-- TRA Test Tank Script

local vehicleName = "Mk6 MBT"

local vehicle = script.Parent

-- References
local base = vehicle:FindFirstChild("Base")
local vehicleSeat = vehicle:WaitForChild("VehicleSeat")
local turretAxle = vehicle:WaitForChild("TurretAxle")
local barrelAxle = vehicle:WaitForChild("BarrelAxle")
local leftThrust = vehicle:WaitForChild("LeftThrust")
local leftBodyThrust = leftThrust:WaitForChild("BodyThrust")
local rightThrust = vehicle:WaitForChild("RightThrust")
local rightBodyThrust = rightThrust:WaitForChild("BodyThrust")
local barrelBreach = vehicle:WaitForChild("Barrel"):WaitForChild("BarrelBreach")
local barrelTip = vehicle:WaitForChild("Barrel"):WaitForChild("BarrelTip")
-- Children References
local bodyParts = vehicle:WaitForChild("Body"):GetChildren()
local turretParts = vehicle:WaitForChild("Turret"):GetChildren()
local barrelParts = vehicle:WaitForChild("Barrel"):GetChildren()
local leftWheels = vehicle:WaitForChild("LeftWheels"):GetChildren()
local rightWheels = vehicle:WaitForChild("RightWheels"):GetChildren()
-- Aiming Values
local aim = script:WaitForChild("Aim")
local target = script:WaitForChild("Target")
-- Sounds
local engineSound = vehicleSeat:FindFirstChild("Engine")
local mainGunFire = vehicleSeat:FindFirstChild("MainGunFire")
local reload = vehicleSeat:FindFirstChild("Reload")
local turn = vehicleSeat:FindFirstChild("Turn")

-- VEHICLE STATISTICS

-- Torque of each wheel
local torque = 900000
-- Maximum speed of the vehicle
local maxVelocity = vehicleSeat.MaxSpeed*.65
-- Acceleration
local maxAcceleration = 30
-- How much force for each suspension wheel
local suspensionForce = 200000
-- Maximum length of the suspension springs
local suspensionMaxLength = 4.24
-- Minimum length of the suspension springs
local suspensionMinLength = 0.5
-- Dampening of the suspension spring
local suspensionDamping = 15
-- Stiffness of the suspension springs
local suspensionStiffness = 7000
-- Idle distance of the suspension when no force is applied
local suspensionFreeLength = 4
-- Turn Sharpness - How easily the vehicle can turn
local turnSharpness = 8
-- Turn Sharpness Stationary - How easily the vehicle can turn when stationary, usually turnSharpness/2
local stationaryTurnSharpness = 4

-- Set at 0
local suspensionLowAngle = 0
-- How much the suspension can raise when pressured on
local suspensionHighAngle = -30

-- Turret traversal speed in degrees/second
local traversalSpeed = 30
-- Gun elevation speed in degrees/second
local elevationSpeed = 5
-- Maximum elevation
local maxElevation = 25
-- Minimum elevation
local minElevation = -10
-- Inverse smoothness of turret traversal and rotation
local smoothness = 30

-- Force for each boat thruster for aquatic capabilities
local boatForce = 13000


-- Weld together a and b
function weldTogether(a, b, parent)
    local CJ = CFrame.new(a.Position)
    local C0 = a.CFrame:inverse()*CJ
    local C1 = b.CFrame:inverse()*CJ
    local weld = Instance.new("Weld", parent)
    weld.C0 = a.CFrame:toObjectSpace(b.CFrame)
    weld.Part0 = a
    weld.Part1 = b
    b.Anchored = false
    return weld
end

