feat: add shop engine with 3-tab support and artifact upgrades

src/config/shop.json

@@ -0,0 +1,63 @@
+{
+  "items": [
+    {
+      "id": "taoist_license",
+      "name": "道碟",
+      "tab": "item",
+      "cost": 500,
+      "unlockConditions": [
+        { "type": "age", "op": ">=", "value": 10 },
+        { "type": "or", "conditions": [
+          { "type": "identity", "value": "taoist_orphan" },
+          { "type": "worldFlag", "flag": "met_taoist_priest", "value": true }
+        ]}
+      ],
+      "effects": [
+        { "type": "unlockCareer", "careerId": "taoist_priest" },
+        { "type": "setFlag", "flag": "has_taoist_license", "value": true }
+      ],
+      "resetOnRebirth": true
+    },
+    {
+      "id": "power_pill",
+      "name": "大力丸",
+      "tab": "item",
+      "cost": 50,
+      "unlockConditions": [],
+      "effects": [
+        { "type": "addStat", "stat": "body", "value": 5 }
+      ],
+      "resetOnRebirth": true
+    }
+  ],
+  "buffs": [
+    {
+      "id": "clever_brush",
+      "name": "妙笔生花",
+      "tab": "buff",
+      "cost": 200,
+      "unlockConditions": [],
+      "effects": [
+        { "type": "addStat", "stat": "wisdom", "value": 10 }
+      ],
+      "resetOnRebirth": true
+    }
+  ],
+  "artifacts": [
+    {
+      "id": "immortal_sword",
+      "name": "仙剑",
+      "tab": "artifact",
+      "baseCost": 1000,
+      "costGrowth": 1.5,
+      "unlockConditions": [
+        { "type": "careerLevel", "careerId": "taoist_priest", "op": ">=", "value": 50 }
+      ],
+      "effects": [
+        { "type": "addStat", "stat": "body", "value": 10 }
+      ],
+      "resetOnRebirth": false,
+      "maxLevel": 10
+    }
+  ]
+}

src/engine/shopEngine.js

@@ -0,0 +1,135 @@
+import { evaluateCondition } from './conditionEvaluator.js';
+import { applyEffect } from './effectApplier.js';
+import { canAfford, spendMoney } from './moneySystem.js';
+
+let _shopConfig = null;
+
+export function setShopConfig(config) {
+  _shopConfig = config;
+}
+
+export function getShopConfig() {
+  return _shopConfig;
+}
+
+export function findEntry(config, id) {
+  if (!config || !id) return null;
+
+  const sections = ['items', 'buffs', 'artifacts'];
+  for (const section of sections) {
+    const list = config[section];
+    if (!Array.isArray(list)) continue;
+    const entry = list.find(e => e.id === id);
+    if (entry) {
+      return { ...entry, section };
+    }
+  }
+  return null;
+}
+
+export function getArtifactUpgradeCost(config, artifactId, currentLevel) {
+  if (!config || !config.artifacts || !artifactId) return null;
+  const entry = config.artifacts.find(a => a.id === artifactId);
+  if (!entry) return null;
+  return Math.floor(entry.baseCost * Math.pow(entry.costGrowth, currentLevel));
+}
+
+export function canBuyItem(config, state, itemId) {
+  const entry = findEntry(config, itemId);
+  if (!entry) return false;
+
+  // Check unlock conditions
+  if (Array.isArray(entry.unlockConditions) && entry.unlockConditions.length > 0) {
+    const allMet = entry.unlockConditions.every(cond => evaluateCondition(cond, state));
+    if (!allMet) return false;
+  }
+
+  // Check max level for artifacts
+  if (entry.section === 'artifacts') {
+    const currentLevel = state.artifacts?.[itemId] || 0;
+    if (entry.maxLevel !== undefined && currentLevel >= entry.maxLevel) {
+      return false;
+    }
+  }
+
+  // Check cost
+  let cost;
+  if (entry.section === 'artifacts') {
+    const currentLevel = state.artifacts?.[itemId] || 0;
+    cost = getArtifactUpgradeCost(config, itemId, currentLevel);
+  } else {
+    cost = entry.cost;
+  }
+
+  if (cost === null || cost === undefined) return false;
+  return canAfford(state, cost);
+}
+
+export function buyItem(config, state, itemId) {
+  if (!canBuyItem(config, state, itemId)) {
+    return false;
+  }
+
+  const entry = findEntry(config, itemId);
+  if (!entry) return false;
+
+  // Calculate cost
+  let cost;
+  if (entry.section === 'artifacts') {
+    const currentLevel = state.artifacts?.[itemId] || 0;
+    cost = getArtifactUpgradeCost(config, itemId, currentLevel);
+  } else {
+    cost = entry.cost;
+  }
+
+  // Spend money
+  if (!spendMoney(state, cost)) {
+    return false;
+  }
+
+  // Apply effects
+  if (Array.isArray(entry.effects)) {
+    for (const effect of entry.effects) {
+      applyEffect(effect, state);
+    }
+  }
+
+  // Record purchase
+  if (entry.section === 'items') {
+    if (!state.shopItems) state.shopItems = {};
+    state.shopItems[itemId] = (state.shopItems[itemId] || 0) + 1;
+  } else if (entry.section === 'buffs') {
+    if (!state.activeBuffs) state.activeBuffs = {};
+    state.activeBuffs[itemId] = { expiresDay: -1 };
+  } else if (entry.section === 'artifacts') {
+    if (!state.artifacts) state.artifacts = {};
+    state.artifacts[itemId] = (state.artifacts[itemId] || 0) + 1;
+  }
+
+  return true;
+}
+
+export function resetShopItems(state) {
+  state.shopItems = {};
+  state.activeBuffs = {};
+  // Artifacts are preserved
+}
+
+export function applyArtifactEffects(config, state) {
+  if (!config || !state.artifacts) return;
+
+  for (const [artifactId, level] of Object.entries(state.artifacts)) {
+    if (level <= 0) continue;
+
+    const entry = config.artifacts?.find(a => a.id === artifactId);
+    if (!entry || !Array.isArray(entry.effects)) continue;
+
+    for (const effect of entry.effects) {
+      const scaledEffect = {
+        ...effect,
+        value: effect.value * level
+      };
+      applyEffect(scaledEffect, state);
+    }
+  }
+}