feature/5-drop-command (#17)

#5

Reviewed-on: https://gitea.vylpes.xyz/External/card-drop/pulls/17
Co-authored-by: Ethan Lane <ethan@vylpes.com>
Co-committed-by: Ethan Lane <ethan@vylpes.com>

src/helpers/CardDropHelper.ts

@@ -0,0 +1,38 @@
+import { CardRarity } from "../constants/CardRarity";
+import CardDataSource from "../database/dataSources/cardDataSource";
+import Card from "../database/entities/card/Card";
+import Series from "../database/entities/card/Series";
+
+export default class CardDropHelper {
+    public static async GetRandomCard(): Promise<Card> {
+        const seriesRepository = CardDataSource.getRepository(Series);
+
+        const allSeries = await Series.FetchAll(Series, [ "Cards", "Cards.Series" ]);
+        const allSeriesWithCards = allSeries.filter(x => x.Cards.length > 0);
+
+        const randomSeriesIndex = Math.floor(Math.random() * allSeriesWithCards.length);
+
+        const randomSeries = allSeriesWithCards[randomSeriesIndex];
+
+        const randomRarity = Math.random() * 100;
+
+        let cardRarity: CardRarity;
+
+        const bronzeChance = 62;
+        const silverChance = bronzeChance + 31;
+        const goldChance = silverChance + 6.4;
+
+        if (randomRarity < bronzeChance) cardRarity = CardRarity.Bronze;
+        else if (randomRarity < silverChance) cardRarity = CardRarity.Silver;
+        else if (randomRarity < goldChance) cardRarity = CardRarity.Gold;
+        else cardRarity = CardRarity.Legendary;
+
+        const allCards = randomSeries.Cards.filter(x => x.Rarity == cardRarity);
+
+        const randomCardIndex = Math.floor(Math.random() * allCards.length);
+
+        const randomCard = allCards[randomCardIndex];
+
+        return randomCard;
+    }
+}