// Copyright (C) 2022 WYATT GROUP
// Please see the AUTHORS file for details.
//
// This program 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 of the License, or
// any later version.
//
// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.

extension ReadingTimeX on String {
  Duration readingTime({
    int wpm = 200,
    String suffix = 'min read',
    String lessMsg = 'less than a minute',
  }) {
    bool _ansiWordBound(String c) {
      return (' ' == c) || ('\n' == c) || ('\r' == c) || ('\t' == c);
    }

    int words = 0, start = 0, end = length - 1;

    while (_ansiWordBound(this[start])) {
      start++;
    }
    while (_ansiWordBound(this[end])) {
      end--;
    }

    // Count real words
    for (int i = start; i <= end;) {
      for (; i <= end && !_ansiWordBound(this[i]); i++) {}
      words++;
      for (; i <= end && _ansiWordBound(this[i]); i++) {}
    }

    final minutes = words / wpm;
    final seconds = (minutes - minutes.floor()) * 60;
    final Duration duration = Duration(minutes: minutes.floor(), seconds: seconds.floor());
    return duration;
  }
}