feat(game): add bag store

Build_God_Game/src/stores/bag.ts

@@ -0,0 +1,86 @@
+import { defineStore } from 'pinia'
+import { ref, computed } from 'vue'
+import { getCharacterBag, getBagItems, type CharacterBag, type BagItem } from '@/api/bag'
+import { useCharacterStore } from './character'
+
+const PAGE_SIZE = 16
+
+export const useBagStore = defineStore('bag', () => {
+  const characterStore = useCharacterStore()
+  
+  const characterBag = ref<CharacterBag | null>(null)
+  const bagItems = ref<BagItem[]>([])
+  const currentPage = ref(1)
+  const loading = ref(false)
+  const error = ref<string | null>(null)
+
+  const currentCharacterId = computed(() => characterStore.currentCharacter?.id)
+  
+  const totalItems = computed(() => bagItems.value.length)
+  
+  const totalPages = computed(() => Math.ceil(totalItems.value / PAGE_SIZE))
+  
+  const paginatedItems = computed(() => {
+    const start = (currentPage.value - 1) * PAGE_SIZE
+    const end = start + PAGE_SIZE
+    return bagItems.value.slice(start, end)
+  })
+
+  const usedCapacity = computed(() => {
+    return bagItems.value.reduce((sum, item) => sum + item.quantity, 0)
+  })
+
+  const loadBag = async () => {
+    if (!currentCharacterId.value) {
+      error.value = '请先选择角色'
+      return
+    }
+
+    try {
+      loading.value = true
+      error.value = null
+      
+      characterBag.value = await getCharacterBag(currentCharacterId.value)
+      
+      if (characterBag.value) {
+        bagItems.value = await getBagItems(characterBag.value.id)
+      } else {
+        bagItems.value = []
+      }
+      
+      currentPage.value = 1
+    } catch (e: any) {
+      error.value = e.message || '加载背包失败'
+      console.error('Load bag error:', e)
+    } finally {
+      loading.value = false
+    }
+  }
+
+  const nextPage = () => {
+    if (currentPage.value < totalPages.value) {
+      currentPage.value++
+    }
+  }
+
+  const prevPage = () => {
+    if (currentPage.value > 1) {
+      currentPage.value--
+    }
+  }
+
+  return {
+    characterBag,
+    bagItems,
+    currentPage,
+    totalPages,
+    totalItems,
+    paginatedItems,
+    usedCapacity,
+    loading,
+    error,
+    loadBag,
+    nextPage,
+    prevPage
+  }
+})