#!/usr/bin/env perl

# TODO: add option to allow recursive sub-directories (in choose_image())
# TODO: license, etc.

use strict;
use warnings;
use POSIX;
use File::Copy;

use lib "$ENV{HOME}/perl5/lib/perl5";
$ENV{PWD} = '/tmp' unless (defined($ENV{PWD}));

use constant ERROR => {
        LOG_EMERG       => 8,
        LOG_ALERT       => 7,
        LOG_CRIT        => 6,
        LOG_ERR         => 5,
        LOG_WARNING     => 4,
        LOG_NOTICE      => 3,
        LOG_INFO        => 2,
        LOG_DEBUG       => 1
};

our @e;

sub usage()
{
        my $self = shift;
        print("$0 [output(s)] [-d|--daemon]\n
Sets a wallpaper by cropping an appropriate sized section of a larger image.\n
All arguments other than the below are assumed to be output names, as defined
in my sway/displays.pl script. If no outputs are provided, all available that
are currently enabled will be set.\n
--path=<path>	Path to wallpaper directory.
-p <path>	Default: $ENV{HOME}/wallpapers\n
--daemon=N	Configures the wallpaper to be periodically rotated for all
-d N		of the given outputs. N indicates the number of seconds between
                each rotation, if provided (default: 300).\n
--nocrop        Don't crop a selection from the image. Instead, pass the whole
-n              image to swaybg and let it handle the scaling\n
--verbose=N     Define minimum log level. Counting from 1: LOG_DEBUG, LOG_INFO,
-v N            LOG_NOTICE, LOG_WARNING, LOG_ERR, LOG_CRIT, LOG_ALERT, LOG_EMERG
                Default: 5; If provided without a value for N then all (1).
--recursive=N   Enumerate images recursively through directories in the path.
-r N            N indicates the directory depth, unlimited if no N is provided.
--help		This menu
-h\n
You can send SIGUSR1 to force the daemon to reload immediately. Rotation timer
will be reset.\n");
        exit(0);
}

sub new
{
        my ($class, %args) = @_;

        use AnyEvent::Sway;
        $args{ipc} = AnyEvent::Sway->new();
        use Image::Magick;
        $args{im} = Image::Magick->new();
        $args{error} = ();

        $args{pidfile} = "/tmp/$ENV{USER}-wallpaper.pid";

        return bless { %args };
}

my $wp = new("Wallpapers");

if (-e $wp->{pidfile}) {
        if (-r $wp->{pidfile}) {
                if (open(my $fh, '<', $wp->{pidfile})) {
                        my $pid = <$fh>;
                        chomp($pid);
                        use Proc::ProcessTable;
                        my $pt = Proc::ProcessTable->new();
                        foreach my $p ( @{ $pt->table() } ) {
                                if ($p->{pid} eq $pid) {
                                        my $name = $0;
                                        $name =~ s/$ENV{PWD}//;
                                        if ($p->{'cmndline'} =~ m#$name#) {
                                                $wp->do_log("LOG_CRIT", "Another process is already running with PID: $pid (running and listed in $wp->{pidfile})");
                                                # Die locally because do_log will remove pidfile that this iteration does not belong to
                                                exit(1);
                                        } else {
                                                $wp->do_log("LOG_CRIT", "Found matching $pid with different cmdline: $p->{cmndline} (not $0)",1);
                                                # PID in pidfile doesn't look like it is another wallpaper
                                                unlink($wp->{pidfile});
                                                last;
                                        }
                                        return $p->{'pid'};
                                }
                        }
                } else {
                        $wp->do_log("LOG_CRIT", "Pidfile $wp->{pidfile} exists, but cannot be opened. Assuming it is running already.");
                        # Die locally because do_log will remove pidfile that this iteration does not belong to
                        exit(1);
                }
        } else {
                $wp->do_log("LOG_CRIT", "Pidfile $wp->{pidfile} exists, but is not readable. Assuming it is running already.");
                # Die locally because do_log will remove pidfile that this iteration does not belong to
                exit(1);
        }
}

# SIGUSR reset the timer, force immediate reload, continue looping
$SIG{USR1} = sub {
        alarm 0;
        $wp->do_log("LOG_INFO", "Reloading due to SIGUSR1");
};

# SIGTERM reset the timer, clean pid, and allow for the main loop to finish run
$SIG{TERM} = sub {
        $wp->do_log("LOG_INFO", "Going down clean due to SIGTERM");
        clean($wp);
        $wp->{daemon} = 0;
};

