package ethernet

import (
	"bytes"
	"io"
	"reflect"
	"testing"
)

func TestVLANMarshalBinary(t *testing.T) {
	tests := []struct {
		desc string
		v    *VLAN
		b    []byte
		err  error
	}{
		{
			desc: "VLAN priority too large",
			v: &VLAN{
				Priority: 8,
			},
			err: ErrInvalidVLAN,
		},
		{
			desc: "VLAN ID too large",
			v: &VLAN{
				ID: 4095,
			},
			err: ErrInvalidVLAN,
		},
		{
			desc: "empty VLAN",
			v:    &VLAN{},
			b:    []byte{0x00, 0x00},
		},
		{
			desc: "VLAN: PRI 1, ID 101",
			v: &VLAN{
				Priority: 1,
				ID:       101,
			},
			b: []byte{0x20, 0x65},
		},
		{
			desc: "VLANs: PRI 0, DROP, ID 100",
			v: &VLAN{
				DropEligible: true,
				ID:           100,
			},
			b: []byte{0x10, 0x64},
		},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {
			b, err := tt.v.MarshalBinary()
			if err != nil {
				if want, got := tt.err, err; want != got {
					t.Fatalf("unexpected error: %v != %v", want, got)
				}

				return
			}

			if want, got := tt.b, b; !bytes.Equal(want, got) {
				t.Fatalf("unexpected VLAN bytes:\n- want: %v\n-  got: %v", want, got)
			}
		})
	}
}

func TestVLANUnmarshalBinary(t *testing.T) {
	tests := []struct {
		desc string
		b    []byte
		v    *VLAN
		err  error
	}{
		{
			desc: "nil buffer",
			err:  io.ErrUnexpectedEOF,
		},
		{
			desc: "short buffer",
			b:    []byte{0},
			err:  io.ErrUnexpectedEOF,
		},
		{
			desc: "VLAN ID too large",
			b:    []byte{0xff, 0xff},
			err:  ErrInvalidVLAN,
		},
		{
			desc: "VLAN: PRI 1, ID 101",
			b:    []byte{0x20, 0x65},
			v: &VLAN{
				Priority: 1,
				ID:       101,
			},
		},
		{
			desc: "VLAN: PRI 0, DROP, ID 100",
			b:    []byte{0x10, 0x64},
			v: &VLAN{
				DropEligible: true,
				ID:           100,
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {
			v := new(VLAN)
			if err := v.UnmarshalBinary(tt.b); err != nil {
				if want, got := tt.err, err; want != got {
					t.Fatalf("unexpected error: %v != %v", want, got)
				}

				return
			}

			if want, got := tt.v, v; !reflect.DeepEqual(want, got) {
				t.Fatalf("unexpected VLAN:\n- want: %v\n-  got: %v", want, got)
			}
		})
	}
}

// Benchmarks for VLAN.MarshalBinary

func BenchmarkVLANMarshalBinary(b *testing.B) {
	v := &VLAN{
		Priority: PriorityBackground,
		ID:       10,
	}

	b.ResetTimer()
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		if _, err := v.MarshalBinary(); err != nil {
			b.Fatal(err)
		}
	}
}

// Benchmarks for VLAN.UnmarshalBinary

func BenchmarkVLANUnmarshalBinary(b *testing.B) {
	v := &VLAN{
		Priority: PriorityBestEffort,
		ID:       20,
	}

	vb, err := v.MarshalBinary()
	if err != nil {
		b.Fatal(err)
	}

	b.ResetTimer()
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		if err := v.UnmarshalBinary(vb); err != nil {
			b.Fatal(err)
		}
	}
}