-- Configure the HingeConstraints
for i = 1, #leftWheels do
    local subject = leftWheels[i]
    if subject.Name == "Stationary" then
        local axle = subject:FindFirstChild("Axle")
        local wheel = subject:FindFirstChild("Wheel")
        -- Axle to Wheel
        local axleAttachment = Instance.new("Attachment", axle)
        axleAttachment.Name = "AxleAttachment"
        axleAttachment.Position = Vector3.new(0,0,0)
        local wheelAttachment = Instance.new("Attachment", wheel)
        wheelAttachment.Name = "WheelAttachment"
        wheelAttachment.Position = Vector3.new(0,0,0)
        local wheelMotor = Instance.new("HingeConstraint", subject.Parent)
        wheelMotor.Name = "WheelMotor"
        wheelMotor.ActuatorType = "Motor"
        wheelMotor.Attachment0 = axleAttachment
        wheelMotor.Attachment1 = wheelAttachment
        wheelMotor.Enabled = true
        wheelMotor.AngularVelocity = 0
        wheelMotor.MotorMaxTorque = torque
        wheelMotor.MotorMaxAcceleration = maxAcceleration
        weldTogether(base,axle,axle)
        axle.Anchroed = false
        wheel.Anchored = false
    elseif subject.Name == "FrontTurn" or subject.Name == "BackTurn" then
        local pivot = rightWheels[i]:FindFirstChild("Pivot")
        local axle = rightWheels[i]:FindFirstChild("Axle")
        local wheel = rightWheels[i]:FindFirstChild("Wheel")
        local axleAttachment = Instance.new("Attachment", axle)
        axleAttachment.Name = "AxleAttachment"
        axleAttachment.Position = Vector3.new(0,0,0)
        local wheelAttachment = Instance.new("Attachment", wheel)
        wheelAttachment.Name = "WheelAttachment"
        wheelAttachment.Position = Vector3.new(0,0,0)
        local wheelMotor = Instance.new("HingeConstraint", subject.Parent)
        wheelMotor.Name = "WheelMotor"
        wheelMotor.ActuatorType = "Motor"
        wheelMotor.Attachment0 = axleAttachment
        wheelMotor.Attachment1 = wheelAttachment
        wheelMotor.Enabled = true
        wheelMotor.AngularVelocity = 0
        wheelMotor.MotorMaxTorque = torque
        wheelMotor.MotorMaxAcceleration = maxAcceleration
        weldTogether(tire,wheel,tire)
        local turnWeld = weldTogether(axle,pivot,subject.Parent)
        if subject.Name == "FrontTurn" then
            turnWeld.Name == "FrontTurnWeld"
        else
            subject.Name == "BackTurnWeld"
        weldTogether(base,pivot,pivot)
        pivot.Anchored = false
        axle.Anchored = false
        wheel.Anchored = false
    elseif subject.Name == "Suspension" then
        local frame = subject:FindFirstChild("Frame")
        local lever = subject:FindFirstChild("Lever")
        local wheel = subject:FindFirstChild("Wheel")
        -- Pivot Movement
        local pivotLeverAttachment = Instance.new("Attachment", lever)
        pivotLeverAttachment.Name = "PivotLeverAttachment"
        pivotLeverAttachment.Position = Vector3.new(0,1.25,-1.25)
        local pivotFrameAttachment = Instance.new("Attachment",frame)
        pivotFrameAttachment.Name = "PivotFrameAttachment"
        pivotFrameAttachment.Position = Vector3.new(0,0.25,-1.25)
        local suspensionPivot = Instance.new("HingeConstraint", frame)
        suspensionPivot.Name = "SuspensionPivot"
        suspensionPivot.Attachment0 = pivotFrameAttachment
        suspensionPivot.Attachment1 = pivotLeverAttachment
        suspensionPivot.LimitsEnabled = true
        suspensionPivot.LowerAngle = suspensionLowAngle
        suspensionPivot.UpperAngle = suspensionHighAngle
        -- Wheel Rotation
        local wheelAttachment = Instance.new("Attachment", wheel)
        wheelAttachment.Name = "WheelAttachment"
        wheelAttachment.Position = Vector3.new(0,0,0)
        local axleLeverAttachment = Instance.new("Attachment", lever)
        axleLeverAttachment.Name = "AxleLeverAttachment"
        axleLeverAttachment.Position = Vector3.new(0,-1.25,1.25)
        local wheelMotor = Instance.new("HingeConstraint", subject.Parent)
        wheelMotor.Name = "WheelMotor"
        wheelMotor.ActuatorType = "Motor"
        wheelMotor.Attachment0 = axleLeverAttachment
        wheelMotor.Attachment1 = wheelAttachment
        wheelMotor.AngularVelocity = 0
        wheelMotor.MotorMaxTorque = torque
        wheelMotor.MotorMaxAcceleration = maxAcceleration
        -- Spring Suspension
        local springFrameAttachment = Instance.new("Attachment", frame)
