#!/usr/bin/perl
  # SPDX-License-Identifier: GPL-2.0
  
  use strict;
  use Pod::Usage;
  use Getopt::Long;
  use File::Find;
  use Fcntl ':mode';

  use Cwd 'abs_path';

  
  my $help;
  my $man;
  my $debug;
  my $arch;
  my $feat;

  
  my $basename = abs_path($0);
  $basename =~ s,/[^/]+$,/,;
  
  my $prefix=$basename . "../Documentation/features";

  # Used only at for full features output. The script will auto-adjust
  # such values for the minimal possible values
  my $status_size = 1;
  my $description_size = 1;

  GetOptions(
  	"debug|d+" => \$debug,
  	"dir=s" => \$prefix,
  	'help|?' => \$help,
  	'arch=s' => \$arch,
  	'feat=s' => \$feat,

  	'feature=s' => \$feat,

  	man => \$man
  ) or pod2usage(2);
  
  pod2usage(1) if $help;
  pod2usage(-exitstatus => 0, -verbose => 2) if $man;

  pod2usage(1) if (scalar @ARGV < 1 || @ARGV > 2);

  
  my ($cmd, $arg) = @ARGV;

  pod2usage(2) if ($cmd ne "current" && $cmd ne "rest" && $cmd ne "validate"
  		&& $cmd ne "ls" && $cmd ne "list");

  
  require Data::Dumper if ($debug);
  
  my %data;
  my %archs;
  
  #
  # Displays an error message, printing file name and line
  #
  sub parse_error($$$$) {
  	my ($file, $ln, $msg, $data) = @_;
  
  	$data =~ s/\s+$/
  /;
  
  	print STDERR "Warning: file $file#$ln:
  \t$msg";
  
  	if ($data ne "") {
  		print STDERR ". Line
  \t\t$data";
  	} else {
  	    print STDERR "
  ";
  	}
  }
  
  #
  # Parse a features file, storing its contents at %data
  #
  
  my $h_name = "Feature";
  my $h_kconfig = "Kconfig";
  my $h_description = "Description";
  my $h_subsys = "Subsystem";
  my $h_status = "Status";
  my $h_arch = "Architecture";
  
  my $max_size_name = length($h_name);
  my $max_size_kconfig = length($h_kconfig);
  my $max_size_description = length($h_description);
  my $max_size_subsys = length($h_subsys);
  my $max_size_status = length($h_status);

  
  my $max_size_arch = 0;
  my $max_size_arch_with_header;
  my $max_description_word = 0;

  
  sub parse_feat {
  	my $file = $File::Find::name;
  
  	my $mode = (stat($file))[2];
  	return if ($mode & S_IFDIR);
  	return if ($file =~ m,($prefix)/arch-support.txt,);
  	return if (!($file =~ m,arch-support.txt$,));
  
  	my $subsys = "";
  	$subsys = $2 if ( m,.*($prefix)/([^/]+).*,);
  
  	if (length($subsys) > $max_size_subsys) {
  		$max_size_subsys = length($subsys);
  	}
  
  	my $name;
  	my $kconfig;
  	my $description;
  	my $comments = "";
  	my $last_status;
  	my $ln;
  	my %arch_table;
  
  	print STDERR "Opening $file
  " if ($debug > 1);
  	open IN, $file;
  
  	while(<IN>) {
  		$ln++;
  
  		if (m/^\#\s+Feature\s+name:\s*(.*\S)/) {
  			$name = $1;
  			if (length($name) > $max_size_name) {
  				$max_size_name = length($name);
  			}
  			next;
  		}
  		if (m/^\#\s+Kconfig:\s*(.*\S)/) {
  			$kconfig = $1;
  			if (length($kconfig) > $max_size_kconfig) {
  				$max_size_kconfig = length($kconfig);
  			}
  			next;
  		}
  		if (m/^\#\s+description:\s*(.*\S)/) {
  			$description = $1;
  			if (length($description) > $max_size_description) {
  				$max_size_description = length($description);
  			}

  
  			foreach my $word (split /\s+/, $description) {
  				if (length($word) > $max_description_word) {
  					$max_description_word = length($word);
  				}
  			}

  			next;
  		}
  		next if (m/^\\s*$/);
  		next if (m/^\s*\-+\s*$/);
  		next if (m/^\s*\|\s*arch\s*\|\s*status\s*\|\s*$/);
  
  		if (m/^\#\s*(.*)/) {
  			$comments .= "$1
  ";
  			next;
  		}
  		if (m/^\s*\|\s*(\S+):\s*\|\s*(\S+)\s*\|\s*$/) {
  			my $a = $1;
  			my $status = $2;
  
  			if (length($status) > $max_size_status) {
  				$max_size_status = length($status);
  			}
  			if (length($a) > $max_size_arch) {
  				$max_size_arch = length($a);
  			}
  
