2단계 - 수강신청(도메인 모델)

src/main/java/nextstep/courses/domain/Course.java

@@ -9,6 +9,8 @@ public class Course {
 
     private Long creatorId;
 
+    private final Sessions sessions = new Sessions();
+
     private LocalDateTime createdAt;
 
     private LocalDateTime updatedAt;
@@ -40,6 +42,11 @@ public LocalDateTime getCreatedAt() {
         return createdAt;
     }
 
+    public void addSession(Session session) {
+        session.toCourse(this);
+        sessions.add(session);
+    }
+
     @Override
     public String toString() {
         return "Course{" +

src/main/java/nextstep/courses/domain/CoverImage.java

@@ -0,0 +1,14 @@
+package nextstep.courses.domain;
+
+public class CoverImage {
+
+    private final CoverImageFileSize size;
+    private final CoverImageType type;
+    private final CoverImageResolution resolution;
+
+    CoverImage(CoverImageType type, long size, int width, int height) {
+        this.size = new CoverImageFileSize(size);
+        this.type = type;
+        this.resolution = new CoverImageResolution(width, height);
+    }
+}

src/main/java/nextstep/courses/domain/CoverImageFactory.java

@@ -0,0 +1,9 @@
+package nextstep.courses.domain;
+
+public class CoverImageFactory {
+
+    public static CoverImage ofGif(long size, int width, int height) {
+        return new CoverImage(CoverImageType.GIF, size, width, height);
+    }
+
+}

src/main/java/nextstep/courses/domain/CoverImageFileSize.java

@@ -0,0 +1,21 @@
+package nextstep.courses.domain;
+
+public class CoverImageFileSize {
+    private static final long MAX_SIZE = 1024 * 1024; // 1MB
+    private final long size;
+
+    public CoverImageFileSize(long size) {
+        validate(size);
+        this.size = size;
+    }
+
+    private static void validate(long size) {
+        if (size <= 0 || size > MAX_SIZE) {
+            throw new IllegalArgumentException("이미지 크기는 0보다 크고 1MB 이하여야 합니다.");
+        }
+    }
+
+    public long getSize() {
+        return size;
+    }
+}

src/main/java/nextstep/courses/domain/CoverImageResolution.java

@@ -0,0 +1,38 @@
+package nextstep.courses.domain;
+
+public class CoverImageResolution {
+    private static final int MIN_WIDTH = 300;
+    private static final int MIN_HEIGHT = 200;
+    private static final int ASPECT_RATIO_WIDTH = 3;
+    private static final int ASPECT_RATIO_HEIGHT = 2;
+
+    private final int width;
+    private final int height;
+
+    public CoverImageResolution(int width, int height) {
+        validate(width, height);
+        this.width = width;
+        this.height = height;
+    }
+
+    private static void validate(int width, int height) {
+        validateWidthAndHeight(width, height);
+        validateAspectRatioValid(width, height);
+    }
+
+    private static void validateWidthAndHeight(int width, int height) {
+        boolean isValid = width >= MIN_WIDTH && height >= MIN_HEIGHT;
+
+        if (!isValid) {
+            throw new IllegalArgumentException("이미지의 width는 300픽셀, height는 200픽셀 이상이어야 합니다.");
+        }
+    }
+
+    private static void validateAspectRatioValid(int width, int height) {
+        boolean isValid = width * ASPECT_RATIO_HEIGHT == height * ASPECT_RATIO_WIDTH;
+
+        if (!isValid) {
+            throw new IllegalArgumentException("width와 height의 비율은 3:2여야 합니다.");
+        }
+    }
+}

src/main/java/nextstep/courses/domain/CoverImageType.java

@@ -0,0 +1,8 @@
+package nextstep.courses.domain;
+
+public enum CoverImageType {
+    GIF,
+    JPG,
+    PNG,
+    SVG
+}

