Default displays changed. Added fallback action.

If a config is selected for which the displays do not exist, either bail
or if in recovery mode, restore 'detached'. The latter was added in
anticipation of the swayidle script which will attempt to restore a
layout that may no longer be possible. Since swayidle disables dpms, it
must allow a backup display to come live if the last logged layout is
not possible.

sway/displays.pl

@@ -36,6 +36,9 @@ my $waybar_temporary = '/tmp';
 # File to log and recover last used layout name
 my $last = "$ENV{'HOME'}/.config/last_display";
 
+# File to log active outputs (used by swayidle, and to attempt to restore
+my $active_outputs = "$ENV{'HOME'}/.config/active_outputs";
+
 ########################################################################
 # Display Serials and Names
 ########################################################################
@@ -45,9 +48,12 @@ my $last = "$ENV{'HOME'}/.config/last_display";
 #   $ swaymsg -t get_outputs
 #   Output eDP-1 'Unknown 0x057D *0x00000000*'
 my %outputs = (
-        '0x00000101' => 'Sam',
+	#'0x00000101' => 'Sam',
+	'HTNCB00059' => 'Sam',
+	#'3CQ3310Q1Q' => 'Sam',
         '3CQ4342S6W' => 'HP-1',
-        '3CQ3310Q1Q' => 'HP-2',
+        '0x00000101' => 'HP-2',
+	#'3CQ3310Q1Q' => 'HP-2',
         '0x00000000' => 'LVDS'
 );
 
@@ -93,7 +99,7 @@ my %configs = (
                         'on' => 1,
                         'width' => 1920,
                         'height' => 1080,
-                        'x' => 0,
+                        'x' => 1920,
                         'y' => 1200,
                         'rotate' => 0,
                         'waybar' => 'top'
@@ -102,7 +108,7 @@ my %configs = (
                         'on' => 1,
                         'width' => 1920,
                         'height' => 1080,
-                        'x' => 1920,
+                        'x' => 0,
                         'y' => 1200,
                         'rotate' => 0,
                         'waybar' => 'top'
@@ -153,6 +159,7 @@ use strict;
 use warnings;
 
 my $waybar_only = 0;
+my $restore = 0; # Set if no config is provided. Requires validation.
 my $config;
 
 if (scalar(@ARGV)) {
@@ -176,13 +183,19 @@ unless (defined $config) {
         $config = <$fh>;
         close($fh);
         chomp $config;
+	$restore = 1;
 }
 
 # Bail if requested config doesn't exist
-unless (defined $configs{$config}) {
+if (!defined($configs{$config})) {
+	if ($restore) {
+		# If restoration is attempted with invalid config, just enable eDP-1
+		$config = 'detached';
+	} else {
         	die "$config is not a defined configuration: "
                 	. join(', ', keys %configs) . "\n";
 	}
+}
 
 # Write config that is to be used so that it can be recovered as default
 open(my $fh, '>', $last) ||
@@ -190,6 +203,7 @@ open(my $fh, '>', $last) ||
 print $fh $config;
 close($fh);
 
+
 # Fetch connected displays
 use JSON::XS;
 my $json = JSON::XS->new();
@@ -224,6 +238,24 @@ for (my $i = 0; $i < scalar(@$displays); $i++) {
 
 }
 
+# Verify that all requested displays are actually available
+my @unavailable;
+foreach my $output (keys %$on) {
+	my $found = 0;
+	foreach my $o (keys %outputs) {
+		if ($outputs{$o} eq $output) {
+			$found = 1;
+			last;
+		}
+	}
+	unless ($found) {
+		push @unavailable, $output;
+	}
+}
+if (scalar(@unavailable)) {
+	die "Config requires unavailable output(s) " . join(', ', @unavailable) . "\n";
+}
+
 # Skip enabling/disabling displays if only running waybar (re)start
 unless ($waybar_only) {
         # Number of simultaneous outputs is limited by gpu, so disabled displays
@@ -279,8 +311,10 @@ $template =~ s/^[^\[\{]*\[(.*)\]$/$1/s;
 my $waybar = '';
 
 # Configure each enabled display
+my @active;
 foreach my $out (keys %$on) {
 
+        push @active, $on->{$out}->{output};
 	unless ($waybar_only) {
                 # Build command, starting by enabling and powering on
                 my $cmd = "sway output $on->{$out}->{output} enable dpms on";
@@ -334,6 +368,11 @@ foreach my $out (keys %$on) {
         }
 }
 
+open($fh, '>', $active_outputs);
+print $fh join(' ', @active);
+close($fh);
+
+
 # Restore array formatting
 $waybar = '[' . $waybar . ']';
 
@@ -348,7 +387,7 @@ unless ($pid) {
         open ($fh, '>', $tmp);
         print $fh $waybar;
         close $fh;
-        `nohup waybar --config=$tmp`;
+        `nohup waybar --config=$tmp >> waybar.log`;
 
         # Remove config
         unlink $tmp;