import { createContext, useContext } from "react";

export type UnsavedNavigationAction = () => void;

export type UnsavedChangesRegistration = {
  title?: string;
  message?: string;
  onSave: () => boolean | Promise<boolean>;
  onDiscard?: () => void;
};

export type UnsavedChangesContextValue = {
  hasUnsavedChanges: boolean;
  registerUnsavedChanges: (registration: UnsavedChangesRegistration | null) => () => void;
  requestNavigation: (action: UnsavedNavigationAction) => void;
  requestDiscard: (action: UnsavedNavigationAction) => void;
};

export const UnsavedChangesContext = createContext<UnsavedChangesContextValue | null>(null);

const fallbackUnsavedChangesContext: UnsavedChangesContextValue = {
  hasUnsavedChanges: false,
  registerUnsavedChanges: () => () => undefined,
  requestNavigation: (action) => action(),
  requestDiscard: (action) => action()
};

export function useUnsavedChanges() {
  return useContext(UnsavedChangesContext) ?? fallbackUnsavedChangesContext;
}