Home-Integration/dmx/state.pl

#!/usr/bin/perl
use strict;
use warnings;
use IO::Select;
use File::Basename;
use File::Temp qw( tempfile );
use Sys::Hostname;
use IPC::System::Simple qw( system capture );

# Local modules
use Cwd qw(abs_path);
use File::Basename qw(dirname);
use lib dirname( abs_path($0) );
use DMX;

# Prototypes
sub mtime($);

# User config
my %DISPLAY_DEVS   = ( 'TV' => 1, 'PROJECTOR' => 1 );
my $DISPLAY        = undef();
my $STATE_TIMEOUT  = 180;
my $EXISTS_TIMEOUT = 900;
my $START_DELAY    = 15;
my %MON_FILES      = ();

# Host-specific config
# This is necessary to avoid contention on shared disks
my $HOST = Sys::Hostname::hostname();
if ( $HOST =~ /loki/i ) {

    # Ensure the media path is available before we get going
    my $MEDIA_PATH = undef();
    {
        my $mount = $ENV{'HOME'} . '/bin/video/mediaPath';
        $MEDIA_PATH = capture($mount);
    }
    if ( !$MEDIA_PATH || !-d $MEDIA_PATH ) {
        die("Unable to access media path\n");
    }

    # Door remote command
    $MON_FILES{ $MEDIA_PATH . '/DMX/cmd/DOOR_CMD' } = 'EXISTS-LINE-CLEAR';

    # Rumble pack
    $MON_FILES{'RUMBLE'}                                    = 'LINE-NOUPDATE';
    $MON_FILES{ $MEDIA_PATH . '/DMX/cmd/RUMBLE_CMD' }       = 'LINE-NOUPDATE';
    $MON_FILES{ $MEDIA_PATH . '/DMX/cmd/RUMBLE_VALUE' }     = 'LINE-NOUPDATE';
    $MON_FILES{ $MEDIA_PATH . '/DMX/cmd/RUMBLE_DELAY_MIN' } = 'LINE-NOUPDATE';
    $MON_FILES{ $MEDIA_PATH . '/DMX/cmd/RUMBLE_DELAY_MAX' } = 'LINE-NOUPDATE';
}

# Available state files
{

    # Plex
    $MON_FILES{'PLEX'}    = 'NONE';
    $MON_FILES{'GUI'}     = 'NONE';
    $MON_FILES{'PLAYING'} = 'PLAYING';

    # RiffTrax
    $MON_FILES{'RIFF'} = 'LINE-NOUPDATE';

    # Motion detection
    $MON_FILES{'MOTION'}        = 'MTIME';
    $MON_FILES{'MOTION_STAIRS'} = 'MTIME-NOUPDATE';
    $MON_FILES{'MOTION_GARAGE'} = 'MTIME-NOUPDATE';
    $MON_FILES{'NO_MOTION'}     = 'EXISTS-NOUPDATE';

    # Projector
    $MON_FILES{'PROJECTOR'}       = 'STATUS';
    $MON_FILES{'PROJECTOR_COLOR'} = 'LINE-NOUPDATE';
    $MON_FILES{'PROJECTOR_INPUT'} = 'LINE-NOUPDATE';
    $MON_FILES{'PROJECTOR_LAMP'}  = 'LINE-NOUPDATE';

    # Projector Control
    $MON_FILES{'PROJECTOR_CTRL_COLOR'} = 'LINE-NOUPDATE';
    $MON_FILES{'PROJECTOR_CTRL_LIFE'}  = 'LINE-NOUPDATE';
    $MON_FILES{'PROJECTOR_CTRL_POWER'} = 'LINE-NOUPDATE';
    $MON_FILES{'PROJECTOR_CTRL_TIMER'} = 'LINE-NOUPDATE';

    # Amplifier
    $MON_FILES{'AMPLIFIER'}       = 'STATUS';
    $MON_FILES{'AMPLIFIER_VOL'}   = 'LINE-NOUPDATE';
    $MON_FILES{'AMPLIFIER_MODE'}  = 'LINE-NOUPDATE';
    $MON_FILES{'AMPLIFIER_INPUT'} = 'LINE-NOUPDATE';
    $MON_FILES{'AUDIO_AMP'}       = 'EXISTS-ON';
    $MON_FILES{'STEREO_CMD'}      = 'EXISTS-ON';

