package rtplpcm

import (
	"bytes"
	"testing"
	"time"

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

var cases = []struct {
	name    string
	samples []byte
	pts     time.Duration
	pkts    []*rtp.Packet
}{
	{
		"single",
		[]byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06},
		25 * time.Millisecond,
		[]*rtp.Packet{
			{
				Header: rtp.Header{
					Version:        2,
					Marker:         false,
					PayloadType:    96,
					SequenceNumber: 17645,
					Timestamp:      2289527557,
					SSRC:           0x9dbb7812,
				},
				Payload: []byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06},
			},
		},
	},
	{
		"splitted",
		bytes.Repeat([]byte{0x41, 0x42, 0x43}, 680),
		25 * time.Millisecond,
		[]*rtp.Packet{
			{
				Header: rtp.Header{
					Version:        2,
					Marker:         false,
					PayloadType:    96,
					SequenceNumber: 17645,
					Timestamp:      2289527557,
					SSRC:           0x9dbb7812,
				},
				Payload: bytes.Repeat([]byte{0x41, 0x42, 0x43}, 486),
			},
			{
				Header: rtp.Header{
					Version:        2,
					Marker:         false,
					PayloadType:    96,
					SequenceNumber: 17646,
					Timestamp:      2289527800,
					SSRC:           0x9dbb7812,
				},
				Payload: bytes.Repeat([]byte{0x41, 0x42, 0x43}, 194),
			},
		},
	},
}

func TestDecode(t *testing.T) {
	for _, ca := range cases {
		t.Run(ca.name, func(t *testing.T) {
			d := &Decoder{
				BitDepth:     24,
				SampleRate:   48000,
				ChannelCount: 2,
			}
			d.Init()

			// send an initial packet downstream
			// in order to compute the right timestamp,
			// that is relative to the initial packet
			pkt := rtp.Packet{
				Header: rtp.Header{
					Version:        2,
					Marker:         false,
					PayloadType:    0,
					SequenceNumber: 17645,
					Timestamp:      2289526357,
					SSRC:           0x9dbb7812,
				},
				Payload: []byte{0x01, 0x02, 0x03, 0x04, 0x05, 0x06},
			}
			_, _, err := d.Decode(&pkt)
			require.NoError(t, err)

			var samples []byte
			expPTS := ca.pts

			for _, pkt := range ca.pkts {
				partial, pts, err := d.Decode(pkt)
				require.NoError(t, err)
				require.Equal(t, expPTS, pts)
				samples = append(samples, partial...)
				expPTS += time.Duration(len(partial)/(24*2/8)) * time.Second / 48000
			}

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