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

export const useTaskStore = defineStore('task', () => {
  // 状态
  const tasks = ref([])
  const currentFilter = ref('all') // all, pending, completed, overdue
  const currentSort = ref('dueDate') // dueDate, priority, created
  const searchKeyword = ref('')

  // 计算属性
  const filteredTasks = computed(() => {
    let filtered = tasks.value

    // 按状态过滤
    if (currentFilter.value === 'pending') {
      filtered = filtered.filter(task => !task.completed)
    } else if (currentFilter.value === 'completed') {
      filtered = filtered.filter(task => task.completed)
    } else if (currentFilter.value === 'overdue') {
      const now = new Date()
      filtered = filtered.filter(task => 
        !task.completed && 
        task.dueDate && 
        new Date(task.dueDate) < now
      )
    }

    // 按关键词搜索
    if (searchKeyword.value) {
      const keyword = searchKeyword.value.toLowerCase()
      filtered = filtered.filter(task => 
        task.title.toLowerCase().includes(keyword) ||
        task.description.toLowerCase().includes(keyword) ||
        task.tags.some(tag => tag.toLowerCase().includes(keyword))
      )
    }

    // 排序
    filtered.sort((a, b) => {
      switch (currentSort.value) {
        case 'priority':
          const priorityOrder = { high: 3, medium: 2, low: 1 }
          return (priorityOrder[b.priority] || 0) - (priorityOrder[a.priority] || 0)
        case 'created':
          return new Date(b.createdAt) - new Date(a.createdAt)
        case 'dueDate':
        default:
          if (!a.dueDate && !b.dueDate) return 0
          if (!a.dueDate) return 1
          if (!b.dueDate) return -1
          return new Date(a.dueDate) - new Date(b.dueDate)
      }
    })

    return filtered
  })

  const taskStats = computed(() => {
    const total = tasks.value.length
    const completed = tasks.value.filter(task => task.completed).length
    const pending = total - completed
    const overdue = tasks.value.filter(task => 
      !task.completed && 
      task.dueDate && 
      new Date(task.dueDate) < new Date()
    ).length

    return {
      total,
      completed,
      pending,
      overdue,
      completionRate: total > 0 ? Math.round((completed / total) * 100) : 0
    }
  })

  // 方法
  const addTask = (taskData) => {
    const newTask = {
      id: Date.now().toString(),
      title: taskData.title,
      description: taskData.description || '',
      priority: taskData.priority || 'medium',
      dueDate: taskData.dueDate || null,
      tags: taskData.tags || [],
      completed: false,
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString()
    }
    
    tasks.value.unshift(newTask)
    saveToStorage()
    return newTask
  }

  const updateTask = (id, updates) => {
    const index = tasks.value.findIndex(task => task.id === id)
    if (index !== -1) {
      tasks.value[index] = {
        ...tasks.value[index],
        ...updates,
        updatedAt: new Date().toISOString()
      }
      saveToStorage()
      return tasks.value[index]
    }
    return null
  }

  const deleteTask = (id) => {
    const index = tasks.value.findIndex(task => task.id === id)
    if (index !== -1) {
      tasks.value.splice(index, 1)
      saveToStorage()
      return true
    }
    return false
  }

  const toggleTask = (id) => {
    const task = tasks.value.find(task => task.id === id)
    if (task) {
      task.completed = !task.completed
      task.updatedAt = new Date().toISOString()
      saveToStorage()
      return task
    }
    return null
  }

  const setFilter = (filter) => {
    currentFilter.value = filter
  }

  const setSort = (sort) => {
    currentSort.value = sort
  }

  const setSearchKeyword = (keyword) => {
    searchKeyword.value = keyword
  }

  const clearCompleted = () => {
    tasks.value = tasks.value.filter(task => !task.completed)
    saveToStorage()
  }

  const getTaskById = (id) => {
    return tasks.value.find(task => task.id === id)
  }

  const getTasksByTag = (tag) => {
    return tasks.value.filter(task => task.tags.includes(tag))
  }

  const getOverdueTasks = () => {
    const now = new Date()
    return tasks.value.filter(task => 
      !task.completed && 
      task.dueDate && 
      new Date(task.dueDate) < now
    )
  }

  const getTodayTasks = () => {
    const today = new Date().toDateString()
    return tasks.value.filter(task => 
      !task.completed && 
      task.dueDate && 
      new Date(task.dueDate).toDateString() === today
    )
  }

  // 本地存储
  const saveToStorage = () => {
    try {
      uni.setStorageSync('tasks', JSON.stringify(tasks.value))
    } catch (error) {
      console.error('保存任务数据失败:', error)
    }
  }

  const loadFromStorage = () => {
    try {
      const stored = uni.getStorageSync('tasks')
      if (stored) {
        tasks.value = JSON.parse(stored)
      }
    } catch (error) {
      console.error('加载任务数据失败:', error)
    }
  }

  // 初始化示例数据
  const initSampleData = () => {
    if (tasks.value.length === 0) {
      const sampleTasks = [
        {
          id: '1',
          title: '完成项目需求分析',
          description: '分析用户需求，制定详细的功能规格说明',
          priority: 'high',
          dueDate: new Date(Date.now() + 2 * 24 * 60 * 60 * 1000).toISOString(),
          tags: ['工作', '项目'],
          completed: false,
          createdAt: new Date(Date.now() - 3 * 24 * 60 * 60 * 1000).toISOString(),
          updatedAt: new Date(Date.now() - 3 * 24 * 60 * 60 * 1000).toISOString()
        },
        {
          id: '2',
          title: '准备会议材料',
          description: '准备下周团队会议的PPT和资料',
          priority: 'medium',
          dueDate: new Date(Date.now() + 1 * 24 * 60 * 60 * 1000).toISOString(),
          tags: ['工作', '会议'],
          completed: false,
          createdAt: new Date(Date.now() - 2 * 24 * 60 * 60 * 1000).toISOString(),
          updatedAt: new Date(Date.now() - 2 * 24 * 60 * 60 * 1000).toISOString()
        },
        {
          id: '3',
          title: '购买生活用品',
          description: '去超市购买日用品和食材',
          priority: 'low',
          dueDate: null,
          tags: ['生活', '购物'],
          completed: true,
          createdAt: new Date(Date.now() - 5 * 24 * 60 * 60 * 1000).toISOString(),
          updatedAt: new Date(Date.now() - 1 * 24 * 60 * 60 * 1000).toISOString()
        },
        {
          id: '4',
          title: '学习新技术',
          description: '学习Vue 3和Pinia状态管理',
          priority: 'medium',
          dueDate: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString(),
          tags: ['学习', '技术'],
          completed: false,
          createdAt: new Date(Date.now() - 1 * 24 * 60 * 60 * 1000).toISOString(),
          updatedAt: new Date(Date.now() - 1 * 24 * 60 * 60 * 1000).toISOString()
        }
      ]
      tasks.value = sampleTasks
      saveToStorage()
    }
  }

  return {
    // 状态
    tasks,
    currentFilter,
    currentSort,
    searchKeyword,
    
    // 计算属性
    filteredTasks,
    taskStats,
    
    // 方法
    addTask,
    updateTask,
    deleteTask,
    toggleTask,
    setFilter,
    setSort,
    setSearchKeyword,
    clearCompleted,
    getTaskById,
    getTasksByTag,
    getOverdueTasks,
    getTodayTasks,
    loadFromStorage,
    initSampleData
  }
})