feat : 메일을 전송하고, 인증 코드를 확인하는 UnivEmailVerificationService 구현 (#28)

src/main/java/com/gdschongik/gdsc/domain/integration/UnivEmailVerificationService.java

@@ -0,0 +1,60 @@
+package com.gdschongik.gdsc.domain.integration;
+
+import com.gdschongik.gdsc.global.exception.CustomException;
+import com.gdschongik.gdsc.global.exception.ErrorCode;
+import java.time.Duration;
+import java.util.Objects;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+
+@Service
+@RequiredArgsConstructor
+public class UnivEmailVerificationService {
+
+    private final HongikUnivEmailValidator hongikUnivEmailValidator;
+    private final VerificationCodeGenerator verificationCodeGenerator;
+    private final VerificationMailContentWriter verificationMailContentWriter;
+
+    private final MailSender mailSender;
+    private final EmailVerificationCodeRepository emailVerificationCodeRepository;
+
+    public static final Duration VERIFICATION_CODE_TIME_TO_LIVE = Duration.ofMinutes(10);
+
+    public void sendEmailVerificationMail(String email) {
+        hongikUnivEmailValidator.validate(email);
+
+        String verificationCode = verificationCodeGenerator.generate();
+        sendMail(email, verificationCode);
+
+        saveVerificationCode(email, verificationCode);
+    }
+
+    private void sendMail(String email, String verificationCode) {
+        String mailContent = verificationMailContentWriter
+            .writeContentWithVerificationCode(verificationCode, VERIFICATION_CODE_TIME_TO_LIVE);
+
+        mailSender.send(email, mailContent);
+    }
+
+    private void saveVerificationCode(String email, String verificationCode) {
+        EmailVerificationCode emailVerificationCode = new EmailVerificationCode(
+            email, verificationCode, VERIFICATION_CODE_TIME_TO_LIVE.toSeconds()
+        );
+
+        emailVerificationCodeRepository.save(emailVerificationCode);
+    }
+
+    public void validateCodeMatch(String email, String userInputCode) {
+        String verificationCode = getVerificationCodeByEmail(email);
+
+        if (!Objects.equals(verificationCode, userInputCode)) {
+            throw new CustomException(ErrorCode.UNIV_EMAIL_VERIFICATION_CODE_NOT_MATCH);
+        }
+    }
+
+    private String getVerificationCodeByEmail(String email) {
+        return emailVerificationCodeRepository.findById(email)
+            .orElseThrow(() -> new CustomException(ErrorCode.VERIFICATION_CODE_NOT_FOUND))
+            .getVerificationCode();
+    }
+}