[feat] 면접 예약 API 구현

src/main/java/dmu/dasom/api/domain/common/exception/ErrorCode.java

@@ -26,7 +26,14 @@ public enum ErrorCode {
     INVALID_TIME_FORMAT(400, "C017", "시간 형식이 올바르지 않습니다."),
     INVALID_INQUIRY_PERIOD(400, "C018", "조회 기간이 아닙니다."),
     SHEET_WRITE_FAIL(400, "C019", "시트에 데이터를 쓰는데 실패하였습니다."),
-    SHEET_READ_FAIL(400, "C200", "시트에 데이터를 쓰는데 실패하였습니다."),
+    SHEET_READ_FAIL(400, "C200", "시트에 데이터를 읽는데 실패하였습니다."),
+    SLOT_NOT_FOUND(400, "C021", "슬롯을 찾을 수 없습니다."),
+    APPLICANT_NOT_FOUND(400, "C022", "지원자를 찾을 수 없습니다."),
+    ALREADY_RESERVED(400, "C023", "이미 예약된 지원자입니다."),
+    RESERVED_SLOT_CANNOT_BE_DELETED(400, "C024", "예약된 슬롯은 삭제할 수 없습니다."),
+    SLOT_FULL(400, "C025", "해당 슬롯이 가득 찼습니다."),
+    RESERVATION_NOT_FOUND(400, "C026", "예약을 찾을 수 없습니다."),
+    SLOT_NOT_ACTIVE(400, "C027", "해당 슬롯이 비활성화 되었습니다."),
     ;
 
     private final int status;

src/main/java/dmu/dasom/api/domain/interview/dto/InterviewReservationRequestDto.java

@@ -0,0 +1,17 @@
+package dmu.dasom.api.domain.interview.dto;
+
+import lombok.*;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewReservationRequestDto {
+
+    private Long slotId; // 예약할 슬롯 ID
+
+    private Long applicantId; // 지원자 ID
+
+    private String reservationCode; // 학번 뒤 4자리 + 전화번호 뒤 4자리 조합 코드
+}

src/main/java/dmu/dasom/api/domain/interview/dto/InterviewReservationResponseDto.java

@@ -0,0 +1,20 @@
+package dmu.dasom.api.domain.interview.dto;
+
+import lombok.*;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewReservationResponseDto {
+
+    private Long reservationId; // 예약 ID
+
+    private Long slotId; // 슬롯 ID
+
+    private Long applicantId; // 지원자 ID
+
+    private String reservationCode; // 예약 코드 (학번+전화번호 조합)
+
+}

src/main/java/dmu/dasom/api/domain/interview/dto/InterviewSlotRequestDto.java

@@ -0,0 +1,22 @@
+package dmu.dasom.api.domain.interview.dto;
+
+import lombok.*;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewSlotRequestDto {
+
+    private LocalDate interviewDate; // 면접 날짜
+
+    private LocalTime startTime; // 시작 시간
+
+    private LocalTime endTime; // 종료 시간
+
+    private Integer maxCandidates; // 최대 지원자 수
+}

src/main/java/dmu/dasom/api/domain/interview/dto/InterviewSlotResponseDto.java

@@ -0,0 +1,32 @@
+package dmu.dasom.api.domain.interview.dto;
+
+import dmu.dasom.api.domain.interview.entity.InterviewSlot;
+import lombok.*;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewSlotResponseDto {
+
+    private Long id; // 슬롯 ID
+    private LocalDate interviewDate; // 면접 날짜
+    private LocalTime startTime; // 시작 시간
+    private LocalTime endTime; // 종료 시간
+    private Integer maxCandidates; // 최대 지원자 수
+    private Integer currentCandidates; // 현재 예약된 지원자 수
+
+    public InterviewSlotResponseDto(InterviewSlot slot){
+        this.id = slot.getId();
+        this.interviewDate = slot.getInterviewDate();
+        this.startTime = slot.getStartTime();
+        this.endTime = slot.getEndTime();
+        this.maxCandidates = slot.getMaxCandidates();
+        this.currentCandidates = slot.getCurrentCandidates();
+    }
+
+}

src/main/java/dmu/dasom/api/domain/interview/entity/InterviewReservation.java

@@ -0,0 +1,29 @@
+package dmu.dasom.api.domain.interview.entity;
+
+import dmu.dasom.api.domain.applicant.entity.Applicant;
+import jakarta.persistence.*;
+import lombok.*;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewReservation {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "slot_id", nullable = false)
+    private InterviewSlot slot; // 연관된 면접 슬롯
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "applicant_id", nullable = false)
+    private Applicant applicant; // 지원자
+
+    @Column(nullable = false, unique = true, length = 8)
+    private String reservationCode; // 학번 뒤 4자리 + 전화번호 뒤 4자리 조합 코드
+}

