// webget.js
//
//   (C) Copyright 2018 Fred Gleason <fredg@paravelsystems.com>
//
//   This program is free software; you can redistribute it and/or modify
//   it under the terms of the GNU General Public License version 2 as
//   published by the Free Software Foundation.
//
//   This program 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 this program; if not, write to the Free Software
//   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//

function Id(id)
{
    return document.getElementById(id);
}


function GetMpegVersion(samprate)
{
    mpeg_ver=1.0;

    switch(samprate) {
    case 32000:
    case 44100:
    case 48000:
	mpeg_ver=1.0;
	break;

    case 16000:
    case 22050:
    case 24000:
	mpeg_ver=2.0;
	break;

    case 8000:
    case 11025:
    case 12000:
	mpeg_ver=2.5;
	break;
    }
    return mpeg_ver;
}


function SetLayerII()
{
    mpeg_ver=GetMpegVersion(parseInt(Id('samprate').value));
    if(mpeg_ver==1.0) {
	if(Id('channels').value=='1') {
	    Id('bitrate').innerHTML=
		'<option value="32000">32 kbit/sec</option>\n'+
		'<option value="48000" selected>48 kbit/sec</option>\n'+
		'<option value="56000">56 kbit/sec</option>\n'+
		'<option value="64000">64 kbit/sec</option>\n'+
		'<option value="80000">80 kbit/sec</option>\n'+
		'<option value="96000">96 kbit/sec</option>\n'+
		'<option value="112000">112 kbit/sec</option>\n'+
		'<option value="128000">128 kbit/sec</option>\n'+
		'<option value="160000">160 kbit/sec</option>\n'+
		'<option value="192000">192 kbit/sec</option>\n';	
	}
	else {
	    Id('bitrate').innerHTML=
		'<option value="32000">32 kbit/sec</option>\n'+
		'<option value="48000" selected>48 kbit/sec</option>\n'+
		'<option value="56000">56 kbit/sec</option>\n'+
		'<option value="64000">64 kbit/sec</option>\n'+
		'<option value="80000">80 kbit/sec</option>\n'+
		'<option value="96000">96 kbit/sec</option>\n'+
		'<option value="112000">112 kbit/sec</option>\n'+
		'<option value="128000">128 kbit/sec</option>\n'+
		'<option value="160000">160 kbit/sec</option>\n'+
		'<option value="192000">192 kbit/sec</option>\n'+
		'<option value="224000">224 kbit/sec</option>\n'+
		'<option value="256000">256 kbit/sec</option>\n'+
		'<option value="320000">320 kbit/sec</option>\n'+
		'<option value="384000">384 kbit/sec</option>\n';
	}
    }
    if(mpeg_ver==2.0) {
	Id('bitrate').innerHTML=
	    '<option value="8000">8 kbit/sec</option>\n'+
	    '<option value="16000" selected>16 kbit/sec</option>\n'+
	    '<option value="24000">24 kbit/sec</option>\n'+
	    '<option value="32000">32 kbit/sec</option>\n'+
	    '<option value="40000">40 kbit/sec</option>\n'+
	    '<option value="48000">48 kbit/sec</option>\n'+
	    '<option value="56000">56 kbit/sec</option>\n'+
	    '<option value="64000">64 kbit/sec</option>\n'+
	    '<option value="80000">80 kbit/sec</option>\n'+
	    '<option value="96000">96 kbit/sec</option>\n'+
	    '<option value="112000">112 kbit/sec</option>\n'+
	    '<option value="128000">128 kbit/sec</option>\n'+
	    '<option value="144000">144 kbit/sec</option>\n'+
	    '<option value="160000">160 kbit/sec</option>\n';
    }
    if(mpeg_ver==2.5) {
	Id('bitrate').innerHTML=
	    '<option value="8000">8 kbit/sec</option>\n'+
	    '<option value="16000" selected>16 kbit/sec</option>\n'+
	    '<option value="24000">24 kbit/sec</option>\n'+
	    '<option value="32000">32 kbit/sec</option>\n'+
	    '<option value="40000">40 kbit/sec</option>\n'+
	    '<option value="48000">48 kbit/sec</option>\n'+
	    '<option value="56000">56 kbit/sec</option>\n'+
	    '<option value="64000">64 kbit/sec</option>\n';
    }
}


function SetLayerIII()
{
    mpeg_ver=GetMpegVersion(parseInt(Id('samprate').value));
    if(mpeg_ver==1.0) {
	Id('bitrate').innerHTML=
	    '<option value="32000">32 kbit/sec</option>\n'+
	    '<option value="40000" selected>40 kbit/sec</option>\n'+
	    '<option value="48000">48 kbit/sec</option>\n'+
	    '<option value="56000">56 kbit/sec</option>\n'+
	    '<option value="64000">64 kbit/sec</option>\n'+
	    '<option value="80000">80 kbit/sec</option>\n'+
	    '<option value="96000">96 kbit/sec</option>\n'+
	    '<option value="112000">112 kbit/sec</option>\n'+
	    '<option value="128000">128 kbit/sec</option>\n'+
	    '<option value="160000">160 kbit/sec</option>\n'+
	    '<option value="192000">192 kbit/sec</option>\n'+
	    '<option value="224000">224 kbit/sec</option>\n'+
	    '<option value="256000">256 kbit/sec</option>\n'+
	    '<option value="320000">320 kbit/sec</option>\n';
    }
    if(mpeg_ver==2.0) {
	Id('bitrate').innerHTML=
	    '<option value="8000">8 kbit/sec</option>\n'+
	    '<option value="16000" selected>16 kbit/sec</option>\n'+
	    '<option value="24000">24 kbit/sec</option>\n'+
	    '<option value="32000">32 kbit/sec</option>\n'+
	    '<option value="40000">40 kbit/sec</option>\n'+
	    '<option value="48000">48 kbit/sec</option>\n'+
	    '<option value="56000">56 kbit/sec</option>\n'+
	    '<option value="64000">64 kbit/sec</option>\n'+
	    '<option value="80000">80 kbit/sec</option>\n'+
	    '<option value="96000">96 kbit/sec</option>\n'+
	    '<option value="112000">112 kbit/sec</option>\n'+
	    '<option value="128000">128 kbit/sec</option>\n'+
	    '<option value="144000">144 kbit/sec</option>\n'+
	    '<option value="160000">160 kbit/sec</option>\n';
    }
    if(mpeg_ver==2.5) {
	Id('bitrate').innerHTML=
	    '<option value="8000">8 kbit/sec</option>\n'+
	    '<option value="16000" selected>16 kbit/sec</option>\n'+
	    '<option value="24000">24 kbit/sec</option>\n'+
	    '<option value="32000">32 kbit/sec</option>\n'+
	    '<option value="40000">40 kbit/sec</option>\n'+
	    '<option value="48000">48 kbit/sec</option>\n'+
	    '<option value="56000">56 kbit/sec</option>\n'+
	    '<option value="64000">64 kbit/sec</option>\n';
    }
}


function samplerateChanged()
{
    if(Id('format').value=='2') {
	SetLayerII();
    }
    if(Id('format').value=='3') {
	SetLayerIII();
    }
}


function formatChanged()
{
    Id('bitrate').disabled=
	!((Id('format').value=="2")||
	  (Id('format').value=="3"));
    Id('quality').disabled=Id('format').value!="5";
    samplerateChanged();
}