package wire

import (
	"bytes"

	"github.com/lucas-clemente/quic-go/internal/protocol"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

var _ = Describe("Version Negotiation Packets", func() {
	It("writes for gQUIC", func() {
		connID := protocol.ConnectionID{0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x13, 0x37}
		versions := []protocol.VersionNumber{1001, 1003}
		data := ComposeGQUICVersionNegotiation(connID, versions)
		b := bytes.NewReader(data)
		iHdr, err := ParseInvariantHeader(b, 4)
		Expect(err).ToNot(HaveOccurred())
		hdr, err := iHdr.Parse(b, protocol.PerspectiveServer, versionPublicHeader)
		Expect(err).ToNot(HaveOccurred())
		Expect(hdr.VersionFlag).To(BeTrue())
		Expect(hdr.DestConnectionID).To(Equal(connID))
		Expect(hdr.SrcConnectionID).To(BeEmpty())
		Expect(hdr.SupportedVersions).To(Equal(versions))
	})

	It("writes in IETF draft style", func() {
		srcConnID := protocol.ConnectionID{0xde, 0xad, 0xbe, 0xef, 0xca, 0xfe, 0x13, 0x37}
		destConnID := protocol.ConnectionID{1, 2, 3, 4, 5, 6, 7, 8}
		versions := []protocol.VersionNumber{1001, 1003}
		data, err := ComposeVersionNegotiation(destConnID, srcConnID, versions)
		Expect(err).ToNot(HaveOccurred())
		Expect(data[0] & 0x80).ToNot(BeZero())
		b := bytes.NewReader(data)
		iHdr, err := ParseInvariantHeader(b, 4)
		Expect(err).ToNot(HaveOccurred())
		hdr, err := iHdr.Parse(b, protocol.PerspectiveServer, versionIETFHeader)
		Expect(err).ToNot(HaveOccurred())
		Expect(hdr.IsVersionNegotiation).To(BeTrue())
		Expect(hdr.DestConnectionID).To(Equal(destConnID))
		Expect(hdr.SrcConnectionID).To(Equal(srcConnID))
		Expect(hdr.Version).To(BeZero())
		// the supported versions should include one reserved version number
		Expect(hdr.SupportedVersions).To(HaveLen(len(versions) + 1))
		for _, version := range versions {
			Expect(hdr.SupportedVersions).To(ContainElement(version))
		}
	})
})