src/main/java/nextstep/courses/domain/FreeRegistrationPolicy.java

@@ -0,0 +1,9 @@
+package nextstep.courses.domain;
+
+public class FreeRegistrationPolicy implements RegistrationPolicy {
+
+    @Override
+    public void validateRegistration(Session session, Money paymentAmount) {
+        // 무조건 패스
+    }
+}

src/main/java/nextstep/courses/domain/Money.java

@@ -0,0 +1,28 @@
+package nextstep.courses.domain;
+
+import java.util.Objects;
+
+public class Money {
+    private final NaturalNumber value;
+
+    public Money(long amount) {
+        this.value = new NaturalNumber(amount);
+    }
+
+    public long getAmount() {
+        return value.getValue();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Money money = (Money) o;
+        return Objects.equals(value, money.value);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(value);
+    }
+}

src/main/java/nextstep/courses/domain/NaturalNumber.java

@@ -0,0 +1,50 @@
+package nextstep.courses.domain;
+
+import java.util.Objects;
+
+public class NaturalNumber implements Comparable<NaturalNumber> {
+
+    private final long value;
+
+    public NaturalNumber(long value) {
+        validate(value);
+        this.value = value;
+    }
+
+    private static void validate(long value) {
+        if (value < 0) {
+            throw new IllegalArgumentException("0을 포함한 자연수만 허용 가능합니다.");
+        }
+    }
+
+    public long getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        NaturalNumber that = (NaturalNumber) o;
+        return value == that.value;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(value);
+    }
+
+    @Override
+    public String toString() {
+        return getValue() + "";
+    }
+
+    @Override
+    public int compareTo(NaturalNumber o) {
+        return Long.compare(getValue(), o.getValue());
+    }
+
+    public int compareTo(int o) {
+        return compareTo(new NaturalNumber(o));
+    }
+}

src/main/java/nextstep/courses/domain/PaidRegistrationPolicy.java

@@ -0,0 +1,24 @@
+package nextstep.courses.domain;
+
+public class PaidRegistrationPolicy implements RegistrationPolicy {
+
+    private final Money sessionFee;
+    private final NaturalNumber maxStudentCount;
+
+    public PaidRegistrationPolicy(int sessionFee, int maxStudentCount) {
+        this.sessionFee = new Money(sessionFee);
+        this.maxStudentCount = new NaturalNumber(maxStudentCount);
+    }
+
+    @Override
+    public void validateRegistration(Session session, Money paymentAmount) {
+        if (!session.isStudentCountLessThan((int) maxStudentCount.getValue())) {
+            throw new IllegalArgumentException("강의 최대 수강 인원을 초과할 수 없습니다.");
+        }
+
+        if (!sessionFee.equals(paymentAmount)) {
+            throw new IllegalArgumentException("수강생이 결제한 금액과 수강료가 일치할 때 수강 신청이 가능합니다.");
+        }
+    }
+
+}

src/main/java/nextstep/courses/domain/RegistrationPolicy.java

@@ -0,0 +1,5 @@
+package nextstep.courses.domain;
+
+public interface RegistrationPolicy {
+    void validateRegistration(Session session, Money paymentAmount);
+}

src/main/java/nextstep/courses/domain/Session.java

@@ -0,0 +1,45 @@
+package nextstep.courses.domain;
+
+import nextstep.payments.domain.Payment;
+import nextstep.users.domain.NsUser;
+import nextstep.users.domain.NsUsers;
+
+public class Session {
+    private Long id;
+    private Course course;
+    private final NsUsers nsUsers = new NsUsers();
+    private CoverImage coverImage;
+    private SessionStatus sessionStatus;
+    private RegistrationPolicy registrationPolicy;
+    private SessionPeriod sessionPeriod;
+
+    Session(long id, CoverImage coverImage, SessionStatus sessionStatus, RegistrationPolicy registrationPolicy, SessionPeriod sessionPeriod) {
+        this.id = id;
+        this.coverImage = coverImage;
+        this.sessionStatus = sessionStatus;
+        this.registrationPolicy = registrationPolicy;
+        this.sessionPeriod = sessionPeriod;
+    }
+
+    public void toCourse(Course course) {
+        this.course = course;
+    }
+
+    public boolean isStudentCountLessThan(int count) {
+        return nsUsers.getSize() < count;
+    }
+
+    public Payment register(NsUser nsUser, Money paymentAmount) {
+        if (!sessionStatus.isRegistrable()) {
+            throw new IllegalStateException("수강신청이 불가능한 상태입니다.");
+        }
+
+        registrationPolicy.validateRegistration(this, paymentAmount);
+
+        nsUsers.add(nsUser);
+
+        return new Payment("", this, nsUser, paymentAmount);
+    }
+
+
+}

