package Class::Usul::Options;

use strict;
use warnings;

use Class::Usul::Constants qw( FALSE TRUE );
use Class::Usul::Functions qw( throw );
use Sub::Install           qw( install_sub );

my @option_attributes
   = qw( autosplit config doc format json negateable order repeatable short );

my @banished_keywords
   = qw( extra_argv new_with_options next_argv option _options_data
         _options_config options_usage unshift_argv untainted_argv );

# Private functions
my $filter_attributes = sub {
   my %attributes = @_; my %filter_key = map { $_ => 1 } @option_attributes;

   return map { ( $_ => $attributes{ $_ } ) }
         grep { not exists $filter_key{ $_ } } keys %attributes;
};

my $validate_and_filter_options = sub {
   my (%options) = @_;

   defined $options{doc  } or $options{doc  } = $options{documentation};
   defined $options{order} or $options{order} = 0;

   if ($options{json}) {
      delete $options{repeatable}; delete $options{autosplit};
      delete $options{negateable}; $options{format} = 's';
   }

   my %cmdline_options = map { ( $_ => $options{ $_ } ) }
      grep { exists $options{ $_ } } @option_attributes, 'required';

   $cmdline_options{autosplit } and $cmdline_options{repeatable} = TRUE;
   $cmdline_options{repeatable}
      and defined $cmdline_options{format}
      and (substr $cmdline_options{format}, -1) ne '@'
      and $cmdline_options{format} .= '@';

   $cmdline_options{negateable} and defined $cmdline_options{format} and
      throw 'Negateable parameters are not usable with a non boolean values';

   return %cmdline_options;
};

# Public functions
sub default_options_config () {
   return getopt_conf        => [],
          prefer_commandline => TRUE,
          protect_argv       => TRUE,
          show_defaults      => FALSE,
          skip_options       => [],
          usage_conf         => {},
          usage_opt          => 'Usage: %c %o [method]';
}

sub import {
   my ($class, @args) = @_; my $target = caller;

   my $options_config = { default_options_config, @args };

   for my $want (grep { not $target->can( $_ ) } qw( around has with )) {
      throw 'Method [_1] not found in class [_2]', [ $want, $target ];
   }

   my $around = $target->can( 'around' );
   my $has    = $target->can( 'has'    );
   my $with   = $target->can( 'with'   );

   my @target_isa; { no strict 'refs'; @target_isa = @{ "${target}::ISA" } };

   if (@target_isa) {
      # Don't add this to a role. The ISA of a role is always empty!
      install_sub { as => '_options_config', into => $target, code => sub {
         return shift->maybe::next::method( @_ );
      }, };

      install_sub { as => '_options_data', into => $target, code => sub {
         return shift->maybe::next::method( @_ );
      }, };

      $around->( '_options_config' => sub {
         my ($orig, $self, @args) = @_;

         return $orig->( $self, @args ), %{ $options_config };
      } );
   }

   my $options_data    = {};
   my $apply_modifiers = sub {
      $target->can( 'new_with_options' ) and return;

      $with->( 'Class::Usul::TraitFor::UntaintedGetopts' );

      $around->( '_options_data' => sub {
         my ($orig, $self, @args) = @_;

         return $orig->( $self, @args ), %{ $options_data };
      } );
   };
   my $option = sub {
      my ($name, %attributes) = @_;

      for my $ban (grep { $_ eq $name } @banished_keywords) {
         throw 'Method [_1] used by class [_2] as an attribute',
               [ $ban, $target ];
      }

      $has->( $name => $filter_attributes->( %attributes ) );

      $options_data->{ $name }
         = { $validate_and_filter_options->( %attributes ) };

      $apply_modifiers->(); # TODO: I think this can go
      return;
   };
   my $info; $info = $Role::Tiny::INFO{ $target }
      and $info->{not_methods}{ $option } = $option;

   install_sub { as => 'option', into => $target, code => $option, };

   $apply_modifiers->();
   return;
}

1;

__END__

=pod

=encoding utf-8

=head1 Name

Class::Usul::Options - Command line processing

=head1 Synopsis

   use Class::Usul::Types qw( Str );
   use Moo;
   use Class::Usul::Options;

   option 'my_attr' => is => 'ro', isa => 'Str',
      documentation => 'This appears in the option usage output',
             format => 's', short => 'a';

