--------------------------------------------------
-- SERVICES
--------------------------------------------------
local Players = game:GetService("Players")
local UserInputService = game:GetService("UserInputService")
local RunService = game:GetService("RunService")

local LocalPlayer = Players.LocalPlayer

--------------------------------------------------
-- CONFIG
--------------------------------------------------
local NORMAL_SPEED = 12
local RUN_SPEED = 22
local RUN_ANIMATION_ID = "rbxassetid://87945256029788"

--------------------------------------------------
-- VARIABLES
--------------------------------------------------
local humanoid
local runTrack
local shiftHeld = false

--------------------------------------------------
-- SETUP CHARACTER
--------------------------------------------------
local function setupCharacter(character)
    humanoid = character:WaitForChild("Humanoid")
    humanoid.WalkSpeed = NORMAL_SPEED

    local animation = Instance.new("Animation")
    animation.AnimationId = RUN_ANIMATION_ID

    runTrack = humanoid:LoadAnimation(animation)
    runTrack.Priority = Enum.AnimationPriority.Movement
end

LocalPlayer.CharacterAdded:Connect(setupCharacter)
if LocalPlayer.Character then
    setupCharacter(LocalPlayer.Character)
end

--------------------------------------------------
-- RENDER LOOP: handles speed + animation
--------------------------------------------------
RunService.RenderStepped:Connect(function()
    if not humanoid then return end

    -- SPEED CONTROL
    if shiftHeld then
        humanoid.WalkSpeed = RUN_SPEED
    else
        humanoid.WalkSpeed = NORMAL_SPEED
    end

    -- ANIMATION CONTROL
    if shiftHeld and humanoid.MoveDirection.Magnitude > 0 then
        if runTrack and not runTrack.IsPlaying then
            runTrack:Play()
        end
    else
        if runTrack and runTrack.IsPlaying then
            runTrack:Stop()
        end
    end
end)

--------------------------------------------------
-- INPUT HANDLING
--------------------------------------------------
UserInputService.InputBegan:Connect(function(input, gpe)
    if gpe then return end
    if input.KeyCode == Enum.KeyCode.LeftShift then
        shiftHeld = true
    end
end)

UserInputService.InputEnded:Connect(function(input)
    if input.KeyCode == Enum.KeyCode.LeftShift then
        shiftHeld = false
    end
end)

print("[Sprint] Movement-based sprint with proper release active.")