Implemented the distance donation response

ref #66

src/models/entities/DistanceDonation.ts

@@ -1,5 +1,6 @@
 import { IsInt, IsNotEmpty, IsPositive } from "class-validator";
 import { ChildEntity, Column, ManyToOne } from "typeorm";
+import { ResponseDistanceDonation } from '../responses/ResponseDistanceDonation';
 import { Donation } from "./Donation";
 import { Runner } from "./Runner";
 
@@ -31,7 +32,7 @@ export class DistanceDonation extends Donation {
    * Get's calculated from the runner's distance ran and the amount donated per kilometer.
    */
   public get amount(): number {
-    let calculatedAmount = -1;
+    let calculatedAmount = 0;
     try {
       calculatedAmount = this.amountPerDistance * (this.runner.distance / 1000);
     } catch (error) {
@@ -43,7 +44,7 @@ export class DistanceDonation extends Donation {
   /**
    * Turns this entity into it's response class.
    */
-  public toResponse(): DistanceDonation {
-    return null;
+  public toResponse(): ResponseDistanceDonation {
+    return new ResponseDistanceDonation(this);
   }
 }

src/models/responses/ResponseDistanceDonation.ts

@@ -0,0 +1,35 @@
+import { IsInt, IsObject, IsPositive } from 'class-validator';
+import { DistanceDonation } from '../entities/DistanceDonation';
+import { ResponseDonation } from './ResponseDonation';
+import { ResponseRunner } from './ResponseRunner';
+
+/**
+ * Defines the distance donation response.
+*/
+export class ResponseDistanceDonation extends ResponseDonation {
+
+    /**
+     * The donation's associated runner.
+     * Used as the source of the donation's distance.
+     */
+    @IsObject()
+    runner: ResponseRunner;
+
+    /**
+     * The donation's amount donated per distance.
+     * The amount the donor set to be donated per kilometer that the runner ran.
+     */
+    @IsInt()
+    @IsPositive()
+    amountPerDistance: number;
+
+    /**
+     * Creates a ResponseDistanceDonation object from a scan.
+     * @param donation The distance donation the response shall be build for.
+     */
+    public constructor(donation: DistanceDonation) {
+        super(donation);
+        this.runner = donation.runner.toResponse();
+        this.amountPerDistance = donation.amountPerDistance;
+    }
+}