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

# Generate a release announcement message.

# Copyright (C) 2002-2023 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 = '2023-02-26 17:15'; # 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 = '2022';

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.
   --gpg-key-email=EMAIL        The email address of the key used to
                                sign the tarballs
   --gpg-keyring-url=URL        URL pointing to keyring containing the key used
                                to sign the tarballs
   --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

# This digest function omits the "=" padding that is required by cksum,
# so add the 0..2 bytes of padding required for each of Digest's algorithms.
sub digest_file_base64_wrap ($$)
{
  my ($file, $alg) = @_;
  my $h = digest_file_base64($file, $alg);
  $alg =~ tr{-}{}d;
  my %pad = (MD5 => 2, SHA1 => 1, SHA256 => 1, SHA384 => 0, SHA512 => 2);
  return $h . '=' x $pad{$alg};
}

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"), "  $f\n";
      print '  ', digest_file_base64_wrap ($f, "SHA-256"), "  $f\n";
    }
  print "\nVerify the base64 SHA256 checksum with cksum -a sha256 --check\n";
  print "from coreutils-9.2 or OpenBSD's cksum since 2007.\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;
}

# Print a more human-friendly representation of $SEC seconds.
sub readable_interval0($)
{
  my $sec = shift;
  $sec < 60 and return "$sec seconds";

  my $min = int($sec / 60); $sec %= 60;
  30 < $sec and $min++;
  $min < 60 and return "$min minutes";

  my $hr = int($min / 60); $min %= 60;
  30 < $min and $hr++;
  $hr < 24 and return "$hr hours";

  my $day = int($hr / 24); $hr %= 24;
  12 < $hr and $day++;
  $day < 50 and return "$day days";

  my $wk = int($day / 7); $day %= 7;
  4 < $day and $wk++;
  return "$wk weeks";
}

# Convert e.g., "1 weeks", to "1 week".
sub readable_interval($)
{
  my $interval_str = shift;
  my $i = readable_interval0 $interval_str;
  $i =~ m{^1 \w+s$} and chop $i;
  return $i;
}

{
  # 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;
  my $gpg_key_email;
  my $gpg_keyring_url;

  # 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,
     'gpg-key-email=s'    => \$gpg_key_email,
     'gpg-keyring-url=s'  => \$gpg_keyring_url,
     '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;

  ! grep (/^gnulib$/, @tool_list) && defined $gnulib_version
    and (warn "with --gnulib-version=V you must use --bootstrap-tools=...\n"
         . "including gnulib in that list"), $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>
This is to announce $package_name-$curr_version, a $release_type release.

FIXME: put comments here

EOF

  my $v0 = $prev_version;
  my $v1 = $curr_version;

  (my $first_name = `git config --global user.name|cut -d' ' -f1`)
    =~ m{\S} or die "no name? set user.name in ~/.gitconfig\n";

  chomp (my $n_ci = `git rev-list "v$v0..v$v1" | wc -l`);
  chomp (my $n_p = `git shortlog "v$v0..v$v1" | grep -c '^[^ ]'`);

  my $prev_release_date = `git log --pretty=%ct -1 "v$v0"`;
  my $this_release_date = `git log --pretty=%ct -1 "v$v1"`;
  my $n_seconds = $this_release_date - $prev_release_date;
  my $time_since_prev = readable_interval $n_seconds;
  my $names = `git shortlog "v$v0..v$v1"|perl -lne '/^(\\w.*):/ and print "  ".\$1'`;

  print <<EOF;
There have been $n_ci commits by $n_p people in the $time_since_prev since $v0.

See the NEWS below for a brief summary.

Thanks to everyone who has contributed!
The following people contributed changes to this release:

$names
$first_name [on behalf of the $package_name maintainers]
==================================================================

Here is the GNU $package_name home page:
    http://gnu.org/s/$package_name/

For a summary of changes and contributors, see:
  http://git.sv.gnu.org/gitweb/?p=$package_name.git;a=shortlog;h=v$v1
or run this command from a git-cloned $package_name directory:
  git shortlog v$v0..v$v1

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

EOF
  my $gpg_fingerprint = `LC_ALL=C gpg --fingerprint $gpg_key_id | grep -v ^sub`;
  if ($gpg_fingerprint =~ /^pub/)
    {
      chop $gpg_fingerprint;
      $gpg_fingerprint =~ s/ \[expires:.*//mg;
      $gpg_fingerprint =~ s/^uid           \[ultimate\]/uid  /mg;
      $gpg_fingerprint =~ s/^/  /mg;
      print<<EOF
The signature should match the fingerprint of the following key:

$gpg_fingerprint
EOF
    }
  print <<EOF;
If that command fails because you don't have the required public key,
or that public key has expired, try the following commands to retrieve
or refresh it, and then rerun the 'gpg --verify' command.
EOF
  if ($gpg_key_email) {
    print <<EOF;

  gpg --locate-external-key $gpg_key_email
EOF
    }
  print <<EOF;

  gpg --recv-keys $gpg_key_id
EOF
    if ($gpg_keyring_url) {
      print <<EOF;

  wget -q -O- '$gpg_keyring_url' | gpg --import -
EOF
      }
  print <<EOF;

As a last resort to find the key, you can try the official GNU
keyring:

  wget -q https://ftp.gnu.org/gnu/gnu-keyring.gpg
  gpg --keyring gnu-keyring.gpg --verify $tarballs[0].sig
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: