import { computed, onMounted, onUnmounted, ref, watch, type Ref } from 'vue'
import { CornerDownLeft, Database, Sparkles, Sun, ListTodo } from 'lucide-vue-next'
import {
  scheduleCenterApi,
  type ScheduleCenterCommanderSummary,
  type ScheduleCenterDateResponse,
  type ScheduleCenterDaySummary,
} from '@/api/scheduleCenter'
import { taskApi, type Task, type TaskDispatchStatus, type TaskQuadrant } from '@/api/task'
import type { Conversation } from '@/api/conversation'

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 interface TodayStatusQuadrantViewTask {
  id: string
  title: string
  completed: boolean
  status: string
  dispatchStatus: string
  assigneeLabel: string
}

export interface TodayStatusQuadrantView {
  id: string
  title: string
  subtitle: string
  color: string
  glowColor: string
  icon: string
  tasks: TodayStatusQuadrantViewTask[]
}

export const sidebarCollapsedModules = [
  { id: 'calendar', label: 'Calendar', icon: Sun },
  { id: 'status', label: 'Status', icon: Database },
  { id: 'focus', label: 'Focus', icon: Sparkles },
  { id: 'kanban', label: 'Issues', icon: ListTodo },
  { id: 'review', label: 'Review', icon: CornerDownLeft },
]

const ISSUE_QUADRANT_META: Record<TaskQuadrant, Omit<TodayStatusQuadrantView, 'tasks'>> = {
  'urgent-important': {
    id: 'urgent-important',
    title: 'Important & Urgent',
    subtitle: 'CRITICAL',
    color: '#ff4757',
    glowColor: 'rgba(255, 71, 87, 0.4)',
    icon: '!',
  },
  'not-urgent-important': {
    id: 'not-urgent-important',
    title: 'Important & Planned',
    subtitle: 'PLANNED',
    color: '#ffd93d',
    glowColor: 'rgba(255, 217, 61, 0.4)',
    icon: 'P',
  },
  'urgent-not-important': {
    id: 'urgent-not-important',
    title: 'Urgent & Delegated',
    subtitle: 'DELEGATE',
    color: '#00d4ff',
    glowColor: 'rgba(0, 212, 255, 0.4)',
    icon: 'D',
  },
  'not-urgent-not-important': {
    id: 'not-urgent-not-important',
    title: 'Backlog / Low Priority',
    subtitle: 'BACKLOG',
    color: '#6bcf7f',
    glowColor: 'rgba(107, 207, 127, 0.4)',
    icon: 'B',
  },
}

export 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}`
}

function toneFromStatus(status: string) {
  if (status === 'done' || status === 'completed') return 'done' as const
  if (status === 'in_progress' || status === 'running' || status === 'queued') return 'doing' as const
  return 'pending' as const
}

function focusLabelByQuadrant(quadrant?: string | null) {
  if (!quadrant) return 'Task'
  if (quadrant === 'urgent-important') return 'Critical'
  if (quadrant === 'not-urgent-important') return 'Planned'
  if (quadrant === 'urgent-not-important') return 'Delegated'
  return 'Backlog'
}

function focusMeta(status: string, dispatchStatus: string, assigneeType?: string | null, assigneeId?: string | null) {
  const statusMap: Record<string, string> = {
    todo: 'Pending',
    in_progress: 'In progress',
    done: 'Done',
    cancelled: 'Cancelled',
  }
  const dispatchMap: Record<string, string> = {
    idle: 'Not dispatched',
    queued: 'Queued',
    running: 'Running',
    completed: 'Completed',
    failed: 'Failed',
  }
  const statusLabel = dispatchStatus !== 'idle' ? dispatchMap[dispatchStatus] : (statusMap[status] || 'Pending')
  if (assigneeType && assigneeId) return `${statusLabel} / ${assigneeType}:${assigneeId}`
  if (assigneeType) return `${statusLabel} / ${assigneeType}`
  return statusLabel
}

function deriveIssueQuadrant(task: Task): TaskQuadrant {
  if (task.quadrant) return task.quadrant
  if (task.priority === 'high' || task.priority === 'urgent') return 'urgent-important'
  if (task.status === 'in_progress') return 'not-urgent-important'
  if (task.priority === 'medium') return 'urgent-not-important'
  return 'not-urgent-not-important'
}

