<?php
/*

 Copyright 2001 - 2005 Ampache.org
 All Rights Reserved

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.

 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

/**
 * delete_now_playing
 * This function checks to see if we should delete the last now playing entry now that it's
 * finished streaming the song. Basicly this is an exception for WMP10
 * @package General
 * @catagory Now Playing
 */
function delete_now_playing($insert_id) { 

        $user_agent = $_SERVER['HTTP_USER_AGENT'];

        if (stristr($user_agent,"Windows-Media-Player")) {
                // Commented out until I can figure out the
                // trick to making this work
                //return true;
        }

        
        // Remove the song from the now_playing table
        $sql = "DELETE FROM now_playing WHERE id = '$insert_id'";
        $db_result = mysql_query($sql, dbh());

} // delete_now_playing

/** 
 * gc_now_playing
 * this is a garbage collection function for now playing this is called every time something
 * is streamed
 * @package General
 * @catagory Now Playing
 */
function gc_now_playing() { 

        $time = time();
        $expire = $time - 1800;  // 86400 seconds = 1 day

        $sql = "DELETE FROM now_playing WHERE start_time < $expire";
        $db_result = mysql_query($sql, dbh());
        
} // gc_now_playing

/**
 * insert_now_playing
 * This function takes care of inserting the now playing data
 * we use this function because we need to do thing differently
 * depending upon which play is actually streaming
 * @package General
 * @catagory Now Playing
 */
function insert_now_playing($song_id,$uid,$song_length) {

        $user_agent = $_SERVER['HTTP_USER_AGENT'];
        $time = time();

        /* Windows Media Player is evil and it makes multiple requests per song */
        if (stristr($user_agent,"NSPlayer")) { return false; }

        /* Set the Expire Time */

        // If they are using Windows media player
        if (stristr($user_agent,"Windows-Media-Player")) {
                // WMP does keep the session open so we need to cheat a little here
                $expire = $time + $song_length;
        }
        else {
                $expire = $time;
        }

        $sql = "INSERT INTO now_playing (`song_id`, `user`, `start_time`)" .
                " VALUES ('$song_id', '$uid', '$expire')";

        $db_result = mysql_query($sql, dbh());

        $insert_id = mysql_insert_id(dbh());

        return $insert_id;

} // insert_now_playing

/**
 * check_lock_songs
 * This checks to see if the song is already playing, if it is then it prevents the user
 * from streaming it
 * @package General
 * @catagory Security
 */
function check_lock_songs($song_id) { 

	$sql = "SELECT COUNT(*) FROM now_playing " . 
		"WHERE song_id = '$song_id'";
	$db_results = mysql_query($sql, dbh());

	if (mysql_num_rows($db_results)) { 
		return false;
	}

	return true;

} // check_lock_songs

/**
 * start_downsample
 * This is a rather complext function that starts the downsampling of a song and returns the 
 * opened file handled
 * @package General
 * @catagory Downsample
 * @param $song	The Song Object
 */
function start_downsample($song,$now_playing_id=0,$song_name=0) { 

	/* Check to see if bitrates are set if so let's go ahead and optomize! */
	$max_bitrate = conf('max_bit_rate');
	$min_bitrate = conf('min_bit_rate');
	$time = time();
	$dbh = dbh();
	$user_sample_rate = $GLOBALS['user']->prefs['sample_rate'];
	$browser = new Browser();

	if (!$song_name) { 
		$song_name = $song->f_artist_full . " - " . $song->title . "." . $song->type;
	}

	if ($max_bitrate > 1 AND $min_bitrate < $max_bitrate) {   
		$last_seen_time = $time - 1200; //20 min.

		/**********************************
		 * Commenting out the following, I'd rather have it slightly less accurate and avoid a 4 table join 
      		// Count the users connected in the last 20 min using downsampling 
		$sql = "SELECT COUNT(DISTINCT session.username) FROM session,user,user_preference,preferences " . 
			"WHERE user.username = session.username AND session.expire > '$time' AND user.last_seen > $last_seen_time " . 
			"AND preferences.name = 'play_type' AND user_preference.preference = preferences.id AND " . 
			"user_preference.user = user.username AND user_preference.value='downsample'";
		$db_result = mysql_query($sql, $dbh);
		$results = mysql_fetch_row($db_result);

		// The current number of connected users 
		$current_users_count = $results[0];
		************************************/
		

		$sql = "SELECT COUNT(*) FROM now_playing, user_preference, preferences " . 
			"WHERE preferences.name = 'play_type' AND user_preference.preference = preferences.id " . 
			"AND now_playing.user = user_preference.user AND user_preference.value='downsample'";
		$db_results = mysql_query($sql,$dbh);
		$results = mysql_fetch_row($db_results);

		// Current number of active streams + 1 (the one we are starting)
		$active_streams = $results[0] + 1;


		/* If only one user, they'll get all available.  Otherwise split up equally. */
		$sample_rate = floor($max_bitrate/$active_streams);

		/* If min_bitrate is set, then we'll exit if the bandwidth would need to be split up smaller than the min. */
		if ($min_bitrate > 1 AND ($max_bitrate/$active_streams) < $min_bitrate) {
               
			/* Log the failure */
			if (conf('debug')) { 
				log_event($user->username,' downsample ',"Error: Max bandwidith already allocated. $active_streams Active Streams"); 
			}
			
			/* Toast the now playing entry, then tell em to try again later */
			delete_now_playing($now_playing_id);
			echo "Maximum bandwidth already allocated.  Try again later.";
        	        exit();

		}
		else {
               		$sample_rate = floor($max_bitrate/$active_streams);
		} // end else
      
		/* Round to standard bitrates */
		$sample_rate = 8*(floor($sample_rate/8));
	
		// Never go over the users sample rate 
		if ($sample_rate > $user_sample_rate) { $sample_rate = $user_sample_rate; }	

		if (conf('debug')) { 
			log_event($GLOBALS['user']->username, ' downsample ',"Downsampled: $active_streams current active streams, downsampling to $sample_rate");
		}

	} // end if we've got bitrates

	else { 
		$sample_rate = $user_sample_rate;
	}

	$sample_ratio = $sample_rate/($song->bitrate/1000);
	
	/* Never Upsample a song */
	if (($sample_rate*1000) > $song->bitrate) {
		$sample_rate = $song->bitrate/1000;
		$sample_ratio = '1';
	}


        $browser->downloadHeaders($song_name, $song->mime, false,$sample_ratio*$song->size);

        /* Get Offset */
	$offset = ( $start*$song->time )/( $sample_ratio*$song->size );
        $offsetmm = floor($offset/60);
        $offsetss = floor($offset-$offsetmm*60);
        $offset   = sprintf("%02d.%02d",$offsetmm,$offsetss);

        /* Get EOF */
	$eofmm  = floor($song->time/60);
        $eofss  = floor($song->time-$eofmm*60);
        $eof    = sprintf("%02d.%02d",$eofmm,$eofss);

        /* Replace Variables */
        $downsample_command = conf('downsample_cmd');
        $downsample_command = str_replace("%FILE%",$song->file,$downsample_command);
        $downsample_command = str_replace("%OFFSET%",$offset,$downsample_command);
        $downsample_command = str_replace("%EOF%",$eof,$downsample_command);
        $downsample_command = str_replace("%SAMPLE%",$sample_rate,$downsample_command);

        // If we are debugging log this event
        if (conf('debug')) {
		$message = "Start Downsample: $downsample_command";
                log_event($GLOBALS['user']->username,' downsample ',$message);
	} // if debug

	$fp = @popen($downsample_command, 'r');

	return ($fp);

} // start_downsample

?>