"use client";

// Inspired by react-hot-toast library
import * as React from "react";

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

const TOAST_LIMIT = 1;
const TOAST_REMOVE_DELAY = 1000000;
const TOAST_DEFAULT_DURATION = 4000;

type ToasterToast = ToastProps & {
  id: string;
  title?: React.ReactNode;
  description?: React.ReactNode;
  action?: ToastActionElement;
  duration?: number;
  /** Optional logical position hint (e.g. "top-left") */
  position?: string;
  /** Custom JSX to render instead of title/description (e.g. "call in progress" card) */
  content?: React.ReactNode;
};

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?: ToasterToast["id"];
    }
  | {
      type: ActionType["REMOVE_TOAST"];
      toastId?: ToasterToast["id"];
    };

interface State {
  toasts: ToasterToast[];
}

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

function clearAutoDismiss(id: string) {
  const t = autoDismissTimeouts.get(id);
  if (t) {
    clearTimeout(t);
    autoDismissTimeouts.delete(id);
  }
}

function scheduleAutoDismiss(id: string, duration?: number) {
  const d = duration ?? TOAST_DEFAULT_DURATION;
  if (!Number.isFinite(d) || d <= 0) return;
  clearAutoDismiss(id);
  const t = setTimeout(() => {
    dispatch({ type: "DISMISS_TOAST", toastId: id });
  }, d);
  autoDismissTimeouts.set(id, t);
}

const addToRemoveQueue = (toastId: string) => {
  if (toastTimeouts.has(toastId)) {
    return;
  }

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

      // ! Side effects ! - This could be extracted into a dismissToast() action,
      // but I'll keep it here for simplicity
      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 "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);
  });
}

type Toast = Omit<ToasterToast, "id">;

export type CustomToastApi = { id: string; dismiss: () => void };

type CustomToastOptions = { duration?: number; position?: string };

type DismissFn = (toastId?: string | CustomToastApi) => void;

export interface ToastFn {
  (props: Toast): ReturnType<typeof toastImpl>;
  custom: (
    render: (api: CustomToastApi) => React.ReactNode,
    options?: CustomToastOptions,
  ) => CustomToastApi;
  dismiss: DismissFn;
}

function toastImpl(props: Toast) {
  const id = genId();

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

  dispatch({
    type: "ADD_TOAST",
    toast: {
      ...props,
      id,
      open: true,
      onOpenChange: (open) => {
        if (!open) dismiss();
      },
    },
  });
  // schedule auto-dismiss using provided duration (or default)
  scheduleAutoDismiss(id, props.duration);

  return { id, dismiss, update };
}

const toast: ToastFn = Object.assign(toastImpl, {
  custom(
    render: (api: CustomToastApi) => React.ReactNode,
    options?: CustomToastOptions,
  ): CustomToastApi {
    const id = genId();
    const dismiss = () => dispatch({ type: "DISMISS_TOAST", toastId: id });
    const api: CustomToastApi = { id, dismiss };
    const content = render(api);

    dispatch({
      type: "ADD_TOAST",
      toast: {
        id,
        content: content ?? undefined,
        open: true,
        duration: options?.duration ?? TOAST_DEFAULT_DURATION,
        position: options?.position,
        onOpenChange: (open) => {
          if (!open) dismiss();
        },
      } as ToasterToast,
    });

    const duration = options?.duration ?? TOAST_DEFAULT_DURATION;
    scheduleAutoDismiss(id, duration);

    return api;
  },
  dismiss: ((toastId?: string | CustomToastApi) =>
    dispatch({
      type: "DISMISS_TOAST",
      toastId: typeof toastId === "object" ? toastId?.id : toastId,
    })) as DismissFn,
});

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 | CustomToastApi) =>
      dispatch({
        type: "DISMISS_TOAST",
        toastId: typeof toastId === "object" ? toastId?.id : toastId,
      }),
  };
}

export { useToast, toast };