import { defineStore } from 'pinia'
import { ref, computed } from 'vue'
import { taskApi, type TaskResponse } from '@/api/tasks'
import type { TaskFormData, TaskFilters } from '@/api/types'
import { matchWithPinyin } from '@/utils/pinyin'
import { formatDate } from '@/utils/date'

export const useTaskStore = defineStore('task', () => {
  const allTasks = ref<TaskResponse[]>([])
  const loading = ref(false)
  const filters = ref<TaskFilters>({
    status: 'all',
    sort_by: 'priority',
    sort_order: 'desc'
  })

  // 所有任务
  const tasks = computed(() => {
    let result = [...allTasks.value]

    // 搜索过滤（支持拼音）
    if (filters.value.search?.trim()) {
      const keyword = filters.value.search.trim()
      result = result.filter(t =>
        matchWithPinyin(t.title, keyword) ||
        (t.description && matchWithPinyin(t.description, keyword)) ||
        t.tags?.some(tag => matchWithPinyin(tag.name, keyword))
      )
    }

    // 状态筛选
    if (filters.value.status === 'active') {
      result = result.filter(t => !t.is_completed)
    } else if (filters.value.status === 'completed') {
      result = result.filter(t => t.is_completed)
    }

    // 分类筛选
    if (filters.value.category_id) {
      result = result.filter(t => t.category_id === filters.value.category_id)
    }

    // 排序
    if (filters.value.sort_by) {
      result.sort((a, b) => {
        let comparison = 0

        if (filters.value.sort_by === 'priority') {
          const priorityOrder: Record<string, number> = { q1: 4, q2: 3, q3: 2, q4: 1 }
          const aOrder = priorityOrder[a.priority] || 0
          const bOrder = priorityOrder[b.priority] || 0
          comparison = aOrder - bOrder
        } else if (filters.value.sort_by === 'due_date') {
          if (!a.due_date && !b.due_date) comparison = 0
          else if (!a.due_date) comparison = 1
          else if (!b.due_date) comparison = -1
          else comparison = new Date(a.due_date).getTime() - new Date(b.due_date).getTime()
        } else {
          comparison = new Date(b.created_at).getTime() - new Date(a.created_at).getTime()
        }

        return filters.value.sort_order === 'asc' ? -comparison : comparison
      })
    }

    return result
  })

  // 计算进行中和已完成的任务数量（基于所有任务）
  const activeTasks = computed(() => allTasks.value.filter(t => !t.is_completed))
  const completedTasks = computed(() => allTasks.value.filter(t => t.is_completed))
  const totalTasks = computed(() => allTasks.value)

  // 按日期分组的任务（用于月视图）
  const tasksByDate = computed(() => {
    const grouped = new Map<string, TaskResponse[]>()
    const today = new Date()
    const todayStr = formatDate(today)

    allTasks.value.forEach(task => {
      let dateKey: string
      if (task.due_date) {
        dateKey = formatDate(new Date(task.due_date))
      } else {
        // 无截止日期的任务显示在当天
        dateKey = todayStr
      }

      if (!grouped.has(dateKey)) {
        grouped.set(dateKey, [])
      }
      grouped.get(dateKey)!.push(task)
    })

    return grouped
  })

  async function fetchTasks() {
    loading.value = true
    try {
      // 一次获取所有任务，在前端进行筛选和排序
      allTasks.value = await taskApi.getTasks({ status: 'all' })
    } catch (error) {
      console.error('获取任务列表失败:', error)
    } finally {
      loading.value = false
    }
  }

  async function createTask(data: TaskFormData) {
    try {
      const newTask = await taskApi.createTask(data)
      allTasks.value.unshift(newTask)
      return newTask
    } catch (error) {
      console.error('创建任务失败:', error)
      return null
    }
  }

  async function updateTask(id: number, data: TaskFormData) {
    try {
      const updatedTask = await taskApi.updateTask(id, data)
      const index = allTasks.value.findIndex((t: TaskResponse) => t.id === id)
      if (index !== -1) {
        allTasks.value[index] = updatedTask
      }
      return updatedTask
    } catch (error) {
      console.error('更新任务失败:', error)
      return null
    }
  }

  async function deleteTask(id: number) {
    try {
      await taskApi.deleteTask(id)
      allTasks.value = allTasks.value.filter((t: TaskResponse) => t.id !== id)
      return true
    } catch (error) {
      console.error('删除任务失败:', error)
      return false
    }
  }

  async function toggleTask(id: number) {
    try {
      const updatedTask = await taskApi.toggleTask(id)
      const index = allTasks.value.findIndex((t: TaskResponse) => t.id === id)
      if (index !== -1) {
        allTasks.value[index] = updatedTask
      }
      return updatedTask
    } catch (error) {
      console.error('切换任务状态失败:', error)
      return null
    }
  }

  function setFilters(newFilters: TaskFilters) {
    filters.value = { ...filters.value, ...newFilters }
    // 筛选现在在前端完成，不需要重新请求
  }

  return {
    tasks,
    loading,
    filters,
    activeTasks,
    completedTasks,
    totalTasks: allTasks,
    tasksByDate,
    fetchTasks,
    createTask,
    updateTask,
    deleteTask,
    toggleTask,
    setFilters
  }
})