From 508e3f0516581b06c04e5dc3123db79cb4e713d6 Mon Sep 17 00:00:00 2001
From: John Mertz <git@john.me.tz>
Date: Sat, 17 Sep 2022 15:22:18 -0400
Subject: [PATCH] Track backlight brightness better to allow reverting (by
 screensaver, etc.)

---
 thinkpad/blc.pl | 52 +++++++++++++++++++++++++++----------------------
 1 file changed, 29 insertions(+), 23 deletions(-)

diff --git a/thinkpad/blc.pl b/thinkpad/blc.pl
index d9ba621..d0fb906 100755
--- a/thinkpad/blc.pl
+++ b/thinkpad/blc.pl
@@ -66,13 +66,13 @@
 # Files containing current and max brightness values
 my $cur_file = "/sys/class/backlight/intel_backlight/brightness";
 my $max_file = "/sys/class/backlight/intel_backlight/max_brightness";
-my $last_file = "/home/jpm/.config/blc.last";
+my $cur_log = $ENV{HOME}."/.spool/blc.current";
+my $last_log = $ENV{HOME}."/.spool/blc.last";
 
 sub to_percent
 {
         my $value = shift;
-        $value = int($value/get_max()*100);
-        return $value . '%';
+        return int($value/get_max()*100);
 }
 
 sub get_offset
@@ -108,7 +108,26 @@ sub writable
         if (! -w $cur_file) {
                 die "You don't have permission to write $cur_file\n";
         }
-	return 1;
+        return 1;
+}
+
+sub logger
+{
+        my ($current, $target) = @_;
+        open(my $fh,'>',$last_log);
+        print $fh to_percent($current);
+        close($fh);
+        open($fh,'>',$cur_log);
+        print $fh to_percent($target);
+        close($fh);
+}
+
+sub writef
+{
+        my $target = shift;
+        open(my $fh,'>',$cur_file);
+        print $fh $target;
+        close($fh);
 }
 
 sub increment
@@ -120,9 +139,6 @@ sub increment
                 if ($target > $max) {
                         $target = $max;
                 }
-                open(my $c,'>',"$cur_file");
-                print $c $target;
-                close $c;
                 return $target;
         }
 }
@@ -136,9 +152,7 @@ sub decrement
                 if ($target < $min) {
                         $target = $min;
                 }
-                open(my $c,'>',"$cur_file");
-                print $c $target;
-                close $c;
+                set($target);
                 return $target;
         }
 }
@@ -147,18 +161,15 @@ sub set
 {
         my $value = shift;
         if (writable()) {
-                $current = get_current();
+                my $current = get_current();
+                logger($current,$value);
                 if ($value > $current) {
                         for (my $i=$current;$i<=$value;$i++) {
-                                open(my $c,'>',"$cur_file");
-                                print $c $i;
-                                close $c;
+                                writef($i);
                         }
                 } else {
                         for (my $i=$current;$i>=$value;$i--) {
-                                open(my $c,'>',"$cur_file");
-                                print $c $i;
-                                close $c;
+                                writef($i);
                         }
                 }
                 return $value;
@@ -243,7 +254,7 @@ my $operation_found = 0;
 if (scalar @ARGV) {
         while ($arg = shift) {
                 if ($arg eq '%') {
-                        push @output,int(get_current()/get_max()*100);
+                        push @output,to_percent(get_current);
                 } elsif ($arg eq '^') {
                         push @output,get_max();
                 } elsif ($arg eq '==') {
@@ -341,11 +352,6 @@ if (scalar @ARGV) {
         );
 }
 
-open(my $fh,'>',$last_file);
-print $fh get_current();
-close($fh);
-
-print $_."\n" foreach(@output);
 if ($silent) {
         exit();
 } elsif ($notify) {