Add Duplicate blocks functionality

Add a context menu with duplicate and delete options. Delete was
previously only available from a Del shortcut.

Duplicate affects snapped blocks. The context menu is displayed when
the canvas receives a mouse right click.

Fixes #201

addons/block_code/ui/blocks/block/block.gd

@@ -43,6 +43,8 @@ var can_delete: bool = true
 
 var _block_extension: BlockExtension
 
+var _block_canvas: Node
+
 @onready var _context := BlockEditorContext.get_default()
 
 
@@ -163,24 +165,58 @@ func _on_block_extension_changed():
 
 func _gui_input(event):
 	if event is InputEventKey:
-		if event.pressed and event.keycode == KEY_DELETE:
-			# Always accept the Delete key so it doesn't propagate to the
-			# BlockCode node in the scene tree.
-			accept_event()
-
-			if not can_delete:
-				return
-
-			var dialog := ConfirmationDialog.new()
-			var num_blocks = _count_child_blocks(self) + 1
-			# FIXME: Maybe this should use block_name or label, but that
-			# requires one to be both unique and human friendly.
-			if num_blocks > 1:
-				dialog.dialog_text = "Delete %d blocks?" % num_blocks
-			else:
-				dialog.dialog_text = "Delete block?"
-			dialog.confirmed.connect(remove_from_tree)
-			EditorInterface.popup_dialog_centered(dialog)
+		if event.pressed:
+			if event.keycode == KEY_DELETE:
+				# Always accept the Delete key so it doesn't propagate to the
+				# BlockCode node in the scene tree.
+				accept_event()
+				confirm_delete()
+			elif event.ctrl_pressed and not event.shift_pressed and not event.alt_pressed and not event.meta_pressed:
+				# Should not accept when other keys are pressed
+				if event.keycode == KEY_D:
+					accept_event()
+					confirm_duplicate()
+
+
+func confirm_delete():
+	if not can_delete:
+		return
+
+	var dialog := ConfirmationDialog.new()
+	var num_blocks = _count_child_blocks(self) + 1
+	# FIXME: Maybe this should use block_name or label, but that
+	# requires one to be both unique and human friendly.
+	if num_blocks > 1:
+		dialog.dialog_text = "Delete %d blocks?" % num_blocks
+	else:
+		dialog.dialog_text = "Delete block?"
+	dialog.confirmed.connect(remove_from_tree)
+	EditorInterface.popup_dialog_centered(dialog)
+
+
+func confirm_duplicate():
+	if not can_delete:
+		return
+
+	var new_block: Block = _context.block_script.instantiate_block(definition)
+
+	var new_parent: Node = get_parent()
+	while not new_parent.name == "Window":
+		new_parent = new_parent.get_parent()
+
+	if not _block_canvas:
+		_block_canvas = get_parent()
+		while not _block_canvas.name == "BlockCanvas":
+			_block_canvas = _block_canvas.get_parent()
+
+	new_parent.add_child(new_block)
+	new_block.global_position = global_position + (Vector2(100, 50) * new_parent.scale)
+
+	_copy_snapped_blocks(self, new_block)
+
+	_block_canvas.reconnect_block.emit(new_block)
+
+	modified.emit()
 
 
 func remove_from_tree():
@@ -236,6 +272,33 @@ func _count_child_blocks(node: Node) -> int:
 	for child in node.get_children():
 		if child is SnapPoint and child.has_snapped_block():
 			count += 1
-		count += _count_child_blocks(child)
+
+		if child is Container:
+			count += _count_child_blocks(child)
 
 	return count
+
+
+func _copy_snapped_blocks(copy_from: Node, copy_to: Node):
+	var copy_to_child: Node
+	var child_index := 0
+	var maximum_count := copy_to.get_child_count()
+
+	for copy_from_child in copy_from.get_children():
+		if child_index + 1 > maximum_count:
+			return
+
+		copy_to_child = copy_to.get_child(child_index)
+		child_index += 1
+
+		if copy_from_child is SnapPoint and copy_from_child.has_snapped_block():
+			copy_to_child.add_child(_context.block_script.instantiate_block(copy_from_child.snapped_block.definition))
+			_block_canvas.reconnect_block.emit(copy_to_child.snapped_block)
+		elif copy_from_child.name.begins_with("ParameterInput"):
+			var raw_input = copy_from_child.get_raw_input()
+
+			if not raw_input is Block:
+				copy_to_child.set_raw_input(raw_input)
+
+		if copy_from_child is Container:
+			_copy_snapped_blocks(copy_from_child, copy_to_child)

addons/block_code/ui/blocks/utilities/drag_drop_area/drag_drop_area.gd

@@ -8,6 +8,7 @@
 extends Control
 
 const Constants = preload("res://addons/block_code/ui/constants.gd")
+const BlockTreeUtil = preload("res://addons/block_code/ui/block_tree_util.gd")
 
 signal drag_started(offset: Vector2)
 
@@ -16,6 +17,7 @@ signal drag_started(offset: Vector2)
 @export var drag_outside: bool = false
 
 var _drag_start_position: Vector2 = Vector2.INF
+var parent_block: Block
 
 
 func _gui_input(event: InputEvent) -> void:
@@ -27,7 +29,7 @@ func _gui_input(event: InputEvent) -> void:
 
 	var button_event: InputEventMouseButton = event as InputEventMouseButton
 
-	if button_event.button_index != MOUSE_BUTTON_LEFT:
+	if button_event.button_index != MOUSE_BUTTON_LEFT and button_event.button_index != MOUSE_BUTTON_RIGHT:
 		return
 
 	if button_event.double_click:
@@ -37,7 +39,27 @@ func _gui_input(event: InputEvent) -> void:
 	elif button_event.pressed:
 		# Keep track of where the mouse click originated, but allow this
 		# event to propagate to other nodes.
-		_drag_start_position = event.global_position
+		if button_event.button_index == MOUSE_BUTTON_LEFT:
+			_drag_start_position = event.global_position
+		else:
+			if not parent_block:
+				parent_block = BlockTreeUtil.get_parent_block(self)
+
+			if parent_block and parent_block.can_delete:
+				# Accepts to avoid menu conflicts
+				accept_event()
+
+				# A new right-click menu with items
+				var _context_menu := PopupMenu.new()
+				_context_menu.add_icon_item(EditorInterface.get_editor_theme().get_icon("Duplicate", "EditorIcons"), "Duplicate")
+				_context_menu.add_icon_item(EditorInterface.get_editor_theme().get_icon("Remove", "EditorIcons"), "Delete")
+				_context_menu.popup_hide.connect(_cleanup)
+				_context_menu.id_pressed.connect(_menu_pressed.bind(_context_menu))
+
+				_context_menu.position = DisplayServer.mouse_get_position()
+				add_child(_context_menu)
+
+				_context_menu.show()
 	else:
 		_drag_start_position = Vector2.INF
 
@@ -64,3 +86,19 @@ func _input(event: InputEvent) -> void:
 	get_viewport().set_input_as_handled()
 	drag_started.emit(_drag_start_position - motion_event.global_position)
 	_drag_start_position = Vector2.INF
+
+
+func _menu_pressed(_index: int, _context_menu: PopupMenu):
+	# Getting which item was pressed and the corresponding function
+	var _pressed_label: String = _context_menu.get_item_text(_index)
+
+	if _pressed_label == "Duplicate":
+		parent_block.confirm_duplicate()
+	elif _pressed_label == "Delete":
+		parent_block.confirm_delete()
+
+
+func _cleanup():
+	for child in get_children():
+		remove_child(child)
+		child.queue_free()