Fix pending link previews in preview options box.

Telegram/Resources/langs/lang.strings

@@ -1166,6 +1166,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 "lng_mute_box_title" = "Mute notifications for...";
 
 "lng_preview_loading" = "Getting Link Info...";
+"lng_preview_cant" = "Could not generate preview for this link.";
 
 "lng_profile_settings_section" = "Settings";
 "lng_profile_bot_settings" = "Bot Settings";

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

@@ -7,6 +7,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 */
 #include "history/view/controls/history_view_draft_options.h"
 
+#include "base/timer_rpl.h"
 #include "base/unixtime.h"
 #include "boxes/peer_list_box.h"
 #include "boxes/peer_list_controllers.h"
@@ -589,6 +590,9 @@ void DraftOptionsBox(
 		QString link;
 		Ui::SettingsSlider *tabs = nullptr;
 		PreviewWrap *wrap = nullptr;
+
+		Fn<void(const QString &link, WebPageData *page)> performSwitch;
+		Fn<void(const QString &link, bool force)> requestAndSwitch;
 		rpl::lifetime resolveLifetime;
 	};
 	const auto state = box->lifetime().make_state<State>();
@@ -740,35 +744,54 @@ void DraftOptionsBox(
 	};
 
 	const auto &resolver = args.resolver;
-	const auto performSwitch = [=](const QString &link, WebPageData *page) {
-		if (page) {
+	state->performSwitch = [=](const QString &link, WebPageData *page) {
+		const auto now = base::unixtime::now();
+		if (!page || page->pendingTill > 0 && page->pendingTill < now) {
+			show->showToast(tr::lng_preview_cant(tr::now));
+		} else if (page->pendingTill > 0) {
+			const auto delay = std::max(page->pendingTill - now, TimeId());
+			base::timer_once(
+				(delay + 1) * crl::time(1000)
+			) | rpl::start_with_next([=] {
+				state->requestAndSwitch(link, true);
+			}, state->resolveLifetime);
+
+			page->owner().webPageUpdates(
+			) | rpl::start_with_next([=](not_null<WebPageData*> updated) {
+				if (updated == page && !updated->pendingTill) {
+					state->resolveLifetime.destroy();
+					state->performSwitch(link, page);
+				}
+			}, state->resolveLifetime);
+		} else {
 			state->preview = page;
 			state->webpage.id = page->id;
 			state->webpage.url = page->url;
 			state->webpage.manual = true;
 			state->link = link;
 			state->shown.force_assign(Section::Link);
-		} else {
-			show->showToast(u"Could not generate preview for this link."_q);
 		}
 	};
+	state->requestAndSwitch = [=](const QString &link, bool force) {
+		resolver->request(link, force);
+
+		state->resolveLifetime = resolver->resolved(
+		) | rpl::start_with_next([=](const QString &resolved) {
+			if (resolved == link) {
+				state->resolveLifetime.destroy();
+				state->performSwitch(
+					link,
+					resolver->lookup(link).value_or(nullptr));
+			}
+		});
+	};
 	const auto switchTo = [=](const QString &link) {
 		if (link == state->link) {
 			return;
-		}
-		if (const auto value = resolver->lookup(link)) {
-			performSwitch(link, *value);
+		} else if (const auto value = resolver->lookup(link)) {
+			state->performSwitch(link, *value);
 		} else {
-			resolver->request(link);
-			state->resolveLifetime = resolver->resolved(
-			) | rpl::start_with_next([=](const QString &resolved) {
-				if (resolved == link) {
-					state->resolveLifetime.destroy();
-					performSwitch(
-						link,
-						resolver->lookup(link).value_or(nullptr));
-				}
-			});
+			state->requestAndSwitch(link, false);
 		}
 	};
 

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

@@ -134,8 +134,8 @@ QString WebpageResolver::find(not_null<WebPageData*> page) const {
 	return QString();
 }
 
-void WebpageResolver::request(const QString &link) {
-	if (_requestLink == link) {
+void WebpageResolver::request(const QString &link, bool force) {
+	if (_requestLink == link && !force) {
 		return;
 	}
 	const auto done = [=](const MTPDmessageMediaWebPage &data) {
@@ -191,7 +191,7 @@ WebpageProcessor::WebpageProcessor(
 	if (!ShowWebPagePreview(_data) || _link.isEmpty()) {
 		return;
 	}
-	_resolver->request(_link);
+	_resolver->request(_link, true);
 }) {
 	_history->session().downloaderTaskFinished(
 	) | rpl::filter([=] {

Telegram/SourceFiles/history/view/controls/history_view_webpage_processor.h

@@ -62,7 +62,7 @@ public:
 
 	[[nodiscard]] QString find(not_null<WebPageData*> page) const;
 
-	void request(const QString &link);
+	void request(const QString &link, bool force = false);
 	void cancel(const QString &link);
 
 private: