package h264

import (
	"testing"

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

var casesAnnexB = []struct {
	name   string
	encin  []byte
	encout []byte
	dec    [][]byte
}{
	{
		"2 zeros, single",
		[]byte{0x00, 0x00, 0x01, 0xaa, 0xbb},
		[]byte{0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb},
		[][]byte{
			{0xaa, 0xbb},
		},
	},
	{
		"2 zeros, multiple",
		[]byte{
			0x00, 0x00, 0x01, 0xaa, 0xbb, 0x00, 0x00, 0x01,
			0xcc, 0xdd, 0x00, 0x00, 0x01, 0xee, 0xff,
		},
		[]byte{
			0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb, 0x00, 0x00,
			0x00, 0x01, 0xcc, 0xdd, 0x00, 0x00, 0x00, 0x01,
			0xee, 0xff,
		},
		[][]byte{
			{0xaa, 0xbb},
			{0xcc, 0xdd},
			{0xee, 0xff},
		},
	},
	{
		"3 zeros, single",
		[]byte{0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb},
		[]byte{0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb},
		[][]byte{
			{0xaa, 0xbb},
		},
	},
	{
		"3 zeros, multiple",
		[]byte{
			0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb, 0x00, 0x00,
			0x00, 0x01, 0xcc, 0xdd, 0x00, 0x00, 0x00, 0x01,
			0xee, 0xff,
		},
		[]byte{
			0x00, 0x00, 0x00, 0x01, 0xaa, 0xbb, 0x00, 0x00,
			0x00, 0x01, 0xcc, 0xdd, 0x00, 0x00, 0x00, 0x01,
			0xee, 0xff,
		},
		[][]byte{
			{0xaa, 0xbb},
			{0xcc, 0xdd},
			{0xee, 0xff},
		},
	},
}

func TestAnnexBDecode(t *testing.T) {
	for _, ca := range casesAnnexB {
		t.Run(ca.name, func(t *testing.T) {
			dec, err := DecodeAnnexB(ca.encin)
			require.NoError(t, err)
			require.Equal(t, ca.dec, dec)
		})
	}
}

func TestAnnexBEncode(t *testing.T) {
	for _, ca := range casesAnnexB {
		t.Run(ca.name, func(t *testing.T) {
			enc, err := EncodeAnnexB(ca.dec)
			require.NoError(t, err)
			require.Equal(t, ca.encout, enc)
		})
	}
}

func TestAnnexBDecodeError(t *testing.T) {
	for _, ca := range []struct {
		name string
		enc  []byte
	}{
		{
			"empty",
			[]byte{},
		},
		{
			"missing initial delimiter",
			[]byte{0xaa, 0xbb},
		},
		{
			"empty initial",
			[]byte{0x00, 0x00, 0x01},
		},
		{
			"empty 2nd",
			[]byte{0x00, 0x00, 0x01, 0xaa, 0x00, 0x00, 0x01},
		},
	} {
		t.Run(ca.name, func(t *testing.T) {
			_, err := DecodeAnnexB(ca.enc)
			require.Error(t, err)
		})
	}
}