Respect the maximum quote length.

Telegram/Resources/langs/lang.strings

@@ -3611,6 +3611,8 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_reply_header_short" = "Reply";
 "lng_reply_quote_selected" = "Quote Selected";
 "lng_reply_from_private_chat" = "This reply is from a private chat.";
+"lng_reply_quote_long_title" = "Quote too long!";
+"lng_reply_quote_long_text" = "The selected text is too long to quote.";
 "lng_link_options_header" = "Link Preview Settings";
 "lng_link_header_short" = "Link";
 "lng_link_move_up" = "Move Up";

Telegram/SourceFiles/history/view/controls/history_view_draft_options.cpp

@@ -35,6 +35,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "ui/widgets/buttons.h"
 #include "ui/widgets/discrete_sliders.h"
 #include "ui/painter.h"
+#include "ui/toast/toast.h"
 #include "ui/vertical_list.h"
 #include "ui/ui_utility.h"
 #include "window/themes/window_theme.h"
@@ -843,7 +844,14 @@ void DraftOptionsBox(
 			: tr::lng_reply_quote_selected();
 	}) | rpl::flatten_latest();
 	box->addButton(std::move(save), [=] {
-		finish(resolveReply(), state->webpage);
+		if (state->quote.current().overflown) {
+			show->showToast({
+				.title = tr::lng_reply_quote_long_title(tr::now),
+				.text = tr::lng_reply_quote_long_text(tr::now),
+				});
+		} else {
+			finish(resolveReply(), state->webpage);
+		}
 	});
 
 	box->addButton(tr::lng_cancel(), [=] {

Telegram/SourceFiles/history/view/history_view_element.cpp

@@ -27,6 +27,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "core/core_settings.h"
 #include "core/click_handler_types.h"
 #include "core/ui_integration.h"
+#include "main/main_app_config.h"
 #include "main/main_session.h"
 #include "chat_helpers/stickers_emoji_pack.h"
 #include "window/window_session_controller.h"
@@ -1652,6 +1653,12 @@ SelectedQuote Element::FindSelectedQuote(
 	if (modified.empty() || modified.to > result.text.size()) {
 		return {};
 	}
+	const auto session = &item->history()->session();
+	const auto limit = session->appConfig().quoteLengthMax();
+	const auto overflown = (modified.from + limit < modified.to);
+	if (overflown) {
+		modified.to = modified.from + limit;
+	}
 	result.text = result.text.mid(
 		modified.from,
 		modified.to - modified.from);
@@ -1678,7 +1685,7 @@ SelectedQuote Element::FindSelectedQuote(
 			++i;
 		}
 	}
-	return { item, result, modified.from };
+	return { item, result, modified.from, overflown };
 }
 
 TextSelection Element::FindSelectionFromQuote(

Telegram/SourceFiles/history/view/history_view_element.h

@@ -294,6 +294,7 @@ struct SelectedQuote {
 	HistoryItem *item = nullptr;
 	TextWithEntities text;
 	int offset = 0;
+	bool overflown = false;
 
 	explicit operator bool() const {
 		return item && !text.empty();

Telegram/SourceFiles/main/main_app_config.cpp

@@ -38,6 +38,10 @@ void AppConfig::start() {
 	}, _lifetime);
 }
 
+int AppConfig::quoteLengthMax() const {
+	return get<int>(u"quote_length_max"_q, 1024);
+}
+
 void AppConfig::refresh(bool force) {
 	if (_requestId || !_api) {
 		if (force) {

Telegram/SourceFiles/main/main_app_config.h

@@ -63,6 +63,8 @@ public:
 		return _ignoreRestrictionChanges.events();
 	}
 
+	[[nodiscard]] int quoteLengthMax() const;
+
 	void refresh(bool force = false);
 
 private: