tangheem/lib/widgets/text_highlight_widget.dart

import 'dart:math';

import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:tangheem/classes/colors.dart';

class TextHighLightWidget extends StatelessWidget {
  final String text;
  final String valueText;
  final Color valueColor;
  final List<String> highlights;
  final TextStyle style;
  final TextAlign textAlign;
  final Color highLightColor;
  final double highLightFontSize;
  final Function(String) onTap;
  final Function(String) onAyaTap;

  TextHighLightWidget(
      {Key key,
      this.text,
      this.textAlign = TextAlign.center,
      this.valueText,
      this.valueColor,
      this.highlights,
      this.highLightColor = ColorConsts.secondaryOrange,
      this.style = const TextStyle(),
      this.highLightFontSize = 18,
      this.onTap,
      this.onAyaTap});

  @override
  Widget build(BuildContext context) {
    if (text == '') {
      return _richText(_normalSpan(text));
    }
    if (highlights.isEmpty) {
      return _richText(_normalSpan(text));
    }
    for (int i = 0; i < highlights.length; i++) {
      if (highlights[i] == null) {
        assert(highlights[i] != null);
        return _richText(_normalSpan(text));
      }
      if (highlights[i].isEmpty) {
        assert(highlights[i].isNotEmpty);
        return _richText(_normalSpan(text));
      }
    }

    List<TextSpan> _spans = List();
    int _start = 0;
    List<String> _lowerCaseHighlights = List();

    highlights.forEach((element) {
      _lowerCaseHighlights.add(element.toLowerCase());
    });

    while (true) {
      Map<int, String> _highlightsMap = Map();

      for (int i = 0; i < highlights.length; i++) {
        int _index = text.toLowerCase().indexOf(_lowerCaseHighlights[i], _start);
        if (_index >= 0) {
          _highlightsMap.putIfAbsent(_index, () => highlights[i]);
        }
      }

      if (_highlightsMap.isNotEmpty) {
        List<int> _indexes = List();
        _highlightsMap.forEach((key, value) => _indexes.add(key));

        int _currentIndex = _indexes.reduce(min);
        String _currentHighlight = text.substring(_currentIndex, _currentIndex + _highlightsMap[_currentIndex].length);

        if (_currentIndex == _start) {
          _spans.add(_highlightSpan(_currentHighlight));
          _start += _currentHighlight.length;
        } else {
          _spans.add(_normalSpan(text.substring(_start, _currentIndex)));
          _spans.add(_highlightSpan(_currentHighlight));
          _start = _currentIndex + _currentHighlight.length;
        }
      } else {
        _spans.add(_normalSpan(text.substring(_start, text.length)));
        break;
      }
    }

    if (valueText != null) {
      _spans.add(TextSpan(
        text: ' ' + valueText,
        style: TextStyle(color: valueColor ?? Color(0xff170026), fontSize: 12, fontWeight: FontWeight.w800),
      ));
    }
    return _richText(TextSpan(children: _spans));
  }

  TextSpan _highlightSpan(String value) {
    if (style.color == null) {
      return TextSpan(
          text: value,
          style: style.copyWith(color: highLightColor, fontSize: highLightFontSize),
          recognizer: TapGestureRecognizer()
            ..onTap = () {
              if (onTap != null) {
                onTap(value);
              }
            });
    } else {
      return TextSpan(text: value, style: style.copyWith(color: valueColor));
    }
  }

  TextSpan _normalSpan(String value) {
    if (style.color == null) {
      return TextSpan(
        text: value,
        style: style.copyWith(color: valueColor),
      );
    } else {
      return TextSpan(text: value, style: style, children: [
        if (valueText != null)
          TextSpan(
            text: ' ' + valueText,
            style: style,
          )
      ]);
    }
  }

  RichText _richText(TextSpan text) {
    return RichText(key: key, text: text, textAlign: textAlign);
  }
}