Allow sending pre-blocks with language.

ui/text/text_entity.cpp

@@ -2032,6 +2032,7 @@ EntitiesInText ConvertTextTagsToEntities(const TextWithTags::Tags &tags) {
 	};
 	struct State {
 		QString link;
+		QString language;
 		uint32 mask = 0;
 
 		void set(EntityType type) {
@@ -2118,28 +2119,34 @@ EntitiesInText ConvertTextTagsToEntities(const TextWithTags::Tags &tags) {
 		}
 		for (const auto type : kInMaskTypes) {
 			if (nextState.has(type) && !state.has(type)) {
-				openType(type);
+				openType(type, nextState.language);
 			}
 		}
 		state = nextState;
 	};
 	const auto stateForTag = [&](const QString &tag) {
+		using Tags = Ui::InputField;
 		auto result = State();
 		const auto list = SplitTags(tag);
+		const auto languageStart = Tags::kTagPre.size();
 		for (const auto &single : list) {
-			if (single == Ui::InputField::kTagBold) {
+			if (single == Tags::kTagBold) {
 				result.set(EntityType::Bold);
-			} else if (single == Ui::InputField::kTagItalic) {
+			} else if (single == Tags::kTagItalic) {
 				result.set(EntityType::Italic);
-			} else if (single == Ui::InputField::kTagUnderline) {
+			} else if (single == Tags::kTagUnderline) {
 				result.set(EntityType::Underline);
-			} else if (single == Ui::InputField::kTagStrikeOut) {
+			} else if (single == Tags::kTagStrikeOut) {
 				result.set(EntityType::StrikeOut);
-			} else if (single == Ui::InputField::kTagCode) {
+			} else if (single == Tags::kTagCode) {
 				result.set(EntityType::Code);
-			} else if (single == Ui::InputField::kTagPre) {
+			} else if (single == Tags::kTagPre) {
 				result.set(EntityType::Pre);
-			} else if (single == Ui::InputField::kTagSpoiler) {
+			} else if (single.size() > languageStart
+				&& single.startsWith(Tags::kTagPre)) {
+				result.set(EntityType::Pre);
+				result.language = single.mid(languageStart).toString();
+			} else if (single == Tags::kTagSpoiler) {
 				result.set(EntityType::Spoiler);
 			} else {
 				result.link = single.toString();
@@ -2235,8 +2242,17 @@ TextWithTags::Tags ConvertEntitiesToTextTags(
 		case EntityType::StrikeOut:
 			push(Ui::InputField::kTagStrikeOut);
 			break;
-		case EntityType::Code: push(Ui::InputField::kTagCode); break; // #TODO entities
+		case EntityType::Code: push(Ui::InputField::kTagCode); break;
-		case EntityType::Pre: push(Ui::InputField::kTagPre); break;
+		case EntityType::Pre: {
+			if (!entity.data().isEmpty()) {
+				const auto language = QRegularExpression("^[a-z0-9\\-]+$");
+				if (language.match(entity.data()).hasMatch()) {
+					push(Ui::InputField::kTagPre + entity.data());
+					break;
+				}
+			}
+			push(Ui::InputField::kTagPre);
+		} break;
 		case EntityType::Spoiler: push(Ui::InputField::kTagSpoiler); break;
 		}
 	}

ui/widgets/fields/input_field.cpp

@@ -65,6 +65,10 @@ const auto kNewlineChars = QString("\r\n")
 // QTextCharFormat with the same properties, including kCustomEmojiText.
 auto GlobalCustomEmojiCounter = 0;
 
