package rtcp

import (
	"errors"
	"reflect"
	"testing"

	"github.com/stretchr/testify/assert"
)

var _ Packet = (*CompoundPacket)(nil) // assert is a Packet

func TestReadEOF(t *testing.T) {
	shortHeader := []byte{
		0x81, 0xc9, // missing type & len
	}

	_, err := Unmarshal(shortHeader)
	assert.Error(t, err)
}

func TestBadCompound(t *testing.T) {
	// trailing data!
	badcompound := realPacket()[:34]
	packets, err := Unmarshal(badcompound)
	assert.Error(t, err)

	assert.Nil(t, packets)

	badcompound = realPacket()[84:104]

	packets, err = Unmarshal(badcompound)
	assert.NoError(t, err)

	compound := CompoundPacket(packets)

	// this should return an error,
	// it violates the "must start with RR or SR" rule
	err = compound.Validate()

	if got, want := err, errBadFirstPacket; !errors.Is(got, want) {
		t.Fatalf("Unmarshal(badcompound) err=%v, want %v", got, want)
	}

	if got, want := len(compound), 2; got != want {
		t.Fatalf("Unmarshal(badcompound) len=%d, want %d", got, want)
	}
	if _, ok := compound[0].(*Goodbye); !ok {
		t.Fatalf("Unmarshal(badcompound); first packet = %#v, want Goodbye", compound[0])
	}
	if _, ok := compound[1].(*PictureLossIndication); !ok {
		t.Fatalf("Unmarshal(badcompound); second packet = %#v, want PictureLossIndication", compound[1])
	}
}

func TestValidPacket(t *testing.T) {
	cname := NewCNAMESourceDescription(1234, "cname")

	for _, test := range []struct {
		Name   string
		Packet CompoundPacket
		Err    error
	}{
		{
			Name:   "empty",
			Packet: CompoundPacket{},
			Err:    errEmptyCompound,
		},
		{
			Name: "no cname",
			Packet: CompoundPacket{
				&SenderReport{},
			},
			Err: errMissingCNAME,
		},
		{
			Name: "just BYE",
			Packet: CompoundPacket{
				&Goodbye{},
			},
			Err: errBadFirstPacket,
		},
		{
			Name: "SDES / no cname",
			Packet: CompoundPacket{
				&SenderReport{},
				&SourceDescription{},
			},
			Err: errMissingCNAME,
		},
		{
			Name: "just SR",
			Packet: CompoundPacket{
				&SenderReport{},
				cname,
			},
			Err: nil,
		},
		{
			Name: "multiple SRs",
			Packet: CompoundPacket{
				&SenderReport{},
				&SenderReport{},
				cname,
			},
			Err: errPacketBeforeCNAME,
		},
		{
			Name: "just RR",
			Packet: CompoundPacket{
				&ReceiverReport{},
				cname,
			},
			Err: nil,
		},
		{
			Name: "multiple RRs",
			Packet: CompoundPacket{
				&ReceiverReport{},
				&ReceiverReport{},
				cname,
			},
			Err: nil,
		},
		{
			Name: "goodbye",
			Packet: CompoundPacket{
				&ReceiverReport{},
				cname,
				&Goodbye{},
			},
			Err: nil,
		},
	} {
		if got, want := test.Packet.Validate(), test.Err; !errors.Is(got, want) {
			t.Fatalf("Valid(%s) = %v, want %v", test.Name, got, want)
		}
	}
}

func TestCNAME(t *testing.T) {
	cname := NewCNAMESourceDescription(1234, "cname")

	for _, test := range []struct {
		Name   string
		Packet CompoundPacket
		Err    error
		Text   string
	}{
		{
			Name: "no cname",
			Packet: CompoundPacket{
				&SenderReport{},
			},
			Err: errMissingCNAME,
		},
		{
			Name: "SDES / no cname",
			Packet: CompoundPacket{
				&SenderReport{},
				&SourceDescription{},
			},
			Err: errMissingCNAME,
		},
		{
			Name: "just SR",
			Packet: CompoundPacket{
				&SenderReport{},
				cname,
			},
			Err:  nil,
			Text: "cname",
		},
		{
			Name: "multiple SRs",
			Packet: CompoundPacket{
				&SenderReport{},
				&SenderReport{},
				cname,
			},
			Err:  errPacketBeforeCNAME,
			Text: "cname",
		},
		{
			Name: "just RR",
			Packet: CompoundPacket{
				&ReceiverReport{},
				cname,
			},
			Err:  nil,
			Text: "cname",
		},
		{
			Name: "multiple RRs",
			Packet: CompoundPacket{
				&ReceiverReport{},
				&ReceiverReport{},
				cname,
			},
			Err:  nil,
			Text: "cname",
		},
		{
			Name: "goodbye",
			Packet: CompoundPacket{
				&ReceiverReport{},
				cname,
				&Goodbye{},
			},
			Err:  nil,
			Text: "cname",
		},
	} {
		if got, want := test.Packet.Validate(), test.Err; !errors.Is(got, want) {
			t.Fatalf("Valid(%s) = %v, want %v", test.Name, got, want)
		}
		name, err := test.Packet.CNAME()
		if got, want := err, test.Err; !errors.Is(got, want) {
			t.Fatalf("CNAME(%s) = %v, want %v", test.Name, got, want)
		}
		if got, want := name, test.Text; got != want {
			t.Fatalf("CNAME(%s) = %v, want %v", test.Name, got, want)
		}
	}
}

func TestCompoundPacketRoundTrip(t *testing.T) {
	cname := NewCNAMESourceDescription(1234, "cname")

	for _, test := range []struct {
		Name   string
		Packet CompoundPacket
		Err    error
	}{
		{
			Name: "bye",
			Packet: CompoundPacket{
				&ReceiverReport{},
				cname,
				&Goodbye{
					Sources: []uint32{1234},
				},
			},
		},
		{
			Name: "no cname",
			Packet: CompoundPacket{
				&ReceiverReport{},
			},
			Err: errMissingCNAME,
		},
	} {
		data, err := test.Packet.Marshal()
		if got, want := err, test.Err; !errors.Is(got, want) {
			t.Fatalf("Marshal(%v) err = %v, want nil", test.Name, err)
		}
		if err != nil {
			continue
		}

		var c CompoundPacket
		if err = c.Unmarshal(data); err != nil {
			t.Fatalf("Unmarshal(%v) err = %v, want nil", test.Name, err)
		}

		data2, err := c.Marshal()
		if err != nil {
			t.Fatalf("Marshal(%v) err = %v, want nil", test.Name, err)
		}

		if got, want := data, data2; !reflect.DeepEqual(got, want) {
			t.Fatalf("Unmarshal(Marshal(%v)) = %v, want %v", test.Name, got, want)
		}
	}
}
