/*
 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 { buildPayto, classifyTalerUri } from "@gnu-taler/taler-util";
import { useTranslationContext } from "@gnu-taler/web-util/lib/index.browser";
import { h, VNode } from "preact";
import { useState } from "preact/hooks";
import { AsyncButton } from "../../../../components/exception/AsyncButton.js";
import { QR } from "../../../../components/exception/QR.js";
import {
  FormErrors,
  FormProvider,
} from "../../../../components/form/FormProvider.js";
import { Input } from "../../../../components/form/Input.js";
import { InputCurrency } from "../../../../components/form/InputCurrency.js";
import { ConfirmModal } from "../../../../components/modal/index.js";
import { useBackendContext } from "../../../../context/backend.js";
import { useConfigContext } from "../../../../context/config.js";
import { useInstanceContext } from "../../../../context/instance.js";
import { MerchantBackend } from "../../../../declaration.js";

type Entity = MerchantBackend.Template.UsingTemplateDetails;

interface Props {
  template: MerchantBackend.Template.TemplateDetails;
  id: string;
  onBack?: () => void;
}

export function QrPage({ template, id: templateId, onBack }: Props): VNode {
  const { i18n } = useTranslationContext();
  const { url: backendUrl } = useBackendContext();
  const { id: instanceId } = useInstanceContext();
  const config = useConfigContext();
  const [setupTOTP, setSetupTOTP] = useState(false);

  const [state, setState] = useState<Partial<Entity>>({
    amount: template.template_contract.amount,
    summary: template.template_contract.summary,
  });

  const errors: FormErrors<Entity> = {};

  const hasErrors = Object.keys(errors).some(
    (k) => (errors as any)[k] !== undefined,
  );

  const fixedAmount = !!template.template_contract.amount;
  const fixedSummary = !!template.template_contract.summary;

  const params = new URLSearchParams();
  if (!fixedAmount) {
    if (state.amount) {
      params.append("amount", state.amount);
    } else {
      params.append("amount", config.currency);
    }
  }
  if (!fixedSummary) {
    params.append("summary", state.summary ?? "");
  }

  const paramsStr = fixedAmount && fixedSummary ? "" : "?" + params.toString();
  const merchantURL = new URL(backendUrl);

  const talerProto =
    merchantURL.protocol === "http:" ? "taler+http:" : "taler:";

  const payTemplateUri = `${talerProto}//pay-template/${merchantURL.hostname}/${templateId}${paramsStr}`;

  const issuer = encodeURIComponent(
    `${new URL(backendUrl).hostname}/${instanceId}`,
  );
  const oauthUri = !template.pos_algorithm
    ? undefined
    : template.pos_algorithm === 1
    ? `otpauth://totp/${issuer}:${templateId}?secret=${template.pos_key}&issuer=${issuer}&algorithm=SHA1&digits=8&period=30`
    : template.pos_algorithm === 2
    ? `otpauth://totp/${issuer}:${templateId}?secret=${template.pos_key}&issuer=${issuer}&algorithm=SHA1&digits=8&period=30`
    : undefined;

  const keySlice = template.pos_key?.substring(0, 4);

  const oauthUriWithoutSecret = !template.pos_algorithm
    ? undefined
    : template.pos_algorithm === 1
    ? `otpauth://totp/${issuer}:${templateId}?secret=${keySlice}...&issuer=${issuer}&algorithm=SHA1&digits=8&period=30`
    : template.pos_algorithm === 2
    ? `otpauth://totp/${issuer}:${templateId}?secret=${keySlice}...&issuer=${issuer}&algorithm=SHA1&digits=8&period=30`
    : undefined;
  return (
    <div>
      {oauthUri && (
        <ConfirmModal
          description="Setup TOTP"
          active={setupTOTP}
          onCancel={() => {
            setSetupTOTP(false);
          }}
        >
          <p>Scan this qr code with your TOTP device</p>
          <QR text={oauthUri} />
          <pre style={{ textAlign: "center" }}>
            <a href={oauthUri}>{oauthUriWithoutSecret}</a>
          </pre>
        </ConfirmModal>
      )}
      <section class="section is-main-section">
        <div class="columns">
          <div class="column" />
          <div class="column is-four-fifths">
            <FormProvider
              object={state}
              valueHandler={setState}
              errors={errors}
            >
              <InputCurrency<Entity>
                name="amount"
                label={i18n.str`Amount`}
                readonly={fixedAmount}
                tooltip={i18n.str`Amount of the order`}
              />
              <Input<Entity>
                name="summary"
                inputType="multiline"
                readonly={fixedSummary}
                label={i18n.str`Order summary`}
                tooltip={i18n.str`Title of the order to be shown to the customer`}
              />
            </FormProvider>

            <div class="buttons is-right mt-5">
              {onBack && (
                <button class="button" onClick={onBack}>
                  <i18n.Translate>Cancel</i18n.Translate>
                </button>
              )}
              <button
                class="button is-info"
                onClick={() => saveAsPDF(templateId)}
              >
                <i18n.Translate>Print</i18n.Translate>
              </button>
              {oauthUri && (
                <button
                  class="button is-info"
                  onClick={() => setSetupTOTP(true)}
                >
                  <i18n.Translate>Setup TOTP</i18n.Translate>
                </button>
              )}
            </div>
          </div>
          <div class="column" />
        </div>
      </section>
      <section id="printThis">
        <QR text={payTemplateUri} />
        <pre style={{ textAlign: "center" }}>
          <a href={payTemplateUri}>{payTemplateUri}</a>
        </pre>
      </section>
    </div>
  );
}

function saveAsPDF(name: string): void {
  const printWindow = window.open("", "", "height=400,width=800");
  if (!printWindow) return;
  const divContents = document.getElementById("printThis");
  if (!divContents) return;
  printWindow.document.write(
    `<html><head><title>Order template for ${name}</title><style>`,
  );
  printWindow.document.write("</style></head><body>&nbsp;</body></html>");
  printWindow.document.close();
  printWindow.document.body.appendChild(divContents.cloneNode(true));
  printWindow.addEventListener("load", () => {
    printWindow.print();
    printWindow.close();
  });
}
