From e0750f7b87d0e3cd05a06f010fa4b4a87bd90ed8 Mon Sep 17 00:00:00 2001
From: 23rd <23rd@vivaldi.net>
Date: Sat, 13 Jun 2020 17:13:56 +0300
Subject: [PATCH] Added drag'n'drop area to SendFilesBox for images.

---
 Telegram/SourceFiles/boxes/send_files_box.cpp | 38 ++++++++++++++++++-
 Telegram/SourceFiles/boxes/send_files_box.h   |  2 +
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/Telegram/SourceFiles/boxes/send_files_box.cpp b/Telegram/SourceFiles/boxes/send_files_box.cpp
index 57f9faa2e8..32ff2af777 100644
--- a/Telegram/SourceFiles/boxes/send_files_box.cpp
+++ b/Telegram/SourceFiles/boxes/send_files_box.cpp
@@ -19,6 +19,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "chat_helpers/tabbed_panel.h"
 #include "chat_helpers/tabbed_selector.h"
 #include "confirm_box.h"
+#include "history/history_drag_area.h"
 #include "history/view/history_view_schedule_box.h"
 #include "core/file_utilities.h"
 #include "core/mime_type.h"
@@ -333,7 +334,7 @@ AlbumThumb::AlbumThumb(
 		- st::sendMediaFileThumbSize
 		// Right buttons.
 		- st::sendBoxAlbumGroupButtonFile.width * 2
-		- st::sendBoxAlbumGroupEditInternalSkip
+		- st::sendBoxAlbumGroupEditInternalSkip * 2
 		- st::sendBoxAlbumGroupSkipRight;
 	const auto filepath = file.path;
 	if (filepath.isEmpty()) {
@@ -1858,6 +1859,40 @@ void SendFilesBox::prepare() {
 		}));
 
 	updateLeftButtonVisibility();
+	setupDragArea();
+}
+
+void SendFilesBox::setupDragArea() {
+	// Avoid both drag areas appearing at one time.
+	auto computeState = [=](const QMimeData *data) {
+		const auto state = Storage::ComputeMimeDataState(data);
+		return (state == Storage::MimeDataState::PhotoFiles)
+			? Storage::MimeDataState::Image
+			: (state == Storage::MimeDataState::Files)
+			// Temporary enable drag'n'drop only for images. TODO.
+			? Storage::MimeDataState::None
+			: state;
+	};
+	const auto areas = DragArea::SetupDragAreaToContainer(
+		this,
+		[=](not_null<const QMimeData*> d) { return canAddFiles(d); },
+		[=](bool f) { _caption->setAcceptDrops(f); },
+		[=] { updateControlsGeometry(); },
+		std::move(computeState));
+
+	const auto droppedCallback = [=](bool compress) {
+		return [=](const QMimeData *data) {
+			addFiles(data);
+			Window::ActivateWindow(_controller);
+		};
+	};
+	areas.document->setDroppedCallback(droppedCallback(false));
+	areas.photo->setDroppedCallback(droppedCallback(true));
+	_albumChanged.events(
+	) | rpl::start_with_next([=] {
+		areas.document->raise();
+		areas.photo->raise();
+	}, lifetime());
 }
 
 void SendFilesBox::updateLeftButtonVisibility() {
@@ -1875,6 +1910,7 @@ void SendFilesBox::refreshAllAfterAlbumChanges() {
 	preparePreview();
 	captionResized();
 	updateLeftButtonVisibility();
+	_albumChanged.fire({});
 }
 
 void SendFilesBox::openDialogToAddFileToAlbum() {
diff --git a/Telegram/SourceFiles/boxes/send_files_box.h b/Telegram/SourceFiles/boxes/send_files_box.h
index 956d9d2c9f..84fe80ad8e 100644
--- a/Telegram/SourceFiles/boxes/send_files_box.h
+++ b/Telegram/SourceFiles/boxes/send_files_box.h
@@ -115,6 +115,7 @@ private:
 	void sendScheduled();
 	void captionResized();
 
+	void setupDragArea();
 	void setupTitleText();
 	void updateBoxSize();
 	void updateControlsGeometry();
@@ -163,6 +164,7 @@ private:
 	std::shared_ptr<Ui::RadioenumGroup<SendFilesWay>> _sendWay;
 
 	rpl::variable<int> _footerHeight = 0;
+	rpl::event_stream<> _albumChanged;
 
 	QWidget *_preview = nullptr;
 	AlbumPreview *_albumPreview = nullptr;