    # A/V Effects
    $MON_FILES{'LIGHTS'} = 'EXISTS-TIMEOUT';
    $MON_FILES{'BRIGHT'} = 'EXISTS-TIMEOUT';
    $MON_FILES{'RAVE'}   = 'EXISTS';
    $MON_FILES{'EFFECT'} = 'EXISTS';

    # Fan
    $MON_FILES{'FAN'}     = 'LINE-NOUPDATE';
    $MON_FILES{'FAN_CMD'} = 'EXISTS-TIMEOUT';

    # Garage
    $MON_FILES{'OIL'}     = 'LINE-NOUPDATE';
    $MON_FILES{'DOOR'}    = 'LINE-NOUPDATE';
    $MON_FILES{'LOCK'}    = 'EXISTS-NOUPDATE';

    # Alarm
    $MON_FILES{'ALARM'}   = 'NONE';

    # OS State
    $MON_FILES{'FRONT_APP'}   = 'LINE-NOUPDATE';
    $MON_FILES{'COLOR'}       = 'LINE-NOUPDATE';
    $MON_FILES{'AUDIO'}       = 'LINE-NOUPDATE';
    $MON_FILES{'AUDIO_STATE'} = 'LINE-NOUPDATE';

    # Game System
    $MON_FILES{'GAME'} = 'EXISTS';

    # Lights
    $MON_FILES{'LED'}          = 'LINE-NOUPDATE';
    $MON_FILES{'OVERHEAD'}     = 'LINE-NOUPDATE';
    $MON_FILES{'ROPE'}         = 'LINE-NOUPDATE';
    $MON_FILES{'STAIRS'}       = 'LINE-NOUPDATE';
    $MON_FILES{'GARAGE'}       = 'LINE-NOUPDATE';
    $MON_FILES{'GARAGE_LEDS'}  = 'LINE-NOUPDATE';
    $MON_FILES{'GARAGE_SHELF'} = 'LINE-NOUPDATE';

    # TV
    $MON_FILES{'TV'}       = 'STATUS';
    $MON_FILES{'TV_VOL'}   = 'LINE-NOUPDATE';
    $MON_FILES{'TV_INPUT'} = 'LINE-NOUPDATE';
}
my %EXTRAS = (
    'PLAYING' => {
        'URL'       => qr/^file:(.+)$/m,
        'YEAR'      => qr/^year:(\d+)/m,
        'SERIES'    => qr/^showtitle:(.+)$/m,
        'SEASON'    => qr/^season:(\d+)/m,
        'EPISODE'   => qr/^episode:(\d+)/m,
        'TITLE'     => qr/^title:(.+)$/m,
        'LENGTH'    => qr/^duration:(\d+)/m,
        'POSITION'  => qr/^time:(\d+(?:\.\d+)?)/m,
        'TYPE'      => qr/^type:(.+)$/m,
        'ALBUM'     => qr/^album:(.+)$/m,
        'ARTIST'    => qr/^artist:(.+)$/m,
        'SELECTION' => qr/^selection:(.+)$/m,
        'WINDOW'    => qr/^window:(.+)$/m,
        'WINDOWID'  => qr/^windowid:(\d+)/m,

        # Available, but big and mostly useless
        #'IMAGE'     => qr/^fanart:(.+)$/m,
        #'THUMB'     => qr/^thumbnail:(.+)$/m,
    }
);

# App config
my $SOCK_TIMEOUT = 5;
my $DATA_DIR     = DMX::dataDir();
my $CMD_FILE     = 'STATE';
my $MAX_CMD_LEN  = DMX::maxCmdLen();
my $RESET_CMD    = $ENV{'HOME'} . '/bin/video/dmx/reset.sh';
my $PUSH_TIMEOUT = 20;