src/main/java/dmu/dasom/api/domain/interview/entity/InterviewSlot.java

@@ -0,0 +1,54 @@
+package dmu.dasom.api.domain.interview.entity;
+
+import dmu.dasom.api.domain.interview.enums.Status;
+import jakarta.persistence.*;
+import lombok.*;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+@Builder
+public class InterviewSlot {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false)
+    private LocalDate interviewDate;
+
+    @Column(nullable = false)
+    private LocalTime startTime;
+
+    @Column(nullable = false)
+    private LocalTime endTime; // 종료 시간
+
+    @Column(nullable = false)
+    private Integer maxCandidates; // 최대 지원자 수
+
+    @Column(nullable = false)
+    private Integer currentCandidates; // 현재 예약된 지원자 수
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false, length = 16)
+    private Status status; // 면접 슬롯 상태 (ACTIVE, INACTIVE, CLOSED)
+
+    public void incrementCurrentCandidates() {
+        this.currentCandidates++;
+        if (this.currentCandidates >= this.maxCandidates) {
+            this.status = Status.CLOSED; // 최대 지원자 수에 도달하면 상태 변경
+        }
+    }
+
+    public void decrementCurrentCandidates() {
+        this.currentCandidates--;
+        if (status == Status.CLOSED && this.currentCandidates < this.maxCandidates) {
+            this.status = Status.ACTIVE; // 지원자 수가 줄어들면 다시 활성화
+        }
+    }
+
+}

src/main/java/dmu/dasom/api/domain/interview/enums/Status.java

@@ -0,0 +1,7 @@
+package dmu.dasom.api.domain.interview.enums;
+
+public enum Status {
+    ACTIVE,     // 활성화된 슬롯
+    INACTIVE,   // 비활성화된 슬롯
+    CLOSED      // 예약 마감된 슬롯
+}

src/main/java/dmu/dasom/api/domain/interview/repositoty/InterviewReservationRepository.java

@@ -0,0 +1,10 @@
+package dmu.dasom.api.domain.interview.repositoty;
+
+import dmu.dasom.api.domain.interview.entity.InterviewReservation;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface InterviewReservationRepository extends JpaRepository<InterviewReservation, Long> {
+    boolean existsByReservationCode(String reservationCode);
+}

src/main/java/dmu/dasom/api/domain/interview/repositoty/InterviewSlotRepository.java

@@ -0,0 +1,18 @@
+package dmu.dasom.api.domain.interview.repositoty;
+
+import dmu.dasom.api.domain.interview.entity.InterviewSlot;
+import dmu.dasom.api.domain.interview.enums.Status;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Collection;
+import java.util.List;
+
+@Repository
+public interface InterviewSlotRepository extends JpaRepository<InterviewSlot, Long> {
+    Collection<InterviewSlot> findAllByCurrentCandidatesLessThanMaxCandidates();
+    List<InterviewSlot> findAllByStatusAndCurrentCandidatesLessThanMaxCandidates(
+            Status status);
+
+    boolean exists();
+}

src/main/java/dmu/dasom/api/domain/interview/service/InterviewService.java

@@ -0,0 +1,26 @@
+package dmu.dasom.api.domain.interview.service;
+
+import dmu.dasom.api.domain.interview.dto.InterviewReservationRequestDto;
+import dmu.dasom.api.domain.interview.dto.InterviewSlotResponseDto;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.util.List;
+
+
+public interface InterviewService {
+
+    // 면접 슬롯 생성
+    List<InterviewSlotResponseDto> createInterviewSlots(LocalDate newStartDate, LocalDate newEndDate, LocalTime newStartTime, LocalTime newEndTime);
+
+    // 예약 가능한 면접 슬롯 조회
+    List<InterviewSlotResponseDto> getAvailableSlots();
+
+    // 면접 예약
+    void reserveInterviewSlot(InterviewReservationRequestDto request);
+
+    // 면접 예약 취소
+    void cancelReservation(Long reservationId, Long applicantId);
+
+
+}