+[[nodiscard]] bool IsTagPre(QStringView tag) {
+	return tag.startsWith(kTagPre);
+}
+
 class InputDocument : public QTextDocument {
 public:
 	InputDocument(QObject *parent, const style::InputField &st);
@@ -169,7 +173,7 @@ bool IsNewline(QChar ch) {
 		}
 		auto found = false;
 		for (const auto &single : TextUtilities::SplitTags(existing.id)) {
-			const auto normalized = (single == QStringView(kTagPre))
+			const auto normalized = IsTagPre(single)
 				? QStringView(kTagCode)
 				: single;
 			if (checkingLink && IsValidMarkdownLink(single)) {
@@ -207,6 +211,17 @@ bool IsNewline(QChar ch) {
 	return !CheckFullTextTag(textWithTags, tag).isEmpty();
 }
 
+[[nodiscard]] QString ReadPreLanguageName(
+		const QString &text,
+		int preStart,
+		int preLength) {
+	auto view = QStringView(text).mid(preStart, preLength);
+	static const auto expression = QRegularExpression(
+		"^([a-zA-Z0-9\\-]+)[\\r\\n]");
+	const auto m = expression.match(view);
+	return m.hasMatch() ? m.captured(1).toLower() : QString();
+}
+
 class TagAccumulator {
 public:
 	TagAccumulator(TextWithTags::Tags &tags) : _tags(tags) {
@@ -739,7 +754,7 @@ QTextCharFormat PrepareTagFormat(
 			font = font->underline();
 		} else if (tag == kTagStrikeOut) {
 			font = font->strikeout();
-		} else if (tag == kTagCode || tag == kTagPre) {
+		} else if (tag == kTagCode || IsTagPre(tag)) {
 			color = st::defaultTextPalette.monoFg;
 			font = font->monospace();
 		} else if (tag == kTagSpoiler) {
@@ -2668,11 +2683,21 @@ TextWithTags InputField::getTextWithAppliedMarkdown() const {
 		}
 		addOriginalTextUpTill(tag.adjustedStart);
 
+		auto tagId = tag.tag;
 		auto entityStart = tag.adjustedStart + tagLength;
-		if (tag.tag == kTagPre) {
+		if (tagId == kTagPre) {
 			// Remove redundant newlines for pre.
 			// If ``` is on a separate line add only one newline.
-			if (IsNewline(originalText[entityStart])
+			const auto languageName = ReadPreLanguageName(
+				originalText,
+				entityStart,
+				entityLength);
+			if (!languageName.isEmpty()) {
+				// ```language-name{\n}code
+				entityStart += languageName.size() + 1;
+				entityLength -= languageName.size() + 1;
+				tagId += languageName;
+			} else if (IsNewline(originalText[entityStart])
 				&& (result.text.isEmpty()
 					|| IsNewline(result.text[result.text.size() - 1]))) {
 				++entityStart;
@@ -2691,7 +2716,7 @@ TextWithTags InputField::getTextWithAppliedMarkdown() const {
 			result.tags.push_back(TextWithTags::Tag{
 				int(result.text.size()),
 				entityLength,
-				tag.tag });
+				tagId });
 			result.text.append(base::StringViewMid(
 				originalText,
 				entityStart,
@@ -3121,7 +3146,7 @@ void InputField::processInstantReplaces(const QString &appended) {
 	for (const auto &tag : _lastMarkdownTags) {
 		if (tag.internalStart < position
 			&& tag.internalStart + tag.internalLength >= position
-			&& (tag.tag == kTagCode || tag.tag == kTagPre)) {
+			&& (tag.tag == kTagCode || IsTagPre(tag.tag))) {
 			return;
 		}
 	}
@@ -3197,10 +3222,10 @@ void InputField::commitInstantReplacement(
 		const auto currentTag = cursor.charFormat().property(
 			kTagProperty
 		).toString();
-		const auto currentTags = TextUtilities::SplitTags(currentTag);
+		for (const auto &tag : TextUtilities::SplitTags(currentTag)) {
-		if (currentTags.contains(QStringView(kTagPre))
+			if (tag == kTagCode || IsTagPre(tag)) {
-			|| currentTags.contains(QStringView(kTagCode))) {
+				return;
-			return;
+			}
 		}
 	}
 	cursor.setPosition(from);