import { computed, onMounted, ref, watch } from 'vue'
import { CornerDownLeft, Database, Sparkles, Sun } from 'lucide-vue-next'
import { scheduleCenterApi, type ScheduleCenterDateResponse, type ScheduleCenterDaySummary } from '@/api/scheduleCenter'

export interface SidebarFocusItem {
  id: string; label: string; title: string; meta: string; tone: 'done' | 'doing' | 'pending'
}
export interface SidebarNewsItem {
  id: string; title: string; meta: string
}

export const sidebarCollapsedModules = [
  { id: 'calendar', label: '日历', icon: Sun },
  { id: 'status', label: '计划', icon: Database },
  { id: 'focus', label: '重点', icon: Sparkles },
  { id: 'review', label: '复盘', icon: CornerDownLeft },
]

function formatDateKey(date: Date) {
  const year = date.getFullYear()
  const month = String(date.getMonth() + 1).padStart(2, '0')
  const day = String(date.getDate()).padStart(2, '0')
  return `${year}-${month}-${day}`
}

function formatMonthKey(date: Date) {
  const year = date.getFullYear()
  const month = String(date.getMonth() + 1).padStart(2, '0')
  return `${year}-${month}`
}

export function useSidebarPlan(clientTimeRef: { value: Date }, loadDailyDigestFn: () => void) {
  const todayPlanDetail = ref<ScheduleCenterDateResponse | null>(null)
  const monthPlanDays = ref<ScheduleCenterDaySummary[]>([])

  const todayDateKey = computed(() => formatDateKey(clientTimeRef.value))
  const monthPlanSummaryMap = computed(() => new Map(monthPlanDays.value.map((item) => [item.date, item])))

  const calendarCells = computed(() => {
    const year = clientTimeRef.value.getFullYear()
    const month = clientTimeRef.value.getMonth()
    const daysInMonth = new Date(year, month + 1, 0).getDate()
    const firstDayOffset = (new Date(year, month, 1).getDay() + 6) % 7
    const cells: Array<{ key: string; value: number | null; active: boolean; busy: boolean }> = []
    for (let index = 0; index < firstDayOffset; index += 1) {
      cells.push({ key: `blank-start-${index}`, value: null, active: false, busy: false })
    }
    for (let day = 1; day <= daysInMonth; day += 1) {
      const monthDate = new Date(year, month, day)
      const dateKey = formatDateKey(monthDate)
      const summary = monthPlanSummaryMap.value.get(dateKey)
      const busy = Boolean(summary && (summary.todo_total + summary.task_due_total + summary.goal_total + summary.reminder_total) > 0)
      cells.push({ key: dateKey, value: day, active: day === clientTimeRef.value.getDate(), busy })
    }
    while (cells.length % 7 !== 0) {
      cells.push({ key: `blank-end-${cells.length}`, value: null, active: false, busy: false })
    }
    return cells
  })

  const todayPlanCounters = computed(() => {
    const detail = todayPlanDetail.value
    if (!detail) return { done: 0, doing: 0, pending: 0, total: 0, completion: 0 }
    const todoDone = detail.todos.filter((item) => item.is_completed).length
    const todoPending = detail.todos.filter((item) => !item.is_completed).length
    const taskDone = detail.tasks.filter((item) => item.status === 'done').length
    const taskDoing = detail.tasks.filter((item) => item.status === 'in_progress').length
    const taskPending = detail.tasks.filter((item) => item.status === 'todo').length
    const goalDone = detail.goals.filter((item) => item.status === 'done').length
    const goalPending = detail.goals.filter((item) => item.status !== 'done').length
    const reminderDone = detail.reminders.filter((item) => item.status === 'done' || item.is_dismissed).length
    const reminderPending = detail.reminders.filter((item) => item.status !== 'done' && !item.is_dismissed).length
    const done = todoDone + taskDone + goalDone + reminderDone
    const doing = taskDoing
    const pending = todoPending + taskPending + goalPending + reminderPending
    const total = done + doing + pending
    return { done, doing, pending, total, completion: total > 0 ? Math.round((done / total) * 100) : 0 }
  })

  const monthReviewStats = computed(() => monthPlanDays.value.reduce(
    (acc, item) => {
      acc.todoTotal += item.todo_total
      acc.todoCompleted += item.todo_completed
      acc.taskTotal += item.task_due_total
      acc.reminderTotal += item.reminder_total
      acc.goalTotal += item.goal_total
      acc.highPriorityTotal += item.high_priority_total
      if (item.todo_total + item.task_due_total + item.reminder_total + item.goal_total > 0) acc.activeDays += 1
      return acc
    },
    { todoTotal: 0, todoCompleted: 0, taskTotal: 0, reminderTotal: 0, goalTotal: 0, highPriorityTotal: 0, activeDays: 0 },
  ))

  const sidebarWeekLabels = ['一', '二', '三', '四', '五', '六', '日']

  const sidebarStatusHeadline = computed(() => (
    todayPlanCounters.value.total
      ? `今日共 ${todayPlanCounters.value.total} 项计划，已完成 ${todayPlanCounters.value.done} 项`
      : '今日计划正在同步，稍后会显示最新状态'
  ))

  const sidebarStatusBreakdown = computed(() => [
    { key: 'done', label: '已完成', value: todayPlanCounters.value.done, tone: 'done' },
    { key: 'doing', label: '进行中', value: todayPlanCounters.value.doing, tone: 'doing' },
    { key: 'pending', label: '未开始', value: todayPlanCounters.value.pending, tone: 'pending' },
  ])