  			$status = "---" if ($status =~ m/^\.\.$/);
  
  			$archs{$a} = 1;
  			$arch_table{$a} = $status;
  			next;
  		}
  
  		#Everything else is an error
  		parse_error($file, $ln, "line is invalid", $_);
  	}
  	close IN;
  
  	if (!$name) {
  		parse_error($file, $ln, "Feature name not found", "");
  		return;
  	}
  
  	parse_error($file, $ln, "Subsystem not found", "") if (!$subsys);
  	parse_error($file, $ln, "Kconfig not found", "") if (!$kconfig);
  	parse_error($file, $ln, "Description not found", "") if (!$description);
  
  	if (!%arch_table) {
  		parse_error($file, $ln, "Architecture table not found", "");
  		return;
  	}
  
  	$data{$name}->{where} = $file;
  	$data{$name}->{subsys} = $subsys;
  	$data{$name}->{kconfig} = $kconfig;
  	$data{$name}->{description} = $description;
  	$data{$name}->{comments} = $comments;
  	$data{$name}->{table} = \%arch_table;

  
  	$max_size_arch_with_header = $max_size_arch + length($h_arch);

  }
  
  #
  # Output feature(s) for a given architecture
  #
  sub output_arch_table {
  	my $title = "Feature status on $arch architecture";
  
  	print "=" x length($title) . "
  ";
  	print "$title
  ";
  	print "=" x length($title) . "
  
  ";
  
  	print "=" x $max_size_subsys;
  	print "  ";
  	print "=" x $max_size_name;
  	print "  ";
  	print "=" x $max_size_kconfig;
  	print "  ";
  	print "=" x $max_size_status;
  	print "  ";
  	print "=" x $max_size_description;
  	print "
  ";
  	printf "%-${max_size_subsys}s  ", $h_subsys;
  	printf "%-${max_size_name}s  ", $h_name;
  	printf "%-${max_size_kconfig}s  ", $h_kconfig;
  	printf "%-${max_size_status}s  ", $h_status;
  	printf "%-${max_size_description}s
  ", $h_description;
  	print "=" x $max_size_subsys;
  	print "  ";
  	print "=" x $max_size_name;
  	print "  ";
  	print "=" x $max_size_kconfig;
  	print "  ";
  	print "=" x $max_size_status;
  	print "  ";
  	print "=" x $max_size_description;
  	print "
  ";
  
  	foreach my $name (sort {
  				($data{$a}->{subsys} cmp $data{$b}->{subsys}) ||

  				("\L$a" cmp "\L$b")

  			       } keys %data) {
  		next if ($feat && $name ne $feat);
  
  		my %arch_table = %{$data{$name}->{table}};
  		printf "%-${max_size_subsys}s  ", $data{$name}->{subsys};
  		printf "%-${max_size_name}s  ", $name;
  		printf "%-${max_size_kconfig}s  ", $data{$name}->{kconfig};
  		printf "%-${max_size_status}s  ", $arch_table{$arch};

  		printf "%-s
  ", $data{$name}->{description};

  	}
  
  	print "=" x $max_size_subsys;
  	print "  ";
  	print "=" x $max_size_name;
  	print "  ";
  	print "=" x $max_size_kconfig;
  	print "  ";
  	print "=" x $max_size_status;
  	print "  ";
  	print "=" x $max_size_description;
  	print "
  ";
  }
  
  #

  # list feature(s) for a given architecture
  #
  sub list_arch_features {
  	print "#
  # Kernel feature support matrix of the '$arch' architecture:
  #
  ";
  
  	foreach my $name (sort {
  				($data{$a}->{subsys} cmp $data{$b}->{subsys}) ||
  				("\L$a" cmp "\L$b")
  			       } keys %data) {
  		next if ($feat && $name ne $feat);
  
  		my %arch_table = %{$data{$name}->{table}};
  
  		my $status = $arch_table{$arch};
  		$status = " " x ((4 - length($status)) / 2) . $status;
  
  		printf " %${max_size_subsys}s/ ", $data{$name}->{subsys};
  		printf "%-${max_size_name}s: ", $name;
  		printf "%-5s|   ", $status;
  		printf "%${max_size_kconfig}s # ", $data{$name}->{kconfig};
  		printf " %s
  ", $data{$name}->{description};
  	}
  }
  
  #

  # Output a feature on all architectures
  #
  sub output_feature {
  	my $title = "Feature $feat";
  
  	print "=" x length($title) . "
  ";
  	print "$title
  ";
  	print "=" x length($title) . "
  
  ";
  
  	print ":Subsystem: $data{$feat}->{subsys} 
  " if ($data{$feat}->{subsys});
  	print ":Kconfig: $data{$feat}->{kconfig} 
  " if ($data{$feat}->{kconfig});
  
  	my $desc = $data{$feat}->{description};
  	$desc =~ s/^([a-z])/\U$1/;
  	$desc =~ s/\.?\s*//;
  	print "
  $desc.
  