        springFrameAttachment.Name = "SpringFrameAttachment"
        springFrameAttachment.Position = Vector3.new(0,0.25,1.25)
        local springSuspension = Instance.new("SpringConstraint",frame)
        springSuspension.Name = "SpringSuspension"
        springSuspension.Attachment0 = springFrameAttachment
        springSuspension.Attachment1 = wheelAttachment
        springSuspension.LimitsEnabled = true
        springSuspension.MaxLength = suspensionMaxLength
        springSuspension.MinLength = suspensionMinLength
        springSuspension.Damping = suspensionDamping
        springSuspension.MaxForce = suspensionForce
        springSuspension.Stiffness = suspensionStiffness
        springSuspension.FreeLength = suspensionFreeLength
        weldTogether(base,frame,frame)
        frame.Anchored = false
        lever.Anchored = false
        wheel.Anchored = false
    elseif subject.Name == "FrontTurnSuspension" or subject.Name == "BackTurnSuspension" then
        local pivot = subject:FindFirstChild("Pivot")
        local frame = subject:FindFirstChild("Frame")
        local lever = subject:FindFirstChild("Lever")
        local wheel = subject:FindFirstChild("Wheel")
        -- Base to Pivot - Turning weld
        local turnWeld = weldTogether(base,pivot,subject.Parent)
        if subject.Name == "FrontTurn" then
            turnWeld.Name = "FrontTurnWeld"
        else
            turnWeld.Name = "BackTurnWeld"
        end
        -- Remember the original position
        local original = Instance.new("CFrameValue",turnWeld)
        original.Name = "Original"
        original.Value = turnWeld.C0
        -- Pivot to Frame - Axis of Rotation to Frame
        weldTogether(pivot,frame,frame)
        -- Frame to Lever - Torsion Bar Suspension Movement
        local pivotLeverAttachment = Instance.new("Attachment", lever)
        pivotLeverAttachment.Name = "PivotLeverAttachment"
        pivotLeverAttachment.Position = Vector3.new(0,1.25,-1.25)
        local pivotFrameAttachment = Instance.new("Attachment",frame)
        pivotFrameAttachment.Name = "PivotFrameAttachment"
        pivotFrameAttachment.Position = Vector3.new(0,0.25,-1.25)
        local suspensionPivot = Instance.new("HingeConstraint", frame)
        suspensionPivot.Name = "SuspensionPivot"
        suspensionPivot.Attachment0 = pivotFrameAttachment
        suspensionPivot.Attachment1 = pivotLeverAttachment
        suspensionPivot.LimitsEnabled = true
        suspensionPivot.LowerAngle = suspensionLowAngle
        suspensionPivot.UpperAngle = suspensionHighAngle
        -- Lever to Wheel for Wheel Rotation
        local wheelAttachment = Instance.new("Attachment", wheel)
        wheelAttachment.Name = "WheelAttachment"
        wheelAttachment.Position = Vector3.new(0,0,0)
        local axleLeverAttachment = Instance.new("Attachment", lever)
        axleLeverAttachment.Name = "AxleLeverAttachment"
        axleLeverAttachment.Position = Vector3.new(0,-1.25,1.25)
        local wheelMotor = Instance.new("HingeConstraint", subject.Parent)
        wheelMotor.Name = "WheelMotor"
        wheelMotor.ActuatorType = "Motor"
        wheelMotor.Attachment0 = axleLeverAttachment
        wheelMotor.Attachment1 = wheelAttachment
        wheelMotor.AngularVelocity = 0
        wheelMotor.MotorMaxTorque = torque
        wheelMotor.MotorMaxAcceleration = maxAcceleration
        -- Spring Suspension
        local springFrameAttachment = Instance.new("Attachment", frame)
        springFrameAttachment.Name = "SpringFrameAttachment"
        springFrameAttachment.Position = Vector3.new(0,0.25,1.25)
        local springSuspension = Instance.new("SpringConstraint",frame)
        springSuspension.Name = "SpringSuspension"
        springSuspension.Attachment0 = springFrameAttachment
        springSuspension.Attachment1 = wheelAttachment
        springSuspension.LimitsEnabled = true
        springSuspension.MaxLength = suspensionMaxLength
        springSuspension.MinLength = suspensionMinLength
        springSuspension.Damping = suspensionDamping
        springSuspension.MaxForce = suspensionForce
        springSuspension.Stiffness = suspensionStiffness
        springSuspension.FreeLength = suspensionFreeLength
        pivot.Anchored = false
        frame.Anchored = false
        lever.Anchored = false
        wheel.Anchored = false
    end
end