# SIGKILL clean pid then exit immediately
$SIG{KILL} = sub {
        $wp->do_log("LOG_INFO", "Hard kill with SIGKILL, attempting to remove pidfile");
        clean($wp);
        exit(0);
};

# simply returns the array of hashes provided by swaymsg
sub get_outputs
{
        my $self = shift;
        my $o = $self->{ipc}->get_outputs->recv() || $self->do_log('LOG_WARNING',"Failed to query 'get_outputs'");
        die "No outputs detected.\n" unless (scalar(@$o) > 0);
        return $o;
}

# returns the same as above but with the 'name' as a hash key for easier lookup
sub get_active
{
        my $self = shift;
        if (defined($self->{outputs}) && scalar($self->{outputs})) {
                my %active = ();
                foreach my $o (@{$self->{outputs}}) {
                        my $name;
                        my %details;
                        next unless ($o->{active});
                        $active{$o->{name}} = ();
                        foreach (keys(%$o)) {
                                $active{$o->{name}}->{$_} = $o->{$_} unless ($_ eq 'name');
                        }
                }
                $self->do_log('LOG_WARNING',"No outputs detected.") unless (scalar(keys(%active)));
                return \%active;
        } else {
                print "You haven't initialized get_outputs";
                $self->do_log('LOG_WARNING',"Output list not defined yet. Try 'get_outputs()' first");
                return \{};
        }
}

sub clean
{
        my $self = shift;
        if (-e $self->{pidfile}) {
                open (my $fh, '<', $self->{pidfile});
                my $p = <$fh>;
                close($fh);
                chomp $p;
                kill($p);
                unlink($self->{pidfile});
        }
}

sub dig_dirs
{
        my $self = shift;
        my $paths_ref = shift;
        my $path = shift;
        my $depth = shift || 0;
        unless (-e $path) {
                return(undef);
        }
        if ($path =~ m/\/\.\.?$/) {
                return;
        }
        foreach (glob("$path/*"), glob("$path/.*")) {
                if ($path =~ m/\/\.\.?$/) {
                        next();
                } elsif (-l $_) {
                        push(@$paths_ref, $_);
                } elsif (-d $_ && ($self->{recursive} == '-1' || $depth < $self->{recursive})) {
                        $self->dig_dirs($paths_ref,$_,$depth+1);
                } else {
                        push(@$paths_ref, $_);
                }
        }
}

sub choose_image
{
        my $self = shift;

        my @i;
        my $depth = 0;
        my @w;
        $self->dig_dirs(\@w,$self->{path});
        return undef unless (scalar(@w));
        $self->do_log("LOG_DEBUG", "Found ".scalar(@w)." files in $self->{path} up to depth $self->{recursive}");
        foreach (@w) {
                if (-d $_) {
                        $self->do_log("LOG_DEBUG", "Ignoring sub-directory $_");
                        next;
                }
                if ($_ =~ m/\.(png|jpg)$/) {
                        push(@i,$_);
                }
        }

        return $i[rand(scalar(@i))] || return undef;
}

sub crop
{
        my $self = shift;
        my $image = shift;
        my $ow = shift;
        my $oh = shift;

        my $cropped = $image;
        $cropped =~ s#^.*/([^/]*)\.([^\.]+)$#$1-cropped.$2#;

        #$image = "/tmp/Pharma-out.png.jpg";
        use Image::Magick;
        my $im = Image::Magick->new();
        die "$image is not readable" unless (-r $image);
        my $ret = $im->Read($image);
        return 0 if ($ret);
        my ($iw, $ih) = $im->Get("columns", "rows");
        $self->do_log("LOG_DEBUG", "Image has dimensions ${iw}x${ih}");

        # Return full size if it is smaller in either dimension then the output
        if ($iw <= $ow || $ih <= $oh) {
                $self->do_log("LOG_DEBUG", "Not cropping because ${iw}x${ih} is smaller or equal to the output (${ow}x${oh}) in at least 1 dimension.");
                return undef;
        }

        my ($x, $y);
        $x = int(rand($iw-$ow));
        $y = int(rand($ih-$oh));

        my $err = $im->Crop(geometry=>"${ow}x${oh}+${x}+${y}");
        die "$err" if ($err);
        $err = $im->Write($cropped);
        die "$err" if ($err);
        return $cropped if ( -e $cropped );
}