# Debug
my $DEBUG = 0;
if ( $ENV{'DEBUG'} ) {
    $DEBUG = 1;
}

# Command-line arguments
my ($DELAY) = @ARGV;
if ( !$DELAY ) {
    $DELAY = 0.5;
}

# Socket init
my $select = DMX::stateSocket($CMD_FILE);

# Add the extras to the main file list
foreach my $file ( keys(%EXTRAS) ) {
    if ( exists( $MON_FILES{$file} ) ) {
        foreach my $extra ( keys( %{ $EXTRAS{$file} } ) ) {
            $MON_FILES{ $file . '_' . $extra } = 'EXTRA';
        }
    }
}

# Init the file tracking structure
my %files = ();
foreach my $name ( keys(%MON_FILES) ) {
    my %file = (
        'name'   => basename($name),
        'type'   => $MON_FILES{$name},
        'path'   => $DATA_DIR . $name,
        'update' => 0,
        'value'  => 0,
        'last'   => 0,
    );

    # Allow absolute paths to override the $DATA_DIR path
    if ( $name =~ /^\// ) {
        $file{'path'} = $name;
    }

    # Record the directory name for folder monitoring
    $file{'dir'} = dirname( $file{'path'} );

    # Set the attribute bits, for use in later update handling logic
    my %attr = (
        'available' => 0,
        'status'    => 0,
        'exists'    => 0,
        'value'     => 0,
        'line'      => 0,
        'clear'     => 0,
        'clear_off' => 0,
        'mtime'     => 0,
        'playing'   => 0,
        'no_update' => 0,
        'no_value'  => 0,
        'extra'     => 0,
    );
    if ( $file{'type'} =~ /\bSTATUS\b/i ) {
        $attr{'status'} = 1;
    }
    if ( $file{'type'} =~ /\bEXISTS\b/i ) {
        $attr{'exists'} = 1;
    }
    if ( $file{'type'} =~ /\bVALUE\b/i ) {
        $attr{'value'} = 1;
    }
    if ( $file{'type'} =~ /\bLINE\b/i ) {
        $attr{'line'} = 1;
    }
    if ( $file{'type'} =~ /\bCLEAR\b/i ) {
        $attr{'clear'} = 1;
    }
    if ( $file{'type'} =~ /\bON\b/i ) {
        $attr{'clear_off'} = 1;
    }
    if ( $file{'type'} =~ /\bTIMEOUT\b/i ) {
        $attr{'clear_timeout'} = 1;
    }
    if ( $file{'type'} =~ /\bMTIME\b/i ) {
        $attr{'mtime'} = 1;
    }
    if ( $file{'type'} =~ /\bPLAYING\b/i ) {
        $attr{'playing'} = 1;
    }
    if ( $file{'type'} =~ /\bNOUPDATE\b/i ) {
        $attr{'no_update'} = 1;
    }
    if ( $file{'type'} =~ /\bNONE\b/i ) {
        $attr{'no_value'} = 1;
    }
    if ( $file{'type'} =~ /\bEXTRA\b/i ) {
        $attr{'extra'} = 1;
    }

    # Cross-match some data types for easy of use
    if ( $attr{'extra'} ) {
        $attr{'no_value'} = 1;
    }
    if ( $attr{'no_value'} ) {
        $attr{'no_update'} = 1;
    }
    if ( $attr{'line'} ) {
        $attr{'value'} = 1;
    }
    if ( $attr{'value'} || $attr{'playing'} ) {
        $attr{'status'} = 1;
    }
    if ( $attr{'status'} || $attr{'exists'} ) {
        $attr{'mtime'} = 1;
    }

    # Push ATTR into the file hash
    $file{'attr'} = \%attr;

    # Push FILE into the files hash
    $files{$name} = \%file;
}

# Delete any existing input files, to ensure our state is reset
foreach my $file ( values(%files) ) {
    if ( -e $file->{'path'} ) {
        if ($DEBUG) {
            print STDERR 'Deleting '
              . $file->{'name'} . ': '
              . $file->{'path'} . "\n";
        }
        unlink( $file->{'path'} );
    }
}

