'use client';

import * as React from 'react';
import { AlertColor } from '@mui/material';

const TOAST_LIMIT = 1;
const TOAST_REMOVE_DELAY = 3000;

export type ToasterToast = {
  id: string;
  title?: React.ReactNode;
  description?: React.ReactNode;
  severity?: AlertColor; // success | error | warning | info
  duration?: number;
  open: boolean;
};

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[];
}

let count = 0;
const genId = () => (++count).toString();

const toastTimeouts = new Map<string, ReturnType<typeof setTimeout>>();
let memoryState: State = { toasts: [] };
const listeners: Array<(state: State) => void> = [];

const addToRemoveQueue = (toastId: string, duration?: number) => {
  if (toastTimeouts.has(toastId)) return;

  const timeout = setTimeout(() => {
    toastTimeouts.delete(toastId);
    dispatch({ type: 'REMOVE_TOAST', toastId });
  }, duration ?? TOAST_REMOVE_DELAY);

  toastTimeouts.set(toastId, timeout);
};

export const 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;

      state.toasts.forEach(t => {
        if (!toastId || t.id === toastId) {
          addToRemoveQueue(t.id, t.duration);
        }
      });

      return {
        ...state,
        toasts: state.toasts.map(t =>
          !toastId || t.id === toastId ? { ...t, open: false } : t
        ),
      };
    }

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

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

type ToastInput = Omit<ToasterToast, 'id' | 'open'>;

export function toast(props: ToastInput) {
  const id = genId();

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

  if (props.duration) {
    setTimeout(() => {
      dispatch({ type: 'DISMISS_TOAST', toastId: id });
    }, props.duration);
  }

  return {
    id,
    dismiss: () => dispatch({ type: 'DISMISS_TOAST', toastId: id }),
    update: (updates: Partial<ToasterToast>) =>
      dispatch({ type: 'UPDATE_TOAST', toast: { ...updates, id } }),
  };
}

export 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);
    };
  }, []);

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