/*
 * Copyright (c) 2010, 2024 BSI Business Systems Integration AG
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 */
import {DesktopNotification, FocusRule, scout, Session, Status, Widget} from '../index';
import $ from 'jquery';

export interface ClipboardTextCopyOptions {
  /**
   * The text to write to the clipboard.
   */
  text: string;
  /**
   * Widget that wants to copy the text. Recommended.
   * Used to retrieve the session and the document.
   */
  parent?: Widget;
  /**
   * Scout session object, used to resolve texts and access the focus manager. Only required when "parent" is not set.
   */
  session?: Session;
  /**
   * If true, a desktop notification is shown when copying has been completed. Requires the "parent" option to be present.
   * If this is true, the {@link copyText} method returns null. Otherwise, it returns a promise that is resolved or rejected when the copying is complete.
   */
  showNotification?: boolean;
}

export const clipboard = {

  /**
   * Copies the given text to the clipboard. To make this work, the method must be called inside
   * a "user action" (i.e. mouse or keyboard event handler). For security reasons, the access to
   * the clipboard is blocked by the browser in other contexts (e.g. asynchronous callbacks).
   *
   * @param options mandatory
   * @returns a promise or null if {@link options.showNotification} is true.
   */
  copyText(options: ClipboardTextCopyOptions): JQuery.Promise<void> {
    scout.assertParameter('options', options);
    if (options.parent && !options.session) {
      options.session = options.parent.session;
    }
    scout.assertProperty(options, 'session');

    let promise = clipboard._copyText(options);

    if (options.parent && scout.nvl(options.showNotification, true)) {
      clipboard._showNotification(options, promise);
      return null;
    }
    return promise;
  },

  /** @internal */
  _copyText(options: ClipboardTextCopyOptions): JQuery.Promise<void> {
    let deferred = $.Deferred();

    // Modern clipboard API
    // https://developer.mozilla.org/en-US/docs/Web/API/Clipboard_API
    let win = options?.parent?.window(true) || window;
    if (win.navigator.clipboard) {
      win.navigator.clipboard.writeText(options.text)
        .then((...args) => deferred.resolve(...args))
        .catch((...args) => deferred.reject(...args));
      return deferred.promise();
    }

    // Fallback for browsers that don't support the modern clipboard API (IE, Safari, Chrome < 66, Firefox < 63)
    // Create invisible textarea field and use document command "copy" to copy the text to the clipboard
    let doc = options?.parent?.document(true) || document;
    let f = doc.createElement('textarea');
    f.style.position = 'fixed';
    f.style.opacity = '0.0';
    f.value = options.text;
    doc.body.appendChild(f);
    // Preserve focus
    let $f = $(f);
    options.session.focusManager.installFocusContext($f, FocusRule.AUTO);
    f.select(); // cannot use jquery select(), because that is overridden by jquery-scout

    try {
      let successful = doc.execCommand('copy');
      if (successful) {
        deferred.resolve();
      } else {
        deferred.reject();
      }
    } catch (err) {
      deferred.reject(err);
    } finally {
      // Restore focus
      options.session.focusManager.uninstallFocusContext($f);
      doc.body.removeChild(f);
    }
    return deferred.promise();
  },

  /** @internal */
  _showNotification(options: ClipboardTextCopyOptions, promise: JQuery.Promise<void>) {
    let status = clipboard._successStatus(options.parent.session);
    promise
      .catch(() => {
        status = clipboard._failedStatus(options.parent.session);
      })
      .then(() => {
        clipboard.showNotification(options.parent, status);
      });
  },

  /** @internal */
  _successStatus(session: Session): Status {
    return new Status({
      message: session.text('ui.CopyToClipboardSuccessStatus'),
      severity: Status.Severity.INFO
    });
  },

  /** @internal */
  _failedStatus(session: Session): Status {
    return new Status({
      message: session.text('ui.CopyToClipboardFailedStatus'),
      severity: Status.Severity.WARNING
    });
  },

  /**
   * Shows a short desktop notification. By default, it informs the user that the content
   * has been copied to the clipboard successfully. By passing a different status, the
   * message can be changed.
   *
   * @param parent Widget that wants to show the notification. Mandatory. Required for NLS texts.
   */
  showNotification(parent: Widget, status?: Status) {
    scout.assertParameter('parent', parent);
    let notification = scout.create(DesktopNotification, {
      parent: parent,
      closable: false,
      duration: 1234,
      status: status || clipboard._successStatus(parent.session)
    });
    notification.show();
  }
};