package ackhandler

import (
	"github.com/lucas-clemente/quic-go/frames"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

var _ = Describe("StopWaitingManager", func() {
	var manager *stopWaitingManager
	BeforeEach(func() {
		manager = &stopWaitingManager{}
	})

	It("returns nil in the beginning", func() {
		Expect(manager.GetStopWaitingFrame()).To(BeNil())
	})

	It("returns a StopWaitingFrame, when a new ACK arrives", func() {
		manager.ReceivedAck(&frames.AckFrame{LargestAcked: 10})
		Expect(manager.GetStopWaitingFrame()).To(Equal(&frames.StopWaitingFrame{LeastUnacked: 11}))
	})

	It("does not decrease the LeastUnacked", func() {
		manager.ReceivedAck(&frames.AckFrame{LargestAcked: 10})
		manager.ReceivedAck(&frames.AckFrame{LargestAcked: 9})
		Expect(manager.GetStopWaitingFrame()).To(Equal(&frames.StopWaitingFrame{LeastUnacked: 11}))
	})

	It("does not send the same StopWaitingFrame twice", func() {
		manager.ReceivedAck(&frames.AckFrame{LargestAcked: 10})
		Expect(manager.GetStopWaitingFrame()).ToNot(BeNil())
		Expect(manager.GetStopWaitingFrame()).To(BeNil())
	})
})