package rtph264

import (
	"bytes"
	"testing"

	"github.com/bluenviron/mediacommon/pkg/codecs/h264"
	"github.com/pion/rtp"
	"github.com/stretchr/testify/require"
)

func TestDecode(t *testing.T) {
	for _, ca := range cases {
		t.Run(ca.name, func(t *testing.T) {
			d := &Decoder{}
			d.Init()

			var nalus [][]byte

			for _, pkt := range ca.pkts {
				clone := pkt.Clone()

				addNALUs, _, err := d.Decode(pkt)

				// test input integrity
				require.Equal(t, clone, pkt)

				if err == ErrMorePacketsNeeded {
					continue
				}

				require.NoError(t, err)
				nalus = append(nalus, addNALUs...)
			}

			require.Equal(t, ca.nalus, nalus)
		})
	}
}

func TestDecodeCorruptedFragment(t *testing.T) {
	d := &Decoder{}
	d.Init()

	_, _, err := d.Decode(&rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         false,
			PayloadType:    96,
			SequenceNumber: 17645,
			Timestamp:      2289527317,
			SSRC:           0x9dbb7812,
		},
		Payload: mergeBytes(
			[]byte{
				0x1c, 0x85,
			},
			bytes.Repeat([]byte{0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07}, 182),
			[]byte{0x00, 0x01},
		),
	})
	require.Equal(t, ErrMorePacketsNeeded, err)

	nalus, _, err := d.Decode(&rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         false,
			PayloadType:    96,
			SequenceNumber: 17646,
			Timestamp:      2289527317,
			SSRC:           0x9dbb7812,
		},
		Payload: []byte{0x01, 0x00},
	})
	require.NoError(t, err)
	require.Equal(t, [][]byte{{0x01, 0x00}}, nalus)
}

func TestDecodeSTAPAWithPadding(t *testing.T) {
	d := &Decoder{}
	d.Init()

	pkt := rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         true,
			PayloadType:    96,
			SequenceNumber: 17645,
			Timestamp:      2289526357,
			SSRC:           0x9dbb7812,
		},
		Payload: []byte{
			0x18, 0x00, 0x02, 0xaa,
			0xbb, 0x00, 0x02, 0xcc, 0xdd, 0x00, 0x00, 0x00,
			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		},
	}

	nalus, _, err := d.Decode(&pkt)
	require.NoError(t, err)
	require.Equal(t, [][]byte{
		{0xaa, 0xbb},
		{0xcc, 0xdd},
	}, nalus)
}

func TestDecodeAnnexB(t *testing.T) {
	d := &Decoder{}
	d.Init()

	nalus, _, err := d.Decode(&rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         true,
			PayloadType:    96,
			SequenceNumber: 17647,
			Timestamp:      2289531307,
			SSRC:           0x9dbb7812,
		},
		Payload: mergeBytes(
			[]byte{0x01, 0x02, 0x03, 0x04},
		),
	})
	require.NoError(t, err)
	require.Equal(t, [][]byte{
		{0x01, 0x02, 0x03, 0x04},
	}, nalus)

	for i := 0; i < 2; i++ {
		nalus, _, err := d.Decode(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         true,
				PayloadType:    96,
				SequenceNumber: 17647,
				Timestamp:      2289531307,
				SSRC:           0x9dbb7812,
			},
			Payload: mergeBytes(
				[]byte{0x00, 0x00, 0x00, 0x01},
				[]byte{0x01, 0x02, 0x03, 0x04},
				[]byte{0x00, 0x00, 0x00, 0x01},
				[]byte{0x01, 0x02, 0x03, 0x04},
			),
		})
		require.NoError(t, err)
		require.Equal(t, [][]byte{
			{0x01, 0x02, 0x03, 0x04},
			{0x01, 0x02, 0x03, 0x04},
		}, nalus)
	}
}

func TestDecodeUntilMarker(t *testing.T) {
	d := &Decoder{}
	d.Init()

	nalus, _, err := d.DecodeUntilMarker(&rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         false,
			PayloadType:    96,
			SequenceNumber: 17647,
			Timestamp:      2289531307,
			SSRC:           0x9dbb7812,
		},
		Payload: []byte{0x01, 0x02},
	})
	require.Equal(t, ErrMorePacketsNeeded, err)
	require.Equal(t, [][]byte(nil), nalus)

	nalus, _, err = d.DecodeUntilMarker(&rtp.Packet{
		Header: rtp.Header{
			Version:        2,
			Marker:         true,
			PayloadType:    96,
			SequenceNumber: 17647,
			Timestamp:      2289531307,
			SSRC:           0x9dbb7812,
		},
		Payload: []byte{0x01, 0x02},
	})
	require.NoError(t, err)
	require.Equal(t, [][]byte{{0x01, 0x02}, {0x01, 0x02}}, nalus)
}

func TestDecoderErrorLimit(t *testing.T) {
	d := &Decoder{}
	d.Init()
	var err error

	for i := 0; i <= h264.MaxNALUsPerAccessUnit; i++ {
		_, _, err = d.DecodeUntilMarker(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         false,
				PayloadType:    96,
				SequenceNumber: 17645,
				Timestamp:      2289527317,
				SSRC:           0x9dbb7812,
			},
			Payload: []byte{1, 2, 3, 4},
		})
	}

	require.EqualError(t, err, "NALU count exceeds maximum allowed (20)")
}

func FuzzDecoder(f *testing.F) {
	f.Fuzz(func(t *testing.T, a []byte, b []byte) {
		d := &Decoder{}
		d.Init()

		d.Decode(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         false,
				PayloadType:    96,
				SequenceNumber: 17645,
				Timestamp:      2289527317,
				SSRC:           0x9dbb7812,
			},
			Payload: a,
		})

		d.Decode(&rtp.Packet{
			Header: rtp.Header{
				Version:        2,
				Marker:         false,
				PayloadType:    96,
				SequenceNumber: 17645,
				Timestamp:      2289527317,
				SSRC:           0x9dbb7812,
			},
			Payload: b,
		})
	})
}