-- Weld the Body to the Base
for i = 1, #bodyParts do
    if bodyParts[i]:IsA("BasePart") or bodyParts[i].ClassName == "UnionOperation" then
        weldTogether(base,bodyParts[i],bodyParts[i])
    end
end

-- Weld the Turret to the TurretAxle
for i = 1, #turretParts do
    if turretParts[i]:IsA("BasePart") or turretParts[i].ClassName == "UnionOperation" then
        weldTogether(turretAxle, turretParts[i],turretParts[i])
    end
end

-- Weld the Barrel to the BarrelAxle
for i = 1, #barrelParts do
    if barrelParts[i]:IsA("BasePart") or barrelParts[i].ClassName == "UnionOperation" then
        weldTogether(barrelAxle, barrelParts[i],barrelParts[i])
    end
end


local traversalWeld = weldTogether(base, turretAxle, vehicle)
traversalWeld.Name = "TraversalWeld"

local elevationWeld = weldTogether(turretAxle, barrelAxle, vehicle)
elevationWeld.Name = "ElevationWeld"

weldTogether(base,vehicleSeat,vehicleSeat)
weldTogether(base,rightThrust,rightThrust)
weldTogether(base,leftThrust,leftThrust)

turretAxle.Anchored = false
barrelAxle.Anchored = false
base.Anchored = false


function setLeftVelocity(velocity)
    local leftCh = vehicle:WaitForChild("LeftWheels"):GetChildren()
    for i = 1, #leftCh do
        if leftCh[i].Name == "WheelMotor" then
            leftCh[i].AngularVelocity = velocity
        end
    end
end

function setRightVelocity(velocity)
    local rightCh = vehicle:WaitForChild("RightWheels"):GetChildren()
    for i = 1, #rightCh do
        if rightCh[i].Name == "WheelMotor" then
            rightCh[i].AngularVelocity = velocity
        end
    end
end

function openHatch()
    local body = vehicle:FindFirstChild("Body"):GetChildren()
    local turret = vehicle:FindFirstChild("Turret"):GetChildren()
    for i = 1, #body do
        if body[i].Name == "Hatch" then
            body[i].CanCollide = false
            body[i].Transparency = 0.5
        end
    end
    for i = 1, #turret do
        if turret[i].Name == "Hatch" then
            turret[i].CanCollide = false
            turret[i].Transparency = 0.5
        end
    end
end

function closeHatch()
    local body = vehicle:FindFirstChild("Body"):GetChildren()
    local turret = vehicle:FindFirstChild("Turret"):GetChildren()
    for i = 1, #body do
        if body[i].Name == "Hatch" then
            body[i].CanCollide = true
            body[i].Transparency = 0
        end
    end
    for i = 1, #turret do
        if turret[i].Name == "Hatch" then
            turret[i].CanCollide = true
            turret[i].Transparency = 0
        end
    end
end

-- Raycast check for turret rotation
function rayCast(start,finish)
    local aimVector=(finish-start).unit
    local hitPart, hitPos = game.Workspace:FindPartOnRayWithIgnoreList(Ray.new(start,aimVector*20), {game.Workspace, vehicle},false)
    return hitPos
end

-- The steering controls
vehicleSeat.Changed:connect(function(p)
    local leftVelocity = 0
    local rightVelocity = 0
    -- Swimming
    local leftSwim = 0
    local rightSwim = 0
    if rightThrust.Position.Y < -3.4 or leftThrust.Position.Y < -3.4 then
        -- Turning Right
        if vehicleSeat.Steer < 0 then
            leftSwim = leftSwim + boatForce/4
            rightSwim = rightSwim - boatForce/4
        -- Turning left
        elseif vehicleSeat.Steer > 0 then
            leftSwim = leftSwim - boatForce/4
            rightSwim = rightSwim + boatForce/4
        end
        -- Forward
        if vehicleSeat.Throttle > 0 then
            leftSwim = leftSwim - 3 * boatForce/4
            rightSwim = rightSwim - 3 * boatForce/4
        -- Backward
        elseif vehicleSeat.Throttle < 0 then
            leftSwim = leftSwim + 3*boatForce/4
            rightSwim = rightSwim + 3*boatForce/4
        end
        leftBodyThrust.Force = Vector3.new(0, 0, leftSwim)
        rightBodyThrust.Force = Vector3.new(0, 0, rightSwim)
    else
        leftBodyThrust.Force = Vector3.new(0, 0, 0)
        rightBodyThrust.Force = Vector3.new(0, 0, 0)
    end

    -- Stationary Turning
    if vehicleSeat.Throttle == 0 then
        -- Turning right
        if vehicleSeat.Steer < 0 then
            leftVelocity = maxVelocity/stationaryTurnSharpness
            rightVelocity = - maxVelocity/stationaryTurnSharpness
        -- Turning left
        elseif vehicleSeat.Steer > 0 then
            leftVelocity = - maxVelocity/stationaryTurnSharpness
            rightVelocity = maxVelocity/stationaryTurnSharpness
        end
    -- Forward
    elseif vehicleSeat.Throttle > 0 then
        rightVelocity = - maxVelocity
        leftVelocity = - maxVelocity
        -- Turning right
        if vehicleSeat.Steer < 0 then
            leftVelocity = leftVelocity / turnSharpness
        -- Turning left
        elseif vehicleSeat.Steer > 0 then
            rightVelocity = rightVelocity / turnSharpness
        end
    -- Backward
    elseif vehicleSeat.Throttle < 0 then
        rightVelocity = maxVelocity
        leftVelocity = maxVelocity
            -- Turning right
        if vehicleSeat.Steer > 0 then
            rightVelocity = rightVelocity / turnSharpness
        -- Turning left
        elseif vehicleSeat.Steer < 0 then
            leftVelocity = leftVelocity / turnSharpness
        end
    end
    setLeftVelocity(leftVelocity)
    setRightVelocity(rightVelocity)
end)

-- Tool Giver
vehicleSeat.ChildAdded:connect(function(child)
    if child.Name == "SeatWeld" then
        if child.Part1.Name == "HumanoidRootPart" then
            local player = game.Players:GetPlayerFromCharacter(child.Part1.Parent)
            if player ~= nil then
                local tool = game.ReplicatedStorage[vehicleName]:Clone()
                tool:WaitForChild("TankReference").Value = vehicle
                tool.Parent = player.Backpack
                tool.ToolScript.Disabled = false
                vehicleSeat:SetNetworkOwner(player)
                base:SetNetworkOwner(player)
                closeHatch()
                engineSound.Volume = .1
                engineSound:Play()
            end
        end
    end
end)

-- Player removed from seat
vehicleSeat.ChildRemoved:connect(function(child)
    if child.Name == "SeatWeld" then
        setLeftVelocity(0)
        setRightVelocity(0)
        aim.Value = false
        openHatch()
        engineSound:Stop()
    end
end)

local traversalWeld = vehicle:WaitForChild("TraversalWeld")
local elevationWeld = vehicle:WaitForChild("ElevationWeld")

-- Turret Control
aim.Changed:Connect(function(newValue)
    if aim.Value then
        turn:Play()
    end
    while aim.Value do
        -- Raycasting
        local mousePos = target.Value
        local hitPos = rayCast(barrelBreach.Position, barrelTip.Position)
        local mouseHitPos = rayCast(barrelBreach.Position, mousePos)
        -- Traversal Calculation
        local traversalAngle = ((- math.atan2((hitPos.z - base.Position.z ) , (hitPos.x - base.Position.x)) * 57.2958)) % 360
        local mouseAngle = ((- math.atan2((mousePos.z - base.Position.z ) , (mousePos.x - base.Position.x)) * 57.2958)) % 360
        local angleDif = (mouseAngle - traversalAngle) % 360
        if (angleDif < (359 - traversalSpeed/smoothness) and angleDif > traversalSpeed/smoothness) then
            if angleDif > 180 then
                traversalWeld.C0 = traversalWeld.C0 * CFrame.Angles(0,-math.rad(traversalSpeed/smoothness),0)
            elseif angleDif < 180  then
                traversalWeld.C0 = traversalWeld.C0 * CFrame.Angles(0,math.rad(traversalSpeed/smoothness),0)
            end
        else
            traversalWeld.C0 = traversalWeld.C0 * CFrame.Angles(0,math.rad(angleDif),0)
        end

        -- Elevation Calculation
        local distDif = mouseHitPos.y - hitPos.y
        local barrelElevation =  barrelAxle.Orientation.x - base.Orientation.x
        local changeAngle = math.acos((200-(distDif*distDif))/200)
        if ( changeAngle > (elevationSpeed/smoothness) ) then
            -- Aim Up
            if distDif > 0 and barrelElevation < maxElevation then
                elevationWeld.C0 = elevationWeld.C0 * CFrame.Angles(0,-math.rad((elevationSpeed/smoothness)),0)
            -- Aim Down
            elseif distDif < 0 and barrelElevation > minElevation then
                elevationWeld.C0 = elevationWeld.C0 * CFrame.Angles(0,math.rad((elevationSpeed/smoothness)),0)
            end
        else
            -- Aim Up
            if distDif > 0 and barrelElevation < maxElevation then
                elevationWeld.C0 = elevationWeld.C0 * CFrame.Angles(0,-math.rad(changeAngle),0)
            -- Aim Down
            elseif distDif < 0 and barrelElevation > minElevation then
                elevationWeld.C0 = elevationWeld.C0 * CFrame.Angles(0,math.rad(changeAngle),0)
            end
        end
        wait(1.0/smoothness)
    end
    turn:Stop()
end)