/*
NAME
  Parser.go

DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Nelson-Milton <saxon.milton@gmail.com>

LICENSE
  RtpToTsConverter.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 parser

import (
  //"bitbucket.org/ausocean/av/itut"
  "../itut"
  "log"
  "sync"
  _"time"
)

// h264 consts
const (
	acceptedLength = 1000
)

var (
	Info *log.Logger
	mutex  *sync.Mutex
)

type Parser interface {
  Stop()
  Start()
  GetInputChan() chan byte
  GetOutputChan() chan []byte
  SetOutputChan(achan chan []byte)
}

type h264Parser struct {
  inputBuffer []byte
  isParsing bool
  parserOutputChanRef chan []byte
  userOutputChanRef chan []byte
  inputChan chan byte
}

func NewH264Parser() (p *h264Parser) {
  p = new(h264Parser)
  p.isParsing = true
  p.inputChan = make(chan byte, 10000)
  return
}

func (p* h264Parser)Stop(){
  p.isParsing = false
}

func (p *h264Parser)Start(){
  go p.parse()
}

func (p *h264Parser)GetInputChan() chan byte {
  return p.inputChan
}

func (p *h264Parser)GetOutputChan() chan []byte {
  return p.userOutputChanRef
}

func (p *h264Parser)SetOutputChan(aChan chan []byte){
  p.parserOutputChanRef = aChan
  p.userOutputChanRef = aChan
}

func (p *h264Parser)parse() {
	outputBuffer := make([]byte, 0, 10000)
	searchingForEnd := false
	for p.isParsing {
    aByte := <-p.inputChan
		outputBuffer = append(outputBuffer, aByte)
		for i:=1; aByte == 0x00 && i != 4; i++ {
			aByte = <-p.inputChan
			outputBuffer = append(outputBuffer, aByte)
			if ( aByte == 0x01 && i == 2 ) || ( aByte == 0x01 && i == 3 ) {
				if searchingForEnd {
          output := append(append(itut.StartCode1(),itut.AUD()...),outputBuffer[:len(outputBuffer)-(i+1)]...)
					p.parserOutputChanRef<-output
					outputBuffer = outputBuffer[len(outputBuffer)-1-i:]
					searchingForEnd = false
				}
				aByte = <-p.inputChan
				outputBuffer = append(outputBuffer, aByte)
				if nalType := aByte & 0x1F; nalType == 1 || nalType == 5 {
					searchingForEnd = true
				}
			}
		}
	}
}


type mjpegParser struct {
  inputBuffer []byte
  isParsing bool
  parserOutputChanRef chan []byte
  userOutputChanRef chan []byte
  inputChan chan byte
}

func NewMJPEGParser(inputChanLen int) (p *mjpegParser){
  p = new(mjpegParser)
  p.isParsing = true
  p.inputChan = make(chan byte, inputChanLen )
  return
}

func (p *mjpegParser)Stop(){
  p.isParsing = false
}

func (p *mjpegParser)Start(){
  go p.parse()
}

func (p *mjpegParser)GetInputChan() chan byte {
  return p.inputChan
}

func (p *mjpegParser)GetOutputChan() chan []byte {
  return p.userOutputChanRef
}

func (p *mjpegParser)SetOutputChan(aChan chan []byte){
  p.parserOutputChanRef = aChan
  p.userOutputChanRef = aChan
}

func (p *mjpegParser)parse() {
  var outputBuffer []byte
	for p.isParsing {
    aByte := <-p.inputChan
		outputBuffer = append(outputBuffer, aByte)
    if aByte == 0xFF && len(outputBuffer) != 0 {
      aByte := <-p.inputChan
      outputBuffer = append(outputBuffer, aByte)
      if aByte == 0xD8 {
        p.parserOutputChanRef<-outputBuffer[:len(outputBuffer)-2]
        outputBuffer = outputBuffer[len(outputBuffer)-2:]
      }
    }
  }
}