# Reset all dependents at starts
system($RESET_CMD);

# Subscribers
my @subscribers = ();

# State
my $state           = 'INIT';
my $stateLast       = $state;
my $status          = '';
my $statusLast      = $status;
my $updateLast      = 0;
my $timeSinceUpdate = 0;
my $startTime       = time() + $START_DELAY;
my $pushLast        = 0;

# Announce startup
DMX::say('System initializing');

# Loop forever
while (1) {

    # Provide a method to force updates
    my $update = 0;

    # Avoid repeated calls to time()
    my $now = time();

    # Check for queued commands
    my @ready_clients = $select->can_read($DELAY);
    foreach my $fh (@ready_clients) {

        # Grab the inbound text
        my $path = undef();
        $fh->recv( $path, $MAX_CMD_LEN );
        $path =~ s/^\s+//;
        $path =~ s/\s+$//;
        $path =~ s/\W/_/g;
        if ($DEBUG) {
            print STDERR 'Got path: ' . $path . "\n";
        }

        # Open the new socket
        my $sub = eval { DMX::clientSock($path); };
        if ( !$sub ) {
            print STDERR 'Unable to open socket: ' . $path . ": ${@}\n";
            next;
        }

        # Add the socket to our subscriber list
        my %tmp = (
            'path'   => $path,
            'socket' => $sub,
        );
        push( @subscribers, \%tmp );

        # Send immediately when someone subscribes
        if ( !$update ) {
            if ($DEBUG) {
                print STDERR "New subscriber\n";
            }
            $update = 1;
        }
    }

    # Use opendir/readdir in each folder to ensure fresh results
    my %folders = ();
    foreach my $file ( values(%files) ) {
        if ( !$folders{ $file->{'dir'} } ) {
            my $dh = undef();
            opendir( $dh, $file->{'dir'} )
              or die( 'Unable to open directory: ' . $file->{'dir'} );
            if ($DEBUG) {
                print STDERR 'Refreshed folder: ' . $file->{'dir'} . "\n";
            }
            my @files = readdir($dh);
            closedir($dh);
            $folders{ $file->{'dir'} } = 1;
        }
    }

    # Monitor files of all types
    foreach my $file ( values(%files) ) {

# Record the previous status and clear the new one, unless the file is type EXTRA
        if ( !$file->{'attr'}->{'extra'} ) {
            $file->{'last'}  = $file->{'value'};
            $file->{'value'} = 0;
        }

        # Skip NO_VALUE files -- their values are abstracted from other data
        if ( $file->{'attr'}->{'no_value'} ) {
            next;
        }

        # Track available/unavailable status in each cycle
        {
            my $wasAvailable = $file->{'attr'}->{'available'};
            $file->{'attr'}->{'available'} = -r $file->{'path'} ? 1 : 0;
            if ( $wasAvailable != $file->{'attr'}->{'available'} ) {

                # Reset and extras for this file
                if ( exists( $EXTRAS{ $file->{'name'} } ) ) {
                    foreach
                      my $extra ( keys( %{ $EXTRAS{ $file->{'name'} } } ) )
                    {
                        my $name = $file->{'name'} . '_' . $extra;
                        $files{$name}{'last'}  = $files{$name}{'value'};
                        $files{$name}{'value'} = 0;
                    }
                }

                # Determine which display device we have (if any)
                if ( exists( $DISPLAY_DEVS{ $file->{'name'} } ) ) {
                    $DISPLAY = $file->{'name'};
                    if ($DEBUG) {
                        print STDERR 'Selecting display device: ' . $DISPLAY
                          . "\n";
                    }
                }

                if ($DEBUG) {
                    if ( $file->{'attr'}->{'available'} ) {
                        print STDERR 'Added file '
                          . $file->{'name'} . ': '
                          . $file->{'path'} . "\n";
                    }
                    else {
                        print STDERR 'Dropped file '
                          . $file->{'name'} . ': '
                          . $file->{'path'} . "\n";
                    }
                }
            }
        }

