#!/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';

    # Oil
    $MON_FILES{'OIL'}         = 'LINE-NOUPDATE';
    $MON_FILES{'OIL_ENABLE'}  = 'EXISTS-NOUPDATE';
    $MON_FILES{'OIL_DISABLE'} = 'EXISTS-NOUPDATE';

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

    # Alarm
    $MON_FILES{'ALARM'}        = 'NONE';
    $MON_FILES{'ALARM_ENABLE'} = 'EXISTS-NOUPDATE';

    # 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';
    $MON_FILES{'VR'}   = 'LINE-NOUPDATE';

    # Lights
    $MON_FILES{'LED'}          = 'LINE-NOUPDATE';
    $MON_FILES{'SHELF_HIGH'}   = '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'} =~ 'tv.openpht.openpht'
            || $files{'FRONT_APP'}->{'value'} eq 'com.apple.ScreenSaver.Engine')
        {
            if (!exists($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 ALARM_ENABLE exists and the master state is not OFF or any motion exists
    {
        my $alarm = 0;
        if (exists($files{'ALARM_ENABLE'}) && $files{'ALARM_ENABLE'}->{'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;
}