/*
NAME
  mtsSender_test.go

DESCRIPTION
  mtsSender_test.go contains tests that validate the functionalilty of the
  mtsSender under senders.go. Tests include checks that the mtsSender is
  segmenting sends correctly, and also that it can correct discontinuities.

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

LICENSE
  mtsSender_test.go is Copyright (C) 2017-2019 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
  along with revid in gpl.txt.  If not, see http://www.gnu.org/licenses.
*/
package revid

import (
	"errors"
	"fmt"
	"testing"
	"time"

	"bitbucket.org/ausocean/av/stream/mts"
	"bitbucket.org/ausocean/av/stream/mts/meta"
	"bitbucket.org/ausocean/utils/logger"
	"bitbucket.org/ausocean/utils/ring"
	"github.com/Comcast/gots/packet"
	"github.com/Comcast/gots/pes"
)

// Ring buffer sizes and read/write timeouts.
const (
	rbSize        = 100
	rbElementSize = 150000
	wTimeout      = 10 * time.Millisecond
	rTimeout      = 10 * time.Millisecond
)

type testSender struct {
	Buf       [][]byte
	tstDiscon bool
	disconAt  int
	curPktNo  int
}

func (ts *testSender) send(d []byte) error {
	if ts.tstDiscon && ts.curPktNo == ts.disconAt {
		return errors.New("could not send")
	}
	cpy := make([]byte, len(d))
	copy(cpy, d)
	ts.Buf = append(ts.Buf, cpy)
	ts.curPktNo++
	return nil
}

func 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"
	}
	fmt.Printf(msg, args)
}

type tstPacker struct {
	rb *ring.Buffer
}

func (p *tstPacker) Write(d []byte) (int, error) {
	n, err := p.rb.Write(d)
	p.rb.Flush()
	return n, err
}

func TestSegment(t *testing.T) {
	mts.Meta = meta.New()
	// Create ringbuffer tst sender, loadsender and the mpegts encoder
	rb := ring.NewBuffer(rbSize, rbElementSize, wTimeout)
	tstSender := &testSender{Buf: make([][]byte, 0)}
	loadSender := newMtsSender(tstSender, log)
	packer := &tstPacker{rb: rb}
	encoder := mts.NewEncoder(packer, 25)

	// Turn time based psi writing off for encoder
	const psiSendCount = 10
	encoder.TimeBasedPsi(false, psiSendCount)

	const noOfPacketsToWrite = 100
	for i := 0; i < noOfPacketsToWrite; i++ {
		// Our payload will just be packet no
		encoder.Encode([]byte{byte(i)})
		rb.Flush()

		for {
			next, err := rb.Next(rTimeout)
			if err != nil {
				break
			}

			err = loadSender.load(next)
			if err != nil {
				t.Fatalf("Unexpected err: %v\n", err)
			}

			err = loadSender.send()
			if err != nil {
				t.Fatalf("Unexpected err: %v\n", err)
			}

			loadSender.release()
		}
	}

	result := tstSender.Buf
	expectData := 0
	for clipNo, clip := range result {
		// Check that the clip is the right length
		clipLen := len(clip)
		if clipLen != psiSendCount*mts.PacketSize {
			t.Fatalf("Clip %v is not correct length. Got: %v Want: %v\n Clip: %v\n", clipNo, clipLen, psiSendCount*mts.PacketSize, clip)
		}

		// Also check that the first packet is a PAT
		firstPkt := clip[:mts.PacketSize]
		var pkt [mts.PacketSize]byte
		copy(pkt[:], firstPkt)
		pid := (*packet.Packet)(&pkt).PID()
		if pid != mts.PatPid {
			t.Fatalf("First packet of clip %v is not pat, but rather: %v\n", clipNo, pid)
		}

		// Check that the clip data is okay
		for i := 0; i < len(clip); i += mts.PacketSize {
			firstPkt := clip[i : i+mts.PacketSize]
			copy(pkt[:], firstPkt)
			p := (*packet.Packet)(&pkt)
			pid := p.PID()
			if pid == mts.VideoPid {
				// Mts payload
				payload, err := p.Payload()
				if err != nil {
					t.Fatalf("Unexpected err: %v\n", err)
				}

				// Parse pes from the mts payload
				pes, err := pes.NewPESHeader(payload)
				if err != nil {
					t.Fatalf("Unexpected err: %v\n", err)
				}

				// Get the data from the pes packet and convert to int
				data := int8(pes.Data()[0])

				// Calc expected data in the pes and then check
				if data != int8(expectData) {
					t.Errorf("Did not get expected pkt data. ClipNo: %v, pktNoInClip: %v, Got: %v, want: %v\n", clipNo, i/mts.PacketSize, data, expectData)
				}
				expectData++
			}
		}
	}
}

func TestSendFailDiscontinuity(t *testing.T) {
	mts.Meta = meta.New()
	// Create ringbuffer tst sender, loadsender and the mpegts encoder
	rb := ring.NewBuffer(rbSize, rbElementSize, wTimeout)
	const disconClipNo = 3
	tstSender := &testSender{tstDiscon: true, disconAt: disconClipNo}
	loadSender := newMtsSender(tstSender, log)
	packer := tstPacker{rb: rb}
	encoder := mts.NewEncoder(&packer, 25)

	// Turn time based psi writing off for encoder
	const psiSendCount = 10
	encoder.TimeBasedPsi(false, psiSendCount)

	const noOfPacketsToWrite = 100
	for i := 0; i < noOfPacketsToWrite; i++ {
		// Our payload will just be packet no
		encoder.Encode([]byte{byte(i)})
		rb.Flush()

		next, err := rb.Next(rTimeout)
		if err != nil {
			t.Fatalf("Unexpected err: %v\n", err)
		}

		err = loadSender.load(next)
		if err != nil {
			t.Fatalf("Unexpected err: %v\n", err)
		}

		_ = loadSender.send()

		loadSender.release()
	}

	result := tstSender.Buf

	// First check that we have less clips
	expectedLen := ((noOfPacketsToWrite / psiSendCount) - 1)
	gotLen := len(result)
	if gotLen != expectedLen {
		t.Errorf("We don't have one less clip as we should. Got: %v, want: %v\n", gotLen, expectedLen)
	}
	// Now check that the discontonuity indicator is set at the disconClip pat
	disconClip := result[disconClipNo]
	firstPkt := disconClip[:mts.PacketSize]
	var pkt [mts.PacketSize]byte
	copy(pkt[:], firstPkt)
	discon, err := (*packet.AdaptationField)((*packet.Packet)(&pkt)).Discontinuity()
	if err != nil {
		t.Fatalf("Unexpected err: %v\n", err)
	}

	if !discon {
		t.Fatalf("Did not get discontinuity indicator for PAT")
	}

}