/*
NAME
  client_test.go

DESCRIPTION
  client_test.go contains testing utilities for functionality provided in client.go.

AUTHORS
  Saxon A. Nelson-Milton <saxon@ausocean.org>

LICENSE
  This is Copyright (C) 2019 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  under the terms of the GNU General Public License as published by the
  Free Software Foundation, either version 3 of the License, or (at your
  option) any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  for more details.

  You should have received a copy of the GNU General Public License
  in gpl.txt.  If not, see http://www.gnu.org/licenses.
*/

package rtcp

import (
	"bytes"
	"encoding/binary"
	"fmt"
	"math"
	"net"
	"strings"
	"testing"
	"time"

	"bitbucket.org/ausocean/av/protocol/rtp"
	"bitbucket.org/ausocean/utils/logger"
)

// TestFromPayload checks that formPayload is working as expected.
func TestFormPayload(t *testing.T) {
	// Expected data from a valid RTCP packet.
	expect := []byte{
		0x81, 0xc9, 0x00, 0x07,
		0xd6, 0xe0, 0x98, 0xda,
		0x6f, 0xad, 0x40, 0xc6,
		0x00, 0xff, 0xff, 0xff,
		0x00, 0x01, 0x83, 0x08,
		0x00, 0x00, 0x00, 0x20,
		0xb9, 0xe1, 0x25, 0x2a,
		0x00, 0x00, 0x2b, 0xf9,
		0x81, 0xca, 0x00, 0x04,
		0xd6, 0xe0, 0x98, 0xda,
		0x01, 0x08, 0x73, 0x61,
		0x78, 0x6f, 0x6e, 0x2d,
		0x70, 0x63, 0x00, 0x00,
	}

	report := ReceiverReport{
		Header: Header{
			Version:     2,
			Padding:     false,
			ReportCount: 1,
			Type:        typeReceiverReport,
		},
		SenderSSRC: 3605043418,
		Blocks: []ReportBlock{
			ReportBlock{
				SourceIdentifier:  1873625286,
				FractionLost:      0,
				PacketsLost:       math.MaxUint32,
				HighestSequence:   99080,
				Jitter:            32,
				SenderReportTs:    3118540074,
				SenderReportDelay: 11257,
			},
		},
		Extensions: nil,
	}

	description := Description{
		Header: Header{
			Version:     2,
			Padding:     false,
			ReportCount: 1,
			Type:        typeDescription,
		},
		Chunks: []Chunk{
			Chunk{
				SSRC: 3605043418,
				Items: []SDESItem{
					SDESItem{
						Type: typeCName,
						Text: []byte("saxon-pc"),
					},
				},
			},
		},
	}

	c := &Client{}
	p := c.formPayload(&report, &description)

	if !bytes.Equal(p, expect) {
		t.Fatalf("unexpected result.\nGot: %v\n Want: %v\n", p, expect)
	}

	bufAddr := fmt.Sprintf("%p", c.buf[:])
	pAddr := fmt.Sprintf("%p", p)
	if bufAddr != pAddr {
		t.Errorf("unexpected result.\nGot: %v\n want: %v\n", pAddr, bufAddr)
	}
}

// dummyLogger will allow logging to be done by the testing pkg.
type dummyLogger testing.T

func (dl *dummyLogger) log(lvl int8, msg string, args ...interface{}) {
	var l string
	switch lvl {
	case logger.Warning:
		l = "warning"
	case logger.Debug:
		l = "debug"
	case logger.Info:
		l = "info"
	case logger.Error:
		l = "error"
	case logger.Fatal:
		l = "fatal"
	}
	msg = l + ": " + msg
	for i := 0; i < len(args); i++ {
		msg += " %v"
	}
	if len(args) == 0 {
		dl.Log(msg + "\n")
		return
	}
	dl.Logf(msg+"\n", args)
}

// TestReceiveAndSend tests basic RTCP client behaviour with a basic RTCP server.
// The RTCP client will send through receiver reports, and the RTCP server will
// respond with sender reports.
func TestReceiveAndSend(t *testing.T) {
	const clientAddr, serverAddr = "localhost:8000", "localhost:8001"
	rtpClt, err := rtp.NewClient("localhost:8002")
	if err != nil {
		t.Fatalf("unexpected error when creating RTP client: %v", err)
	}

	c, err := NewClient(
		clientAddr,
		serverAddr,
		rtpClt,
		(*dummyLogger)(t).log,
	)
	if err != nil {
		t.Fatalf("unexpected error when creating client: %v\n", err)
	}

	go func() {
		for {
			select {
			case err := <-c.Err():
				const errConnClosed = "use of closed network connection"
				if !strings.Contains(err.Error(), errConnClosed) {
					t.Fatalf("error received from client error chan: %v\n", err)
				}

			default:
			}
		}
	}()

	c.Start()

	sAddr, err := net.ResolveUDPAddr("udp", serverAddr)
	if err != nil {
		t.Fatalf("could not resolve test server address, failed with error: %v", err)
	}

	cAddr, err := net.ResolveUDPAddr("udp", clientAddr)
	if err != nil {
		t.Fatalf("could not resolve client address, failed with error: %v", err)
	}

	conn, err := net.DialUDP("udp", sAddr, cAddr)
	if err != nil {
		t.Fatalf("could not dial, failed with error: %v\n", err)
	}

	buf := make([]byte, 4096)
	for i := 0; i < 5; i++ {
		t.Log("SERVER: waiting for receiver report\n")
		n, _, _ := conn.ReadFromUDP(buf)
		t.Logf("SERVER: receiver report received: \n%v\n", buf[:n])

		now := time.Now().Second()
		var time [8]byte
		binary.BigEndian.PutUint64(time[:], uint64(now))
		msw := binary.BigEndian.Uint32(time[:4])
		lsw := binary.BigEndian.Uint32(time[4:])

		report := SenderReport{
			Header: Header{
				Version:     rtcpVer,
				Padding:     false,
				ReportCount: 0,
				Type:        typeSenderReport,
			},
			SSRC:         1234567,
			TimestampMSW: msw,
			TimestampLSW: lsw,
			RTPTimestamp: 0,
			PacketCount:  0,
			OctetCount:   0,
		}
		r := report.Bytes()
		t.Logf("SERVER: sending sender report: \n%v\n", r)
		_, err := conn.Write(r)
		if err != nil {
			t.Errorf("did not expect error: %v\n", err)
		}
	}
	c.Stop()
}