#!/bin/sh
#! -*-perl-*-

# Generate a release announcement message.

# Copyright (C) 2002-2021 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# Written by Jim Meyering

# This is a prologue that allows to run a perl script as an executable
# on systems that are compliant to a POSIX version before POSIX:2017.
# On such systems, the usual invocation of an executable through execlp()
# or execvp() fails with ENOEXEC if it is a script that does not start
# with a #! line.  The script interpreter mentioned in the #! line has
# to be /bin/sh, because on GuixSD systems that is the only program that
# has a fixed file name.  The second line is essential for perl and is
# also useful for editing this file in Emacs.  The next two lines below
# are valid code in both sh and perl.  When executed by sh, they re-execute
# the script through the perl program found in $PATH.  The '-x' option
# is essential as well; without it, perl would re-execute the script
# through /bin/sh.  When executed by perl, the next two lines are a no-op.
eval 'exec perl -wSx "$0" "$@"'
     if 0;

my $VERSION = '2021-08-04 09:17'; # UTC
# The definition above must lie within the first 8 lines in order
# for the Emacs time-stamp write hook (at end) to update it.
# If you change this file with Emacs, please let the write hook
# do its job.  Otherwise, update this string manually.

my $copyright_year = '2021';

use strict;
use Getopt::Long;
use POSIX qw(strftime);

(my $ME = $0) =~ s|.*/||;

my %valid_release_types = map {$_ => 1} qw (alpha beta stable);
my @archive_suffixes = qw (tar.gz tar.bz2 tar.lz tar.lzma tar.xz);
my $srcdir = '.';

sub usage ($)
{
  my ($exit_code) = @_;
  my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR);
  if ($exit_code != 0)
    {
      print $STREAM "Try '$ME --help' for more information.\n";
    }
  else
    {
      my @types = sort keys %valid_release_types;
      print $STREAM <<EOF;
Usage: $ME [OPTIONS]
Generate an announcement message.  Run this from builddir.

OPTIONS:

These options must be specified:

   --release-type=TYPE          TYPE must be one of @types
   --package-name=PACKAGE_NAME
   --previous-version=VER
   --current-version=VER
   --gpg-key-id=ID         The GnuPG ID of the key used to sign the tarballs
   --url-directory=URL_DIR

The following are optional:

   --news=NEWS_FILE             include the NEWS section about this release
                                from this NEWS_FILE; accumulates.
   --srcdir=DIR                 where to find the NEWS_FILEs (default: $srcdir)
   --bootstrap-tools=TOOL_LIST  a comma-separated list of tools, e.g.,
                                autoconf,automake,bison,gnulib
   --gnulib-version=VERSION     report VERSION as the gnulib version, where
                                VERSION is the result of running git describe
                                in the gnulib source directory.
                                required if gnulib is in TOOL_LIST.
   --no-print-checksums         do not emit SHA1 or SHA256 checksums
   --archive-suffix=SUF         add SUF to the list of archive suffixes
   --mail-headers=HEADERS       a space-separated list of mail headers, e.g.,
                                To: x\@example.com Cc: y-announce\@example.com,...

   --help             display this help and exit
   --version          output version information and exit

EOF
    }
  exit $exit_code;
}


=item C<%size> = C<sizes (@file)>

Compute the sizes of the C<@file> and return them as a hash.  Return
C<undef> if one of the computation failed.

=cut

sub sizes (@)
{
  my (@file) = @_;

  my $fail = 0;
  my %res;
  foreach my $f (@file)
    {
      my $cmd = "du -h $f";
      my $t = `$cmd`;
      # FIXME-someday: give a better diagnostic, a la $PROCESS_STATUS
      $@
        and (warn "command failed: '$cmd'\n"), $fail = 1;
      chomp $t;
      $t =~ s/^\s*([\d.]+[MkK]).*/${1}B/;
      $res{$f} = $t;
    }
  return $fail ? undef : %res;
}

=item C<print_locations ($title, \@url, \%size, @file)

Print a section C<$title> dedicated to the list of <@file>, which
sizes are stored in C<%size>, and which are available from the C<@url>.

=cut

sub print_locations ($\@\%@)
{
  my ($title, $url, $size, @file) = @_;
  print "Here are the $title:\n";
  foreach my $url (@{$url})
    {
      for my $file (@file)
        {
          print "  $url/$file";
          print "   (", $$size{$file}, ")"
            if exists $$size{$file};
          print "\n";
        }
    }
  print "\n";
}

=item C<print_checksums (@file)

Print the SHA1 and SHA256 signature section for each C<@file>.

