feat: First iteration, multi themes, I18N

public/js/engine/context.js

@@ -0,0 +1,27 @@
+import { EFFECT_TYPES } from './effects.js';
+
+/**
+ * Bundle the static game data (data/*.json) with lookup tables and validate it,
+ * so a typo in a JSON file fails loudly at startup instead of mid-game.
+ */
+export function buildContext({ rules, generators, upgrades }) {
+  const generatorsById = new Map(generators.map((g) => [g.id, g]));
+  const upgradesById = new Map(upgrades.map((u) => [u.id, u]));
+
+  if (generatorsById.size !== generators.length) throw new Error('Duplicate generator id');
+  if (upgradesById.size !== upgrades.length) throw new Error('Duplicate upgrade id');
+
+  for (const u of upgrades) {
+    if (!EFFECT_TYPES.includes(u.effect?.type)) {
+      throw new Error(`Upgrade "${u.id}": unknown effect type "${u.effect?.type}"`);
+    }
+    if (u.effect.target && !generatorsById.has(u.effect.target)) {
+      throw new Error(`Upgrade "${u.id}": unknown generator "${u.effect.target}"`);
+    }
+    if (u.requires && !upgradesById.has(u.requires)) {
+      throw new Error(`Upgrade "${u.id}": unknown requirement "${u.requires}"`);
+    }
+  }
+
+  return { rules, generators, upgrades, generatorsById, upgradesById };
+}