src/main/java/dmu/dasom/api/domain/interview/service/InterviewServiceImpl.java

@@ -0,0 +1,131 @@
+package dmu.dasom.api.domain.interview.service;
+
+import dmu.dasom.api.domain.applicant.entity.Applicant;
+import dmu.dasom.api.domain.applicant.repository.ApplicantRepository;
+import dmu.dasom.api.domain.common.exception.CustomException;
+import dmu.dasom.api.domain.common.exception.ErrorCode;
+import dmu.dasom.api.domain.interview.dto.InterviewReservationRequestDto;
+import dmu.dasom.api.domain.interview.dto.InterviewSlotResponseDto;
+import dmu.dasom.api.domain.interview.entity.InterviewReservation;
+import dmu.dasom.api.domain.interview.entity.InterviewSlot;
+import dmu.dasom.api.domain.interview.enums.Status;
+import dmu.dasom.api.domain.interview.repositoty.InterviewReservationRepository;
+import dmu.dasom.api.domain.interview.repositoty.InterviewSlotRepository;
+import dmu.dasom.api.domain.recruit.service.RecruitServiceImpl;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.util.ArrayList;
+import java.util.List;
+
+@RequiredArgsConstructor
+@Service
+@Transactional(readOnly = true)
+public class InterviewServiceImpl implements InterviewService{
+
+    private final InterviewSlotRepository interviewSlotRepository;
+    private final InterviewReservationRepository interviewReservationRepository;
+    private final ApplicantRepository applicantRepository;
+    private final RecruitServiceImpl recruitService;
+
+    // 면접 슬롯 생성
+    @Override
+    @Transactional
+    public List<InterviewSlotResponseDto> createInterviewSlots(LocalDate newStartDate, LocalDate newEndDate, LocalTime newStartTime, LocalTime newEndTime) {
+        boolean slotsExist = interviewSlotRepository.exists();
+
+        if(slotsExist){
+            interviewSlotRepository.deleteAll();
+        }
+
+        List<InterviewSlotResponseDto> newSlots = new ArrayList<>();
+        for(LocalDate date = newStartDate; !date.isAfter(newEndDate); date = date.plusDays(1)){
+            LocalTime currentTime = newStartTime;
+            while (currentTime.isBefore(newEndTime)){
+                LocalTime slotEndTime = currentTime.plusMinutes(20);
+
+                InterviewSlot slot = InterviewSlot.builder()
+                        .interviewDate(date)
+                        .startTime(currentTime)
+                        .endTime(slotEndTime)
+                        .maxCandidates(2)
+                        .currentCandidates(0)
+                        .status(Status.ACTIVE)
+                        .build();
+
+                interviewSlotRepository.save(slot);
+                newSlots.add(new InterviewSlotResponseDto(slot));
+                currentTime = slotEndTime;
+            }
+        }
+
+        return newSlots;
+    }
+
+    // 예약 가능한 면접 슬롯 조회
+    @Override
+    public List<InterviewSlotResponseDto> getAvailableSlots() {
+        return interviewSlotRepository.findAllByStatusAndCurrentCandidatesLessThanMaxCandidates(Status.ACTIVE)
+                .stream()
+                .map(InterviewSlotResponseDto::new)
+                .toList();
+    }
+
+    @Override
+    @Transactional
+    public void reserveInterviewSlot(InterviewReservationRequestDto request) {
+        InterviewSlot slot = interviewSlotRepository.findById(request.getSlotId())
+                .orElseThrow(() -> new CustomException(ErrorCode.SLOT_NOT_FOUND));
+
+        if(!slot.getStatus().equals(Status.ACTIVE)){
+            throw new CustomException(ErrorCode.SLOT_NOT_ACTIVE);
+        }
+
+        if (slot.getCurrentCandidates() >= slot.getMaxCandidates()) {
+            throw new CustomException(ErrorCode.SLOT_FULL);
+        }
+
+        Applicant applicant = applicantRepository.findById(request.getApplicantId())
+                .orElseThrow(() -> new CustomException(ErrorCode.APPLICANT_NOT_FOUND));
+
+        boolean alreadyReserved = interviewReservationRepository.existsByReservationCode(request.getReservationCode());
+        if (alreadyReserved) {
+            throw new CustomException(ErrorCode.ALREADY_RESERVED);
+        }
+
+        // 예약 정보 저장
+        InterviewReservation reservation = InterviewReservation.builder()
+                .slot(slot)
+                .applicant(applicant)
+                .reservationCode(request.getReservationCode())
+                .build();
+
+        interviewReservationRepository.save(reservation);
+
+        // 현재 예약 인원 증가
+        slot.incrementCurrentCandidates();
+    }
+
+    // 면접 예약 취소
+    @Override
+    @Transactional
+    public void cancelReservation(Long reservationId, Long applicantId) {
+        InterviewReservation reservation = interviewReservationRepository.findById(reservationId)
+                .orElseThrow(() -> new CustomException(ErrorCode.RESERVATION_NOT_FOUND));
+
+        if (!reservation.getApplicant().getId().equals(applicantId)) {
+            throw new CustomException(ErrorCode.UNAUTHORIZED);
+        }
+
+        // 현재 예약 인원 감소
+        InterviewSlot slot = reservation.getSlot();
+        slot.decrementCurrentCandidates();
+
+        // 예약 삭제
+        interviewReservationRepository.delete(reservation);
+    }
+
+}