import { defineStore } from 'pinia'
import { openDashboardLiveStream } from '../services/live'
import type { BoardGroup, DashboardTaskDto } from './tasks'
import type { NotificationItem } from './notifications'
import type { TaskItem } from '../components/dashboard/v2/types'
import { useTaskStore } from './tasks'
import { useNotificationStore } from './notifications'
import type { DashboardLiveEventDto, LiveCursorDto, LiveUpdateEnvelope } from '../services/live'

interface NotificationSnapshotDto {
  notifications: NotificationItem[]
  unreadCount: number
  forUser: string
}

interface DashboardLiveSnapshotDto {
  board: BoardGroup
  notifications: NotificationSnapshotDto
  cursor: LiveCursorDto
}

function isBoardGroup(value: unknown): value is BoardGroup {
  const v = value as BoardGroup
  return !!v && Array.isArray(v.offen) && Array.isArray(v.inProgress) && Array.isArray(v.review) && Array.isArray(v.blocked) && Array.isArray(v.done)
}

function mapTasks(board: BoardGroup): DashboardTaskDto[] {
  return [...board.offen, ...board.inProgress, ...board.review, ...board.blocked, ...board.done]
}

function mapTaskStripItem(t: DashboardTaskDto): TaskItem {
  return {
    id: t.id,
    title: t.title,
    agent: t.assignedTo ?? '—',
    priority: (['high', 'critical', 'urgent'].includes(t.priority.toLowerCase()) ? 'high' : ['low', 'minor'].includes(t.priority.toLowerCase()) ? 'low' : 'medium') as 'high' | 'medium' | 'low',
    status: (t.state.toLowerCase() === 'blocked' ? 'blocked' : (['in progress', 'active', 'working'].includes(t.state.toLowerCase()) ? 'active' : 'pending')) as 'active' | 'blocked' | 'pending',
    progress: t.state.toLowerCase() === 'done' ? 100 : t.state.toLowerCase() === 'blocked' ? 30 : (['in progress', 'active', 'working'].includes(t.state.toLowerCase()) ? 50 : 0),
    detail: t.detail,
    source: t.source,
  }
}

export const useLiveSyncStore = defineStore('liveSync', {
  state: () => ({
    connected: false,
    connecting: false,
    lastEventAt: null as string | null,
    lastHeartbeatAt: null as string | null,
    error: null as string | null,
    controller: null as AbortController | null,
    reconnectTimer: null as ReturnType<typeof setTimeout> | null,
    mode: 'polling' as 'polling' | 'live',
    lastSequence: 0,
    reconnectAttempts: 0,
  }),

  getters: {
    liveIndicatorLabel: (state) => {
      if (state.connecting) return 'Verbinde…'
      if (state.connected) return `Live · #${state.lastSequence}`
      return state.mode === 'polling' ? 'Polling' : 'Offline'
    },
    connectionHealth: (state) => {
      if (state.connected) return 'healthy'
      if (state.connecting) return 'connecting'
      return 'degraded'
    },
  },

  actions: {
    async connect(forUser = 'bao') {
      if (this.connecting || this.connected) return
      this.connecting = true
      this.error = null
      this.controller = new AbortController()

      const taskStore = useTaskStore()
      const notificationStore = useNotificationStore()

      try {
        const stream = await openDashboardLiveStream((event, data) => {
          this.lastEventAt = new Date().toISOString()

          if (event === 'heartbeat') {
            const cursor = data as LiveCursorDto
            this.lastHeartbeatAt = cursor.timestamp
            this.lastSequence = Math.max(this.lastSequence, cursor.sequence)
            return
          }

          if (event === 'snapshot') {
            const snapshot = data as DashboardLiveSnapshotDto
            taskStore.board = snapshot.board
            taskStore.tasks = mapTasks(snapshot.board).map(mapTaskStripItem)
            notificationStore.notifications = snapshot.notifications.notifications
            notificationStore.unreadCount = snapshot.notifications.unreadCount
            this.lastSequence = snapshot.cursor.sequence
            this.connected = true
            this.mode = 'live'
            this.reconnectAttempts = 0
            taskStore.stopBoardPolling()
            return
          }

          const eventDto = data as DashboardLiveEventDto
          this.applyEnvelope(eventDto.envelope, forUser)
          this.lastSequence = eventDto.cursor.sequence
          this.connected = true
          this.mode = 'live'
          this.reconnectAttempts = 0
          taskStore.stopBoardPolling()
        }, { forUser, signal: this.controller.signal, afterSequence: this.lastSequence || null })

        await stream.closed
      } catch (error) {
        if (this.controller?.signal.aborted) return
        console.warn('[liveSync] stream failed, falling back to polling', error)
        this.error = 'Live updates unavailable'
        this.connected = false
        this.mode = 'polling'
        taskStore.startBoardPolling()
        this.scheduleReconnect(forUser)
      } finally {
        this.connecting = false
        if (!this.controller?.signal.aborted && !this.connected) {
          this.mode = 'polling'
        }
      }
    },

    applyEnvelope(envelope: LiveUpdateEnvelope, forUser: string) {
      const taskStore = useTaskStore()
      const notificationStore = useNotificationStore()

      if (envelope.type === 'tasks.board.snapshot' && isBoardGroup(envelope.payload)) {
        taskStore.board = envelope.payload
        taskStore.tasks = mapTasks(envelope.payload).map(mapTaskStripItem)
        return
      }

      if (envelope.type === 'notifications.snapshot') {
        const snapshot = envelope.payload as NotificationSnapshotDto
        if (snapshot.forUser !== forUser) return
        notificationStore.notifications = snapshot.notifications
        notificationStore.unreadCount = snapshot.unreadCount
      }
    },

    disconnect() {
      this.controller?.abort()
      this.controller = null
      this.connected = false
      this.connecting = false
      this.mode = 'polling'
      if (this.reconnectTimer) {
        clearTimeout(this.reconnectTimer)
        this.reconnectTimer = null
      }
    },

    scheduleReconnect(forUser = 'bao') {
      if (this.reconnectTimer) return
      const delay = Math.min(30000, 5000 * Math.max(1, this.reconnectAttempts + 1))
      this.reconnectAttempts += 1
      this.reconnectTimer = setTimeout(() => {
        this.reconnectTimer = null
        this.connect(forUser)
      }, delay)
    },
  },
})