import * as React from "react";

import type { ToastActionElement, ToastProps } from "@/components/ui/toast";

type ToasterToast = ToastProps & {
  id: string;
  title?: React.ReactNode;
  description?: React.ReactNode;
  action?: ToastActionElement;
};

type ToastState = {
  toasts: ToasterToast[];
};

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

const TOAST_LIMIT = 5;
const TOAST_REMOVE_DELAY = 1000;

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

const listeners = new Set<(state: ToastState) => void>();

let memoryState: ToastState = { toasts: [] };

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

function reducer(state: ToastState, action: ToastAction): ToastState {
  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(toast => (toast.id === action.toast.id ? { ...toast, ...action.toast } : toast)),
      };
    }
    case "DISMISS_TOAST": {
      const { toastId } = action;
      if (toastId) {
        addToRemoveQueue(toastId);
      } else {
        state.toasts.forEach(toast => {
          addToRemoveQueue(toast.id);
        });
      }

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

function addToRemoveQueue(toastId: string) {
  if (toastTimeouts.has(toastId)) {
    return;
  }

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

  toastTimeouts.set(toastId, timeout);
}

function genId() {
  return Math.random().toString(36).slice(2, 10);
}

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

  React.useEffect(() => {
    listeners.add(setState);
    return () => {
      listeners.delete(setState);
    };
  }, []);

  return {
    ...state,
    toast: (props: Omit<ToasterToast, "id">) => {
      const id = genId();
      dispatch({ type: "ADD_TOAST", toast: { ...props, id, open: true } });
      return id;
    },
    dismiss: (toastId?: string) => dispatch({ type: "DISMISS_TOAST", toastId }),
  };
}

export const toast = (props: Omit<ToasterToast, "id">) => {
  const id = genId();
  dispatch({ type: "ADD_TOAST", toast: { ...props, id, open: true } });
  return id;
};