#!/usr/bin/php
<?php
  /**
  * Script to record digital TV to file
  * @author Iain Wallace http://strawp.net
  * based on http://www.ethics-gradient.net/myth/mythdvb.html and http://www.mythtv.org/wiki/Tzap
  * Yes I'm aware that PHP really isn't the best choice for writing a script which forks and controls processes :P
  */
  require_once( "tv.func.php" );

  // Catch user ticks to terminate script
  declare( ticks = 1 );
  
  define( "DVR_DEVICE", "/dev/dvb/adapter0/dvr0" );
  define( "COMPLETE_RECORDINGS_DIR", "/share/" );
  define( "RECORDINGS_DIR", "/media/dock/" );
  define( "RECORDINGS_OWNER", "iain" );
  define( "RECORDINGS_ORGANISESCRIPT", "/home/iain/scripts/tv/show_organise.php" ); // Shuffles files around. Optional: http://svn.strawp.net/scripts/tv/show_organise.php
  define( "DEBUG", true );
  define( "AD_DETECT_SCRIPT", "/home/iain/bin/addetect" );

  $arg = "";
  for( $i=1; $i<sizeof($argv); $i++ ){
    $arg .= " ".$argv[$i];
  }
  $arg = trim( $arg );
  
  // Catch shutdown commands
  pcntl_signal(SIGTERM, "shutdown");
  pcntl_signal(SIGINT, "shutdown");
  
  if( preg_match( "/(.*) on (.*?) for (\d+)(s|seconds|m|minute|minutes|h|hour|hours)?/", $arg, $m ) ){
    $channel = $m[2];
    $showname = $m[1];
    $duration = $m[3];

    define( "CURRENT_CHANNEL", $channel );

    if( DEBUG ) echo "Recording $showname on $channel for $duration minutes\n";
    
    // Subtitling?
    if( preg_match( "/([^:]+):(.*?)(s\d+e\d+)/", $showname, $m ) ){
      $showname = trim( $m[1] )." ".trim($m[3])." ".trim($m[2]);
    }
    
    // Stop any running recordings
    while( killOtherRecordings() == false ){};
    startRecording( $showname, $channel );
    sleep( $duration * 60 );
    if( DEBUG ) echo "Recording timeout reached\n";
    stopRecording();
    
    organiseRecordings();
  }else{
    die( "e.g. record Eastenders on BBC ONE for 30\n" );
  }

