Library._ConnectorTabs = Library._ConnectorTabs or setmetatable({}, { __mode = "k" });
Library._ConnectorBound = false;

function Library:_BindConnectors()
	if Library._ConnectorBound then return end;
	Library._ConnectorBound = true;
	RunService:BindToRenderStep("CorruptSubTabConnectors", Enum.RenderPriority.Camera.Value + 1, function()
		for Tab in pairs(Library._ConnectorTabs) do
			local Ok = pcall(Library._UpdateSubTabConnector, Library, Tab);
			if not Ok then
				Library._ConnectorTabs[Tab] = nil;
			end;
		end;
	end);
end;

function Library:_RebuildSubTabConnector(Tab)
	if typeof(Drawing) ~= "table" or typeof(Drawing.new) ~= "function" then return end;
	if not Tab then return end;

	if Tab._ConnectorConn then
		pcall(function() Tab._ConnectorConn:Disconnect() end);
		Tab._ConnectorConn = nil;
	end;

	if Tab._ConnectorLines then
		for _, L in Tab._ConnectorLines do
			local Idx = table.find(self.Drawings, L);
			if Idx then table.remove(self.Drawings, Idx) end;
			pcall(function() L:Remove() end);
		end;
	end;
	Tab._ConnectorLines = {};
	Tab._ConnectorCurves = {};
	Tab._ConnectorTrunk = nil;
	Tab._ConnectorShown = false;
	Tab._ConnectorStale = 0;
	Tab._TrunkCache = {};

	local Count = #Tab.SubTabs;
	if Count == 0 then
		Library._ConnectorTabs[Tab] = nil;
		return;
	end;

	local function NewLine()
		local L = Drawing.new("Line");
		L.Thickness = 2;
		L.Color = Library.Palette.Toggle;
		L.Transparency = 1;
		L.Visible = false;
		L.From = Vector2.new(0, 0);
		L.To = Vector2.new(0, 0);
		table.insert(self.Drawings, L);
		table.insert(Tab._ConnectorLines, L);
		return L;
	end;

	Tab._ConnectorTrunk = NewLine();

	for I = 1, Count do
		local Curve = { Cache = {} };
		for _ = 1, 10 do table.insert(Curve, NewLine()) end;
		Curve.Tail = NewLine();
		table.insert(Tab._ConnectorCurves, Curve);
	end;

	Library._ConnectorTabs[Tab] = true;
	self:_BindConnectors();
	self:_UpdateSubTabConnector(Tab);
end;

function Library:_UpdateSubTabConnector(Tab)
	local Trunk = Tab._ConnectorTrunk;
	if not Trunk then return end;

	local Curves = Tab._ConnectorCurves;

	local function HideAll()
		if Tab._ConnectorShown ~= true then return end;
		Tab._ConnectorShown = false;
		Trunk.Visible = false;
		for _, Curve in Curves do
			for S = 1, 10 do
				local Seg = Curve[S];
				if Seg and Seg.Visible then Seg.Visible = false end;
			end;
			if Curve.Tail and Curve.Tail.Visible then Curve.Tail.Visible = false end;
		end;
	end;

	local function SetLine(Line, Cache, Key, FX, FY, TX, TY)
		local C = Cache[Key];
		if C and C[1] == FX and C[2] == FY and C[3] == TX and C[4] == TY then
			if not Line.Visible then Line.Visible = true end;
			return;
		end;
		if C then
			C[1], C[2], C[3], C[4] = FX, FY, TX, TY;
		else
			Cache[Key] = { FX, FY, TX, TY };
		end;
		Line.From = Vector2.new(FX, FY);
		Line.To = Vector2.new(TX, TY);
		if not Line.Visible then Line.Visible = true end;
	end;

	local Subtabs = Tab.SubTabs;
	local Count = #Subtabs;
	if Count == 0 then HideAll(); return end;

	local Container = Tab.SubTabsContainer;
	if not Container or Container.Parent == nil or not self:IsEffectivelyVisible(Container) then
		HideAll(); return;
	end;

	local First = Subtabs[1].Frame;
	local Last = Subtabs[Count].Frame;
	if First.AbsoluteSize.X <= 0 or Last.AbsoluteSize.X <= 0 then
		Tab._ConnectorStale = (Tab._ConnectorStale or 0) + 1;
		if Tab._ConnectorStale > 30 then HideAll() end;
		return;
	end;
	Tab._ConnectorStale = 0;

	local TrunkCache = Tab._TrunkCache;
	if not TrunkCache then TrunkCache = {}; Tab._TrunkCache = TrunkCache end;

	local TrunkX  = First.AbsolutePosition.X - 14;
	local TopY    = First.AbsolutePosition.Y + GuiInset + 2;
	local LastCy  = Last.AbsolutePosition.Y + Last.AbsoluteSize.Y / 2 + GuiInset;
	local BottomY = LastCy - 10;

	if BottomY > TopY then
		SetLine(Trunk, TrunkCache, "T", TrunkX, TopY, TrunkX, BottomY);
	elseif Trunk.Visible then
		Trunk.Visible = false;
		TrunkCache["T"] = nil;
	end;

	for I = 1, Count do
		local Curve = Curves[I];
		if Curve then
			local F  = Subtabs[I].Frame;
			local Cy = F.AbsolutePosition.Y + F.AbsoluteSize.Y / 2 + GuiInset;
			local Cx = TrunkX + 10;
			local CenterY = Cy - 10;
			local PrevX, PrevY = TrunkX, Cy - 10;
			for S = 1, 10 do
				local T = S / 10;
				local Ang = math.pi - T * (math.pi / 2);
				local Px = Cx + 10 * math.cos(Ang);
				local Py = CenterY + 10 * math.sin(Ang);
				SetLine(Curve[S], Curve.Cache, S, PrevX, PrevY, Px, Py);
				PrevX, PrevY = Px, Py;
			end;
			SetLine(Curve.Tail, Curve.Cache, "Tail", TrunkX + 10, Cy, F.AbsolutePosition.X - 2, Cy);
		end;
	end;

	Tab._ConnectorShown = true;
end;