {
            checkPhoneNotRegistered(phone);
        }
        else if (SmsSceneEnum.LOGIN == sceneEnum || SmsSceneEnum.RESET == sceneEnum)
        {
            checkPhoneRegistered(phone);
        }

        // STEP 3: 发送频率控制（同一场景同一手机号 30s 内仅允许发送一次）
        String limitKey = CacheConstants.SMS_CODE_LIMIT_KEY + sceneEnum.getCode() + ":" + phone;
        boolean acquired = redisService.setCacheObjectIfAbsent(limitKey, "1", SmsConstants.SEND_INTERVAL_SECONDS, TimeUnit.SECONDS);
        if (!acquired)
        {
            throw new ServiceException("验证码发送过于频繁，请稍后再试");
        }

        // STEP 4: 生成验证码，写入缓存（TTL 5 分钟），同时清零历史错误次数
        String code = generateCode();
        String codeKey = buildCodeKey(sceneEnum, phone);
        redisService.setCacheObject(codeKey, code, SmsConstants.CODE_EXPIRE_MINUTES, TimeUnit.MINUTES);
        redisService.deleteObject(buildErrorKey(sceneEnum, phone));

        // STEP 5: 调用短信发送器下发
        try
        {
            smsSender.send(phone, code);
        }
        catch (Exception e)
        {
            log.error("[SMS_SEND] send failed, phone={}", maskPhone(phone), e);
            throw new ServiceException("短信发送失败");
        }
    }

    /**
     * 校验并消费验证码（一次性使用）
     *
     * @param phone 手机号
     * @param scene 场景编码
     * @param inputCode 用户输入的验证码
     */
    public void verifyAndConsume(String phone, String scene, String inputCode)
    {
        SmsSceneEnum sceneEnum = SmsSceneEnum.getByCode(scene);

        // STEP 0: 测试便利——命中通用验证码直接放行（仅 login / register / reset 场景；配置为空即关闭）
        if (isUniversalCodeHit(sceneEnum, inputCode))
        {
            log.warn("[SMS_VERIFY] universal code hit, phone={}, scene={}", maskPhone(phone), sceneEnum.getCode());
            return;
        }

        String codeKey = buildCodeKey(sceneEnum, phone);

        // STEP 1: 读取缓存验证码，不存在视为已失效
        Object cacheCode = redisService.getCacheObject(codeKey);
        if (StringUtils.isNull(cacheCode))
        {
            throw new ServiceException("验证码已失效，请重新获取");
        }

        // STEP 2: 比对失败累加错误次数，达到上限删除验证码
        String code = Convert.toStr(cacheCode);
        if (!code.equals(Convert.toStr(inputCode)))
        {
            recordVerifyFailure(sceneEnum, phone, codeKey);
            throw new ServiceException("验证码错误");
        }

        // STEP 3: 校验通过，删除验证码（一次性使用）
        redisService.deleteObject(codeKey);
        redisService.deleteObject(buildErrorKey(sceneEnum, phone));
    }

    /**
     * 判定是否命中通用验证码（测试便利）
     *
     * 仅 login / register / reset 场景生效；命中即直接放行，不读缓存、不计数、不消费。
     *
     * @param sceneEnum 场景枚举
     * @param inputCode 用户输入的验证码
     * @return 命中返回 true
     */
    private boolean isUniversalCodeHit(SmsSceneEnum sceneEnum, String inputCode)
    {
        String universalCode = universalCodeProperties.getUniversalSmsCode();
        // 未配置通用验证码时关闭该能力
        if (StringUtils.isEmpty(universalCode) || StringUtils.isEmpty(inputCode))
        {
            return false;
        }
        // 仅登录 / 注册 / 重置密码场景放行，避免其它场景被通用码绕过
        if (SmsSceneEnum.LOGIN != sceneEnum && SmsSceneEnum.REGISTER != sceneEnum && SmsSceneEnum.RESET != sceneEnum)
        {
            return false;
        }
        return universalCode.equals(inputCode);
    }

    /**
     * 校验手机号是否已被注册
     *
     * @param phone 手机号
     */
    private void checkPhoneNotRegistered(String phone)
    {
        R<AccountMember> memberResult = remoteAccountUserService.getMemberByPhone(phone, SecurityConstants.INNER);
        if (R.FAIL == memberResult.getCode())
        {
            throw new ServiceException(memberResult.getMsg());
        }
        if (StringUtils.isNotNull(memberResult.getData()))
        {
            throw new ServiceException("手机号已注册，请前往登录");
        }
    }

    /**
     * 校验手机号是否已注册
     *
     * @param phone 手机号
     */
    private void checkPhoneRegistered(String phone)
    {
        R<AccountMember> memberResult = remoteAccountUserService.getMemberByPhone(phone, SecurityConstants.INNER);
        if (R.FAIL == memberResult.getCode())
        {
            throw new ServiceException(memberResult.getMsg());
        }
        if (StringUtils.isNull(memberResult.getData()))
        {
            throw new ServiceException("该手机号未注册，请先注册");
        }
    }

    /**
     * 记录一次验证码校验失败，达到最大次数时删除验证码
     *
     * @param sceneEnum 场景枚举
     * @param phone 手机号
     * @param codeKey 验证码缓存键
     */
    private void recordVerifyFailure(SmsSceneEnum sceneEnum, String phone, String codeKey)
    {
        String errorKey = buildErrorKey(sceneEnum, phone);
        int failCount = Convert.toInt(redisService.getCacheObject(errorKey), 0) + 1;

        if (failCount >= SmsConstants.MAX_VERIFY_ATTEMPTS)
        {
            // 错误次数过多，验证码作废，需重新获取
            redisService.deleteObject(codeKey);
            redisService.deleteObject(errorKey);
            log.warn("[SMS_VERIFY] too many failures, phone={}", maskPhone(phone));
            throw new ServiceException("验证码错误次数过多，请重新获取");
        }

        // 错误计数有效期与验证码保持一致，避免长期占用
        long expireSeconds = redisService.getExpire(codeKey);
        if (expireSeconds <= 0)
        {
            expireSeconds = SmsConstants.CODE_EXPIRE_MINUTES * 60;
        }
        redisService.setCacheObject(errorKey, failCount, expireSeconds, TimeUnit.SECONDS);
    }

    /**
     * 生成指定长度的数字验证码
     *
     * @return 验证码
     */
    private String generateCode()
    {
        StringBuilder builder = new StringBuilder(SmsConstants.CODE_LENGTH);
        for (int i = 0; i < SmsConstants.CODE_LENGTH; i++)
        {
            builder.append(RANDOM.nextInt(10));
        }
        return builder.toString();
    }

    /**
     * 构建验证码缓存键
     */
    private String buildCodeKey(SmsSceneEnum sceneEnum, String phone)
    {
        return CacheConstants.SMS_CODE_KEY + sceneEnum.getCode() + ":" + phone;
    }

    /**
     * 构建错误次数缓存键
     */
    private String buildErrorKey(SmsSceneEnum sceneEnum, String phone)
    {
        return CacheConstants.SMS_CODE_ERR_KEY + sceneEnum.getCode() + ":" + phone;
    }

    /**
     * 手机号脱敏，形如 138****0000
     */
    private String maskPhone(String phone)
    {
        if (StringUtils.isEmpty(phone) || phone.length() < 7)
        {
            return phone;
        }
        return phone.substring(0, 3) + "****" + phone.substring(phone.length() - 4);
    }
}