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

local player = Players.LocalPlayer
local playerGui = player:WaitForChild("PlayerGui")
local camera = workspace.CurrentCamera

local gui = Instance.new("ScreenGui")
gui.Name = "Tracer GUI"
gui.ResetOnSpawn = false
gui.IgnoreGuiInset = true
gui.DisplayOrder = -2147483648
gui.Parent = playerGui

local tracers = {}

local function getHRP(targetPlayer)
    if not targetPlayer or not targetPlayer.Parent then
        return nil
    end
    local char = targetPlayer.Character
    if not char or not char.Parent then
        return nil
    end
    local hrp = char:FindFirstChild("HumanoidRootPart")
    if not hrp or not hrp:IsA("BasePart") then
        return nil
    end
    return hrp
end

local function removeTracer(targetPlayer)
    local data = tracers[targetPlayer]
    if not data then
        return
    end
    if data.pivot then
        data.pivot:Destroy()
    end
    tracers[targetPlayer] = nil
end

local function addTracer(targetPlayer)
    if targetPlayer == player then
        return
    end
    if tracers[targetPlayer] then
        return
    end

    local pivot = Instance.new("Frame")
    pivot.Name = "Tracer_" .. targetPlayer.UserId
    pivot.AnchorPoint = Vector2.new(0.5, 0.5)
    pivot.Position = UDim2.fromScale(0.5, 1)
    pivot.Size = UDim2.fromOffset(1, 1)
    pivot.BackgroundTransparency = 1
    pivot.Visible = false
    pivot.ZIndex = -2147483648
    pivot.Parent = gui

    local line = Instance.new("Frame")
    line.Name = "Line"
    line.AnchorPoint = Vector2.new(0.5, 1)
    line.Position = UDim2.fromScale(0.5, 0.5)
    line.Size = UDim2.fromOffset(2, 0)
    line.BackgroundColor3 = Color3.fromRGB(255, 0, 0)
    line.BorderSizePixel = 0
    line.ZIndex = -2147483648
    line.Parent = pivot

    tracers[targetPlayer] = {
        pivot = pivot,
        line = line,
        lastPos = nil,
    }
end

local function hookPlayer(targetPlayer)
    if targetPlayer == player then
        return
    end

    targetPlayer.CharacterAdded:Connect(function()
        addTracer(targetPlayer)
    end)

    targetPlayer.CharacterRemoving:Connect(function()
        local data = tracers[targetPlayer]
        if data then
            data.lastPos = nil
            data.pivot.Visible = false
        end
    end)

    addTracer(targetPlayer)
end

for _, other in ipairs(Players:GetPlayers()) do
    hookPlayer(other)
end

Players.PlayerAdded:Connect(hookPlayer)
Players.PlayerRemoving:Connect(removeTracer)

RunService.RenderStepped:Connect(function()
    local viewport = camera.ViewportSize
    local originX = viewport.X * 0.5
    local originY = viewport.Y

    for targetPlayer, data in pairs(tracers) do
        if not targetPlayer.Parent then
            removeTracer(targetPlayer)
        else
            local hrp = getHRP(targetPlayer)
            local worldv Pos = nil
            if hrp then
                worldPos = hrp.Position
                data.lastPos = worldPos
            else
                worldPos = data.lastPos
            end

            if not worldPos then
                data.pivot.Visible = false
            else
                local screenPos = camera:WorldToViewportPoint(worldPos)
                local dirX = screenPos.X - originX
                local dirY = screenPos.Y - originY
                if screenPos.Z < 0 then
                    dirX = -dirX
                    dirY = -dirY
                end

                if dirX ~= dirX or dirY ~= dirY then
                    data.pivot.Visible = false
                else
                    data.pivot.Visible = true
                    data.pivot.Rotation = math.deg(math.atan2(dirX, -dirY))
                    data.line.Size = UDim2.fromOffset(2, math.sqrt(dirX * dirX + dirY * dirY))
                end
            end
        end
    end
end)