#!/usr/bin/perl

# This is free software.  You may redistribute copies of it under the terms of
# the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
# There is NO WARRANTY, to the extent permitted by law.

# This script was originally written by Ken Estes Mail.com
# kestes@staff.mail.com

# a simple script used to generate dependencies of Perl modules and scripts.

# It does not parse the perl grammar but instead just lex it looking for
# what we want. It takes special care to ignore comments and pod's.

# The filenames to scan are either passed on the command line or if
# that is empty they are passed via stdin.

# If there are strings in the file which match the pattern
#     m/^\s*\$RPM_Requires\s*=\s*["'](.*)['"]/i
# then these are treated as additional names which are required by the
# file and are printed as well.

my $perl_req = "__SCL_NAME__";

$HAVE_VERSION = 0;
eval { require version; $HAVE_VERSION = 1; };


if ("@ARGV") {
  foreach (@ARGV) {
    process_file($_);
  }
} else {

  # notice we are passed a list of filenames NOT as common in unix the
  # contents of the file.

  foreach (<>) {
    process_file($_);
  }
}


foreach $perlver (sort keys %perlreq) {
  print "$perl_req >= $perlver\n";
}
foreach $module (sort keys %require) {
  if (length($require{$module}) == 0) {
    print "$perl_req($module)\n";
  } else {

    # I am not using rpm3.0 so I do not want spaces around my
    # operators. Also I will need to change the processing of the
    # $RPM_* variable when I upgrade.

    print "$perl_req($module) >= $require{$module}\n";
  }
}

exit 0;



sub add_require {
  my ($module, $newver) = @_;
  my $oldver = $require{$module};
  if ($oldver) {
    $require{$module} = $newver
      if ($HAVE_VERSION && $newver && version->new($oldver) < $newver);
  }
  else {
    $require{$module} = $newver;
  }
}

sub process_file {

  my ($file) = @_;
  chomp $file;

  if (!open(FILE, $file)) {
    warn("$0: Warning: Could not open file '$file' for reading: $!\n");
    return;
  }

  while (<FILE>) {

    # skip the "= <<" block

    if (m/^\s*\$(?:.*)\s*=\s*<<\s*(["'`])(.+?)\1/ ||
        m/^\s*\$(.*)\s*=\s*<<(\w+)\s*;/) {
      $tag = $2;
      while (<FILE>) {
        chomp;
        ( $_ eq $tag ) && last;
      }
      $_ = <FILE>;
    }

    # skip q{} quoted sections - just hope we don't have curly brackets
    # within the quote, nor an escaped hash mark that isn't a comment
    # marker, such as occurs right here. Draw the line somewhere.
    if ( m/^.*\Wq[qxwr]?\s*([{([#|\/])[^})\]#|\/]*$/ && ! m/^\s*(require|use)\s/ ) {
      $tag = $1;
      $tag =~ tr/{\(\[\#|\//})]#|\//;
      $tag = quotemeta($tag);
      while (<FILE>) {
        ( $_ =~ m/$tag/ ) && last;
      }
    }

    # skip the documentation

    # we should not need to have item in this if statement (it
    # properly belongs in the over/back section) but people do not
    # read the perldoc.

    if (/^=(head[1-4]|pod|for|item)/) {
      /^=cut/ && next while <FILE>;
    }

    if (/^=over/) {
      /^=back/ && next while <FILE>;
    }

    # skip the data section
    if (m/^__(DATA|END)__$/) {
      last;
    }

    # Each keyword can appear multiple times.  Don't
    #  bother with datastructures to store these strings,
    #  if we need to print it print it now.
    #
        # Again allow for "our".
    if (m/^\s*(our\s+)?\$RPM_Requires\s*=\s*["'](.*)['"]/i) {
      foreach $_ (split(/\s+/, $2)) {
        print "$_\n";
      }
    }

    my $modver_re = qr/[.0-9]+/;
    my $begin_re = qr#qw\s*[(\/'"!|{]\s*|qq?\s*[(\/'"!|{]\s*|['"]#;
    my $end_re   = qr#[)\/"'!|}]#;

    if (

# ouch could be in a eval, perhaps we do not want these since we catch
# an exception they must not be required

#   eval { require Term::ReadLine } or die $@;
#   eval "require Term::Rendezvous;" or die $@;
#   eval { require Carp } if defined $^S; # If error/warning during compilation,