  const sidebarFocusItems = computed<SidebarFocusItem[]>(() => {
    const detail = todayPlanDetail.value
    if (!detail) return []
    const goalItems = detail.goals.filter((goal) => goal.status !== 'done').map((goal) => ({
      id: `goal-${goal.id}`, label: '目标', title: goal.title, meta: goal.note || '今日目标推进', tone: 'doing' as const,
    }))
    const taskItems = detail.tasks.filter((task) => task.status !== 'done' && task.status !== 'cancelled')
      .sort((a, b) => { const r = { urgent: 0, high: 1, medium: 2, low: 3 }; return r[a.priority] - r[b.priority] })
      .map((task) => ({
        id: `task-${task.id}`, label: task.priority === 'urgent' || task.priority === 'high' ? '高优任务' : '任务',
        title: task.title, meta: task.status === 'in_progress' ? '处理中' : '待启动',
        tone: task.status === 'in_progress' ? 'doing' as const : 'pending' as const,
      }))
    const reminderItems = detail.reminders.filter((r) => r.status !== 'done' && !r.is_dismissed)
      .map((r) => ({ id: `reminder-${r.id}`, label: '提醒', title: r.title, meta: r.reminder_at.slice(11, 16), tone: 'pending' as const }))
    const todoItems = detail.todos.filter((t) => !t.is_completed)
      .map((t) => ({ id: `todo-${t.id}`, label: '待办', title: t.title, meta: t.source === 'manual' ? '手动记录' : '系统同步', tone: 'pending' as const }))
    return [...goalItems, ...taskItems, ...reminderItems, ...todoItems].slice(0, 5)
  })

  const sidebarReviewAchievements = computed(() => {
    const stats = monthReviewStats.value
    const items = [
      stats.todoCompleted > 0 ? `累计完成 ${stats.todoCompleted} 项待办，执行节啬已形成闭环。` : '',
      stats.activeDays > 0 ? `本月已有 ${stats.activeDays} 天产生有效计划记录，日程连贯性稳定。` : '',
      stats.highPriorityTotal > 0 ? `高优事项共 ${stats.highPriorityTotal} 项进行中，重点任务没有脱离视野。` : '',
    ].filter(Boolean)
    if (items.length > 0) return items.slice(0, 3)
    return ['本月计划数据还在积累中，可以从今日重点开始逐步建立复盘样本。']
  })

  const sidebarReviewReflections = computed(() => {
    const stats = monthReviewStats.value
    const pendingTodoCount = Math.max(stats.todoTotal - stats.todoCompleted, 0)
    const items = [
      pendingTodoCount > 0 ? `仍有 ${pendingTodoCount} 项待办未完成，建议拆成更短的收尾窗口。` : '',
      stats.highPriorityTotal >= 8 ? '高优事项密度偏高，最好提前锁定 1 到 2 个绝对优先级别。' : '',
      stats.reminderTotal >= Math.max(6, stats.activeDays) ? '提醒数量较多，说明执行中断点偏多，适合增加固定回固时段。' : '',
    ].filter(Boolean)
    if (items.length > 0) return items.slice(0, 3)
    return ['本月节啬相对稳定，下一步可以把重点事项再收到更清晰的主线。']
  })

  const sidebarFeedItems = computed<SidebarNewsItem[]>(() => [
    { id: 'fallback-1', title: 'AI 研发节啬继续升温，模型与工作流一体化成为主溜话题。', meta: 'Industry' },
    { id: 'fallback-2', title: '本地知识库与计划系统的联动体验，正在成为效率工具的新竞争点。', meta: 'Product' },
    { id: 'fallback-3', title: '建议接入真实 RSS 源后替换当前占位卡片，以获得即时资讯流。', meta: 'System' },
  ])

  const topbarFeedItems = computed(() => sidebarFeedItems.value.length > 0 ? [...sidebarFeedItems.value, ...sidebarFeedItems.value] : [])

  async function loadSidebarPlanSnapshot(date = new Date()) {
    const dateKey = formatDateKey(date)
    const monthKey = formatMonthKey(date)
    try {
      const [todayResponse, monthResponse] = await Promise.all([
        scheduleCenterApi.date(dateKey),
        scheduleCenterApi.month(monthKey),
      ])
      todayPlanDetail.value = todayResponse.data
      monthPlanDays.value = monthResponse.data.days
    } catch (err) {
      console.warn('Failed to load sidebar plan snapshot:', err)
      todayPlanDetail.value = null
      monthPlanDays.value = []
    }
  }

  watch(todayDateKey, (next, previous) => {
    if (next === previous) return
    void loadDailyDigestFn()
    void loadSidebarPlanSnapshot(clientTimeRef.value)
  })

  onMounted(() => {
    void loadDailyDigestFn()
    void loadSidebarPlanSnapshot(new Date())
  })

  return {
    todayPlanDetail, monthPlanDays, todayDateKey, monthPlanSummaryMap,
    calendarCells, todayPlanCounters, monthReviewStats,
    sidebarWeekLabels, sidebarStatusHeadline, sidebarStatusBreakdown,
    sidebarFocusItems, sidebarReviewAchievements, sidebarReviewReflections,
    sidebarFeedItems, topbarFeedItems, loadSidebarPlanSnapshot, sidebarCollapsedModules
  }
}