=cut

sub print_checksums (@)
{
  my (@file) = @_;

  print "Here are the SHA1 and SHA256 checksums:\n";
  print "\n";

  use Digest::file qw(digest_file_hex digest_file_base64);

  foreach my $f (@file)
    {
      print digest_file_hex($f, "SHA-1"), "  $f\n";
      print digest_file_base64($f, "SHA-256"), "  $f\n";
    }
  print "\nThe SHA256 checksum is base64 encoded, instead of the\n";
  print "hexadecimal encoding that most checksum tools default to.\n\n";
}

=item C<print_news_deltas ($news_file, $prev_version, $curr_version)

Print the section of the NEWS file C<$news_file> addressing changes
between versions C<$prev_version> and C<$curr_version>.

=cut

sub print_news_deltas ($$$)
{
  my ($news_file, $prev_version, $curr_version) = @_;

  my $news_name = $news_file;
  $news_name =~ s|^\Q$srcdir\E/||;

  print "\n$news_name\n\n";

  # Print all lines from $news_file, starting with the first one
  # that mentions $curr_version up to but not including
  # the first occurrence of $prev_version.
  my $in_items;

  my $re_prefix = qr/(?:\* )?(?:Noteworthy c|Major c|C)(?i:hanges)/;

  my $found_news;
  open NEWS, '<', $news_file
    or die "$ME: $news_file: cannot open for reading: $!\n";
  while (defined (my $line = <NEWS>))
    {
      if ( ! $in_items)
        {
          # Match lines like these:
          # * Major changes in release 5.0.1:
          # * Noteworthy changes in release 6.6 (2006-11-22) [stable]
          $line =~ /^$re_prefix.*(?:[^\d.]|$)\Q$curr_version\E(?:[^\d.]|$)/o
            or next;
          $in_items = 1;
          print $line;
        }
      else
        {
          # This regexp must not match version numbers in NEWS items.
          # For example, they might well say "introduced in 4.5.5",
          # and we don't want that to match.
          $line =~ /^$re_prefix.*(?:[^\d.]|$)\Q$prev_version\E(?:[^\d.]|$)/o
            and last;
          print $line;
          $line =~ /\S/
            and $found_news = 1;
        }
    }
  close NEWS;

  $in_items
    or die "$ME: $news_file: no matching lines for '$curr_version'\n";
  $found_news
    or die "$ME: $news_file: no news item found for '$curr_version'\n";
}

sub print_changelog_deltas ($$)
{
  my ($package_name, $prev_version) = @_;

  # Print new ChangeLog entries.

  # First find all CVS-controlled ChangeLog files.
  use File::Find;
  my @changelog;
  find ({wanted => sub {$_ eq 'ChangeLog' && -d 'CVS'
                          and push @changelog, $File::Find::name}},
        '.');

  # If there are no ChangeLog files, we're done.
  @changelog
    or return;
  my %changelog = map {$_ => 1} @changelog;

  # Reorder the list of files so that if there are ChangeLog
  # files in the specified directories, they're listed first,
  # in this order:
  my @dir = qw ( . src lib m4 config doc );

  # A typical @changelog array might look like this:
  # ./ChangeLog
  # ./po/ChangeLog
  # ./m4/ChangeLog
  # ./lib/ChangeLog
  # ./doc/ChangeLog
  # ./config/ChangeLog
  my @reordered;
  foreach my $d (@dir)
    {
      my $dot_slash = $d eq '.' ? $d : "./$d";
      my $target = "$dot_slash/ChangeLog";
      delete $changelog{$target}
        and push @reordered, $target;
    }

  # Append any remaining ChangeLog files.
  push @reordered, sort keys %changelog;

  # Remove leading './'.
  @reordered = map { s!^\./!!; $_ } @reordered;

  print "\nChangeLog entries:\n\n";
  # print join ("\n", @reordered), "\n";