   # OR
   # Causes Getopt::Long:Descriptive::Usage to produce it's new default output

   use Class::Usul::Options 'usage_conf' => {
       highlight => 'none', option_type => 'verbose', tabstop => 8 };

   # OR
   # Causes Getopt::Long:Descriptive::Usage to produce it's old default output

   use Class::Usul::Options 'usage_conf' => {
       highlight => 'none', option_type => 'none', tabstop => 8 };

=head1 Description

This is an extended clone of L<MooX::Options> but is closer to
L<MooseX::Getopt::Dashes>

=head1 Configuration and Environment

The C<option> function accepts the following attributes in addition to those
already supported by C<has>

=over 3

=item C<autosplit>

If set split the option value using this string. Automatically creates a list
of values

=item C<config>

A hash reference passed as the third element in the
list of tuples which forms the second argument to the
L<describe options|Getopt::Long::Descriptive/describe_options> function

For example;

   option 'my_attr' => is => 'ro', isa => 'Str', config => { hidden => 1 },
      documentation => 'This appears in the option usage output',
             format => 's', short => 'a';

would prevent the option from appearing in the usage text

=item C<doc>

Alias for C<documentation>. Used to describe the attribute in the usage output

=item C<format>

Format of the parameters, same as L<Getopt::Long::Descriptive>

    i : integer

    i@: array of integer

    s : string

    s@: array of string

    s%: hash of string

    f : float value

By default, it's a boolean value.

=item C<json>

Boolean which if true means that the argument to the option is in JSON format
and will be decoded as such

=item C<negateable>

Applies only to boolean types. Means you can use C<--nooption-name> to
explicitly indicate false

=item C<order>

Specifies the order in which usage options appear. Attributes with no C<order>
value are alpha sorted

=item C<repeatable>

Boolean which if true means that the option can appear multiple times on the
command line

=item C<short>

A single character that can be used as a short option, e.g. C<-s> instead
of the longer C<--long-option>

=back

Defines no attributes

=head1 Subroutines/Methods

=head2 C<default_options_config>

Returns a list of keys and values. These are the defaults for the configuration
options listed in L</import>

=head2 C<import>

Injects the C<option> function into the caller

Accepts the following configuration options;

=over 3

=item C<getopf_conf>

An array reference of options passed to L<Getopt::Long::Configure>, defaults to
an empty list

=item C<prefer_commandline>

A boolean which defaults to true. Prefer the command line values

=item C<protect_argv>

A boolean which defaults to true. Localises the C<@ARGV> variable before any
processing takes place. Means that C<@ARGV> will contain all of the passed
command line arguments

=item C<show_defaults>

A boolean which defaults to false. If true the default values are added to
use options usage text output

=item C<skip_options>

An array reference which defaults to an empty list. List of options to
ignore when processing the attributes passed to the C<option> subroutine

=item C<usage_conf>

By default an empty hash reference. Attributes can be any of;

=over 3

=item C<highlight>

Defaults to C<bold> which causes the option argument types to be displayed
in a bold font. Set to C<none> to turn off highlighting

=item C<option_type>

One of; C<none>, C<short>, or C<verbose>. Determines the amount of option
type information displayed by the L<option_text|Class::Usul::Usage/option_text>
method. Defaults to C<short>

=item C<tabstop>

Defaults to 3. The number of spaces to expand the leading tab in the usage
string

=item C<width>

The total line width available for displaying usage text, defaults to 78

=back

=item C<usage_opt>

The usage option string passed as the first argument to the
L<describe options|Getopt::Long::Descriptive/describe_options> function.
Defaulted in L</default_options_config> to C<Usage: %c %o [method]>

=back

=head1 Diagnostics

None

=head1 Dependencies

=over 3

=item L<Sub::Install>

=back

=head1 Incompatibilities

There are no known incompatibilities in this module

=head1 Bugs and Limitations

There are no known bugs in this module. Please report problems to
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Class-Usul.
Patches are welcome

=head1 Acknowledgements

Larry Wall - For the Perl programming language

=head1 Author

Peter Flanigan, C<< <pjfl@cpan.org> >>

=head1 License and Copyright

Copyright (c) 2017 Peter Flanigan. All rights reserved

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See L<perlartistic>

This program is distributed in the hope that it will be useful,
but WITHOUT WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE

=cut

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