#!/usr/local/bin/perl -w

#
#  Danger!  Danger!  Running with scissors!  Carry handgrenades without pins!  Driving without brakes!
#
#  This code is a super simple super stupid web-based MP3 player concept program.  It has *no* error
#  checking.  It probably has security holes out the whazoo.  It uses a template system so lame, the
#  person who wrote it should be shot (wait a minute!).  If two users try to use it at the same time,
#  bad things will happen (because of the stupid HTTP::Daemon not supporting printing a string as a
#  response, not so much anything else).  And worst of all, I wrote it using Windows(tm) based tools
#  (VisualSlickEdit and HotMetalPro ROCK!)
#
#  On the other hand, it does demonstrate a standalone web-based application, using all those great
#  little CPAN modules.  I'm sure [merlyn] and [tilly] will pump dozens of rounds into it, saying
#  how there's a better way to do it.  On the third hand, I wrote it half an hour, it passes use strict
#  and -w, and I did it first.  Nyah! (I also don't care that stuff goes past column 80)
#
#  Last, and leastly, sometimes if you control-c out of the app (or Dog forbid, it should crash), you
#  may have to wait a few seconds for the socket to clear before restarting it.  I don't know why the
#  socket stays allocated for a brief time after the app has exited.
#

use strict;

use HTTP::Daemon;
use HTTP::Status;
use CGI;
   
my $serverport = 2000;

my %actions = ('Next'      => \&mp3_next,
               'Last'      => \&mp3_last,
               'Stop'      => \&mp3_stop,
               'Play'      => \&mp3_play,
               'Vol +10%'  => \&mp3_volumeup,
               'Vol -10%'  => \&mp3_volumedown,
               'Left 10%'  => \&mp3_balanceleft,
               'Right 10%' => \&mp3_balanceright,
              );

my @tracklist = ('Pink Floyd - Dark Side Of The Moon',
                 'Widespread Panic - Bombs & Butterflies',
                 'Allgood - Trilogy',
                 'Mox - Dr. Bombay',
                 'Soundtrack - Debbie Does Dallas',
                 'The Orb - Perpetual Dawn',
                 'Tangerine Dream - Underwater Sunlight'
                );

my $mode       = 'Stopped';
my $curtrack   = 0;
my $volume     = 50;
my $balance    = 50;

#
#
#
{  
   my $htmltext = 0;

   #
   #  Stupid HTTP::Daemon doesn't support sending a string as a response, only a file.  So
   #  we generate index.html, and keep the page in $htmltext for when we change parameters.
   #
   {
      local $/ = undef;

      $htmltext = <DATA>;
   }

   my $d = new HTTP::Daemon (LocalPort => $serverport) || die "Can't bind to port! ($serverport already in use?)";

   print "Please contact me at: <URL:", $d->url, ">\n";

   while (my $c = $d->accept) 
   {
      while (my $r = $c->get_request) 
      {
         if ($r->method eq 'GET')
         {
            ultralame_template_system ($htmltext);

            $c->send_file_response ("index.html");
         } 
         else
         {
            my $q = new CGI ($r->content);

            &{$actions {$q->param ('Action')}} if ($q->param ('Action'));

            ultralame_template_system ($htmltext);

            $c->send_file_response ("index.html");
         }
      }

      $c->close;
      undef ($c);
   }
}

sub ultralame_template_system
{
   my $temptext = shift;

   $temptext =~ s/<!--##rewrite trackname-->/@tracklist [$curtrack]/ei;
   $temptext =~ s/<!--##rewrite mode-->/$mode/ei;
   $temptext =~ s/<!--##rewrite volume-->/$volume/ei;
   $temptext =~ s/<!--##rewrite balance-->/$balance/ei;
   
   open (FH, ">index.html") || die "Can't open file: $!";
   print FH $temptext;
   close FH;
}

#
#  Normally, I don't condone oneliners like this, but for sample code, it'll work
#
sub mp3_next         { $curtrack = ++$curtrack % scalar @tracklist;  }
sub mp3_last         { $curtrack = --$curtrack % scalar @tracklist;  }
sub mp3_stop         { $mode = 'Stopped';                            }
sub mp3_play         { $mode = 'Playing';                            }
sub mp3_volumeup     { $volume = min (100, $volume + 10);            }
sub mp3_volumedown   { $volume = max (0, $volume - 10);              }
sub mp3_balanceleft  { $balance = max (10, $balance - 10);           }
sub mp3_balanceright { $balance = min (100, $balance + 10);          }

#
#
#
sub min { return ($_[0] < $_[1] ? $_[0] : $_[1]); }
sub max { return ($_[0] > $_[1] ? $_[0] : $_[1]); }

__DATA__
<!DOCTYPE HTML PUBLIC "-//SoftQuad Software//DTD HoTMetaL PRO 5.0::19981217::extensions to HTML 4.0//EN" "hmpro5.dtd">
<HTML>
  <HEAD>
    <TITLE>Stupid Sample Code For a Pico MP3 Server</TITLE>
  </HEAD>
  <BODY>
    <FORM METHOD="POST">
    <TABLE BORDER="0\" ALIGN="CENTER">
      <TR>
        <TD><FONT SIZE="3" FACE="Verdana">Track Now Playing:</FONT></TD>
        <TD><FONT SIZE="3" FACE="Verdana"><B><!--##rewrite trackname--></B></FONT></TD>
      </TR>
    </TABLE>
    <BR>
    <TABLE BORDER="0" ALIGN="CENTER">
      <TR>
        <TD><FONT SIZE="3" FACE="Verdana">Mode:</FONT></TD>
        <TD><FONT SIZE="3" FACE="Verdana"><B><!--##rewrite mode--></B></FONT></TD>
      </TR>
      <TR>
        <TD><FONT SIZE="3" FACE="Verdana">Volume:</FONT></TD>
        <TD><FONT SIZE="3" FACE="Verdana"><B><!--##rewrite volume-->%</B></FONT></TD>
      </TR>
      <TR>
        <TD><FONT SIZE="3" FACE="Verdana">Balance:</FONT></TD>
        <TD><FONT SIZE="3" FACE="Verdana"><B><!--##rewrite balance-->%</B></FONT></TD>
      </TR>
    </TABLE>
    <BR>
    <TABLE BORDER="0" ALIGN="CENTER">
      <TR>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Next"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Last"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Stop"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Play"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Vol +10%"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Vol -10%"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Left 10%"></TD>
        <TD><INPUT TYPE="SUBMIT" NAME="Action" VALUE="Right 10%"></TD>
      </TR>
    </TABLE>
    </FORM>
  </BODY>
</HTML>