import * as React from 'react'

const TOAST_LIMIT = 5
const TOAST_AUTO_DISMISS = 5000

export type ToastVariant = 'default' | 'destructive' | 'success' | 'warning' | 'info'

export interface ToasterToast {
  id: string
  title?: string
  description?: string
  action?: React.ReactNode
  variant?: ToastVariant
  duration?: number
}

type Action =
  | { type: 'ADD_TOAST'; toast: ToasterToast }
  | { type: 'UPDATE_TOAST'; toast: Partial<ToasterToast> & { id: string } }
  | { type: 'DISMISS_TOAST'; toastId?: string }
  | { type: 'REMOVE_TOAST'; toastId?: string }

interface State {
  toasts: ToasterToast[]
}

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

function addToRemoveQueue(toastId: string, delay: number) {
  if (toastTimeouts.has(toastId)) {
    return
  }

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

  toastTimeouts.set(toastId, timeout)
}

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

    case 'UPDATE_TOAST':
      return {
        ...state,
        toasts: state.toasts.map((t) =>
          t.id === action.toast.id ? { ...t, ...action.toast } : t
        ),
      }

    case 'DISMISS_TOAST': {
      const { toastId } = action

      if (toastId) {
        addToRemoveQueue(toastId, 300)
      } else {
        state.toasts.forEach((t) => addToRemoveQueue(t.id, 300))
      }

      return state
    }

    case 'REMOVE_TOAST':
      if (action.toastId === undefined) {
        return { ...state, toasts: [] }
      }
      return {
        ...state,
        toasts: state.toasts.filter((t) => t.id !== action.toastId),
      }
  }
}

const listeners: Array<(state: State) => void> = []

let memoryState: State = { toasts: [] }

function dispatch(action: Action) {
  memoryState = reducer(memoryState, action)
  listeners.forEach((listener) => listener(memoryState))
}

let count = 0

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

type ToastInput = Omit<ToasterToast, 'id'>

function toast(props: ToastInput) {
  const id = genId()
  const duration = props.duration ?? TOAST_AUTO_DISMISS

  dispatch({
    type: 'ADD_TOAST',
    toast: { ...props, id },
  })

  // Auto-dismiss
  if (duration > 0) {
    addToRemoveQueue(id, duration)
  }

  const update = (updateProps: Partial<ToasterToast>) =>
    dispatch({ type: 'UPDATE_TOAST', toast: { ...updateProps, id } })

  const dismiss = () => dispatch({ type: 'DISMISS_TOAST', toastId: id })

  return { id, dismiss, update }
}

function clearAllToasts() {
  // Clear all pending timeouts
  toastTimeouts.forEach((timeout) => clearTimeout(timeout))
  toastTimeouts.clear()
  dispatch({ type: 'REMOVE_TOAST', toastId: undefined })
}

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: 'DISMISS_TOAST', toastId }),
    clear: clearAllToasts,
  }
}

export { useToast, toast, clearAllToasts }