  $prev_version =~ s/\./_/g;
  my $prev_cvs_tag = "\U$package_name\E-$prev_version";

  my $cmd = "cvs -n diff -u -r$prev_cvs_tag -rHEAD @reordered";
  open DIFF, '-|', $cmd
    or die "$ME: cannot run '$cmd': $!\n";
  # Print two types of lines, making minor changes:
  # Lines starting with '+++ ', e.g.,
  # +++ ChangeLog   22 Feb 2003 16:52:51 -0000      1.247
  # and those starting with '+'.
  # Don't print the others.
  my $prev_printed_line_empty = 1;
  while (defined (my $line = <DIFF>))
    {
      if ($line =~ /^\+\+\+ /)
        {
          my $separator = "*"x70 ."\n";
          $line =~ s///;
          $line =~ s/\s.*//;
          $prev_printed_line_empty
            or print "\n";
          print $separator, $line, $separator;
        }
      elsif ($line =~ /^\+/)
        {
          $line =~ s///;
          print $line;
          $prev_printed_line_empty = ($line =~ /^$/);
        }
    }
  close DIFF;

  # The exit code should be 1.
  # Allow in case there are no modified ChangeLog entries.
  $? == 256 || $? == 128
    or warn "warning: '$cmd' had unexpected exit code or signal ($?)\n";
}

sub get_tool_versions ($$)
{
  my ($tool_list, $gnulib_version) = @_;
  @$tool_list
    or return ();

  my $fail;
  my @tool_version_pair;
  foreach my $t (@$tool_list)
    {
      if ($t eq 'gnulib')
        {
          push @tool_version_pair, ucfirst $t . ' ' . $gnulib_version;
          next;
        }
      # Assume that the last "word" on the first line of
      # 'tool --version' output is the version string.
      my ($first_line, undef) = split ("\n", `$t --version`);
      if ($first_line =~ /.* (\d[\w.-]+)$/)
        {
          $t = ucfirst $t;
          push @tool_version_pair, "$t $1";
        }
      else
        {
          defined $first_line
            and $first_line = '';
          warn "$t: unexpected --version output\n:$first_line";
          $fail = 1;
        }
    }

  $fail
    and exit 1;

  return @tool_version_pair;
}

{
  # Use the C locale so that, for instance, "du" does not
  # print "1,2" instead of "1.2", which would confuse our regexps.
  $ENV{LC_ALL} = "C";

  my $mail_headers;
  my $release_type;
  my $package_name;
  my $prev_version;
  my $curr_version;
  my $gpg_key_id;
  my @url_dir_list;
  my @news_file;
  my $bootstrap_tools;
  my $gnulib_version;
  my $print_checksums_p = 1;

  # Reformat the warnings before displaying them.
  local $SIG{__WARN__} = sub
    {
      my ($msg) = @_;
      # Warnings from GetOptions.
      $msg =~ s/Option (\w)/option --$1/;
      warn "$ME: $msg";
    };

  GetOptions
    (
     'mail-headers=s'     => \$mail_headers,
     'release-type=s'     => \$release_type,
     'package-name=s'     => \$package_name,
     'previous-version=s' => \$prev_version,
     'current-version=s'  => \$curr_version,
     'gpg-key-id=s'       => \$gpg_key_id,
     'url-directory=s'    => \@url_dir_list,
     'news=s'             => \@news_file,
     'srcdir=s'           => \$srcdir,
     'bootstrap-tools=s'  => \$bootstrap_tools,
     'gnulib-version=s'   => \$gnulib_version,
     'print-checksums!'   => \$print_checksums_p,
     'archive-suffix=s'   => \@archive_suffixes,

     help => sub { usage 0 },
     version =>
       sub
       {
         print "$ME version $VERSION\n";
         print "Copyright (C) $copyright_year Free Software Foundation, Inc.\n";
         print "License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.\n"
             . "This is free software: you are free to change and redistribute it.\n"
             . "There is NO WARRANTY, to the extent permitted by law.\n";
         print "\n";
         my $author = "Jim Meyering";
         print "Written by $author.\n";
         exit
       },
    ) or usage 1;

  my $fail = 0;
  # Ensure that each required option is specified.
  $release_type
    or (warn "release type not specified\n"), $fail = 1;
  $package_name
    or (warn "package name not specified\n"), $fail = 1;
  $prev_version
    or (warn "previous version string not specified\n"), $fail = 1;
  $curr_version
    or (warn "current version string not specified\n"), $fail = 1;
  $gpg_key_id
    or (warn "GnuPG key ID not specified\n"), $fail = 1;
  @url_dir_list
    or (warn "URL directory name(s) not specified\n"), $fail = 1;

  my @tool_list = split ',', $bootstrap_tools
    if $bootstrap_tools;

  grep (/^gnulib$/, @tool_list) ^ defined $gnulib_version
    and (warn "when specifying gnulib as a tool, you must also specify\n"
        . "--gnulib-version=V, where V is the result of running git describe\n"
        . "in the gnulib source directory.\n"), $fail = 1;

