/*
 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 {
  Amounts,
  NotificationType,
  WalletBalance,
} from "@gnu-taler/taler-util";
import { WalletApiOperation } from "@gnu-taler/taler-wallet-core";
import { useTranslationContext } from "@gnu-taler/web-util/browser";
import { Fragment, VNode, h } from "preact";
import { useEffect, useState } from "preact/hooks";
import { BalanceTable } from "../components/BalanceTable.js";
import { ErrorAlertView } from "../components/CurrentAlerts.js";
import { Loading } from "../components/Loading.js";
import { MultiActionButton } from "../components/MultiActionButton.js";
import {
  ErrorAlert,
  alertFromError,
  useAlertContext,
} from "../context/alert.js";
import { useBackendContext } from "../context/backend.js";
import { useAsyncAsHook } from "../hooks/useAsyncAsHook.js";
import { Button } from "../mui/Button.js";
import { ButtonHandler } from "../mui/handlers.js";
import { StateViewMap, compose } from "../utils/index.js";
import { AddNewActionView } from "../wallet/AddNewActionView.js";
import { NoBalanceHelp } from "./NoBalanceHelp.js";

export interface Props {
  goToWalletDeposit: (currency: string) => Promise<void>;
  goToWalletHistory: (currency: string) => Promise<void>;
  goToWalletManualWithdraw: () => Promise<void>;
}

export type State = State.Loading | State.Error | State.Action | State.Balances;

export namespace State {
  export interface Loading {
    status: "loading";
    error: undefined;
  }

  export interface Error {
    status: "error";
    error: ErrorAlert;
  }

  export interface Action {
    status: "action";
    error: undefined;
    cancel: ButtonHandler;
  }

  export interface Balances {
    status: "balance";
    error: undefined;
    balances: WalletBalance[];
    addAction: ButtonHandler;
    goToWalletDeposit: (currency: string) => Promise<void>;
    goToWalletHistory: (currency: string) => Promise<void>;
    goToWalletManualWithdraw: ButtonHandler;
  }
}

function useComponentState({
  goToWalletDeposit,
  goToWalletHistory,
  goToWalletManualWithdraw,
}: Props): State {
  const api = useBackendContext();
  const { i18n } = useTranslationContext();
  const { pushAlertOnError } = useAlertContext();
  const [addingAction, setAddingAction] = useState(false);
  const state = useAsyncAsHook(() =>
    api.wallet.call(WalletApiOperation.GetBalances, {}),
  );

  useEffect(() =>
    api.listener.onUpdateNotification(
      [NotificationType.TransactionStateTransition],
      state?.retry,
    ),
  );

  if (!state) {
    return {
      status: "loading",
      error: undefined,
    };
  }
  if (state.hasError) {
    return {
      status: "error",
      error: alertFromError(          i18n,
        i18n.str`Could not load the balance`, state),
    };
  }
  if (addingAction) {
    return {
      status: "action",
      error: undefined,
      cancel: {
        onClick: pushAlertOnError(async () => setAddingAction(false)),
      },
    };
  }
  return {
    status: "balance",
    error: undefined,
    balances: state.response.balances,
    addAction: {
      onClick: pushAlertOnError(async () => setAddingAction(true)),
    },
    goToWalletManualWithdraw: {
      onClick: pushAlertOnError(goToWalletManualWithdraw),
    },
    goToWalletDeposit,
    goToWalletHistory,
  };
}

const viewMapping: StateViewMap<State> = {
  loading: Loading,
  error: ErrorAlertView,
  action: ActionView,
  balance: BalanceView,
};

export const BalancePage = compose(
  "BalancePage",
  (p: Props) => useComponentState(p),
  viewMapping,
);

function ActionView({ cancel }: State.Action): VNode {
  return <AddNewActionView onCancel={cancel.onClick!} />;
}

export function BalanceView(state: State.Balances): VNode {
  const { i18n } = useTranslationContext();
  const currencyWithNonZeroAmount = state.balances
    .filter((b) => !Amounts.isZero(b.available))
    .map((b) => {
      b.flags
      return b.available.split(":")[0]
    });

  if (state.balances.length === 0) {
    return (
      <NoBalanceHelp
        goToWalletManualWithdraw={state.goToWalletManualWithdraw}
      />
    );
  }

  return (
    <Fragment>
      <section>
        <BalanceTable
          balances={state.balances}
          goToWalletHistory={state.goToWalletHistory}
        />
      </section>
      <footer style={{ justifyContent: "space-between" }}>
        <Button
          variant="contained"
          onClick={state.goToWalletManualWithdraw.onClick}
        >
          <i18n.Translate>Receive</i18n.Translate>
        </Button>
        {currencyWithNonZeroAmount.length > 0 && (
          <MultiActionButton
            label={(s) => i18n.str`Send ${s}`}
            actions={currencyWithNonZeroAmount}
            onClick={(c) => state.goToWalletDeposit(c)}
          />
        )}
      </footer>
    </Fragment>
  );
}