feat(tiered_pricing): 🔴 push logic to Subscriptions

Author: adrianliz

exercises/graduated_tiered_prices/solutions/adrianliz/src/GraduatedTier.ts

@@ -1,3 +1,5 @@
+import Subscriptions from "./Subscriptions";
+
 export default class GraduatedTier {
   constructor(
     private readonly from: number,
@@ -28,4 +30,16 @@ export default class GraduatedTier {
 
     return (subscriptions - this.from + 1) * this.price;
   }
+
+  totalFor2(subscriptions: Subscriptions): number {
+    if (subscriptions.covers(this)) {
+      return this.total();
+    }
+
+    if (!subscriptions.reaches(this)) {
+      return 0;
+    }
+
+    return subscriptions.numberOfSubscriptionsInTier(this) * this.price;
+  }
 }

exercises/graduated_tiered_prices/solutions/adrianliz/src/GraduatedTieredPricing.ts

@@ -1,5 +1,4 @@
 import GraduatedTier from "./GraduatedTier";
-import NumberOfSubscriptionsNotAllowed from "./NumberOfSubscriptionsNotAllowed";
 import Subscriptions from "./Subscriptions";
 
 export default class GraduatedTieredPricing {
@@ -13,23 +12,7 @@ export default class GraduatedTieredPricing {
     ];
   }
 
-  priceFor(subscriptions: number): number {
-    if (subscriptions < 1) {
-      throw new NumberOfSubscriptionsNotAllowed();
-    }
-
-    const tiers = this.tiers();
-
-    return (
-      tiers[0].totalFor(subscriptions) +
-      tiers[1].totalFor(subscriptions) +
-      tiers[2].totalFor(subscriptions) +
-      tiers[3].totalFor(subscriptions) +
-      tiers[4].totalFor(subscriptions)
-    );
-  }
-
-  priceFor2(subscriptions: Subscriptions): number {
+  priceFor(subscriptions: Subscriptions): number {
     return subscriptions.priceFor(this.tiers());
   }
 }

exercises/graduated_tiered_prices/solutions/adrianliz/src/Subscriptions.ts

@@ -9,9 +9,23 @@ export default class Subscriptions {
   }
 
   priceFor(tiers: GraduatedTier[]): number {
-    return tiers.reduce(
-      (total, tier) => total + tier.totalFor(this.subscriptions),
-      0
-    );
+    // return tiers.reduce(
+    //   (total, tier) => total + tier.totalFor(this.subscriptions),
+    //   0
+    // );
+
+    return tiers.reduce((total, tier) => total + tier.totalFor2(this), 0);
+  }
+
+  covers(tier: GraduatedTier): boolean {
+    return false;
+  }
+
+  reaches(tier: GraduatedTier): boolean {
+    return false;
+  }
+
+  numberOfSubscriptionsInTier(tier: GraduatedTier): number {
+    return 0;
   }
 }

exercises/graduated_tiered_prices/solutions/adrianliz/tests/GraduatedTieredPricing.test.ts

@@ -7,7 +7,7 @@ import Subscriptions from "../src/Subscriptions";
 describe("Graduated tiered pricing should", () => {
   it("throw number of subscriptions not allowed for 0 subscriptions", () => {
     const pricing = new GraduatedTieredPricing();
-    expect(() => pricing.priceFor2(new Subscriptions(0))).toThrow(
+    expect(() => pricing.priceFor(new Subscriptions(0))).toThrow(
       NumberOfSubscriptionsNotAllowed
     );
   });
@@ -24,7 +24,7 @@ describe("Graduated tiered pricing should", () => {
     "calculate the price for %i subscriptions",
     (subscriptions: number, expectedPrice: number) => {
       const pricing = new GraduatedTieredPricing();
-      expect(pricing.priceFor2(new Subscriptions(subscriptions))).toBe(
+      expect(pricing.priceFor(new Subscriptions(subscriptions))).toBe(
         expectedPrice
       );
     }