SR: cap interval, fair scheduling correction.

1 files changed, 42 insertions, 7 deletions

diff --git a/mailer.pl b/mailer.pl
index 41bd06e..20fc412 100644
--- a/mailer.pl
+++ b/mailer.pl
@@ -16,6 +16,8 @@ my $subject     = 'Daily word';
 my $sendmail    = '/usr/sbin/sendmail';
 my $syslog_tag  = 'lex-mail';
 
+my $max_interval = 365; # Upper bound limit (1 year)
+
 # Connect to /dev/log before pledge/unveil so no late 'unix' 
 # socket creation occurs
 openlog($syslog_tag, 'ndelay,pid', LOG_MAIL);
@@ -98,12 +100,34 @@ foreach my $file (@current_files) {
 	}
 }
 
-# Select candidate file (spaced repetition) 
+# Select candidate file (spaced repetition + fair scheduling) 
 my @due_files = grep { $state{$_}{next_due} le $today } @current_files;
 
 my $selected_file;
-if (@due_files) {
-	$selected_file = $due_files[rand @due_files];
+if (@due_files == 1) {
+	$selected_file = $due_files[0];
+} elsif (@due_files > 1) {
+	# Weighted random choice: files with fewer reviews get higher probability weights
+	my %weights;
+	my $total_weight = 0;
+	
+	foreach my $file (@due_files) {
+		# Inversely proportional weight (1 / (reviews + 1))
+		my $w = 1.0 / ($state{$file}{reviews} + 1);
+		$weights{$file} = $w;
+		$total_weight += $w;
+	}
+
+	my $rand_point = rand($total_weight);
+	my $accum = 0;
+	foreach my $file (@due_files) {
+		$accum += $weights{$file};
+		if ($rand_point <= $accum) {
+			$selected_file = $file;
+			last;
+		}
+	}
+	$selected_file //= $due_files[-1]; # Fallback
 } else {
 	@current_files = sort { $state{$a}{next_due} cmp $state{$b}{next_due} } @current_files;
 	$selected_file = $current_files[0];
@@ -150,6 +174,11 @@ if ($item->{reviews} == 0) {
 	$interval = int($interval * $factor);
 }
 
+# Cap interval
+if ($interval > $max_interval) {
+	$interval = $max_interval;
+}
+
 $item->{interval} = $interval;
 $item->{reviews} += 1;
 
@@ -161,15 +190,21 @@ foreach my $file (keys %state) {
 	delete $state{$file} unless $active_files{$file};
 }
 
+# Atomic write using a temporary state file
+my $tmp_file = "$state_file.tmp";
 my $out_fh;
-if (!open($out_fh, '>', $state_file)) {
-	log_die("Cannot write to $state_file: $!");
+if (!open($out_fh, '>', $tmp_file)) {
+	log_die("Cannot write to $tmp_file: $!");
 }
 foreach my $file (keys %state) {
 	my $i = $state{$file};
 	print $out_fh join("\t", $file, $i->{next_due}, $i->{interval}, $i->{reviews}, $i->{factor}), "\n";
 }
-close($out_fh);
+close($out_fh) or log_die("Error closing $tmp_file: $!");
+
+if (!rename($tmp_file, $state_file)) {
+	log_die("Cannot atomic swap $tmp_file to $state_file: $!");
+}
 
 syslog(LOG_INFO, "Mailed %s to %s (next due: %s)", $selected_file, $to, $item->{next_due});
-closelog();
+closelog();
\ No newline at end of file