CameraAdditiveEffectManager = class("CameraAdditiveEffectManager")

function CameraAdditiveEffectManager.Me()
	if nil == CameraAdditiveEffectManager.me then
		CameraAdditiveEffectManager.me = CameraAdditiveEffectManager.new()
	end
	return CameraAdditiveEffectManager.me
end

-- static function begin
function CameraAdditiveEffectManager.CheckPriority(effect, priority)
	local manager = FunctionCameraAdditiveEffect.Me()
	local currentEffect = manager:GetEffect(effect.type)
	return not (nil ~= currentEffect and currentEffect.running and nil ~= currentEffect.priority and currentEffect.priority > priority)
end

function CameraAdditiveEffectManager.CheckToken(effect, token)
	return effect.running and effect.token == token
end

function CameraAdditiveEffectManager.StartEffect(effect, priority)
	local manager = FunctionCameraAdditiveEffect.Me()
	manager:EndEffectByType(effect.type)
	manager:StartEffect(effect)
	effect.priority = priority
	if nil == effect.token then
		effect.token = 1
	else
		effect.token = effect.token + 1
	end
end

function CameraAdditiveEffectManager.EndEffect(effect)
	local manager = FunctionCameraAdditiveEffect.Me()
	manager:EndEffect(effect)
end

-- static function end

function CameraAdditiveEffectManager:ctor()
	self.effectShake = CameraAdditiveEffectShake.new()
end

-- return token
function CameraAdditiveEffectManager:StartShake(range, duration, curve, priority)
	priority = priority or 1

	if not CameraAdditiveEffectManager.CheckPriority(self.effectShake, priority) then 
		return nil
	end
	
	CameraAdditiveEffectManager.EndEffect(self.effectShake)
	self.effectShake:SetParams(range, duration, curve)
	CameraAdditiveEffectManager.StartEffect(self.effectShake, priority)
	return self.effectShake.token
end

function CameraAdditiveEffectManager:EndShake(token)
	if not CameraAdditiveEffectManager.CheckToken(self.effectShake, token) then
		return
	end
	CameraAdditiveEffectManager.EndEffect(self.effectShake)
end