        # Skip unavailable files
        if ( !$file->{'attr'}->{'available'} ) {
            next;
        }

        # Record the last update for MTIME files
        if ( $file->{'attr'}->{'mtime'} ) {
            my $mtime = mtime( $file->{'path'} );

# All EXISTS files have MTIME set, and mtime returns 0 if the file does not exist, so we can overload this check
            if ( $file->{'attr'}->{'exists'} ) {
                if ( $mtime > 0 ) {
                    $file->{'update'} = $mtime;
                    $file->{'value'}  = 1;
                }
                elsif ( $file->{'last'} ) {
                    $file->{'update'} = $now;
                }
            }
            else {
                $file->{'update'} = $mtime;

# Set the value if the update is recent -- VALUE and STATUS will overwrite as needed
                if ( $mtime >= $now ) {
                    $file->{'value'} = 1;
                }
            }

            if ($DEBUG) {
                print STDERR 'Mtime: '
                  . $file->{'name'} . ': '
                  . $file->{'value'} . ':'
                  . $file->{'update'} . "\n";
            }
        }

        # Grab the state from STATUS files (including VALUE files)
        if ( $file->{'attr'}->{'status'} ) {

            # Overwrite the mtime-based value
            $file->{'value'} = 0;

            my $text = '';
            {
                if ( !open( my $fh, $file->{'path'} ) ) {
                    warn( 'Unable to open ' . $file->{'path'} . "\n" );
                }
                else {
                    local $/;
                    $text = <$fh>;
                    close($fh);
                }
            }

            # Parse the value for the file
            if ( $file->{'attr'}->{'value'} ) {
                if ( $file->{'attr'}->{'line'} ) {
                    ($text) = $text =~ /^([^\n]+)\s*\n/;
                }
                else {
                    $text =~ s/\s+$//;
                }
                $file->{'value'} = $text;
            }
            elsif ( $file->{'attr'}->{'playing'} ) {
                if ( $text =~ /^playing:1/m ) {
                    $file->{'value'} = 1;
                }
            }
            else {
                if ( $text =~ /1/ ) {
                    $file->{'value'} = 1;
                }
            }
            if ($DEBUG) {
                print STDERR 'Status: '
                  . $file->{'name'} . ': '
                  . $file->{'value'} . "\n";
            }

            # Handle extras, if any
            if ( exists( $EXTRAS{ $file->{'name'} } ) ) {
                foreach my $extra ( keys( %{ $EXTRAS{ $file->{'name'} } } ) ) {

                    my $name = $file->{'name'} . '_' . $extra;
                    $files{$name}{'last'}   = $files{$name}{'value'};
                    $files{$name}{'value'}  = 0;
                    $files{$name}{'update'} = $file->{'update'};

                    if ( $text =~ $EXTRAS{ $file->{'name'} }{$extra} ) {
                        $files{$name}{'value'} = $1;
                    }

                    if ($DEBUG) {
                        print STDERR "\t"
                          . $name . ': '
                          . $files{$name}{'value'} . "\n";
                    }
                }
            }
        }
    }

    # Simulate the old GUI indicator
    {
        my $gui = 0;
        if ( exists( $files{'PLAYING_WINDOW'} )
            && $files{'PLAYING_WINDOW'}->{'value'} ne 'Fullscreen video' )
        {
            $gui = 1;
        }
        $files{'GUI'}->{'value'} = $gui;
    }
    if ( exists( $files{'PLAYING'} ) ) {
        $files{'GUI'}->{'update'} = $files{'PLAYING'}->{'update'};
    }

    # Ignore the MOTION file if NO_MOTION is set
    if ( exists( $files{'NO_MOTION'} ) && $files{'NO_MOTION'}->{'value'} ) {
        if ( exists( $files{'MOTION'} ) ) {
            $files{'MOTION'}->{'value'}  = 0;
            $files{'MOTION'}->{'update'} = 0;
        }
    }

    # Set the global update timestamp, excluding files marked NOUPDATE
    foreach my $file ( values(%files) ) {
        if (   $file->{'update'} > $updateLast
            && !$file->{'attr'}->{'no_update'}
            && $file->{'update'} > $startTime )
        {
            $updateLast = $file->{'update'};
        }
    }
    $timeSinceUpdate = $now - $updateLast;

