refactor : (review) 상수, 세션 제거/추가 기능, register 시 payment 유효성 session에서처리

Author: heewonham

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

@@ -1,6 +1,7 @@
 package nextstep.courses.domain;
 
 import java.time.LocalDateTime;
+import java.util.ArrayList;
 
 public class Course {
     private Long id;
@@ -42,6 +43,20 @@ public LocalDateTime getCreatedAt() {
         return createdAt;
     }
 
+    public void addSession(Session session) {
+        if (sessions == null) {
+            sessions = new Sessions(new ArrayList<>());
+        }
+        sessions.add(session);
+    }
+
+    public void removeSession(Session session) {
+        if (sessions == null) {
+            return;
+        }
+        sessions.remove(session);
+    }
+
     @Override
     public String toString() {
         return "Course{" +

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

@@ -6,31 +6,36 @@ public class Image {
     private long sizeInBytes;
     private int width;
     private int height;
+    private static final int IMAGE_SIZE_1MB = 1024 * 1024;
+    private static final int WIDTH_LIMIT = 300;
+    private static final int HEIGHT_LIMIT = 200;
+    private static final double REQUIRED_ASPECT_RATIO = 1.5;
+    private static final double ASPECT_RATIO_TOLERANCE = 0.01;
 
     public Image(String fileName, String contentType, long sizeInBytes, int width, int height) {
+        validate(contentType, sizeInBytes, width, height);
         this.fileName = fileName;
         this.contentType = contentType;
         this.sizeInBytes = sizeInBytes;
         this.width = width;
         this.height = height;
-        validate();
     }
 
-    private void validate() {
-        if (sizeInBytes > 1024 * 1024) {
+    private void validate(String contentType, long sizeInBytes, int width, int height) {
+        if (sizeInBytes > IMAGE_SIZE_1MB) {
             throw new IllegalArgumentException("이미지 크기는 1MB 이하여야 합니다.");
         }
 
         if (!contentType.matches("(gif|jpeg|jpg|png|svg)")) {
             throw new IllegalArgumentException("허용되지 않는 이미지 형식입니다.");
         }
 
-        if (width < 300 || height < 200) {
+        if (width < WIDTH_LIMIT || height < HEIGHT_LIMIT) {
             throw new IllegalArgumentException("이미지 크기가 너무 작습니다.");
         }
 
         double ratio = (double) width / height;
-        if (Math.abs(ratio - 1.5) > 0.01) {
+        if (Math.abs(ratio - REQUIRED_ASPECT_RATIO) > ASPECT_RATIO_TOLERANCE) {
             throw new IllegalArgumentException("이미지 비율은 3:2여야 합니다.");
         }
     }

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

@@ -21,7 +21,15 @@ protected void validateRegistration(Long studentId, Payment payment) {
         if (payment == null) {
             throw new IllegalArgumentException("결제 정보가 없습니다.");
         }
-        payment.isValidatePayment(id, studentId, tuitionFee);
+        if (!this.id.equals(payment.getSessionId())) {
+            throw new IllegalArgumentException("결제한 강의와 일치하지 않습니다.");
+        }
+        if (!studentId.equals(payment.getNsUserId())) {
+            throw new IllegalArgumentException("결제한 사용자와 일치하지 않습니다.");
+        }
+        if (this.tuitionFee.getAmount() != payment.getAmount()) {
+            throw new IllegalArgumentException("결제 금액과 일치하지 않습니다.");
+        }
     }
 
     @Override

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

@@ -4,7 +4,16 @@
 
 public class Sessions {
     private final List<Session> sessions;
+
     public Sessions(List<Session> sessions) {
         this.sessions = sessions;
     }
+
+    public void add(Session session) {
+        sessions.add(session);
+    }
+
+    public void remove(Session session) {
+        sessions.remove(session);
+    }
 }

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

@@ -12,30 +12,30 @@ public class Payment {
     private Long nsUserId;
 
     // 결제 금액
-    private Long amount;
+    private int amount;
 
     private LocalDateTime createdAt;
 
     public Payment() {
     }
 
-    public Payment(String id, Long sessionId, Long nsUserId, Long amount) {
+    public Payment(String id, Long sessionId, Long nsUserId, int amount) {
         this.id = id;
         this.sessionId = sessionId;
         this.nsUserId = nsUserId;
         this.amount = amount;
         this.createdAt = LocalDateTime.now();
     }
 
-    public void isValidatePayment(Long sessionId, Long nsUserId, Long amount) {
-        if (this.sessionId != sessionId) {
-            throw new IllegalArgumentException("결제한 강의와 일치하지 않습니다.");
-        }
-        if (this.nsUserId != nsUserId) {
-            throw new IllegalArgumentException("결제한 사용자와 일치하지 않습니다.");
-        }
-        if (this.amount != amount) {
-            throw new IllegalArgumentException("결제 금액과 일치하지 않습니다.");
-        }
+    public Long getSessionId() {
+        return sessionId;
+    }
+
+    public Long getNsUserId() {
+        return nsUserId;
+    }
+
+    public int getAmount() {
+        return amount;
     }
 }