Display consistent caption/comment placeholder.

After latest PRs regarding sticker sending with comment (#5500)
and album sending with caption (#4869) the input field placeholder
in SendFilesBox was inconsistent with the sending behaviour. Fix it.

Telegram/SourceFiles/apiwrap.cpp

@@ -4302,14 +4302,10 @@ void ApiWrap::sendFiles(
 		TextWithTags &&caption,
 		std::shared_ptr<SendingAlbum> album,
 		const SendOptions &options) {
-	const auto isSticker = [&] {
-		if (list.files.empty() || type != SendMediaType::File) {
-			return false;
-		}
-		return list.files.front().mime == qstr("image/webp");
-	};
-	if ((list.files.size() > 1 || isSticker())
-		&& !caption.text.isEmpty() && !album) {
+	const auto haveCaption = !caption.text.isEmpty();
+	const auto isAlbum = (album != nullptr);
+	const auto compressImages = (type == SendMediaType::Photo);
+	if (haveCaption && !list.canAddCaption(isAlbum, compressImages)) {
 		auto message = MessageToSend(options.history);
 		message.textWithTags = std::move(caption);
 		message.replyTo = options.replyTo;

Telegram/SourceFiles/boxes/send_files_box.cpp

@@ -896,10 +896,14 @@ rpl::producer<int> SingleFilePreview::desiredHeightValue() const {
 	return rpl::single(st::boxPhotoPadding.top() + h + st::msgShadow);
 }
 
-Fn<QString()> FieldPlaceholder(const Storage::PreparedList &list) {
-	return langFactory(list.files.size() > 1
-		? lng_photos_comment
-		: lng_photo_caption);
+Fn<QString()> FieldPlaceholder(
+		const Storage::PreparedList &list,
+		SendFilesWay way) {
+	const auto isAlbum = (way == SendFilesWay::Album);
+	const auto compressImages = (way != SendFilesWay::Files);
+	return langFactory(list.canAddCaption(isAlbum, compressImages)
+		? lng_photo_caption
+		: lng_photos_comment);
 }
 
 } // namespace
@@ -1339,7 +1343,7 @@ SendFilesBox::SendFilesBox(
 	this,
 	st::confirmCaptionArea,
 	Ui::InputField::Mode::MultiLine,
-	FieldPlaceholder(_list),
+	nullptr,
 	caption) {
 }
 
@@ -1433,8 +1437,8 @@ void SendFilesBox::setupShadows(
 void SendFilesBox::prepare() {
 	_send = addButton(langFactory(lng_send_button), [this] { send(); });
 	addButton(langFactory(lng_cancel), [this] { closeBox(); });
-	setupCaption();
 	initSendWay();
+	setupCaption();
 	preparePreview();
 	boxClosing() | rpl::start_with_next([=] {
 		if (!_confirmed && _cancelledCallback) {
@@ -1469,6 +1473,7 @@ void SendFilesBox::initSendWay() {
 	}();
 	_sendWay = std::make_shared<Ui::RadioenumGroup<SendFilesWay>>(value);
 	_sendWay->setChangedCallback([this](SendFilesWay value) {
+		updateCaptionPlaceholder();
 		applyAlbumOrder();
 		if (_albumPreview) {
 			_albumPreview->setSendWay(value);
@@ -1477,6 +1482,10 @@ void SendFilesBox::initSendWay() {
 	});
 }
 
+void SendFilesBox::updateCaptionPlaceholder() {
+	_caption->setPlaceholder(FieldPlaceholder(_list, _sendWay->value()));
+}
+
 void SendFilesBox::refreshAlbumMediaCount() {
 	_albumVideosCount = _list.albumIsPossible
 		? ranges::count(
@@ -1505,7 +1514,6 @@ void SendFilesBox::preparePreview() {
 void SendFilesBox::setupControls() {
 	setupTitleText();
 	setupSendWayControls();
-	_caption->setPlaceholder(FieldPlaceholder(_list));
 }
 
 void SendFilesBox::setupSendWayControls() {
@@ -1593,6 +1601,7 @@ void SendFilesBox::setupCaption() {
 		getDelegate()->outerContainer(),
 		_caption);
 
+	updateCaptionPlaceholder();
 	setupEmojiPanel();
 }
 

Telegram/SourceFiles/boxes/send_files_box.h

@@ -101,6 +101,7 @@ private:
 	void setupTitleText();
 	void updateBoxSize();
 	void updateControlsGeometry();
+	void updateCaptionPlaceholder();
 
 	bool canAddFiles(not_null<const QMimeData*> data) const;
 	bool canAddUrls(const QList<QUrl> &urls) const;

Telegram/SourceFiles/storage/storage_media_prepare.cpp

@@ -311,6 +311,16 @@ void PreparedList::mergeToEnd(PreparedList &&other) {
 	}
 }
 
+bool PreparedList::canAddCaption(bool isAlbum, bool compressImages) const {
+	const auto isSticker = [&] {
+		if (files.empty() || compressImages) {
+			return false;
+		}
+		return (files.front().mime == qstr("image/webp"));
+	};
+	return isAlbum || (files.size() == 1 && !isSticker());
+}
+
 int MaxAlbumItems() {
 	return kMaxAlbumCount;
 }

Telegram/SourceFiles/storage/storage_media_prepare.h

@@ -61,6 +61,8 @@ struct PreparedList {
 		std::vector<int> order);
 	void mergeToEnd(PreparedList &&other);
 
+	bool canAddCaption(bool isAlbum, bool compressImages) const;
+
 	Error error = Error::None;
 	QString errorData;
 	std::vector<PreparedFile> files;