function buildIssueCommanderSummary(tasks: Task[]): ScheduleCenterCommanderSummary {
  const summary: ScheduleCenterCommanderSummary = {
    total: 0,
    queued: 0,
    running: 0,
    completed: 0,
    failed: 0,
    overall_status: 'idle',
  }

  tasks.forEach((task) => {
    const state = task.dispatch_status as TaskDispatchStatus
    if (state === 'idle') return

    summary.total += 1
    if (state === 'queued') summary.queued += 1
    if (state === 'running') summary.running += 1
    if (state === 'completed') summary.completed += 1
    if (state === 'failed') summary.failed += 1
  })

  if (summary.running > 0) {
    summary.overall_status = 'running'
  } else if (summary.queued > 0) {
    summary.overall_status = 'queued'
  } else if (summary.failed > 0 && summary.completed === 0) {
    summary.overall_status = 'failed'
  }

  return summary
}

export function useSidebarPlan(
  clientTimeRef: { value: Date },
  loadDailyDigestFn: () => void,
  conversationsRef: Ref<Conversation[]> | Conversation[] = [],
) {
  const todayPlanDetail = ref<ScheduleCenterDateResponse | null>(null)
  const monthPlanDays = ref<ScheduleCenterDaySummary[]>([])
  const issueTasks = ref<Task[]>([])
  const selectedDate = ref<string | null>(null)

  const conversationDateMap = computed(() => {
    const map = new Map<string, boolean>()
    const conversations = Array.isArray(conversationsRef) ? conversationsRef : (conversationsRef.value ?? [])
    conversations.forEach((conv) => {
      map.set(formatDateKey(new Date(conv.updated_at)), true)
    })
    return map
  })

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

  const issueStatusQuadrants = computed<TodayStatusQuadrantView[]>(() => (
    Object.values(ISSUE_QUADRANT_META).map((meta) => ({
      ...meta,
      tasks: issueTasks.value
        .filter((task) => deriveIssueQuadrant(task) === meta.id)
        .map((task) => ({
          id: task.id,
          title: task.title,
          completed: task.status === 'done',
          status: task.status,
          dispatchStatus: task.dispatch_status,
          assigneeLabel: task.assignee_id ? `${task.assignee_type ?? 'owner'}:${task.assignee_id}` : (task.assignee_type ?? 'unassigned'),
        })),
    }))
  ))

  const issueCommanderSummary = computed<ScheduleCenterCommanderSummary>(() => buildIssueCommanderSummary(issueTasks.value))

  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 todayKey = todayDateKey.value
    const cells: Array<{ key: string; value: number | null; active: boolean; busy: boolean; selected: boolean; hasConversation: boolean }> = []

    for (let index = 0; index < firstDayOffset; index += 1) {
      cells.push({ key: `blank-start-${index}`, value: null, active: false, busy: false, selected: false, hasConversation: 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)
      const hasConv = conversationDateMap.value.get(dateKey) || false
      cells.push({ key: dateKey, value: day, active: dateKey === todayKey, busy, selected: dateKey === selectedDate.value, hasConversation: hasConv })
    }

    while (cells.length % 7 !== 0) {
      cells.push({ key: `blank-end-${cells.length}`, value: null, active: false, busy: false, selected: false, hasConversation: false })
    }

    return cells
  })

  const calendarYear = computed(() => clientTimeRef.value.getFullYear())
  const calendarMonth = computed(() => clientTimeRef.value.getMonth() + 1)

  const issueStatusCounters = computed(() => {
    const done = issueTasks.value.filter((item) => item.status === 'done').length
    const doing = issueTasks.value.filter((item) => item.status === 'in_progress').length
    const pending = issueTasks.value.filter((item) => item.status === 'todo').length
    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 = [
    { label: 'M', isWeekend: false },
    { label: 'T', isWeekend: false },
    { label: 'W', isWeekend: false },
    { label: 'T', isWeekend: false },
    { label: 'F', isWeekend: false },
    { label: 'S', isWeekend: true },
    { label: 'S', isWeekend: true },
  ]

  const sidebarStatusHeadline = computed(() => '')

  const sidebarStatusBreakdown = computed(() => [
    { key: 'done', label: 'Completed', value: issueStatusCounters.value.done, tone: 'done' },
    { key: 'doing', label: 'In Progress', value: issueStatusCounters.value.doing, tone: 'doing' },
    { key: 'pending', label: 'Pending', value: issueStatusCounters.value.pending, tone: 'pending' },
    { key: 'total', label: 'Total', value: issueStatusCounters.value.total, tone: 'total' },
  ])

