#!/usr/bin/env perl

use strict;
use warnings;
use POSIX;

use lib "$ENV{HOME}/perl5/lib/perl5";

our $debug = 1;	# For testing, will output configuration and errors if true
our %settings;
our @e;
our $pidfile = "/tmp/$ENV{USER}-wallpaper.pid";

use AnyEvent::Sway;
our $s = AnyEvent::Sway->new();

our $o = $s->get_outputs->recv();
die "No outputs detected.\n" unless (scalar(@$o));

sub usage()
{
        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
--help		This menu
-h\n");
        exit(0);
}

# SIGUSR reset the timer, force immediate reload, continue looping
$SIG{USR1} = sub {
        alarm 0;
        run(%settings);
};

# SIGTERM reset the timer, clean pid, and allow for the main loop to finish run
$SIG{TERM} = sub {
        alarm 0;
        clean();
        $settings{daemon} = 0;
};

# SIGKILL clean pid then exit immediately
$SIG{KILL} = sub {
        clean();
        exit(0);
};

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

sub choose_image
{
        my @w = glob("$settings{path}/*");
        return undef unless (scalar(@w));

        my @i;
        foreach (@w) {
                if (-d "$settings{path}/$_") {
                        next;
                }
                if ($_ =~ m/\.(png|jpg)$/) {
                        push(@i,$_);
                }
        }

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

sub get_size
{
        my $target = shift;
        foreach my $output (@$o) {
                if ($output->{'name'} eq $target) {
                        return (
                                #$output->{'current_mode'}->{'width'},
                                #$output->{'current_mode'}->{'height'}
                                $output->{'rect'}->{'width'},
                                $output->{'rect'}->{'height'}
                        );
                }
        }
        return undef;
}

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

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

        use Image::Magick;
        my $im = Image::Magick->new();

        $im->Read($image);
        my ($iw, $ih) = $im->Get("columns", "rows");

        # Return full size if it is smaller in either dimension then the output
        if ($iw <= $ow || $ih <= $oh) {
                print "Not cropping $image because it is too small\n";
                $cropped =~ s#-cropped\.([^\.]+)$#\.$1#;
                use File::Copy;
                File::Copy::copy($image,$cropped);
                return $cropped if (-e $cropped);
                return undef;
        }

        print "Image size: $iw $ih\n";
        print "output size: $ow $oh\n";

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

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

sub get_active
{
        my @targets;
        foreach (@$o) {
                push (@targets, $_->{name});
        }
        return @targets;
}

sub set_background
{
        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";
        print "Running $cmd\n";
        my $ret = $s->message(0,$cmd)->recv;
        if ($ret->[0]->{success}) {
                print "Success!\n";
                return undef;
        }
        return "Failed to run Sway IPC command '$cmd'";
}

sub run
{
        my @err;
        # Local copy of targets so that it will re-check active every time
        my @t = $settings{targets} if (defined($settings{targets}));
        unless (scalar(@t)) {
                @t = get_active();
                push(@err, "No target outputs") unless (scalar(@t));
        }
        foreach my $a (@t) {
                my $image = choose_image($settings{path});
                if (defined($image)) {
                        if ( -r "$image" ) {
                        print "selected $image\n";
                                my $cropped;
                                if ($settings{crop}) {
                                        if ($settings{debug}) {
                                                print "Cropping image for '$a' using '$image'\n";
                                        }
                                        my ($ow, $oh) = get_size($a);
                                        $cropped = crop($image, $ow, $oh);
                                        unless ($cropped) {
                                                push(@err, "Failed to generate cropped image") unless ($cropped);
                                                next;
                                        }
                                } else {
                                        $cropped = $image;
                                }
                                my $e = set_background($a,$cropped);
                                push(@err, $e) if (defined($e));
                                if ($settings{crop}) {
                                        print "Deleting $cropped\n";
                                        #unlink($cropped) || push(@err, "Failed to delete $cropped after setting: $!");
                                }
                        } else {
                                push(@err, "$a: Unable to read image $image");
                        }
                } else {
                        push(@err, "$a: Unable to select image from $settings{path}");
                }
        }
        if ($settings{debug} && $settings{daemon}) {
                print STDERR join("\n",@err);
        } else {
                @e = @err;
        }
}

################################################################################
# Collect arguments
################################################################################
my @targets;
my $daemon;
my $delay;
my $crop;
my $path;
while (my $arg = shift(@ARGV)) {
        if ($arg eq '-h' || $arg eq '--help') {
                usage();
        } elsif ($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;
                $daemon = 1;
        } elsif ($arg eq '-d') {
                die "Redundant argument '$arg'. Daemon mode already set.\n" if ($daemon);
                if ($ARGV[0] =~ m/^\d+$/) {
                        $delay = shift(@ARGV);
                }
                $daemon = 1;
        } elsif ($arg eq '--nocrop' || $arg eq '-') {
                die "Redundant argument '$arg'. No-crop already set.\n" unless ($crop);
        } else {
                push(@targets,$arg);
        }
}

################################################################################
# Validate 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);

if (scalar(@targets)) {
        my @kept;
        foreach my $t (@targets) {
                my $hit = 0;
                foreach (@$o) {
                        if ($_->{name} eq $t) {
                                push(@kept, $t);
                                $hit++;
                                last;
                        }
                }
                print STDERR "Requested output '$t' not found\n" unless ($hit);
        }
        die "None of the requested outputs are active" unless (scalar(@kept));
        @targets = @kept;
}

$settings{targets} = @targets || undef;
$settings{daemon}  = $daemon || 0;
$settings{path}    = $path || "$ENV{HOME}/wallpapers";
$settings{crop}    = $crop || 1;
$settings{delay}   = $delay || 300;
$settings{debug}   = $debug || 0;

################################################################################
# For if daemonized
################################################################################

if ($settings{daemon}) {
        my $p = fork();
        if ($p) {
                if (open(my $fh, ">", $pidfile)) {
                        print $fh "$p" || die "Failed to write pid ($p) to pidfile $pidfile";
                        close($fh);
                } else {
                        print "Failed to open pidfile: $pidfile: $!\n";
                }
                exit(0);
        }
        #setpgrp;
        #setsid;
        umask 0;
        # TODO: configure systemD logging
}

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

do {
        run(%settings);
        if ($settings{daemon}) {
                my $normal = "reload wallpaper";
                eval {
                        $SIG{ALRM} = sub { print "$normal\n" };
                        alarm $settings{delay};
                        POSIX::pause();
                        alarm 0;
                };
                if ($@ && $@ !~ quotemeta($normal)) {
                        if ($settings{debug}) {
                                print $normal;
                        }
                }
        }
} while ($settings{daemon});

################################################################################
# If we made it to here, it was not daemonized. Output errors and exit
################################################################################

if (scalar(@e)) {
        die "Failure while not running as daemon:\n" .
                join("\n",@e);
}

exit(0);