-- ServerScriptService > Script

local Players = game:GetService("Players")
local Workspace = game:GetService("Workspace")

local KEY_NAME = "Key"

local function countPlayerKeys(player)
	local count = 0

	local backpack = player:FindFirstChildOfClass("Backpack")
	if backpack then
		for _, obj in ipairs(backpack:GetChildren()) do
			if obj:IsA("Tool") and obj.Name == KEY_NAME then
				count += 1
			end
		end
	end

	local character = player.Character
	if character then
		for _, obj in ipairs(character:GetChildren()) do
			if obj:IsA("Tool") and obj.Name == KEY_NAME then
				count += 1
			end
		end
	end

	return count
end

local function getPlayerFromTool(tool)
	local parent = tool.Parent
	if not parent then
		return nil
	end

	if parent:IsA("Backpack") and parent.Parent and parent.Parent:IsA("Player") then
		return parent.Parent
	end

	if parent:IsA("Model") then
		return Players:GetPlayerFromCharacter(parent)
	end

	return nil
end

local function hookKey(tool)
	if not tool:IsA("Tool") then
		return
	end

	if tool.Name ~= KEY_NAME then
		return
	end

	if tool:GetAttribute("PickupHooked") then
		return
	end
	tool:SetAttribute("PickupHooked", true)

	tool.AncestryChanged:Connect(function()
		local player = getPlayerFromTool(tool)
		if not player then
			return
		end

		task.defer(function()
			if not tool.Parent then
				return
			end

			if countPlayerKeys(player) > 1 then
				tool:Destroy()
			end
		end)
	end)
end

for _, inst in ipairs(Workspace:GetDescendants()) do
	hookKey(inst)
end

Workspace.DescendantAdded:Connect(hookKey)