  const sidebarFocusItems = computed<SidebarFocusItem[]>(() => (
    (todayPlanDetail.value?.focus_tasks ?? []).map((task) => ({
      id: task.id,
      label: focusLabelByQuadrant(task.quadrant),
      title: task.title,
      meta: focusMeta(task.status, task.dispatch_status, task.assignee_type, task.assignee_id),
      tone: toneFromStatus(task.dispatch_status !== 'idle' ? task.dispatch_status : task.status),
    }))
  ))

  const sidebarReviewAchievements = computed(() => {
    const stats = monthReviewStats.value
    const items = [
      stats.todoCompleted > 0 ? `Completed ${stats.todoCompleted} todos this month.` : '',
      stats.activeDays > 0 ? `${stats.activeDays} active planning days recorded this month.` : '',
      stats.highPriorityTotal > 0 ? `${stats.highPriorityTotal} high-priority items were tracked.` : '',
    ].filter(Boolean)

    if (items.length > 0) return items.slice(0, 3)
    return ['Monthly review data is still accumulating.']
  })

  const sidebarReviewReflections = computed(() => {
    const stats = monthReviewStats.value
    const pendingTodoCount = Math.max(stats.todoTotal - stats.todoCompleted, 0)
    const items = [
      pendingTodoCount > 0 ? `${pendingTodoCount} todos are still open and may need to be broken down further.` : '',
      stats.highPriorityTotal >= 8 ? 'High-priority load is dense. Consider narrowing the active mainline.' : '',
      stats.reminderTotal >= Math.max(6, stats.activeDays) ? 'Reminder volume is high. A fixed review block may help reduce interruption cost.' : '',
    ].filter(Boolean)

    if (items.length > 0) return items.slice(0, 3)
    return ['Execution rhythm looks stable.']
  })

  const sidebarFeedItems = computed<SidebarNewsItem[]>(() => [
    { id: 'fallback-1', title: 'Task orchestration is replacing simple one-shot assistants in modern AI workflows.', meta: 'Industry' },
    { id: 'fallback-2', title: 'Shared planning state across chat and execution surfaces is becoming a core product boundary.', meta: 'Product' },
    { id: 'fallback-3', title: 'This feed is still placeholder content and can be replaced by a real RSS source later.', meta: 'System' },
  ])

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

  async function loadIssueStatusSnapshot() {
    try {
      const response = await taskApi.list()
      issueTasks.value = response.data.filter((task) => task.status !== 'cancelled')
    } catch (err) {
      console.warn('Failed to load issue status snapshot:', err)
      issueTasks.value = []
    }
  }

  async function loadDailyPlanSnapshot(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 = []
    }
  }

  async function loadSidebarPlanSnapshot(date = new Date()) {
    await Promise.all([
      loadDailyPlanSnapshot(date),
      loadIssueStatusSnapshot(),
    ])
  }

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

  function selectCalendarDate(dateKey: string) {
    selectedDate.value = dateKey
  }

  onMounted(() => {
    void loadDailyDigestFn()
    void loadSidebarPlanSnapshot(clientTimeRef.value)
    if (typeof window !== 'undefined') {
      window.addEventListener('jarvis:today-status-refresh', handleExternalRefresh)
    }
  })

  function handleExternalRefresh() {
    void loadSidebarPlanSnapshot(clientTimeRef.value)
  }

  onUnmounted(() => {
    if (typeof window !== 'undefined') {
      window.removeEventListener('jarvis:today-status-refresh', handleExternalRefresh)
    }
  })

  return {
    todayPlanDetail,
    monthPlanDays,
    todayDateKey,
    monthPlanSummaryMap,
    calendarCells,
    calendarYear,
    calendarMonth,
    issueStatusCounters,
    monthReviewStats,
    sidebarWeekLabels,
    sidebarStatusHeadline,
    sidebarStatusBreakdown,
    sidebarFocusItems,
    issueStatusQuadrants,
    issueCommanderSummary,
    sidebarReviewAchievements,
    sidebarReviewReflections,
    sidebarFeedItems,
    topbarFeedItems,
    loadSidebarPlanSnapshot,
    sidebarCollapsedModules,
    selectedDate,
    selectCalendarDate,
    conversationDateMap,
  }
}