refactor: use subclasses for different item types

src/item/spell/calculate-spell-price.ts

@@ -0,0 +1,32 @@
+// SPDX-FileCopyrightText: 2021 Johannes Loher
+//
+// SPDX-License-Identifier: MIT
+
+import { CooldownDuration, DS4SpellDataSourceData } from "./spell-data-source";
+
+export function calculateSpellPrice(data: DS4SpellDataSourceData): number | null {
+    const spellPriceFactor = calculateSpellPriceFactor(data.cooldownDuration);
+    const baseSpellPrices = [
+        data.minimumLevels.healer !== null ? 10 + (data.minimumLevels.healer - 1) * 35 : null,
+        data.minimumLevels.wizard !== null ? 10 + (data.minimumLevels.wizard - 1) * 50 : null,
+        data.minimumLevels.sorcerer !== null ? 10 + (data.minimumLevels.sorcerer - 1) * 65 : null,
+    ].filter((baseSpellPrice: number | null): baseSpellPrice is number => baseSpellPrice !== null);
+    const baseSpellPrice = Math.min(...baseSpellPrices);
+    return baseSpellPrice === Infinity ? null : baseSpellPrice * spellPriceFactor;
+}
+
+function calculateSpellPriceFactor(cooldownDuration: CooldownDuration): number {
+    switch (cooldownDuration) {
+        case "0r":
+        case "1r":
+        case "2r":
+        case "5r":
+        case "10r":
+        case "100r":
+            return 1;
+        case "1d":
+            return 2;
+        case "d20d":
+            return 3;
+    }
+}