package com.xuqm.tenant.service;

import com.xuqm.common.exception.BusinessException;
import com.xuqm.tenant.entity.EmailVerificationEntity;
import com.xuqm.tenant.repository.EmailVerificationRepository;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.mail.SimpleMailMessage;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.security.SecureRandom;
import java.time.LocalDateTime;
import java.util.UUID;

@Service
public class EmailService {

    private final JavaMailSender mailSender;
    private final EmailVerificationRepository verificationRepository;

    @Value("${spring.mail.username}")
    private String fromAddress;

    @Value("${email-verify.expire-seconds:600}")
    private int expireSeconds;

    private static final SecureRandom random = new SecureRandom();

    public EmailService(JavaMailSender mailSender, EmailVerificationRepository verificationRepository) {
        this.mailSender = mailSender;
        this.verificationRepository = verificationRepository;
    }

    @Transactional
    public void sendVerificationCode(String email, String purpose) {
        String code = String.format("%06d", random.nextInt(1_000_000));

        EmailVerificationEntity entity = new EmailVerificationEntity();
        entity.setId(UUID.randomUUID().toString());
        entity.setEmail(email);
        entity.setCode(code);
        entity.setPurpose(purpose);
        entity.setUsed(false);
        entity.setCreatedAt(LocalDateTime.now());
        entity.setExpiresAt(LocalDateTime.now().plusSeconds(expireSeconds));
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom(fromAddress);
        message.setTo(email);
        message.setSubject("XuqmGroup - 邮箱验证码");
        message.setText(String.format("您的验证码是：%s，%d分钟内有效。", code, expireSeconds / 60));

        verificationRepository.save(entity);
        mailSender.send(message);
    }

    public void verify(String email, String code, String purpose) {
        EmailVerificationEntity entity = verificationRepository
                .findTopByEmailAndPurposeAndUsedFalseOrderByCreatedAtDesc(email, purpose)
                .orElseThrow(() -> new BusinessException("验证码无效"));

        if (entity.getExpiresAt().isBefore(LocalDateTime.now())) {
            throw new BusinessException("验证码已过期");
        }
        if (!entity.getCode().equals(code)) {
            throw new BusinessException("验证码错误");
        }

        entity.setUsed(true);
        verificationRepository.save(entity);
    }
}