/*
NAME
  MPEGTSGenerator.go

DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Nelson-Milton <saxon@ausocean.org>

LICENSE
  MPEGTSGenerator.go is Copyright (C) 2017 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 [GNU licenses](http://www.gnu.org/licenses).
*/
package generator

import (
	_ "fmt"
	_ "os"
	//"bitbucket.org/ausocean/av/mpegts"
	//"bitbucket.org/ausocean/av/pes"
	//"bitbucket.org/ausocean/av/tools"
	//"bitbucket.org/ausocean/av/rtp"
	"../mpegts"
	"../pes"
	"../rtp"
	"../tools"
)

var (
	patTable= []byte{0, 0, 176, 13, 0, 1, 193, 0, 0, 0, 1, 240, 0, 42, 177, 4, 178, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255}

	pmtTable = []byte{0, 2, 176, 18, 0, 1, 193, 0, 0, 0xE1, 0x00, 0xF0, 0, 0x1B, 0xE1, 0, 0xF0, 0, 0x15, 0xBD, 0x4D, 0x56, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255}
)

const (
	SdtPid   = 17
	PatPid   = 0
	pmtPid   = 4096
	videoPid = 256
	streamID = 0xE0
)

type tsGenerator struct {
	rtpInputChan    chan rtp.RtpPacket
	outputChan      chan []byte
	nalInputChan    chan []byte
	currentTsPacket *mpegts.MpegTsPacket
	payloadByteChan chan byte
	currentCC       byte
	currentPtsTime  float64
	currentPcrTime  float64
	fps             uint
	pesPktChan      chan []byte
	ccMap           map[int]int
}

func (g *tsGenerator) GetInputChan() chan []byte {
	return g.nalInputChan
}

func (g *tsGenerator) GetOutputChan() chan []byte {
	return g.outputChan
}

func NewTsGenerator(fps uint) (g *tsGenerator) {
	g = new(tsGenerator)
	g.outputChan = make(chan []byte, 100)
	g.rtpInputChan = make(chan rtp.RtpPacket, 100)
	g.nalInputChan = make(chan []byte, 10000)
	g.currentCC = 0
	g.fps = fps
	g.currentPcrTime = .0
	g.currentPtsTime = .7
	g.pesPktChan = make(chan []byte, 1000)
	g.payloadByteChan = make(chan byte, 100000)
	g.ccMap = make(map[int]int, 4)
	g.ccMap[SdtPid] = 0
	g.ccMap[PatPid] = 0
	g.ccMap[pmtPid] = 0
	g.ccMap[videoPid] = 0
	return
}

func (g *tsGenerator) genPts() (pts uint64) {
	pts = uint64(g.currentPtsTime * float64(90000))
	g.currentPtsTime += 1.0 / float64(g.fps)
	return
}

func (g *tsGenerator) genPcr() (pcr uint64) {
	pcr = uint64(g.currentPcrTime * float64(90000))
	g.currentPcrTime += 1.0 / float64(g.fps)
	return
}

func (g *tsGenerator) Start() {
	go g.generate()
}

func (g *tsGenerator) generate() {
	var rtpBuffer [](*rtp.RtpPacket)
	for {
		select {
		case nalUnit := <-g.nalInputChan:
			g.pesPktChan <- pes.PESPacket{
				StreamID:     streamID,
				PDI:          byte(2),
				PTS:          g.genPts(),
				Data:         nalUnit,
				HeaderLength: 5,
			}.ToByteSlice()
		case pesPkt := <-g.pesPktChan:
			for ii := range pesPkt {
				g.payloadByteChan <- pesPkt[ii]
			}
			pusi := true
			for len(g.payloadByteChan) > 0 {
				pkt := mpegts.MpegTsPacket{
					PUSI: pusi,
					PID:  videoPid,
					RAI:  pusi,
					CC:   byte(g.getCC(videoPid)),
					AFC:  byte(3),
					PCRF: pusi,
				}
				pkt.FillPayload(g.payloadByteChan)

				if pusi {
					// Create pat table and send off
					patPkt := mpegts.MpegTsPacket{
						PUSI:    pusi,
						PID:     PatPid,
						CC:      byte(g.getCC(PatPid)),
						AFC:     1,
						Payload: PatTable,
					}

					patPktAsByteSlice, _ := patPkt.ToByteSlice()
					g.outputChan <- patPktAsByteSlice

					// Create pmt table and send off
					pmtPkt := mpegts.MpegTsPacket{
						PUSI:    pusi,
						PID:     pmtPid,
						CC:      byte(g.getCC(pmtPid)),
						AFC:     1,
						Payload: pmtTable,
					}
					pmtPktAsByteSlice, _ := pmtPkt.ToByteSlice()
					g.outputChan <- pmtPktAsByteSlice

					pkt.PCR = g.genPcr()
					pusi = false
				}
				pktAsBytelice, _ := pkt.ToByteSlice()
				g.outputChan <- pktAsBytelice
			}
		}
	}
}

func (g *tsGenerator) getCC(pid int) int {
	temp := g.ccMap[pid]
	if g.ccMap[pid]++; g.ccMap[pid] > 15 {
		g.ccMap[pid] = 0
	}
	return temp
}