use strict;
use warnings;
package Getopt::Long::Descriptive::Usage 0.111;
# ABSTRACT: the usage description for GLD

use List::Util qw(max);

#pod =head1 SYNOPSIS
#pod
#pod   use Getopt::Long::Descriptive;
#pod   my ($opt, $usage) = describe_options( ... );
#pod
#pod   $usage->text; # complete usage message
#pod
#pod   $usage->die;  # die with usage message
#pod
#pod =head1 DESCRIPTION
#pod
#pod This document only describes the methods of the Usage object.  For information
#pod on how to use L<Getopt::Long::Descriptive>, consult its documentation.
#pod
#pod =head1 METHODS
#pod
#pod =head2 new
#pod
#pod   my $usage = Getopt::Long::Descriptive::Usage->new(\%arg);
#pod
#pod You B<really> don't need to call this.  GLD will do it for you.
#pod
#pod Valid arguments are:
#pod
#pod   options     - an arrayref of options
#pod   leader_text - the text that leads the usage; this may go away!
#pod
#pod =cut

sub new {
  my ($class, $arg) = @_;

  my @to_copy = qw(leader_text options show_defaults);

  my %copy;
  @copy{ @to_copy } = @$arg{ @to_copy };

  bless \%copy => $class;
}

#pod =head2 text
#pod
#pod This returns the full text of the usage message.
#pod
#pod =cut

sub text {
  my ($self) = @_;

  return join qq{\n}, $self->leader_text, $self->option_text;
}

#pod =head2 leader_text
#pod
#pod This returns the text that comes at the beginning of the usage message.
#pod
#pod =cut

sub leader_text { $_[0]->{leader_text} }

#pod =head2 option_text
#pod
#pod This returns the text describing the available options.
#pod
#pod =cut

sub option_text {
  my ($self) = @_;

  my $string   = q{};

  my @options  = @{ $self->{options} || [] };
  my @specs    = map { $_->{spec} } grep { $_->{desc} ne 'spacer' } @options;
  my $length   = (max(map { _option_length($_) } @specs) || 0);
  my $spec_fmt = "\t%-${length}s";

  while (@options) {
    my $opt  = shift @options;
    my $spec = $opt->{spec};
    my $desc = $opt->{desc};

    if ($desc eq 'spacer') {
      if (ref $opt->{spec}) {
        $string .= "${ $opt->{spec} }\n";
        next;
      } else {
        my @lines = $self->_split_description($length, $opt->{spec});

        $string .= length($_) ? sprintf("$spec_fmt\n", $_) : "\n" for @lines;
        next;
      }
    }

    ($spec, my $assign) = Getopt::Long::Descriptive->_strip_assignment($spec);

    my ($pre, $post) = _parse_assignment($assign);
    my @names = split /\|/, $spec;

    my $primary = shift @names;
    my $short;
    my ($i) = grep {; length $names[$_] == 1 } (0 .. $#names);
    if (defined $i) {
      $short = splice @names, $i, 1;
    }

    $spec = length $primary > 1 ? "--$pre$primary$post" : "-$primary$post";
    $spec .= " (or -$short)" if $short;

    my @desc = $self->_split_description($length, $desc);

    if (@names) {
      push @desc,
        "aka " . join q{, }, map { length > 1 ? "--$_" : "-$_" } @names;
    }

    # add default value if it exists
    if (exists $opt->{constraint}->{default} and $self->{show_defaults}) {
      my $dflt = $opt->{constraint}->{default};
      $dflt = ! defined $dflt ? '(undef)'
            : ! length  $dflt ? '(empty string)'
            :                   $dflt;
      push @desc, "(default value: $dflt)";
    }

    $string .= sprintf "$spec_fmt  %s\n", $spec, shift @desc;
    for my $line (@desc) {
        $string .= "\t";
        $string .= q{ } x ( $length + 2 );
        $string .= "$line\n";
    }
  }

  return $string;
}

sub _option_length {
    my ($fullspec) = @_;

    my ($spec, $argspec) = Getopt::Long::Descriptive->_strip_assignment($fullspec);

    my ($pre, $post) = _parse_assignment($argspec);
    my @names = split /\|/, $spec;

    my $primary = shift @names;
    my $short   = (@names && length $names[0] eq 1)
                ? shift @names
                : undef;

    $spec = length $primary > 1 ? "--$pre$primary$post" : "-$primary$post";
    $spec .= " (or -$short)" if $short;

    return length $spec;
}

sub _max_line_length {
  return $Getopt::Long::Descriptive::TERM_WIDTH - 2;
}

sub _split_description {
  my ($self, $length, $desc) = @_;

  # 8 for a tab, 2 for the space between option & desc, 2 more for gutter
  my $max_length = $self->_max_line_length - ( $length + 8 + 2 );

  return $desc if length $desc <= $max_length;

  my @lines;
  while (length $desc > $max_length) {
    my $idx = rindex( substr( $desc, 0, $max_length ), q{ }, );
    last unless $idx >= 0;
    push @lines, substr($desc, 0, $idx);
    substr($desc, 0, $idx + 1) = q{};
  }
  push @lines, $desc;

  return @lines;
}

sub _parse_assignment {
    my ($assign_spec) = @_;

    my $result = 'STR';
    my $desttype;
    if (length($assign_spec) < 2) {
        # empty, ! or +
        return ('[no-]', '') if $assign_spec eq '!';
        return ('', '');
    }

    my $optional = substr($assign_spec, 0, 1) eq ':';
    my $argument = substr $assign_spec, 1, 2;

    if ($argument =~ m/^[io]/ or $assign_spec =~ m/^:[+0-9]/) {
        $result = 'INT';
    } elsif ($argument =~ m/^f/) {
        $result = 'NUM';
    }

    if (length($assign_spec) > 2) {
        $desttype = substr($assign_spec, 2, 1);
        if ($desttype eq '@') {
            # Imply it can be repeated
            $result .= '...';
        } elsif ($desttype eq '%') {
            $result = "KEY=${result}...";
        }
    }

    if ($optional) {
        return ("", "[=$result]");
    }

    # with leading space so it can just blindly be appended.
    return ("", " $result");
}

#pod =head2 warn
#pod
#pod This warns with the usage message.
#pod
#pod =cut

sub warn { warn shift->text }

#pod =head2 die
#pod
#pod This throws the usage message as an exception.
#pod
#pod   $usage_obj->die(\%arg);
#pod
#pod Some arguments can be provided
#pod
#pod   pre_text  - text to be prepended to the usage message
#pod   post_text - text to be appended to the usage message
#pod
#pod The C<pre_text> and C<post_text> arguments are concatenated with the usage
#pod message with no line breaks, so supply this if you need them.
#pod
#pod =cut

sub die  {
  my $self = shift;
  my $arg  = shift || {};

  die(
    join q{}, grep { defined } $arg->{pre_text}, $self->text, $arg->{post_text}
  );
}

use overload (
  q{""} => "text",

  # This is only needed because Usage used to be a blessed coderef that worked
  # this way.  Later we can toss a warning in here. -- rjbs, 2009-08-19
  '&{}' => sub {
    my ($self) = @_;
    Carp::cluck("use of __PACKAGE__ objects as a code ref is deprecated");
    return sub { return $_[0] ? $self->text : $self->warn; };
  }
);

1;

__END__

=pod

=encoding UTF-8

=head1 NAME

Getopt::Long::Descriptive::Usage - the usage description for GLD

=head1 VERSION

version 0.111

=head1 SYNOPSIS

  use Getopt::Long::Descriptive;
  my ($opt, $usage) = describe_options( ... );

  $usage->text; # complete usage message

  $usage->die;  # die with usage message

=head1 DESCRIPTION

This document only describes the methods of the Usage object.  For information
on how to use L<Getopt::Long::Descriptive>, consult its documentation.

=head1 PERL VERSION

This library should run on perls released even a long time ago.  It should work
on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the
minimum required version will not be increased.  The version may be increased
for any reason, and there is no promise that patches will be accepted to lower
the minimum required perl.

=head1 METHODS

=head2 new

  my $usage = Getopt::Long::Descriptive::Usage->new(\%arg);

You B<really> don't need to call this.  GLD will do it for you.

Valid arguments are:

  options     - an arrayref of options
  leader_text - the text that leads the usage; this may go away!

=head2 text

This returns the full text of the usage message.

=head2 leader_text

This returns the text that comes at the beginning of the usage message.

=head2 option_text

This returns the text describing the available options.

=head2 warn

This warns with the usage message.

=head2 die

This throws the usage message as an exception.

  $usage_obj->die(\%arg);

Some arguments can be provided

  pre_text  - text to be prepended to the usage message
  post_text - text to be appended to the usage message

The C<pre_text> and C<post_text> arguments are concatenated with the usage
message with no line breaks, so supply this if you need them.

=head1 AUTHORS

=over 4

=item *

Hans Dieter Pearcey <hdp@cpan.org>

=item *

Ricardo Signes <cpan@semiotic.systems>

=back

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2005 by Hans Dieter Pearcey.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut