feat: add condition evaluator with full operator support

src/engine/conditionEvaluator.js

@@ -0,0 +1,111 @@
+/**
+ * Condition evaluator for the Rebirth Incremental game.
+ * Evaluates condition objects against the current game state.
+ */
+
+/**
+ * Operator functions for comparing values.
+ * All operators perform loose equality/inequality checks where applicable.
+ */
+export const OPS = {
+  '==': (a, b) => a == b,
+  '===': (a, b) => a === b,
+  '!=': (a, b) => a != b,
+  '!==': (a, b) => a !== b,
+  '>': (a, b) => a > b,
+  '>=': (a, b) => a >= b,
+  '<': (a, b) => a < b,
+  '<=': (a, b) => a <= b,
+};
+
+/**
+ * Evaluates a condition object against the game state.
+ * @param {Object} condition - The condition to evaluate
+ * @param {Object} state - The current game state
+ * @returns {boolean} - Whether the condition is satisfied
+ */
+export function evaluateCondition(condition, state) {
+  if (!condition || typeof condition !== 'object') {
+    return false;
+  }
+
+  const { type } = condition;
+
+  switch (type) {
+    case 'age': {
+      const opFn = OPS[condition.op];
+      if (!opFn) return false;
+      return opFn(state.age ?? 0, condition.value);
+    }
+
+    case 'stat': {
+      const opFn = OPS[condition.op];
+      if (!opFn) return false;
+      const statValue = state.stats?.[condition.stat] ?? 0;
+      return opFn(statValue, condition.value);
+    }
+
+    case 'careerLevel': {
+      const opFn = OPS[condition.op];
+      if (!opFn) return false;
+      const level = state.careers?.[condition.careerId]?.level ?? 0;
+      return opFn(level, condition.value);
+    }
+
+    case 'money': {
+      const opFn = OPS[condition.op];
+      if (!opFn) return false;
+      return opFn(state.money ?? 0, condition.value);
+    }
+
+    case 'identity': {
+      return state.identity === condition.value;
+    }
+
+    case 'worldFlag': {
+      const flagValue = state.worldFlags?.[condition.flag];
+      if (condition.value !== undefined) {
+        return flagValue === condition.value;
+      }
+      return !!flagValue;
+    }
+
+    case 'hasItem': {
+      const itemCount = state.shopItems?.[condition.itemId] ?? 0;
+      return itemCount > 0;
+    }
+
+    case 'hasArtifact': {
+      const artifactValue = state.artifacts?.[condition.artifactId] ?? 0;
+      if (condition.op) {
+        const opFn = OPS[condition.op];
+        if (!opFn) return false;
+        return opFn(artifactValue, condition.value);
+      }
+      return artifactValue > 0;
+    }
+
+    case 'reincarnation': {
+      const opFn = OPS[condition.op];
+      if (!opFn) return false;
+      return opFn(state.reincarnation ?? 0, condition.value);
+    }
+
+    case 'and': {
+      if (!Array.isArray(condition.conditions)) return false;
+      return condition.conditions.every(sub => evaluateCondition(sub, state));
+    }
+
+    case 'or': {
+      if (!Array.isArray(condition.conditions)) return false;
+      return condition.conditions.some(sub => evaluateCondition(sub, state));
+    }
+
+    case 'not': {
+      return !evaluateCondition(condition.condition, state);
+    }
+
+    default:
+      return false;
+  }
+}