/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @format
 * @flow strict-local
 * @emails oncall+draft_js
 */
'use strict';

import type { BlockMap } from "./BlockMap";
import type SelectionState from "./SelectionState";

const DraftModifier = require("./DraftModifier");

const EditorState = require("./EditorState");

const getContentStateFragment = require("./getContentStateFragment");

const nullthrows = require("fbjs/lib/nullthrows");

let clipboard: ?BlockMap = null;
/**
 * Some systems offer a "secondary" clipboard to allow quick internal cut
 * and paste behavior. For instance, Ctrl+K (cut) and Ctrl+Y (paste).
 */

const SecondaryClipboard = {
  cut: function (editorState: EditorState): EditorState {
    const content = editorState.getCurrentContent();
    const selection = editorState.getSelection();
    let targetRange: ?SelectionState = null;

    if (selection.isCollapsed()) {
      const anchorKey = selection.getAnchorKey();
      const blockEnd = content.getBlockForKey(anchorKey).getLength();

      if (blockEnd === selection.getAnchorOffset()) {
        const keyAfter = content.getKeyAfter(anchorKey);

        if (keyAfter == null) {
          return editorState;
        }

        targetRange = selection.set('focusKey', keyAfter).set('focusOffset', 0);
      } else {
        targetRange = selection.set('focusOffset', blockEnd);
      }
    } else {
      targetRange = selection;
    }

    targetRange = nullthrows(targetRange); // TODO: This should actually append to the current state when doing
    // successive ^K commands without any other cursor movement

    clipboard = getContentStateFragment(content, targetRange);
    const afterRemoval = DraftModifier.removeRange(content, targetRange, 'forward');

    if (afterRemoval === content) {
      return editorState;
    }

    return EditorState.push(editorState, afterRemoval, 'remove-range');
  },
  paste: function (editorState: EditorState): EditorState {
    if (!clipboard) {
      return editorState;
    }

    const newContent = DraftModifier.replaceWithFragment(editorState.getCurrentContent(), editorState.getSelection(), clipboard);
    return EditorState.push(editorState, newContent, 'insert-fragment');
  }
};
module.exports = SecondaryClipboard;