    # Calculate the PLEX state
    if ( exists( $files{'FRONT_APP'} ) ) {
        if (   $files{'FRONT_APP'}->{'value'} =~ 'com.plexapp.plexhometheater'
            || $files{'FRONT_APP'}->{'value'} eq
            'com.apple.ScreenSaver.Engine' )
        {
            if ( !exists( $files{'GAME'} ) || !$files{'GAME'}->{'value'} ) {
                $files{'PLEX'}->{'value'} = 1;
            }
        }
    }
    if ( $files{'PLEX'}->{'last'} != $files{'PLEX'}->{'value'} ) {
        $files{'PLEX'}->{'update'} = $now;
    }

    # Determine some intermediate state data
    my $playing = 0;
    if ( exists( $files{'PLAYING'} ) && $files{'PLAYING'}->{'value'} ) {
        $playing = 1;
    }
    my $video = 0;
    if ( exists( $files{'PLAYING_TYPE'} )
        && $files{'PLAYING_TYPE'}->{'value'} ne 'audio' )
    {
        $video = 1;
    }
    elsif ( !exists( $files{'PLAYING_TYPE'} ) ) {
        $video = 1;
    }

    # Non-plex apps are always "playing" and "video"
    if ( exists( $files{'PLEX'} ) && !$files{'PLEX'}->{'value'} ) {
        $playing = 1;
        $video   = 1;
    }

    # Calculate the new state
    $stateLast = $state;
    if ( !defined($DISPLAY) || !exists( $files{$DISPLAY} ) ) {

# If there's no display the state is always PLAY or PAUSE, as indicated by the master
        if ($playing) {
            $state = 'PLAY';
        }
        else {
            $state = 'PAUSE';
        }

    }
    elsif ( $files{$DISPLAY}->{'value'} ) {

        # If a display exists and is on:
        # PLAY when video is active and playing
        # PAUSE any other time (including when audio is active)
        if ( $playing && $video ) {
            $state = 'PLAY';
        }
        else {
            $state = 'PAUSE';
        }

    }
    else {

# If the display exists but is off, check the timeouts to determine MOTION vs. OFF
        if ( $timeSinceUpdate > $STATE_TIMEOUT ) {
            $state = 'OFF';
        }
        elsif ( $timeSinceUpdate < $STATE_TIMEOUT ) {
            $state = 'MOTION';
        }
    }
    if ( $state eq 'INIT' ) {
        $state = 'OFF';
    }

    # ALARM if LOCK exists and the master state is not OFF or any motion exists
    {
        my $alarm = 0;
        if ( exists( $files{'LOCK'} ) && $files{'LOCK'}->{'value'} ) {
            if (
                   $state ne 'OFF'
                || ( exists( $files{'MOTION'} ) && $files{'MOTION'}->{'value'} )
                || ( exists( $files{'MOTION_STAIRS'} )
                    && $files{'MOTION_STAIRS'}->{'value'} )
                || ( exists( $files{'MOTION_GARAGE'} )
                    && $files{'MOTION_GARAGE'}->{'value'} )
              )
            {
                $alarm = 1;
            }
        }
        if ( !exists( $files{'ALARM'}->{'value'} )
            || $files{'ALARM'}->{'value'} != $alarm )
        {
            $files{'ALARM'}->{'update'} = $now;
        }
        $files{'ALARM'}->{'value'} = $alarm;
    }

# Clear EXISTS_ON files when the main state is "OFF" (and before we append their status)
    foreach my $file ( values(%files) ) {
        if (   $file->{'attr'}->{'clear_off'}
            && $file->{'value'}
            && $state eq 'OFF' )
        {
            unlink( $file->{'path'} );
            $file->{'status'} = 0;
            if ($DEBUG) {
                print STDERR 'Clearing exists flag for: '
                  . $file->{'name'} . "\n";
            }
        }
    }