src/main/java/nextstep/courses/domain/SessionPeriod.java

@@ -0,0 +1,15 @@
+package nextstep.courses.domain;
+
+import java.time.LocalDateTime;
+
+public class SessionPeriod {
+
+    private final LocalDateTime startedAt;
+    private final LocalDateTime endedAt;
+
+    public SessionPeriod(LocalDateTime startedAt, LocalDateTime endedAt) {
+        this.startedAt = startedAt;
+        this.endedAt = endedAt;
+    }
+
+}

src/main/java/nextstep/courses/domain/SessionStatus.java

@@ -0,0 +1,11 @@
+package nextstep.courses.domain;
+
+public enum SessionStatus {
+    PREPARING,
+    RECRUITING,
+    ENDED;
+
+    public boolean isRegistrable() {
+        return this == RECRUITING;
+    }
+}

src/main/java/nextstep/courses/domain/Sessions.java

@@ -0,0 +1,24 @@
+package nextstep.courses.domain;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Sessions {
+    private final List<Session> sessions;
+
+    public Sessions(List<Session> sessions) {
+        this.sessions = sessions;
+    }
+
+    public Sessions() {
+        this(new ArrayList<>());
+    }
+
+    public void add(Session session) {
+        sessions.add(session);
+    }
+
+    public List<Session> getSessions() {
+        return sessions;
+    }
+}

src/main/java/nextstep/payments/domain/Payment.java

@@ -2,28 +2,44 @@
 
 import java.time.LocalDateTime;
 
+import nextstep.courses.domain.Money;
+import nextstep.courses.domain.Session;
+import nextstep.users.domain.NsUser;
+
 public class Payment {
     private String id;
 
-    // 결제한 강의 아이디
-    private Long sessionId;
+    // 결제한 강의
+    private Session session;
 
-    // 결제한 사용자 아이디
-    private Long nsUserId;
+    // 결제한 사용자
+    private NsUser nsUser;
 
     // 결제 금액
-    private Long amount;
+    private Money amount;
 
     private LocalDateTime createdAt;
 
     public Payment() {
     }
 
-    public Payment(String id, Long sessionId, Long nsUserId, Long amount) {
+    public Payment(String id, Session session, NsUser nsUser, Money amount) {
         this.id = id;
-        this.sessionId = sessionId;
-        this.nsUserId = nsUserId;
+        this.session = session;
+        this.nsUser = nsUser;
         this.amount = amount;
         this.createdAt = LocalDateTime.now();
     }
+
+    public Session getSession() {
+        return session;
+    }
+
+    public NsUser getNsUser() {
+        return nsUser;
+    }
+
+    public Money getAmount() {
+        return amount;
+    }
 }

src/main/java/nextstep/qna/domain/Answer.java

@@ -75,7 +75,7 @@ public DeleteHistory delete(NsUser loginUser) {
         validateDelete(loginUser);
         this.deleted = true;
         this.updatedDate = LocalDateTime.now();
-        return new DeleteHistory(ContentType.ANSWER, getId(), getWriter(), LocalDateTime.now());
+        return DeleteHistoryFactory.ofAnswer(getId(), loginUser, LocalDateTime.now());
     }
 
     @Override