#!/usr/bin/perl -w

  # SPDX-License-Identifier: GPL-2.0

  
  use strict;

  my $P = $0;

  # sort comparison functions

  sub by_category($$) {
      my ($a, $b) = @_;
  
      $a = uc $a;
      $b = uc $b;
  
      # This always sorts last
      $a =~ s/THE REST/ZZZZZZ/g;
      $b =~ s/THE REST/ZZZZZZ/g;

      return $a cmp $b;
  }
  
  sub by_pattern($$) {
      my ($a, $b) = @_;
      my $preferred_order = 'MRPLSWTQBCFXNK';
  
      my $a1 = uc(substr($a, 0, 1));
      my $b1 = uc(substr($b, 0, 1));
  
      my $a_index = index($preferred_order, $a1);
      my $b_index = index($preferred_order, $b1);
  
      $a_index = 1000 if ($a_index == -1);
      $b_index = 1000 if ($b_index == -1);
  
      if (($a1 =~ /^F$/ && $b1 =~ /^F$/) ||
  	($a1 =~ /^X$/ && $b1 =~ /^X$/)) {
  	return $a cmp $b;
      }
  
      if ($a_index < $b_index) {
  	return -1;
      } elsif ($a_index == $b_index) {
  	return 0;
      } else {
  	return 1;
      }

  }

  sub trim {
      my $s = shift;
      $s =~ s/\s+$//;
      $s =~ s/^\s+//;
      return $s;
  }

  sub alpha_output {

      my ($hashref, $filename) = (@_);
  
      open(my $file, '>', "$filename") or die "$P: $filename: open failed - $!
  ";
      foreach my $key (sort by_category keys %$hashref) {

  	if ($key eq " ") {

  	    chomp $$hashref{$key};
  	    print $file $$hashref{$key};

  	} else {

  	    print $file "
  " . $key . "
  ";
  	    foreach my $pattern (sort by_pattern split('
  ', %$hashref{$key})) {
  		print $file ($pattern . "
  ");

  	    }
  	}

      }

      close($file);

  }
  
  sub file_input {

      my ($hashref, $filename) = (@_);

      my $lastline = "";
      my $case = " ";

      $$hashref{$case} = "";
  
      open(my $file, '<', "$filename") or die "$P: $filename: open failed - $!
  ";

      while (<$file>) {

          my $line = $_;
  
          # Pattern line?
          if ($line =~ m/^([A-Z]):\s*(.*)/) {
              $line = $1 . ":\t" . trim($2) . "
  ";
              if ($lastline eq "") {

                  $$hashref{$case} = $$hashref{$case} . $line;

                  next;
              }
              $case = trim($lastline);

              exists $$hashref{$case} and die "Header '$case' already exists";
              $$hashref{$case} = $line;

              $lastline = "";
              next;
          }
  
          if ($case eq " ") {

              $$hashref{$case} = $$hashref{$case} . $lastline;

              $lastline = $line;
              next;
          }
          trim($lastline) eq "" or die ("Odd non-pattern line '$lastline' for '$case'");
          $lastline = $line;
      }

      $$hashref{$case} = $$hashref{$case} . $lastline;
      close($file);

  }

  my %hash;

  my %new_hash;

  
  file_input(\%hash, "MAINTAINERS");

  
  foreach my $type (@ARGV) {
      foreach my $key (keys %hash) {
  	if ($key =~ /$type/ || $hash{$key} =~ /$type/) {
  	    $new_hash{$key} = $hash{$key};
  	    delete $hash{$key};
  	}
      }
  }

  alpha_output(\%hash, "MAINTAINERS.new");

  alpha_output(\%new_hash, "SECTION.new");

  exit(0);