sub set_background
{
        my $self = shift;
        my $target = shift || return "No target or image provided";
        my $cropped = shift || return "No image provided";
        # TODO get fallback from javascript
        my $cmd = "output $target background $cropped fill #000000";
        $self->do_log("LOG_DEBUG", "Running $cmd\n");
        my $ret = $self->{ipc}->message(0,$cmd)->recv;
        if ($ret->[0]->{success}) {
                $self->do_log("LOG_DEBUG", "Success!");
                return undef;
        }
        return "Failed to run Sway IPC command '$cmd'";
}

sub do_log
{
        my $self = shift;
        my $level = shift;
        my $msg = shift;
        my $die = shift || 0;
        my $min = $self->{verbose} || 5;

        if ($self->{daemon}) {
                use Log::Journald qw(send);
                send(
                        PRIORITY        => ERROR->{$level},
                        MESSAGE         => $msg,
                        PERL_PACKAGE    => 'Sway Wallpapers'
                ) || warn "Could not send log ($level $msg): $!";
                if ($die) {
                        $msg = '(FATAL) ' . $msg;
                        exit(1);
                }
        } else {
                if (ERROR->{$level} >= $min) {
                        printf("%11s %s\n", $level, $msg);
                }
        }
        if ($die) {
                $self->clean();
                exit(1);
        }
}

sub run
{
        my $self = shift;
        $self->do_log("LOG_DEBUG", "Fetching outputs from IPC");
        $self->{outputs} = $self->get_outputs();
        # Local copy of targets so that it will re-check active every time
        my @t = @{$self->{targets}} if (scalar(@{$self->{targets}}));
        $self->do_log("LOG_DEBUG", "Removing inactive ouputs");
        my $active = $self->get_active();
        # If specific targets were not defined, use all active
        unless (scalar(@t)) {
                @t = keys(%$active);
                push(@{$self->{error}}, "No target outputs") unless (scalar(@t));
        }
        $self->do_log("LOG_DEBUG", "Looping desired ouputs");
        foreach my $target (@t) {
                $self->do_log("LOG_DEBUG", "Ensuring that desired output is active");
                unless (defined($active->{$target})) {
                        $self->do_log('LOG_DEBUG', "Target $target is not an active output");
                        next;
                }
                $self->do_log("LOG_DEBUG", "Selecting image for $target");
                my $image = $self->choose_image();
                if (defined($image)) {
                        $self->do_log('LOG_DEBUG', "Selected $image");
                        if ( -r "$image" ) {
                                my $cropped;
                                if ($self->{crop}) {
                                        $self->do_log('LOG_DEBUG',"Cropping image for '$target' using '$image'");
                                        $cropped = $self->crop(
                                                $image,
                                                $active->{$target}->{rect}->{width},
                                                $active->{$target}->{rect}->{height}
                                        );
                                        if ($cropped) {
                                        } else {
                                                # Create a tmp copy since it will be deleted later
                                                # If PWD is the wallpaper path, make the tmp in /tmp
                                                if ($self->{path} eq $ENV{PWD}) {
                                                        $cropped = $image;
                                                        $cropped =~ s%$ENV{PWD}%/tmp%;
                                                # Else make the tmp in PWD
                                                } else {
                                                        $cropped = '/'.$image;
                                                        $cropped =~ s%.*/([^/+])%$ENV{PWD}/$1%;
                                                }
                                                $self->do_log('LOG_DEBUG',"Creating copy of original: $cropped");
                                                File::Copy::copy($image,$cropped) || $self->do_log('LOG_WARNING',"Failed to copy to $cropped: $!");
                                        }
                                } else {
                                        $self->do_log('LOG_DEBUG', "Cropping is disabled");
                                        $cropped = $image;
                                }
                                $self->set_background($target,$cropped);
                                if ($self->{crop}) {
                                        $self->do_log('LOG_DEBUG', "Deleting $cropped");
                                        # Give swaybg a second, otherwise the file will be missing before it ends
                                        sleep(1);
                                        unlink($cropped) || $self->do_log("LOG_WARNING", "Failed to delete $cropped after setting: $!");
                                }
                        } else {
                                $self->do_log("LOG_WARNING", "Failed to read $image");
                        }
                } else {
                        $self->do_log("LOG_WARNING", "Failed to select image from $self->{path}");
                }
        }
}