  ";
  
  	my $com = $data{$feat}->{comments};
  	$com =~ s/^\s+//;
  	$com =~ s/\s+$//;
  	if ($com) {
  		print "Comments
  ";
  		print "--------
  
  ";
  		print "$com
  
  ";
  	}

  	print "=" x $max_size_arch_with_header;

  	print "  ";
  	print "=" x $max_size_status;
  	print "
  ";
  
  	printf "%-${max_size_arch}s  ", $h_arch;
  	printf "%-${max_size_status}s", $h_status . "
  ";

  	print "=" x $max_size_arch_with_header;

  	print "  ";
  	print "=" x $max_size_status;
  	print "
  ";
  
  	my %arch_table = %{$data{$feat}->{table}};
  	foreach my $arch (sort keys %arch_table) {
  		printf "%-${max_size_arch}s  ", $arch;
  		printf "%-${max_size_status}s
  ", $arch_table{$arch};
  	}

  	print "=" x $max_size_arch_with_header;

  	print "  ";
  	print "=" x $max_size_status;
  	print "
  ";
  }
  
  #
  # Output all features for all architectures
  #

  sub matrix_lines($$$) {
  	my $desc_size = shift;
  	my $status_size = shift;

  	my $header = shift;

  	my $fill;
  	my $ln_marker;
  
  	if ($header) {
  		$ln_marker = "=";
  	} else {
  		$ln_marker = "-";
  	}

  	$fill = $ln_marker;

  	print "+";

  	print $fill x $max_size_name;

  	print "+";

  	print $fill x $desc_size;

  	print "+";

  	print $ln_marker x $status_size;

  	print "+
  ";

  }
  
  sub output_matrix {

  	my $title = "Feature status on all architectures";

  	my $notcompat = "Not compatible";

  
  	print "=" x length($title) . "
  ";
  	print "$title
  ";
  	print "=" x length($title) . "
  
  ";

  	my $desc_title = "$h_kconfig / $h_description";
  
  	my $desc_size = $max_size_kconfig + 4;

  	if (!$description_size) {
  		$desc_size = $max_size_description if ($max_size_description > $desc_size);
  	} else {
  		$desc_size = $description_size if ($description_size > $desc_size);
  	}
  	$desc_size = $max_description_word if ($max_description_word > $desc_size);

  	$desc_size = length($desc_title) if (length($desc_title) > $desc_size);

  	$max_size_status = length($notcompat) if (length($notcompat) > $max_size_status);
  
  	# Ensure that the status will fit
  	my $min_status_size = $max_size_status + $max_size_arch + 6;
  	$status_size = $min_status_size if ($status_size < $min_status_size);

  	my $cur_subsys = "";
  	foreach my $name (sort {
  				($data{$a}->{subsys} cmp $data{$b}->{subsys}) or

  				("\L$a" cmp "\L$b")

  			       } keys %data) {

  		if ($cur_subsys ne $data{$name}->{subsys}) {
  			if ($cur_subsys ne "") {
  				printf "
  ";
  			}

  			$cur_subsys = $data{$name}->{subsys};

  			my $title = "Subsystem: $cur_subsys";
  			print "$title
  ";
  			print "=" x length($title) . "
  
  ";

  			matrix_lines($desc_size, $status_size, 0);
  
  			printf "|%-${max_size_name}s", $h_name;
  			printf "|%-${desc_size}s", $desc_title;

  			printf "|%-${status_size}s|
  ", "Status per architecture";
  			matrix_lines($desc_size, $status_size, 1);

  		}

  		my %arch_table = %{$data{$name}->{table}};

  		my $cur_status = "";

  		my (@lines, @descs);

  		my $line = "";
  		foreach my $arch (sort {

  					($arch_table{$b} cmp $arch_table{$a}) or

  					("\L$a" cmp "\L$b")
  				       } keys %arch_table) {
  
  			my $status = $arch_table{$arch};
  
  			if ($status eq "---") {

  				$status = $notcompat;

  			}
  
  			if ($status ne $cur_status) {
  				if ($line ne "") {
  					push @lines, $line;
  					$line = "";
  				}
  				$line = "- **" . $status . "**: " . $arch;
  			} elsif (length($line) + length ($arch) + 2 < $status_size) {
  				$line .= ", " . $arch;

  			} else {

  				push @lines, $line;
  				$line = "  " . $arch;
  			}
  			$cur_status = $status;
  		}
  		push @lines, $line if ($line ne "");

  		my $description = $data{$name}->{description};
  		while (length($description) > $desc_size) {
  			my $d = substr $description, 0, $desc_size;
  
  			# Ensure that it will end on a space
  			# if it can't, it means that the size is too small
  			# Instead of aborting it, let's print what we have
  			if (!($d =~ s/^(.*)\s+.*/$1/)) {
  				$d = substr $d, 0, -1;
  				push @descs, "$d\\";
  				$description =~ s/^\Q$d\E//;
  			} else {
  				push @descs, $d;
  				$description =~ s/^\Q$d\E\s+//;
  			}
  		}
  		push @descs, $description;
  
  		# Ensure that the full description will be printed
  		push @lines, "" while (scalar(@lines) < 2 + scalar(@descs));

  		my $ln = 0;
  		for my $line(@lines) {
  			if (!$ln) {
  				printf "|%-${max_size_name}s", $name;
  				printf "|%-${desc_size}s", "``" . $data{$name}->{kconfig} . "``";

  			} elsif ($ln >= 2 && scalar(@descs)) {

  				printf "|%-${max_size_name}s", "";

  				printf "|%-${desc_size}s", shift @descs;

  			} else {

  				printf "|%-${max_size_name}s", "";

  				printf "|%-${desc_size}s", "";

  			}

  
  			printf "|%-${status_size}s|
  ", $line;
  
  			$ln++;

  		}

  		matrix_lines($desc_size, $status_size, 0);

  	}

  }
  
  
  #
  # Parses all feature files located at $prefix dir
  #
  find({wanted =>\&parse_feat, no_chdir => 1}, $prefix);
  
  print STDERR Data::Dumper->Dump([\%data], [qw(*data)]) if ($debug);
  
  #
  # Handles the command
  #
  if ($cmd eq "current") {
  	$arch = qx(uname -m | sed 's/x86_64/x86/' | sed 's/i386/x86/');
  	$arch =~s/\s+$//;
  }

  if ($cmd eq "ls" or $cmd eq "list") {
  	if (!$arch) {
  		$arch = qx(uname -m | sed 's/x86_64/x86/' | sed 's/i386/x86/');
  		$arch =~s/\s+$//;
  	}
  
  	list_arch_features;
  
  	exit;
  }

  if ($cmd ne "validate") {
  	if ($arch) {
  		output_arch_table;
  	} elsif ($feat) {
  		output_feature;
  	} else {
  		output_matrix;
  	}
  }
  
  __END__
  
  =head1 NAME
  
  get_feat.pl - parse the Linux Feature files and produce a ReST book.
  
  =head1 SYNOPSIS

  B<get_feat.pl> [--debug] [--man] [--help] [--dir=<dir>] [--arch=<arch>]
  	       [--feature=<feature>|--feat=<feature>] <COMAND> [<ARGUMENT>]

  
  Where <COMMAND> can be:
  
  =over 8

  B<current>               - output table in ReST compatible ASCII format
  			   with features for this machine's architecture
  
  B<rest>                  - output table(s)  in ReST compatible ASCII format
  			   with features in ReST markup language. The output
  			   is affected by --arch or --feat/--feature flags.

  B<validate>              - validate the contents of the files under
  			   Documentation/features.

  B<ls> or B<list>         - list features for this machine's architecture,
  			   using an easier to parse format.
  			   The output is affected by --arch flag.

  
  =back
  
  =head1 OPTIONS
  
  =over 8
  
  =item B<--arch>
  
  Output features for an specific architecture, optionally filtering for
  a single specific feature.

  =item B<--feat> or B<--feature>

  Output features for a single specific feature.

  
  =item B<--dir>
  
  Changes the location of the Feature files. By default, it uses
  the Documentation/features directory.
  
  =item B<--debug>
  
  Put the script in verbose mode, useful for debugging. Can be called multiple
  times, to increase verbosity.
  
  =item B<--help>
  
  Prints a brief help message and exits.
  
  =item B<--man>
  
  Prints the manual page and exits.
  
  =back
  
  =head1 DESCRIPTION
  
  Parse the Linux feature files from Documentation/features (by default),
  optionally producing results at ReST format.
  
  It supports output data per architecture, per feature or a
  feature x arch matrix.
  
  When used with B<rest> command, it will use either one of the tree formats:
  
  If neither B<--arch> or B<--feature> arguments are used, it will output a
  matrix with features per architecture.
  
  If B<--arch> argument is used, it will output the features availability for
  a given architecture.
  
  If B<--feat> argument is used, it will output the content of the feature
  file using ReStructured Text markup.
  
  =head1 BUGS
  
  Report bugs to Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
  
  =head1 COPYRIGHT
  
  Copyright (c) 2019 by Mauro Carvalho Chehab <mchehab+samsung@kernel.org>.
  
  License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>.
  
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.
  
  =cut