  !$release_type || exists $valid_release_types{$release_type}
    or (warn "'$release_type': invalid release type\n"), $fail = 1;

  @ARGV
    and (warn "too many arguments:\n", join ("\n", @ARGV), "\n"),
      $fail = 1;
  $fail
    and usage 1;

  my $my_distdir = "$package_name-$curr_version";

  my $xd = "$package_name-$prev_version-$curr_version.xdelta";

  my @candidates = map { "$my_distdir.$_" } @archive_suffixes;
  my @tarballs = grep {-f $_} @candidates;

  @tarballs
    or die "$ME: none of " . join(', ', @candidates) . " were found\n";
  my @sizable = @tarballs;
  -f $xd
    and push @sizable, $xd;
  my %size = sizes (@sizable);
  %size
    or exit 1;

  my $headers = '';
  if (defined $mail_headers)
    {
      ($headers = $mail_headers) =~ s/\s+(\S+:)/\n$1/g;
      $headers .= "\n";
    }

  # The markup is escaped as <\# so that when this script is sent by
  # mail (or part of a diff), Gnus is not triggered.
  print <<EOF;

${headers}Subject: $my_distdir released [$release_type]

<\#secure method=pgpmime mode=sign>

FIXME: put comments here

EOF

  if (@url_dir_list == 1 && @tarballs == 1)
    {
      # When there's only one tarball and one URL, use a more concise form.
      my $m = "$url_dir_list[0]/$tarballs[0]";
      print "Here are the compressed sources and a GPG detached signature[*]:\n"
        . "  $m\n"
        . "  $m.sig\n\n";
    }
  else
    {
      print_locations ("compressed sources", @url_dir_list, %size, @tarballs);
      -f $xd
        and print_locations ("xdelta diffs (useful? if so, "
                             . "please tell bug-gnulib\@gnu.org)",
                             @url_dir_list, %size, $xd);
      my @sig_files = map { "$_.sig" } @tarballs;
      print_locations ("GPG detached signatures[*]", @url_dir_list, %size,
                       @sig_files);
    }

  if ($url_dir_list[0] =~ "gnu\.org")
    {
      print "Use a mirror for higher download bandwidth:\n";
      if (@tarballs == 1 && $url_dir_list[0] =~ m!https://ftp\.gnu\.org/gnu/!)
        {
          (my $m = "$url_dir_list[0]/$tarballs[0]")
            =~ s!https://ftp\.gnu\.org/gnu/!https://ftpmirror\.gnu\.org/!;
          print "  $m\n"
              . "  $m.sig\n\n";

        }
      else
        {
          print "  https://www.gnu.org/order/ftp.html\n\n";
        }
    }

  $print_checksums_p
    and print_checksums (@sizable);

  print <<EOF;
[*] Use a .sig file to verify that the corresponding file (without the
.sig suffix) is intact.  First, be sure to download both the .sig file
and the corresponding tarball.  Then, run a command like this:

  gpg --verify $tarballs[0].sig

If that command fails because you don't have the required public key,
then run this command to import it:

  gpg --keyserver keys.gnupg.net --recv-keys $gpg_key_id

and rerun the 'gpg --verify' command.
EOF

  my @tool_versions = get_tool_versions (\@tool_list, $gnulib_version);
  @tool_versions
    and print "\nThis release was bootstrapped with the following tools:",
      join ('', map {"\n  $_"} @tool_versions), "\n";

  print_news_deltas ($_, $prev_version, $curr_version)
    foreach @news_file;

  $release_type eq 'stable'
    or print_changelog_deltas ($package_name, $prev_version);

  exit 0;
}

### Setup "GNU" style for perl-mode and cperl-mode.
## Local Variables:
## mode: perl
## perl-indent-level: 2
## perl-continued-statement-offset: 2
## perl-continued-brace-offset: 0
## perl-brace-offset: 0
## perl-brace-imaginary-offset: 0
## perl-label-offset: -2
## perl-extra-newline-before-brace: t
## perl-merge-trailing-else: nil
## eval: (add-hook 'before-save-hook 'time-stamp)
## time-stamp-line-limit: 50
## time-stamp-start: "my $VERSION = '"
## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
## time-stamp-time-zone: "UTC0"
## time-stamp-end: "'; # UTC"
## End:
