Clutch = class('Clutch')

function Clutch:initialize(options)
    options = options or {}

    self.stiffness = options.Stiffness or 10
    self.capacity = options.Capacity or 2
    self.damping = options.Damping or 0.3
    self.maxTorque = options.MaxTorque or 150

    self.press = 0
    self.slip = 0
    self.targetTorque = 0
    self.torque = 0

    self._engine = nil
    self._gearbox = nil
end

function Clutch:update()
    local someConversionCoeff = 0.10472

    local engRPM = self._engine and self._engine.rpm or 0
    local gboxRPM = self._gearbox and self._gearbox.rpm or 0
    local gboxRatio = self._gearbox and self._gearbox.ratio or 0
    local gboxRatioNotZero = gboxRatio ~= 0 and 1 or 0

    self.slip = ((engRPM - gboxRPM) * someConversionCoeff) * gboxRatioNotZero / 2
    self.targetTorque = math.clamp(self.slip * self.stiffness * (1 - self.press), -self.maxTorque, self.maxTorque)

    self.torque = math.lerp(self.damping, self.torque, self.targetTorque)
end

function Clutch:linkEngine(engine)
    self._engine = engine
end

function Clutch:linkGearbox(gbox)
    self._gearbox = gbox
end

function Clutch:setPress(val)
    self.press = math.clamp(val, 0, 1)
end