# Clear EXISTS_TIMEOUT files when the main state is "OFF" and EXISTS_TIMEOUT has expired (and before we append their status)
    foreach my $file ( values(%files) ) {
        if (   $file->{'attr'}->{'clear_timeout'}
            && $file->{'value'}
            && $state eq 'OFF'
            && $timeSinceUpdate > $EXISTS_TIMEOUT )
        {

            unlink( $file->{'path'} );
            $file->{'status'} = 0;
            if ($DEBUG) {
                print STDERR 'Clearing exists flag for: '
                  . $file->{'name'} . "\n";
            }
        }
    }

    # Calculate the new status
    $statusLast = $status;
    {
        my @statTime = ();
        foreach my $file ( values(%files) ) {
            my $text = $file->{'value'};
            $text =~ s/\s/ /g;
            $text =~ s/\|/-/g;
            push( @statTime,
                $file->{'name'} . '|' . $text . '|' . $file->{'update'} );
        }
        $status = "\n" . join( "\n", @statTime );
    }

    # Clear EXISTS_CLEAR files immediately (but after we append their status)
    foreach my $file ( values(%files) ) {
        if ( $file->{'attr'}->{'clear'} && $file->{'value'} ) {
            unlink( $file->{'path'} );
            $file->{'status'} = 0;
            if ($DEBUG) {
                print STDERR 'Clearing exists flag for: '
                  . $file->{'name'} . "\n";
            }
        }
    }

    # Update on a periodic basis, so we don't timeout
    if ( !$update && $now - $pushLast > $PUSH_TIMEOUT ) {
        if ($DEBUG) {
            print STDERR "Periodic update\n";
        }
        $update = 1;
    }

    # Update on a master state change
    if ( !$update && $stateLast ne $state ) {
        if ($DEBUG) {
            print STDERR 'State change: ' . $stateLast . ' => ' . $state . "\n";
        }
        $update = 1;
    }

    # Update on any mtime change
    if ( !$update ) {
        foreach my $file ( values(%files) ) {
            if ( $file->{'update'} > $pushLast ) {
                if ($DEBUG) {
                    print STDERR 'Mtime change: '
                      . $file->{'name'} . ' ('
                      . $file->{'update'} . ")\n";
                }
                $update = 1;
                last;
            }
        }
    }

    # Update on any value change
    if ( !$update ) {
        foreach my $file ( values(%files) ) {
            if ( $file->{'value'} ne $file->{'last'} ) {
                if ($DEBUG) {
                    print STDERR 'Value change: '
                      . $file->{'name'} . ' ('
                      . $file->{'last'} . ' => '
                      . $file->{'value'} . ")\n";
                }
                $update = 1;
                last;
            }
        }
    }

    # Push the update
    if ($update) {

        # Note the push
        $pushLast = $now;

        # Send notifications to all subscribers
        my $msg = $state . $status;
        if ($DEBUG) {
            print STDERR '<STATE ('
              . length($msg) . ")>\n"
              . $msg
              . "\n<END STATE>\n\n";
        }
        foreach my $sub (@subscribers) {

            # Drop subscribers that are not available
            if ( !eval { $sub->{'socket'}->send( $state . $status ) } ) {
                print STDERR 'Dropping bad socket from subscriber list: '
                  . $sub->{'path'} . "\n";

                my @new_subscribers = ();
                foreach my $new (@subscribers) {
                    if ( $new->{'socket'} eq $sub->{'socket'} ) {
                        next;
                    }
                    push( @new_subscribers, $new );
                }
                @subscribers = @new_subscribers;
            }
        }

        # Save the state and value to disk
        my ( $fh, $tmp ) =
          tempfile( $DATA_DIR . 'STATE.XXXXXXXX', 'UNLINK' => 0 );
        print $fh $state . "\n";
        close($fh);
        rename( $tmp, $DATA_DIR . 'STATE' );
    }
}

sub mtime($) {
    my ($file) = @_;
    my $mtime = 0;
    if ( -r $file ) {
        (
            undef(), undef(), undef(), undef(), undef(), undef(), undef(),
            undef(), undef(), $mtime,  undef(), undef(), undef()
        ) = stat($file);
    }
    return $mtime;
}