"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.getActiveFormats = getActiveFormats;
var _isFormatEqual = require("./is-format-equal");
/** @typedef {import('./types').RichTextValue} RichTextValue */
/** @typedef {import('./types').RichTextFormatList} RichTextFormatList */

/**
 * Internal dependencies
 */

/**
 * Gets the all format objects at the start of the selection.
 *
 * @param {RichTextValue} value                Value to inspect.
 * @param {Array}         EMPTY_ACTIVE_FORMATS Array to return if there are no
 *                                             active formats.
 *
 * @return {RichTextFormatList} Active format objects.
 */
function getActiveFormats(value, EMPTY_ACTIVE_FORMATS = []) {
  const {
    formats,
    start,
    end,
    activeFormats
  } = value;
  if (start === undefined) {
    return EMPTY_ACTIVE_FORMATS;
  }
  if (start === end) {
    // For a collapsed caret, it is possible to override the active formats.
    if (activeFormats) {
      return activeFormats;
    }
    const formatsBefore = formats[start - 1] || EMPTY_ACTIVE_FORMATS;
    const formatsAfter = formats[start] || EMPTY_ACTIVE_FORMATS;

    // By default, select the lowest amount of formats possible (which means
    // the caret is positioned outside the format boundary). The user can
    // then use arrow keys to define `activeFormats`.
    if (formatsBefore.length < formatsAfter.length) {
      return formatsBefore;
    }
    return formatsAfter;
  }

  // If there's no formats at the start index, there are not active formats.
  if (!formats[start]) {
    return EMPTY_ACTIVE_FORMATS;
  }
  const selectedFormats = formats.slice(start, end);

  // Clone the formats so we're not mutating the live value.
  const _activeFormats = [...selectedFormats[0]];
  let i = selectedFormats.length;

  // For performance reasons, start from the end where it's much quicker to
  // realise that there are no active formats.
  while (i--) {
    const formatsAtIndex = selectedFormats[i];

    // If we run into any index without formats, we're sure that there's no
    // active formats.
    if (!formatsAtIndex) {
      return EMPTY_ACTIVE_FORMATS;
    }
    let ii = _activeFormats.length;

    // Loop over the active formats and remove any that are not present at
    // the current index.
    while (ii--) {
      const format = _activeFormats[ii];
      if (!formatsAtIndex.find(_format => (0, _isFormatEqual.isFormatEqual)(format, _format))) {
        _activeFormats.splice(ii, 1);
      }
    }

    // If there are no active formats, we can stop.
    if (_activeFormats.length === 0) {
      return EMPTY_ACTIVE_FORMATS;
    }
  }
  return _activeFormats || EMPTY_ACTIVE_FORMATS;
}
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