import { ref, computed, watch } from 'vue'
import { defineStore, acceptHMRUpdate } from 'pinia'

// 定义 Store 状态类型
interface CounterState {
  count: number
  name: string
  history: number[]
  lastUpdated: string | null
}

// 本地存储键名
const STORAGE_KEY = 'counter-store'

// 从本地存储恢复状态
function restoreFromStorage(): Partial<CounterState> {
  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    return stored ? JSON.parse(stored) : {}
  } catch (error) {
    console.warn('Failed to restore counter state from localStorage:', error)
    return {}
  }
}

// 保存状态到本地存储
function saveToStorage(state: CounterState) {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(state))
  } catch (error) {
    console.warn('Failed to save counter state to localStorage:', error)
  }
}

/**
 * 计数器 Store 示例 - 使用 Pinia 3.0.3 最佳实践
 * 包含数据持久化、类型安全、HMR 支持等特性
 */
export const useCounterStore = defineStore('counter', () => {
  // 从本地存储恢复初始状态
  const restored = restoreFromStorage()
  
  // 状态 (state) - 使用 ref 实现响应式
  const count = ref(restored.count ?? 0)
  const name = ref(restored.name ?? 'Vue3 + Pinia 3.0.3')
  const history = ref<number[]>(restored.history ?? [])
  const lastUpdated = ref<string | null>(restored.lastUpdated ?? null)

  // 计算属性 (getters) - 使用 computed
  const doubleCount = computed(() => count.value * 2)
  const isEven = computed(() => count.value % 2 === 0)
  const isPositive = computed(() => count.value > 0)
  const historyLength = computed(() => history.value.length)
  const averageValue = computed(() => {
    if (history.value.length === 0) return 0
    return history.value.reduce((sum, val) => sum + val, 0) / history.value.length
  })

  // 私有方法：更新历史记录和时间戳
  function updateMetadata() {
    history.value.push(count.value)
    // 限制历史记录长度
    if (history.value.length > 50) {
      history.value = history.value.slice(-50)
    }
    lastUpdated.value = new Date().toISOString()
  }

  // 方法 (actions)
  function increment() {
    count.value++
    updateMetadata()
  }

  function decrement() {
    count.value--
    updateMetadata()
  }

  function reset() {
    count.value = 0
    history.value = []
    lastUpdated.value = new Date().toISOString()
  }

  function setCount(newCount: number) {
    if (typeof newCount !== 'number' || !Number.isFinite(newCount)) {
      throw new Error('Count must be a finite number')
    }
    count.value = newCount
    updateMetadata()
  }

  function setName(newName: string) {
    if (typeof newName !== 'string' || newName.trim().length === 0) {
      throw new Error('Name must be a non-empty string')
    }
    name.value = newName.trim()
    lastUpdated.value = new Date().toISOString()
  }

  // 批量操作
  function addToCount(value: number) {
    if (typeof value !== 'number' || !Number.isFinite(value)) {
      throw new Error('Value must be a finite number')
    }
    count.value += value
    updateMetadata()
  }

  function multiplyCount(multiplier: number) {
    if (typeof multiplier !== 'number' || !Number.isFinite(multiplier)) {
      throw new Error('Multiplier must be a finite number')
    }
    count.value *= multiplier
    updateMetadata()
  }

  // 异步操作示例
  async function incrementAsync(delay: number = 1000): Promise<void> {
    if (delay < 0) {
      throw new Error('Delay must be non-negative')
    }
    
    return new Promise<void>((resolve, reject) => {
      const timeoutId = setTimeout(() => {
        try {
          increment()
          resolve()
        } catch (error) {
          reject(error)
        }
      }, delay)
      
      // 可以在这里添加取消逻辑
      // 例如：store.cancelAsyncOperation = () => clearTimeout(timeoutId)
    })
  }

  // 模拟 API 调用
  async function fetchCountFromAPI(): Promise<void> {
    try {
      // 模拟 API 延迟
      await new Promise(resolve => setTimeout(resolve, 1000))
      
      // 模拟 API 响应
      const apiResponse = Math.floor(Math.random() * 100)
      setCount(apiResponse)
      
      if (import.meta.env.DEV) {
        console.log('📡 Fetched count from API:', apiResponse)
      }
    } catch (error) {
      console.error('Failed to fetch count from API:', error)
      throw error
    }
  }

  // 清除历史记录
  function clearHistory() {
    history.value = []
    lastUpdated.value = new Date().toISOString()
  }

  // 导出状态用于备份
  function exportState(): CounterState {
    return {
      count: count.value,
      name: name.value,
      history: [...history.value],
      lastUpdated: lastUpdated.value
    }
  }

  // 导入状态用于恢复
  function importState(state: Partial<CounterState>) {
    if (state.count !== undefined) count.value = state.count
    if (state.name !== undefined) name.value = state.name
    if (state.history !== undefined) history.value = [...state.history]
    if (state.lastUpdated !== undefined) lastUpdated.value = state.lastUpdated
  }

  // 数据持久化：监听状态变化并自动保存
  watch(
    () => ({ count: count.value, name: name.value, history: history.value, lastUpdated: lastUpdated.value }),
    (state) => {
      saveToStorage(state as CounterState)
    },
    { deep: true, immediate: false }
  )

  return {
    // 状态
    count,
    name,
    history,
    lastUpdated,
    // 计算属性
    doubleCount,
    isEven,
    isPositive,
    historyLength,
    averageValue,
    // 基础方法
    increment,
    decrement,
    reset,
    setCount,
    setName,
    // 扩展方法
    addToCount,
    multiplyCount,
    clearHistory,
    // 异步方法
    incrementAsync,
    fetchCountFromAPI,
    // 工具方法
    exportState,
    importState
  }
})

// HMR 支持 (Hot Module Replacement)
if (import.meta.hot) {
  import.meta.hot.accept(acceptHMRUpdate(useCounterStore, import.meta.hot))
}