-- HRP PREDICTIVE LOCK-ON (RAW + SHIFTLOCK)
-- StarterPlayer > StarterPlayerScripts
-- Roblox Studio LocalScript
local Players = game:GetService("Players")
local RunService = game:GetService("RunService")
local UserInputService = game:GetService("UserInputService")
local LocalPlayer = Players.LocalPlayer
local PlayerGui = LocalPlayer:WaitForChild("PlayerGui")

local Settings = {
	Prediction = 0.22,
	MaxPrediction = 0.65,
	SearchRadius = 120,
	RequireLineOfSight = true,
	UsePrediction = true, -- set to false for pure raw HRP aim
}

local State = {
	Mode = "Idle",
	Selected = nil,
	Target = nil,
	Connection = nil,
}

-- SHIFTLOCK CONTROL
local function shiftLockOn()
	UserInputService.MouseBehavior = Enum.MouseBehavior.LockCenter
	UserInputService.MouseIconEnabled = false
end

local function shiftLockOff()
	UserInputService.MouseBehavior = Enum.MouseBehavior.Default
	UserInputService.MouseIconEnabled = true
end

-- GUI
local Gui = Instance.new("ScreenGui")
Gui.Name = "HRPLockOn"
Gui.ResetOnSpawn = false
Gui.Parent = PlayerGui

local Button = Instance.new("TextButton")
Button.Name = "LockButton"
Button.Size = UDim2.fromOffset(48, 48)
Button.Position = UDim2.new(0.82, 0, 0.65, 0)
Button.BackgroundColor3 = Color3.fromRGB(25, 25, 30)
Button.Text = "🔓"
Button.TextSize = 25
Button.Parent = Gui

local Corner = Instance.new("UICorner")
Corner.CornerRadius = UDim.new(1, 0)
Corner.Parent = Button

local Stroke = Instance.new("UIStroke")
Stroke.Thickness = 2
Stroke.Color = Color3.fromRGB(100, 100, 110)
Stroke.Parent = Button

local Status = Instance.new("TextLabel")
Status.Size = UDim2.fromOffset(190, 28)
Status.Position = UDim2.new(0.5, -95, 0, -34)
Status.BackgroundColor3 = Color3.fromRGB(20, 20, 25)
Status.TextColor3 = Color3.new(1, 1, 1)
Status.TextSize = 11
Status.Font = Enum.Font.GothamBold
Status.Visible = false
Status.Parent = Button

local StatusCorner = Instance.new("UICorner")
StatusCorner.CornerRadius = UDim.new(0, 7)
StatusCorner.Parent = Status

-- DRAGGING
local dragging = false
local dragStart
local startPosition
local dragInput

Button.InputBegan:Connect(function(input)
	if input.UserInputType == Enum.UserInputType.MouseButton1
		or input.UserInputType == Enum.UserInputType.Touch then
		dragging = true
		dragStart = input.Position
		startPosition = Button.Position
		input.Changed:Connect(function()
			if input.UserInputState == Enum.UserInputState.End then
				dragging = false
			end
		end)
	end
end)

Button.InputChanged:Connect(function(input)
	if input.UserInputType == Enum.UserInputType.MouseMovement
		or input.UserInputType == Enum.UserInputType.Touch then
		dragInput = input
	end
end)

UserInputService.InputChanged:Connect(function(input)
	if dragging and input == dragInput then
		local delta = input.Position - dragStart
		Button.Position = UDim2.new(
			startPosition.X.Scale,
			startPosition.X.Offset + delta.X,
			startPosition.Y.Scale,
			startPosition.Y.Offset + delta.Y
		)
	end
end)

-- CHARACTER HELPERS
local function getCharacter(player)
	if not player then return end
	local character = player.Character
	if not character then return end
	local humanoid = character:FindFirstChildOfClass("Humanoid")
	local hrp = character:FindFirstChild("HumanoidRootPart")
	if not humanoid or not hrp or humanoid.Health <= 0 then
		return
	end
	return character, humanoid, hrp
end

-- TARGET VISIBILITY
local function canSee(character, part)
	if not Settings.RequireLineOfSight then
		return true
	end
	local myCharacter = LocalPlayer.Character
	local camera = workspace.CurrentCamera
	if not camera then return false end
	local params = RaycastParams.new()
	params.FilterType = Enum.RaycastFilterType.Exclude
	params.FilterDescendantsInstances = {
		myCharacter,
		camera
	}
	local direction = part.Position - camera.CFrame.Position
	local result = workspace:Raycast(
		camera.CFrame.Position,
		direction,
		params
	)
	return result ~= nil
		and result.Instance:IsDescendantOf(character)
end

