drag module

-- Dragger
-- I overcomplicated it but I don't care
--[[ Written by
				Nebula the Zoroark#6969 (Discord, UserId 138946947842179072)
				Nebula_Zoroark (ROBLOX, UserId 5719877)
]]

--[[
	Module:Connect(GuiObject gui[, table<GuiObject> parts])
		When you drag on 'gui', it will move either the GUI itself or if parts is supplied then every GUI in that table instead.
		Returns DragInstance

	DragInstance.GuiObject
		The GUI to be dragged.

	DragInstance.Affected
		All GUIs that are moved when the GUI is dragged.

	DragInstance:Disconnect() / DragInstance:disconnect()
		Disables dragging for the instance.
		Returns nil

	DragInstance:SetDragTime(number time)
		If time is 0, the GUI(s) won't tween to the new position when tweened.
		If the time is above 0, the GUI(s) will tween to the new position over the specified time
--]]

function Tween(obj,props,time,easing,direction,repeats,backwards)
	local info = TweenInfo.new(time or .5, easing or Enum.EasingStyle.Quad, direction or Enum.EasingDirection.Out, repeats or 0, backwards or false)
	local tween = game:service'TweenService':Create(obj, info, props)

	tween:Play()
end

local Drag = {Current=nil;Draggers={}}
function Drag:Disconnect()
	local g = self;
	if(typeof(g)=='table' and g.GuiObject)then g = g.GuiObject end
	if(self.Draggers[g])then
		if(Drag.Current==g)then
			Drag.Current=nil
		end
		for i = 1,#self.Draggers[g].Connections do self.Draggers[g].Connections[i]:disconnect() end
		self.Draggers[g]=nil;
	else
		warn("Make sure to make "..g.Name.." draggable!")
	end
end
Drag.disconnect=Drag.Disconnect

function Drag:SetDragTime(t)
	local g = self;
	local t = tonumber(t)
	if(typeof(g)=='table' and g.GuiObject)then g = g.GuiObject end
	if(self.Draggers[g])then
		self.Draggers[g].DragTime=t
	else
		warn("Make sure to make "..g.Name.." draggable!")
	end
end


function Drag:Connect(g,parts)
	local parts = typeof(parts)=='table' and parts or {g}
	local partsToDrag = {}
	for i = 1,#parts do
		table.insert(partsToDrag,{GUI=parts[i],Position=parts[i].Position})
	end
	if(g:IsA'GuiObject')then
		local con1=g.InputBegan:connect(function(io,gpe)
			if(gpe)then return end
			local data = self.Draggers[g]
			if(data and io.UserInputType==Enum.UserInputType.MouseButton1 and not Drag.Current)then
				Drag.Current=g;
				data.LastPos=io.Position
			end
		end)
		local con2=g.InputEnded:connect(function(io,gpe)
			if(gpe)then return end
			local data = self.Draggers[g]
			if(data and io.UserInputType==Enum.UserInputType.MouseButton1 and Drag.Current==g)then
				Drag.Current=nil;
			end
		end)
		local con3=game:service'UserInputService'.InputChanged:connect(function(io,gpe)
			if(gpe)then return end
			local data = self.Draggers[g]
			if(data and Drag.Current==g and data.LastPos~=nil and io.UserInputType==Enum.UserInputType.MouseMovement)then
				local lp=data.LastPos
				local delta=lp-io.Position;
				for i = 1,#partsToDrag do
					local g = partsToDrag[i].GUI
					partsToDrag[i].Position = partsToDrag[i].Position+UDim2.new(0,-delta.x,0,-delta.y)
					if(data.DragTime>0)then
						Tween(g,{Position=partsToDrag[i].Position},data.DragTime,Enum.EasingStyle.Quad,Enum.EasingDirection.Out,0,false)
					else
						g.Position=partsToDrag[i].Position
					end
				end
				data.LastPos=io.Position;
			end
		end)
		self.Draggers[g]=setmetatable({
			DragTime=0;
			LastPos=Vector3.new();
			Connections={con1,con2,con3};
		},{__index=Drag})

		return setmetatable({
			GuiObject=g;
			Affected=parts;
		},{__index=self.Draggers[g]})
	else
		error(g.ClassName.." is not a valid GuiObject")
	end
end

return Drag;