/**
 * Copyright 2015 CANAL+ Group
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import getTimeDelimiters from "../get_time_delimiters";
import type { IParsedTTMLCue } from "../parse_ttml";
import createElement from "./create_element";

export interface ITTMLHTMLCue {
  start: number;
  end: number;
  element: HTMLElement;
}

/**
 * @param {Object} parsedCue
 * @returns {Object|null}
 */
export default function parseCue(parsedCue: IParsedTTMLCue): ITTMLHTMLCue | null {
  const {
    paragraph,
    ttParams,
    body,
    regionStyles,
    idStyles,
    paragraphStyle,
    timeOffset,
    shouldTrimWhiteSpace,
  } = parsedCue;

  // Disregard empty elements:
  // TTML allows for empty elements like <div></div>.
  // If paragraph has neither time attributes, nor
  // non-whitespace text, don't try to make a cue out of it.
  if (
    !paragraph.hasAttribute("begin") &&
    !paragraph.hasAttribute("end") &&
    /^\s*$/.test(paragraph.textContent === null ? "" : paragraph.textContent)
  ) {
    return null;
  }

  const { cellResolution } = ttParams;
  const { start, end } = getTimeDelimiters(paragraph, ttParams);
  const element = createElement(paragraph, body, regionStyles, idStyles, paragraphStyle, {
    cellResolution,
    shouldTrimWhiteSpace,
  });
  return { start: start + timeOffset, end: end + timeOffset, element };
}