################################################################################
# Collect arguments
################################################################################
my @targets;
my $daemon;
my $delay;
my $crop;
my $path;
my $verbose;
my $recursive = 0;
while (my $arg = shift(@ARGV)) {
        if ($arg eq '-h' || $arg eq '--help') {
                $wp->usage();
        } elsif ($arg =~ m/^\-\-path=?(.+)$/) {
                die "Redundant argument '$arg'. Wallpaper path already set.\n" if ($path);
                $path = $1;
        } elsif ($arg eq '-p') {
                die "Redundant argument '$arg'. Wallpaper path already set.\n" if ($path);
                $path = shift(@ARGV);
        } elsif ($arg =~ m/^\-\-daemon=?(.+)?$/) {
                die "Redundant argument '$arg'. Daemon mode already set.\n" if ($daemon);
                $delay = $1 || 300;
                $daemon = 1;
        } elsif ($arg eq '-d') {
                die "Redundant argument '$arg'. Daemon mode already set.\n" if ($daemon);
                if (scalar(@ARGV) && $ARGV[0] =~ m/^\d+$/) {
                        $delay = shift(@ARGV);
                }
                $daemon = 1;
        } elsif ($arg eq '--nocrop' || $arg eq '-n') {
                die "Redundant argument '$arg'. No-crop already set.\n" if (defined($crop));
                $crop = 0;
        } elsif ($arg =~ m/^\-\-verbose=?(.+)?$/) {
                die "Redundant argument '$arg'. Verbosity already set.\n" if ($verbose);
                $verbose = $1 || 1;
        } elsif ($arg eq '-v') {
                die "Redundant argument '$arg'. Verbosity already set.\n" if ($verbose);
                if (scalar(@ARGV) && $ARGV[0] =~ m/^\d$/) {
                        $verbose = shift(@ARGV);
                }
        } elsif ($arg =~ m/^\-\-recursive=?(.+)?$/) {
                die "Redundant argument '$arg'. Recursive search already set.\n" unless ($recursive == 0);
                $recursive = $1 || -1;
        } elsif ($arg eq '-r') {
                die "Redundant argument '$arg'. Recursive search already set.\n" unless ($recursive == 0);
                if (scalar(@ARGV) && $ARGV[0] =~ m/^\d+$/) {
                        $recursive = shift(@ARGV);
                } else {
                        $recursive = -1;
                }
        } elsif ($arg =~ m/^-/) {
                die "Unrecognized argument: $arg\n";
        } else {
                push(@targets,$arg);
        }
}

################################################################################
# Validate arguments
################################################################################

$wp->do_log("LOG_DEBUG", "Validating arguments");
die "Invalid rotation delay: $delay" if (defined($delay) && $delay !~ m/^\d+$/);
die "Invalid wallpaper path '$path'. Not a directory." if (defined($path) && !-d $path);
die "Invalid verbosity level: '$verbose'\n" if (defined($verbose) && $verbose !~ m/^[1-8]$/);

$wp->do_log("LOG_DEBUG", "Configuring object");
$wp->{targets}  = \@targets || undef;
$wp->{daemon}   = $daemon || 0;
$wp->{path}     = $path || "$ENV{HOME}/wallpapers";
$wp->{crop}     = $crop || 1;
$wp->{delay}    = $delay || 300;
$wp->{verbose}  = $verbose || 0;
$wp->{recursive}= $recursive;
$wp->{error}    = [];

################################################################################
# Fork if daemonized
################################################################################

if ($wp->{daemon}) {
        $wp->do_log("LOG_DEBUG", "Forking daemon");
        my $p = fork();
        if ($p) {
                $wp->do_log("LOG_DEBUG", "Writing PID ($p) to pidfile ($wp->{pidfile})");
                if (open(my $fh, ">", $wp->{pidfile})) {
                        print $fh "$p" || die "Failed to write pid ($p) to pidfile ".$wp->{pidfile};
                        close($fh);
                } else {
                        print "Failed to open pidfile ".$wp->{pidfile}.": $!\n";
                }
                # Short delay necessary for SystemD to find PID
                sleep(1);
                exit(0);
        }
        $wp->do_log("LOG_DEBUG", "Daemon running");
        setpgrp(0, 0);
        umask 0;
}

################################################################################
# Main
################################################################################

my $first = 1;
do {
        $wp->do_log("LOG_INFO", "Reloading wallpaper") unless ($first);
        $wp->run();
        if ($wp->{daemon}) {
                my $normal = "reload wallpaper";
                eval {
                        $SIG{ALRM} = sub { return "$normal" };
                        alarm $wp->{delay};
                        POSIX::pause();
                        alarm 0;
                };
                $wp->do_log("LOG_WARNING", "Reload failed: $@") if ($@ && $@ !~ quotemeta($normal));
        }
        $first = 0 if ($first);
} while ($wp->{daemon});

# If we made it to here, it was not daemonized. Output errors and exit
$wp->do_log("LOG_DEBUG", "Finishing") unless ($wp->{daemon});

exit(0);