/*
 This file is part of GNU Taler
 (C) 2021-2023 Taler Systems S.A.

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

/**
 *
 * @author Sebastian Javier Marchano (sebasjm)
 */

import { createContext, h, VNode } from "preact";
import { useCallback, useContext, useState } from "preact/hooks";
import { useBackendDefaultToken, useBackendURL } from "../hooks/index.js";

interface BackendContextType {
  url: string;
  token?: string;
  triedToLog: boolean;
  resetBackend: () => void;
  clearAllTokens: () => void;
  addTokenCleaner: (c: () => void) => void;
  updateLoginStatus: (url: string, token?: string) => void;
  updateToken: (token?: string) => void;
}

const BackendContext = createContext<BackendContextType>({
  url: "",
  token: undefined,
  triedToLog: false,
  resetBackend: () => null,
  clearAllTokens: () => null,
  addTokenCleaner: () => null,
  updateLoginStatus: () => null,
  updateToken: () => null,
});

function useBackendContextState(
  defaultUrl?: string,
  initialToken?: string,
): BackendContextType {
  const [url, triedToLog, changeBackend, resetBackend] =
    useBackendURL(defaultUrl);
  const [token, _updateToken] = useBackendDefaultToken(initialToken);
  const updateToken = (t?: string) => {
    _updateToken(t);
  };

  const tokenCleaner = useCallback(() => {
    updateToken(undefined);
  }, []);
  const [cleaners, setCleaners] = useState([tokenCleaner]);
  const addTokenCleaner = (c: () => void) => setCleaners((cs) => [...cs, c]);
  const addTokenCleanerMemo = useCallback(
    (c: () => void) => {
      addTokenCleaner(c);
    },
    [tokenCleaner],
  );

  const clearAllTokens = () => {
    cleaners.forEach((c) => c());
    for (let i = 0; i < localStorage.length; i++) {
      const k = localStorage.key(i);
      if (k && /^backend-token/.test(k)) localStorage.removeItem(k);
    }
    resetBackend();
  };

  const updateLoginStatus = (url: string, token?: string) => {
    changeBackend(url);
    if (token) updateToken(token);
  };

  return {
    url,
    token,
    triedToLog,
    updateLoginStatus,
    resetBackend,
    clearAllTokens,
    updateToken,
    addTokenCleaner: addTokenCleanerMemo,
  };
}

export const BackendContextProvider = ({
  children,
  defaultUrl,
  initialToken,
}: {
  children: any;
  defaultUrl?: string;
  initialToken?: string;
}): VNode => {
  const value = useBackendContextState(defaultUrl, initialToken);

  return h(BackendContext.Provider, { value, children });
};

export const useBackendContext = (): BackendContextType =>
  useContext(BackendContext);