Material TextBox (lua)

local parent = script.Parent
local mouse = game.Players.LocalPlayer:GetMouse()

local xsize = parent.Size.X.Offset
local ysize = parent.Size.Y.Offset
parent.Visible = true
parent.Active = true
parent.Selectable = true

local Underline = Instance.new("Frame")
local UnderlineBase = Instance.new("Frame")

Underline.Name = "Underline"
Underline.Parent = parent
Underline.BackgroundColor3 = parent.TextColor3
Underline.BorderSizePixel = 0
Underline.Position = UDim2.new(0, 0, 1, 0)
Underline.Size = UDim2.new(0, 0, 0, 1)

UnderlineBase.Name = "UnderlineBase"
UnderlineBase.Parent = parent
UnderlineBase.BackgroundColor3 = parent.TextColor3
UnderlineBase.BackgroundTransparency = 0.85
UnderlineBase.BorderSizePixel = 0
UnderlineBase.Position = UDim2.new(0, 0, 1, 0)
UnderlineBase.Size = UDim2.new(0, xsize, 0, 1)

parent.Focused:connect(function()
    if Underline.Size == UDim2.new(0, 0, 0, 1) then
        local x = (mouse.X) - (parent.AbsolutePosition.X)
        Underline.BackgroundTransparency = 0
        Underline.Position = UDim2.new(0,x,1,0)
        wait()
        Underline:TweenSizeAndPosition(
            UDim2.new(0, xsize, 0, 1),
            UDim2.new(0, 0, 1, 0),
            "Out",
            "Quint",
            0.2
        )
    end
end)

parent.FocusLost:connect(function()
    if parent.Text == "" then
        parent.Text = "TextBox"
    end

    local TweenService = game:GetService("TweenService")

    local Info = TweenInfo.new(
        0.15,
        Enum.EasingStyle.Linear,
        Enum.EasingDirection.Out,
        0,
        false,
        0
    )
    local Goals =
    {
        BackgroundTransparency = 1;
    }

    local tween = TweenService:Create(Underline,Info,Goals)
    tween:Play()

    wait(0.15)
    Underline.Size = UDim2.new(0,0,0,1)
end)