-- TARGET SELECTION
local function findTarget()
	local camera = workspace.CurrentCamera
	if not camera then return nil end
	local viewport = camera.ViewportSize
	local center = Vector2.new(
		viewport.X / 2,
		viewport.Y / 2
	)
	local bestTarget
	local bestDistance = Settings.SearchRadius
	for _, player in ipairs(Players:GetPlayers()) do
		if player ~= LocalPlayer then
			local character, humanoid, hrp = getCharacter(player)
			if character and hrp then
				local screen, visible =
					camera:WorldToViewportPoint(hrp.Position)
				if visible and screen.Z > 0 then
					local distance = (
						Vector2.new(screen.X, screen.Y) - center
					).Magnitude
					if distance < bestDistance
						and canSee(character, hrp) then
						bestDistance = distance
						bestTarget = player
					end
				end
			end
		end
	end
	return bestTarget
end

-- PREDICTION
local StopThreshold = 0.5 -- studs/sec; below this the target counts as stopped

local function predictPosition(hrp)
	local velocity = hrp.AssemblyLinearVelocity
	local speed = velocity.Magnitude
	-- Target fully stopped: no prediction, raw HRP aim.
	if speed < StopThreshold then
		return hrp.Position
	end
	local predictionTime = math.clamp(
		Settings.Prediction + speed / 150,
		0,
		Settings.MaxPrediction
	)
	return hrp.Position + velocity * predictionTime
end

-- UNLOCK
local function unlock()
	if State.Connection then
		State.Connection:Disconnect()
		State.Connection = nil
	end
	State.Target = nil
	State.Selected = nil
	State.Mode = "Idle"
	shiftLockOff()
	Button.Text = "🔓"
	Button.BackgroundColor3 = Color3.fromRGB(25, 25, 30)
	Stroke.Color = Color3.fromRGB(100, 100, 110)
	Status.Visible = false
end

-- LOCK
local function lock(player)
	local character, humanoid, hrp = getCharacter(player)
	if not character then
		unlock()
		return
	end
	local myCharacter = LocalPlayer.Character
	local myHumanoid = myCharacter
		and myCharacter:FindFirstChildOfClass("Humanoid")
	local myHRP = myCharacter
		and myCharacter:FindFirstChild("HumanoidRootPart")
	if not myHumanoid or not myHRP then
		unlock()
		return
	end

	State.Target = player
	State.Mode = "Locked"
	shiftLockOn()
	Button.Text = "🔒"
	Button.BackgroundColor3 = Color3.fromRGB(20, 115, 55)
	Stroke.Color = Color3.fromRGB(65, 255, 110)
	Status.Text = "HRP LOCKED: " .. player.DisplayName
	Status.Visible = true

	State.Connection = RunService.RenderStepped:Connect(function()
		local targetCharacter, targetHumanoid, targetHRP =
			getCharacter(State.Target)
		local currentCharacter = LocalPlayer.Character
		local currentHRP = currentCharacter
			and currentCharacter:FindFirstChild("HumanoidRootPart")
		local currentHumanoid = currentCharacter
			and currentCharacter:FindFirstChildOfClass("Humanoid")
		if not targetCharacter
			or not currentHRP
			or not currentHumanoid then
			unlock()
			return
		end

		-- Keep shiftlock held every frame (Roblox resets it on camera changes).
		shiftLockOn()

		-- Aim point: predicted position, or the raw HRP itself.
		local aimPosition = targetHRP.Position
		if Settings.UsePrediction then
			aimPosition = predictPosition(targetHRP)
		end

		-- RAW lock-on: face the aim point instantly, no smoothing/lerp.
		local origin = currentHRP.Position
		local flatTarget = Vector3.new(
			aimPosition.X,
			origin.Y,
			aimPosition.Z
		)
		local difference = flatTarget - origin
		if difference.Magnitude > 0.01 then
			currentHRP.CFrame = CFrame.lookAt(
				origin,
				flatTarget
			)
		end
	end)
end

-- BUTTON
Button.Activated:Connect(function()
	if State.Mode == "Idle" then
		local target = findTarget()
		if target then
			State.Selected = target
			State.Mode = "Selected"
			Button.Text = "✅"
			Button.BackgroundColor3 =
				Color3.fromRGB(20, 130, 65)
			Stroke.Color = Color3.fromRGB(65, 255, 110)
			Status.Text = "SAVE TARGET: " .. target.DisplayName
			Status.Visible = true
		else
			Status.Text = "NO TARGET FOUND"
			Status.Visible = true
			task.delay(1.5, function()
				if State.Mode == "Idle" then
					Status.Visible = false
				end
			end)
		end
	elseif State.Mode == "Selected" then
		if State.Selected and getCharacter(State.Selected) then
			lock(State.Selected)
		else
			unlock()
		end
	elseif State.Mode == "Locked" then
		unlock()
	end
end)

-- TARGET LEAVING
Players.PlayerRemoving:Connect(function(player)
	if player == State.Target or player == State.Selected then
		unlock()
	end
end)

-- RESPAWN
LocalPlayer.CharacterAdded:Connect(function()
	unlock()
end)

print("[HRP Lock-On] Raw + ShiftLock loaded successfully.")