import 'package:color/color.dart' as cc; import 'package:flutter/material.dart'; class FormatNode { String text; final FormatData format; final List children; FormatNode({required this.text, required this.format, required this.children}); bool get isUnformatted => format.isUnformatted && children.isEmpty; bool get isEmpty => text.isEmpty && children.isEmpty; factory FormatNode.unformatted(String? text) { return FormatNode(text: text ?? "", format: FormatData.unformatted(), children: const []); } factory FormatNode.fromText(String? text) { if (text == null) return FormatNode.unformatted(text); var tags = FormatTag.parseTags(text); if (tags.isEmpty) return FormatNode.unformatted(text); final root = FormatNode( format: FormatData.unformatted(), text: text.substring(0, tags.first.startIndex), children: [], ); final activeTags = []; for (int i = 0; i < tags.length; i++) { final tag = tags[i]; final substr = text.substring(tag.endIndex, (i + 1 < tags.length) ? tags[i + 1].startIndex : null); if (tag.format.isAdditive) { activeTags.add(tag.format); } else { final idx = activeTags.lastIndexWhere((element) => element.name == tag.format.name); if (idx != -1) { activeTags.removeAt(idx); } } if (substr.isNotEmpty) { root.children.add( FormatNode.buildFromStyles(activeTags, substr) ); } } return root; } TextSpan toTextSpan({required TextStyle baseStyle}) { final spanTree = TextSpan( text: text, style: format.isUnformatted ? baseStyle : format.style(), children: children.map((e) => e.toTextSpan(baseStyle: baseStyle)).toList() ); return spanTree; } @override String toString() { return text + children.join(); } static FormatNode buildFromStyles(List styles, String text) { if (styles.isEmpty) return FormatNode(format: FormatData.unformatted(), children: [], text: text); final root = FormatNode(text: "", format: styles.first, children: []); var current = root; for (final style in styles.sublist(1)) { final next = FormatNode(text: "", format: style, children: []); current.children.add(next); current = next; } current.text = text; return root; } } class FormatTag { final int startIndex; final int endIndex; final FormatData format; const FormatTag({ required this.startIndex, required this.endIndex, required this.format, }); static List parseTags(String text) { final startMatches = RegExp(r"<(.+?)>").allMatches(text); final spans = []; for (final startMatch in startMatches) { final fullTag = startMatch.group(1); if (fullTag == null) continue; final tag = FormatData.parse(fullTag); spans.add( FormatTag( startIndex: startMatch.start, endIndex: startMatch.end, format: tag, ) ); } return spans; } } class FormatAction { final String Function(String input, String parameter)? transform; final TextStyle Function(String? parameter, TextStyle baseStyle)? style; FormatAction({this.transform, this.style}); } class FormatData { static Color? tryParseColor(String? text) { if (text == null) return null; var color = cc.RgbColor.namedColors[text]; if (color != null) { return Color.fromARGB(255, color.r.round(), color.g.round(), color.b.round()); } try { color = cc.HexColor(text); return Color.fromARGB(255, color.r.round(), color.g.round(), color.b.round()); } catch (_) { return null; } } static final Map _richTextTags = { "align": FormatAction(), "alpha": FormatAction(style: (param, baseStyle) { if (param == null || !param.startsWith("#")) return baseStyle; final alpha = int.tryParse(param.substring(1), radix: 16); if (alpha == null) return baseStyle; return baseStyle.copyWith(color: baseStyle.color?.withAlpha(alpha)); }), "color": FormatAction(style: (param, baseStyle) { if (param == null) return baseStyle; final color = tryParseColor(param); if (color == null) return baseStyle; return baseStyle.copyWith(color: color); }), "b": FormatAction(style: (param, baseStyle) => baseStyle.copyWith(fontWeight: FontWeight.bold)), "br": FormatAction(transform: (text, param) => "\n$text"), "i": FormatAction(style: (param, baseStyle) => baseStyle.copyWith(fontStyle: FontStyle.italic)), "cspace": FormatAction(), "font": FormatAction(), "indent": FormatAction(), "line-height": FormatAction(), "line-indent": FormatAction(), "link": FormatAction(), "lowercase": FormatAction(transform: (input, parameter) => input.toLowerCase(),), "uppercase": FormatAction(transform: (input, parameter) => input.toUpperCase(),), "smallcaps": FormatAction(), "margin": FormatAction(), "mark": FormatAction(style: (param, baseStyle) { if (param == null) return baseStyle; final color = tryParseColor(param); if (color == null) return baseStyle; return baseStyle.copyWith(backgroundColor: color); }), "mspace": FormatAction(), "noparse": FormatAction(), "nobr": FormatAction(), "page": FormatAction(), "pos": FormatAction(), "size": FormatAction( style: (param, baseStyle) { if (param == null) return baseStyle; final baseSize = baseStyle.fontSize ?? 12; if (param.endsWith("%")) { final percentage = int.tryParse(param.replaceAll("%", "")); if (percentage == null || percentage <= 0) return baseStyle; return baseStyle.copyWith(fontSize: baseSize * (percentage / 100)); } else { final size = num.tryParse(param); if (size == null || size <= 0) return baseStyle; final realSize = baseSize * (size / 1000); return baseStyle.copyWith(fontSize: realSize.toDouble().clamp(8, 400)); } } ), "space": FormatAction(), "sprite": FormatAction(), "s": FormatAction(style: (param, baseStyle) => baseStyle.copyWith(decoration: TextDecoration.lineThrough)), "u": FormatAction(style: (param, baseStyle) => baseStyle.copyWith(decoration: TextDecoration.underline)), "style": FormatAction(), "sub": FormatAction(), "sup": FormatAction(), "voffset": FormatAction(), "width": FormatAction(), }; final String name; final String parameter; final bool isAdditive; const FormatData({required this.name, required this.parameter, required this.isAdditive}); factory FormatData.parse(String text) { if (text.contains("/")) return FormatData(name: text.replaceAll("/", ""), parameter: "", isAdditive: false); final sepIdx = text.indexOf("="); if (sepIdx == -1) { return FormatData(name: text, parameter: "", isAdditive: true); } else { return FormatData( name: text.substring(0, sepIdx).trim().toLowerCase(), parameter: text.substring(sepIdx + 1, text.length).trim().toLowerCase(), isAdditive: true, ); } } factory FormatData.unformatted() => const FormatData(name: "", parameter: "", isAdditive: false); bool get isUnformatted => name.isEmpty && parameter.isEmpty && !isAdditive; bool get isValid => _richTextTags.containsKey(name); String? apply(String? text) => text == null ? null : _richTextTags[name]?.transform?.call(text, parameter); TextStyle style() => _richTextTags[name]?.style?.call(parameter, const TextStyle()) ?? const TextStyle(); }