        (m/^(\s*)         # we hope the inclusion starts the line
         (require|use)\s+(?!\{)     # do not want 'do {' loops
         # quotes around name are always legal
         $begin_re?\s*
         ([\w:\.\/]+?)
         \s*$end_re?[^\w]*?[\t; \n]
         # the syntax for 'use' allows version requirements
         \s*($modver_re)?\s*
         # catch parameter like '-norequire,'
         (-[\w,]+)?\s*
         # the latter part is for "use base qw(Foo)" and friends special case
         (?:$begin_re\s*
         ([^)\/"'\$!|}]*?)
         \s*$end_re|['"][^'"]+['"]|)\s*
         /x)
       ) {
      my ($whitespace, $statement, $module, $version, $params, $list) = ($1, $2, $3, $4, $5, $6);
      $version = undef if ($version eq '');

      # we only consider require statements that are flushed against
      # the left edge. any other require statements give too many
      # false positives, as they are usually inside of an if statement
      # as a fallback module or a rarely used option

      ($whitespace ne "" && $statement eq "require") && next;

      # if there is some interpolation of variables just skip this
      # dependency, we do not want
      #        do "$ENV{LOGDIR}/$rcfile";

      ($module =~ m/\$/) && next;

      # ignore variables
      ($module =~ m/^\s*[\$%@\*]/) && next;

      # skip if the phrase was "use of" -- shows up in gimp-perl, et al.
      next if $module eq 'of';

      # if the module ends in a comma we probably caught some
      # documentation of the form 'check stuff,\n do stuff, clean
      # stuff.' there are several of these in the perl distribution

      ($module  =~ m/[,>]$/) && next;

      # if the module name starts in a dot it is not a module name.
      # Is this necessary?  Please give me an example if you turn this
      # back on.

      #      ($module =~ m/^\./) && next;

      # if the module starts with /, it is an absolute path to a file
      if ($module =~ m(^/)) {
        print "$module\n";
        next;
      }

      # sometimes people do use POSIX qw(foo), or use POSIX(qw(foo)) etc.
      # we can strip qw.*$, as well as (.*$:
      $module =~ s/qw.*$//;
      $module =~ s/\(.*$//;

      # if the module ends with .pm, strip it to leave only basename.
      # .pm files are not accepted by 'use'
      ($module =~ s/\.pm$// && $statement eq 'use' ) && next;

      # some perl programmers write 'require URI/URL;' when
      # they mean 'require URI::URL;'

      ($module =~ s/\//::/ && $statement eq 'use' ) && next;

      # trim off trailing parentheses if any.  Sometimes people pass
      # the module an empty list.

      $module =~ s/\(\s*\)$//;

      if ( $module =~ m/^v?([0-9._]+)$/ ) {
        # if module is a number then both require and use interpret that
        # to mean that a particular version of perl is specified

        my $ver = $1;
        if ($ver =~ /5.00/) {
          $perlreq{"0:$ver"} = 1;
          next;
        }
        else {
          $perlreq{"1:$ver"} = 1;
          next;
        }

      };

      # ph files do not use the package name inside the file.
      # perlmodlib documentation says:

      #       the .ph files made by h2ph will probably end up as
      #       extension modules made by h2xs.

      # so do not expend much effort on these.


      # there is no easy way to find out if a file named systeminfo.ph
      # will be included with the name sys/systeminfo.ph so only use the
      # basename of *.ph files

      ($module =~ m/\.ph$/) && next;

      # use base|parent qw(Foo) dependencies
      # use aliased qw(Foo::Bar) dependencies
      if ($statement eq "use" && ($module eq "base" || $module eq "aliased")) {
        add_require($module, $version);
        if (defined($list) && $list ne "") {
          add_require($_, undef) for split(' ', $list);
        }
        next;
      }
      if ($statement eq "use" && $module eq "parent") {
        add_require($module, $version);
        if (defined($list) && $list ne "" && $params !~ /-norequire/) {
          add_require($_, undef) for split(' ', $list);
        }
        next;
      }

      # use Any::Moose dependencies
      # Mouse or Mouse::Role will be added
      if ($statement eq "use" && $module eq "Any::Moose") {
        add_require($module, $version);
        if (defined($list) && $list ne "") {
          if (grep { !/^Role$/ } split(' ', $list)) {
            add_require('Mouse::Role', undef);
          } else {
            add_require('Mouse', undef);
          }
        } else {
          add_require('Mouse', undef);
        }
        next;
      }

      add_require($module, $version);
    }

  }

  close(FILE) ||
    die("$0: Could not close file: '$file' : $!\n");

  return;
}