import * as React from "react"

const TOAST_LIMIT = 5 // 최대 5개로 제한
export const TOAST_REMOVE_DELAY = 5000 // 5초 후 DOM에서 제거

export type ToasterToast = {
  id: string
  title?: React.ReactNode
  description?: React.ReactNode
  action?: React.ReactNode
  variant?: "default" | "destructive"
  duration?: number
  open?: boolean
  onOpenChange?: (open: boolean) => void
}

const actionTypes = {
  ADD_TOAST: "ADD_TOAST",
  UPDATE_TOAST: "UPDATE_TOAST",
  DISMISS_TOAST: "DISMISS_TOAST",
  REMOVE_TOAST: "REMOVE_TOAST",
} as const

let count = 0

function genId() {
  count = (count + 1) % Number.MAX_SAFE_INTEGER
  return count.toString()
}

type ActionType = typeof actionTypes

type Action =
  | {
      type: ActionType["ADD_TOAST"]
      toast: ToasterToast
    }
  | {
      type: ActionType["UPDATE_TOAST"]
      toast: Partial<ToasterToast> & { id: string }
    }
  | {
      type: ActionType["DISMISS_TOAST"]
      toastId?: string
    }
  | {
      type: ActionType["REMOVE_TOAST"]
      toastId?: string
    }

interface State {
  toasts: ToasterToast[]
}

const toastTimeouts = new Map<string, ReturnType<typeof setTimeout>>()

// 토스트 자동 제거 함수
const addToRemoveQueue = (toastId: string) => {
  if (toastTimeouts.has(toastId)) {
    return
  }

  const timeout = setTimeout(() => {
    toastTimeouts.delete(toastId)
    dispatch({
      type: actionTypes.REMOVE_TOAST,
      toastId: toastId,
    })
  }, TOAST_REMOVE_DELAY)

  toastTimeouts.set(toastId, timeout)
}

export const reducer = (state: State, action: Action): State => {
  switch (action.type) {
    case actionTypes.ADD_TOAST:
      return {
        ...state,
        toasts: [action.toast, ...state.toasts].slice(0, TOAST_LIMIT),
      }

    case actionTypes.UPDATE_TOAST:
      return {
        ...state,
        toasts: state.toasts.map((t) =>
          t.id === action.toast.id ? { ...t, ...action.toast } : t
        ),
      }

    case actionTypes.DISMISS_TOAST: {
      const { toastId } = action

      if (toastId) {
        addToRemoveQueue(toastId)
      } else {
        state.toasts.forEach((toast) => {
          addToRemoveQueue(toast.id)
        })
      }

      return {
        ...state,
        toasts: state.toasts.map((t) =>
          t.id === toastId || toastId === undefined
            ? {
                ...t,
                open: false,
              }
            : t
        ),
      }
    }
    case actionTypes.REMOVE_TOAST:
      if (action.toastId === undefined) {
        return {
          ...state,
          toasts: [],
        }
      }
      return {
        ...state,
        toasts: state.toasts.filter((t) => t.id !== action.toastId),
      }
    default:
      return state
  }
}

// 전역 상태 및 리스너
const listeners: Array<(state: State) => void> = []
let memoryState: State = { toasts: [] }

// 마지막 액션 추적 (중복 방지용)
let lastAction: { type: string; id?: string; time: number } | null = null

function dispatch(action: Action) {
  // 마지막 액션 정보 추출
  let actionId: string | undefined = undefined;
  if ('toast' in action && action.toast) {
    actionId = action.toast.id;
  } else if ('toastId' in action) {
    actionId = action.toastId;
  }
  
  // 동일한 토스트에 대한 중복 액션 방지
  const now = Date.now();
  const isSameAction = lastAction && 
                      lastAction.type === action.type && 
                      ((action.type === actionTypes.ADD_TOAST && 
                        lastAction.time > now - 1000) || // ADD 액션은 1초 내 중복 방지
                       (action.type !== actionTypes.ADD_TOAST && 
                        actionId === lastAction.id && 
                        lastAction.time > now - 300)); // 다른 액션은 300ms 내 중복 방지
  
  if (isSameAction) {
    console.log('중복 토스트 액션 무시:', action.type);
    return;
  }
  
  // 액션 추적 업데이트
  lastAction = { 
    type: action.type, 
    id: actionId, 
    time: now 
  };
  
  // 실제 상태 업데이트 및 리스너 호출
  memoryState = reducer(memoryState, action)
  listeners.forEach((listener) => {
    listener(memoryState)
  })
}

type Toast = Omit<ToasterToast, "id">

function toast({ ...props }: Toast) {
  const id = genId()

  const update = (props: ToasterToast) =>
    dispatch({
      type: actionTypes.UPDATE_TOAST,
      toast: { ...props, id },
    })
  const dismiss = () => dispatch({ type: actionTypes.DISMISS_TOAST, toastId: id })

  dispatch({
    type: actionTypes.ADD_TOAST,
    toast: {
      ...props,
      id,
      open: true,
      onOpenChange: (open) => {
        if (!open) dismiss()
      },
      duration: props.duration || 3000, // 기본 지속 시간 3초로 단축
    },
  })

  return {
    id,
    dismiss,
    update,
  }
}

function useToast() {
  const [state, setState] = React.useState<State>(memoryState)

  React.useEffect(() => {
    listeners.push(setState)
    return () => {
      const index = listeners.indexOf(setState)
      if (index > -1) {
        listeners.splice(index, 1)
      }
    }
  }, [state])

  return {
    ...state,
    toast,
    dismiss: (toastId?: string) => dispatch({ type: actionTypes.DISMISS_TOAST, toastId }),
  }
}

export { useToast, toast }