  function stopRecording(){
    if( DEBUG ) echo "Stopping recording\n";
    killTzap();
    adDetect( killWriteVideo() );
  }
  function startRecording( $showname, $channel ){
    forkTzap( $channel );
    $showname = preg_replace( "/[^-'a-zA-Z_\.0-9\/]/", ".", $showname );
    $showname = str_replace( "..", ".", $showname );
    $file = RECORDINGS_DIR.$showname.".mpg";
    define( "RECORDING_FILE", $file );
    forkWriteVideo( $file );
    if( DEBUG ) echo "Recording, ctrl-c to stop\n";
  }
  function shutdown(){
    if( DEBUG ) echo "Caught shutdown command\n";
    stopRecording();
  }
  function forkTzap($channel){
    $channel = getClosestChannelName( $channel );
    $cmd = "/usr/bin/tzap -r ".escapeshellarg( $channel )." 2> /dev/null 1> /dev/null &";
    // $cmd = "/usr/bin/tzap -r ".escapeshellarg( $channel )." & 2> /dev/null";
    if( DEBUG ) echo "Attempting to fork tzap with $cmd...\n";
    echo exec( $cmd );
  }
  function killOtherRecordings(){
    $cmd = "/bin/ps ax | /bin/grep \"record \" | /bin/grep php | grep -v grep";
    exec( $cmd, $out );
    $thispid = posix_getpid();
    $killed = true;
    foreach( $out as $line ){
      if( preg_match( "/^\s*(\d+).*?([\s]+)/", $line, $m ) ){
        $pid = $m[1];
        if( $thispid != $pid ){
          $killed = false;
          if( DEBUG ) echo "other pid recording: ".$pid.", killing\n";
          kill( $pid );
          sleep(3);
        }
      }
    }
    return $killed;
  }
  function killTzap(){
    if( DEBUG ) echo "Attempting to kill tzap\n";
    $cmd = "/usr/bin/killall tzap";
    exec( $cmd );
  }
  function forkWriteVideo($file){
    $cmd = "/bin/cat ".DVR_DEVICE." > ".escapeshellcmd( $file )." &";
    if( DEBUG ) echo "Attempting to fork $cmd\n";
    exec( $cmd );
  }
  function kill($pid){
    posix_kill( $pid, SIGINT );
  }
  function killWriteVideo(){
    if( DEBUG ) echo "Attempting to kill write of video file\n";
    $cmd = "/bin/ps ax | /bin/grep ".escapeshellarg( " \/bin\/cat ".str_replace( "\/", "\\/", DVR_DEVICE ) );
    if( DEBUG ) echo "Looking for process with $cmd\n";
    exec( $cmd, $out );
    $line = join( "\n", $out );
    if( DEBUG ) echo $line."\n";
    if( preg_match( "/^\s*(\d+).*?([\s]+)/", $line, $m ) ){
      if( DEBUG ) echo "Process ".$m[1]." found for writing video, attempting to kill\n";
      /*
      $cmd = "/bin/kill ".escapeshellarg( $m[1] );
      exec( $cmd );
      */
      posix_kill( $m[1], SIGKILL );

      // Increase file permissions on recording file
      setRecordingPermissions( RECORDING_FILE, RECORDINGS_OWNER );

      if( filesize( RECORDINGS_DIR.basename( RECORDING_FILE ) ) == 0 ){
        if( DEBUG ) echo "Recording appears to be zero length, deleting\n";
        unlink( RECORDINGS_DIR.basename( RECORDING_FILE ) );
      }

      // Move to completed dir
      if( file_exists(RECORDINGS_DIR.basename( RECORDING_FILE ) ) ){ 
        rename( RECORDINGS_DIR.basename( RECORDING_FILE ), COMPLETE_RECORDINGS_DIR.basename( RECORDING_FILE ) );
        return COMPLETE_RECORDINGS_DIR.basename( RECORDING_FILE );
      }
    }else{
      if( DEBUG ) echo "No suitable file write processes found\n";
    }
  }
  function adDetect($path){
    if( !$path ) return false;
    if( !defined( "AD_DETECT_SCRIPT" ) ){ 
      return false;
    }
    // Everything except BBC has ads
    if( preg_match( "/^BBC /", CURRENT_CHANNEL ) ) return false;
    echo "Current channel: ".CURRENT_CHANNEL." has ads, attempting to detect...\n";
    exec( AD_DETECT_SCRIPT." ".escapeshellarg( $path ) );
  }
  function organiseRecordings(){
    if( file_exists( RECORDINGS_ORGANISESCRIPT ) ){
      if( DEBUG ) echo "Running show organise script...\n";
      $user = exec( "/usr/bin/whoami" );
      $cmd = "";
      if( $user == "root" ) $cmd = "sudo -u ".RECORDINGS_OWNER." ";
      $cmd .= "/usr/bin/php ".RECORDINGS_ORGANISESCRIPT;
      if( DEBUG ) echo $cmd."\n";
      passthru( $cmd );
    }
  }
  function setRecordingPermissions( $file, $owner ){
    if( !file_exists( $file ) ) return false;
    if( DEBUG ) echo "Changing permissions on file ".$file."...\n";
    $cmd = "/bin/chown ".$owner." ".escapeshellarg( $file );
    exec( $cmd );
    $cmd = "/bin/chmod u+wr ".escapeshellarg( $file );
    exec( $cmd );
  }
?>