/*
 This file is part of GNU Taler
 (C) 2022 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 { Codec, buildCodecForObject, codecForBoolean, codecForList, codecForMap, codecForString, codecOptional } from "@gnu-taler/taler-util";

export interface BankUiSettings {
  // Where libeufin backend is localted
  // default: window.origin without "webui/"
  backendBaseURL?: string;
  // Shows a button "create random account" in the registration form
  // Useful for testing
  // default: false
  allowRandomAccountCreation?: boolean;
  // Create all random accounts with password "123"
  // Useful for testing
  // default: false
  simplePasswordForRandomAccounts?: boolean;
  // Bank name shown in the header
  // default: "Taler Bank"
  bankName?: string;
  // URL where the user is going to be redirected after 
  // clicking in Taler Logo
  // default: home page
  iconLinkURL?: string;
  // Mapping for every link shown in the top navitation bar
  //  - key: link label, what the user will read
  //  - value: link target, where the user is going to be redirected
  // default: empty list
  topNavSites?: Record<string, string>;
}

/**
 * Global settings for the bank UI.
 */
const defaultSettings: BankUiSettings = {
  backendBaseURL: buildDefaultBackendBaseURL(),
  iconLinkURL: undefined,
  bankName: "Taler Bank",
  simplePasswordForRandomAccounts: false,
  allowRandomAccountCreation: false,
  topNavSites: {},
};

const codecForBankUISettings = (): Codec<BankUiSettings> =>
  buildCodecForObject<BankUiSettings>()
    .property("backendBaseURL", codecOptional(codecForString()))
    .property("allowRandomAccountCreation", codecOptional(codecForBoolean()))
    .property("simplePasswordForRandomAccounts", codecOptional(codecForBoolean()))
    .property("bankName", codecOptional(codecForString()))
    .property("iconLinkURL", codecOptional(codecForString()))
    .property("topNavSites", codecOptional(codecForMap(codecForString())))
    .build("BankUiSettings");

function removeUndefineField(obj: any): object {
  return Object.keys(obj).reduce((prev, cur) => {
    if (typeof prev[cur] === "undefined") {
      delete prev[cur]
    }
    return prev
  }, obj)
}

export function fetchSettings(listener: (s: BankUiSettings) => void): void {
  fetch("./settings.json")
    .then(resp => resp.json())
    .then(json => codecForBankUISettings().decode(json))
    .then(result => listener({
      ...defaultSettings,
      ...removeUndefineField(result),
    }))
    .catch(e => {
      console.log("failed to fetch settings", e)
      listener(defaultSettings)
    })
}



function buildDefaultBackendBaseURL(): string | undefined {
  if (typeof window !== "undefined") {
    const currentLocation = new URL(window.location.pathname, window.location.origin).href
    return currentLocation.replace("/webui", "")
  }
  return undefined
}