/*
 This file is part of GNU Taler
 (C) 2022-2024 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/>
 */

import {
  ChallengerApi,
  Codec,
  buildCodecForObject,
  codecForBoolean,
  codecForChallengeStatus,
  codecForNumber,
  codecForString,
  codecForStringURL,
  codecOptional,
} from "@gnu-taler/taler-util";
import { buildStorageKey, useLocalStorage } from "@gnu-taler/web-util/browser";
import { mutate } from "swr";

/**
 * Has the information to reach and
 * authenticate at the bank's backend.
 */
export type SessionId = {
  clientId: string;
  redirectURL: string;
  state: string;
};

export type LastChallengeResponse = {
  attemptsLeft: number;
  nextSend: string;
  transmitted: boolean;
};

export type SessionState = SessionId & {
  lastTry: LastChallengeResponse | undefined;
  lastStatus: ChallengerApi.ChallengeStatus | undefined;
  completedURL: string | undefined;
};
export const codecForLastChallengeResponse = (): Codec<LastChallengeResponse> =>
  buildCodecForObject<LastChallengeResponse>()
    .property("attemptsLeft", codecForNumber())
    .property("nextSend", codecForString())
    .property("transmitted", codecForBoolean())
    .build("LastChallengeResponse");

export const codecForSessionState = (): Codec<SessionState> =>
  buildCodecForObject<SessionState>()
    .property("clientId", codecForString())
    .property("redirectURL", codecForStringURL())
    .property("state", codecForString())
    .property("completedURL", codecOptional(codecForStringURL()))
    .property("lastStatus", codecOptional(codecForChallengeStatus()))
    .property("lastTry", codecOptional(codecForLastChallengeResponse()))
    .build("SessionState");

export interface SessionStateHandler {
  state: SessionState | undefined;
  start(s: SessionId): void;
  accepted(l: LastChallengeResponse): void;
  completed(e: URL): void;
  updateStatus(s: ChallengerApi.ChallengeStatus): void;
}

const SESSION_STATE_KEY = buildStorageKey(
  "challenger-session",
  codecForSessionState(),
);

/**
 * Return getters and setters for
 * login credentials and backend's
 * base URL.
 */
export function useSessionState(): SessionStateHandler {
  const { value: state, update } = useLocalStorage(SESSION_STATE_KEY);

  return {
    state,
    start(info) {
      update({
        ...info,
        lastTry: undefined,
        completedURL: undefined,
        lastStatus: undefined,
      });
      cleanAllCache();
    },
    accepted(lastTry) {
      if (!state) return;
      update({
        ...state,
        lastTry,
      });
    },
    completed(url) {
      if (!state) return;
      update({
        ...state,
        completedURL: url.href,
      });
    },
    updateStatus(st: ChallengerApi.ChallengeStatus) {
      if (!state) return;
      if (!state.lastStatus) {
        update({
          ...state,
          lastStatus: st,
        });
        return;
      }
      // current status, FIXME: better check to know if the sate changed
      const ls = state.lastStatus;
      if (
        ls.changes_left !== st.changes_left ||
        ls.fix_address !== st.fix_address || ls.last_address !== st.last_address
      ) {
        update({
          ...state,
          lastStatus: st,
        });
        return;
      }
    },
  };
}

function cleanAllCache(): void {
  mutate(() => true, undefined, { revalidate: false });
}