package App::CLI;

use strict;
use warnings;
use 5.006;
use Class::Load qw( load_class );

our $VERSION = '0.49';

=encoding utf8

=head1 NAME

App::CLI - Dispatcher module for command line interface programs

=head1 SYNOPSIS

    package MyApp;
    use base 'App::CLI';        # the DISPATCHER of your App
                                # it's not necessary to put the dispatcher
                                # on the top level of your App

    package main;

    MyApp->dispatch;            # call the dispatcher where you want


    package MyApp::List;
    use base qw(App::CLI::Command); # any (SUB)COMMAND of your App

    use constant options => (
        "h|help"   => "help",
        "verbose"  => "verbose",
        'n|name=s'  => 'name',
    );

    use constant subcommands => qw(User Nickname type); # if you want subcommands
                                                        # automatically dispatch to subcommands
                                                        # when invoke $ myapp list [user|nickname|--type]
                                                        # note 'type' is not capitalized
                                                        # it is a deprecated subcommand

    sub run {
        my ($self, @args) = @_;

        print "verbose" if $self->{verbose};
        my $name = $self->{name}; # get arg following long option --name

        if ($self->{help}) {
            # if $ myapp list --help or $ myapp list -h
            # only output PODs
        } else {
            # do something when invoking $ myapp list
            # without subcommand and --help
        }
    }


    package MyApp::List::User;
    use base qw(App::CLI::Command);
    use constant options => (
        "h|help"  =>  "help",
    );

    sub run {
        my ($self,@args) = @_;
        # code for listing user
    }


    pakcage MyApp::List::Nickname;
    use base qw(App::CLI::Command);
    use constant options => (
        "sort=s"  =>  "sort",
    );

    sub run {
        my ($self,@args) = @_;
        # code for listing nickname
    }


    package MyApp::List::type;   # old genre of subcommand could not cascade infinitely
    use base qw(MyApp::List);    # should inherit its parent's command

    sub run {
        my ($self, @args);
        # run to here when invoking $ myapp list --type
    }


    package MyApp::Help;
    use base 'App::CLI::Command::Help';

    use constant options => (
        'verbose' => 'verbose',
    );

    sub run {
        my ($self, @arg) = @_;
        # do something
        $self->SUPER(@_); # App::CLI::Command::Help would output POD of each command
    }

=head1 DESCRIPTION

C<App::CLI> dispatches CLI (command line interface) based commands
into command classes.  It also supports subcommand and per-command
options.

=head2 Methods

=cut

use App::CLI::Helper;
use Getopt::Long ();

use constant alias          => ();
use constant global_options => ();
use constant options        => ();

sub new {
    my ( $class, @args ) = @_;
    my $self = bless {@args}, $class;
    $self->{'app_argv'} = undef;

    return $self;
}

sub app_argv {
    my $self = shift;

    if (@_) {
        $self->{'app_argv'} = shift;
    }

    return $self->{'app_argv'};
}

sub prepare {
    my $self = shift;
    my $data = {};

    $self->get_opt(
        [qw(no_ignore_case bundling pass_through)],
        opt_map( $data, $self->global_options )
    );

    my $command_name = shift @ARGV;
    my $cmd = $self->get_cmd( $command_name, @_, $data );

    while ( $cmd->cascadable ) {
        $cmd = $cmd->cascading;
    }

    $self->get_opt( [qw(no_ignore_case bundling)],
        opt_map( $cmd, $cmd->command_options ) );

    $cmd = $cmd->subcommand;

    return $cmd;
}

=head3 get_opt([@config], %opt_map)

Give options map, processed by L<Getopt::Long::Parser>.

=cut

sub get_opt {
    my ( $self, $config, @app_options ) = @_;
    my $p = Getopt::Long::Parser->new;
    $p->configure(@$config);
    my $err = '';
    local $SIG{__WARN__} = sub {
        my $msg = shift;
        $err .= "$msg";
    };
    my @current_argv = @ARGV;
    $self->app_argv( \@current_argv );
    die $self->error_opt($err) unless $p->getoptions(@app_options);
}

sub opt_map {
    my ( $self, %opt ) = @_;
    return
      map { $_ => ref( $opt{$_} ) ? $opt{$_} : \$self->{ $opt{$_} } } keys %opt;
}

=head3 dispatch(@args)

Interface of dispatcher

=cut

sub dispatch {
    my ( $self, @args ) = @_;
    $self = $self->new unless ref $self;

    $self->app($self) if $self->can('app');

    my $cmd = $self->prepare(@args);
    $cmd->run_command(@ARGV);
}

=head3 cmd_map($cmd)

Find the name of the package implementing the requested command.

The command is first searched for in C<alias>. If the alias exists and points
to a package name starting with the C<+> sign, then that package name (minus
the C<+> sign) is returned. This makes it possible to map commands to arbitrary
packages.

Otherwise, the package is searched for in the result of calling C<commands>,
and a package name is constructed by upper-casing the first character of the
command name, and appending it to the package name of the app itself.

If both of these fail, and the command does not map to any package name,
C<undef> is returned instead.

=cut

sub cmd_map {
    my ( $self, $cmd ) = @_;

    my %alias = $self->alias;

    if ( exists $alias{$cmd} ) {
        $cmd = $alias{$cmd};

        # Alias points to package name, return immediately
        return $cmd if $cmd =~ s/^\+//;
    }

    ($cmd) = grep { $_ eq $cmd } $self->commands;

    # No such command
    return unless $cmd;

    my $base = ref $self;
    return join '::', $base, ucfirst $cmd;
}

sub error_cmd {
    my ( $self, $pkg ) = @_;

    my $cmd;
    if ( defined($pkg) ) {
        $cmd = ref($pkg) || $pkg;
    }
    elsif ( ${ $self->app_argv }[0] ) {
        $cmd = ${ $self->app_argv }[0];
    }
    else {
        $cmd = '<empty command>';
    }

    return "Command '$cmd' not recognized, try $0 --help.\n";
}

sub error_opt { $_[1] }

=head3 get_cmd($cmd, @arg)

Return subcommand of first level via C<$ARGV[0]>.

=cut

sub get_cmd {
    my ( $self, $cmd, $data ) = @_;
    die $self->error_cmd($cmd) unless $cmd && $cmd eq lc($cmd);

    my $base = ref $self;
    my $pkg  = $self->cmd_map($cmd);

    die $self->error_cmd($cmd) unless $pkg;

    load_class $pkg;

    die $self->error_cmd($cmd) unless $pkg->can('run');

    my @arg = defined $data ? %$data : ();
    $cmd = $pkg->new(@arg);
    $cmd->app($self);
    return $cmd;
}

=head1 SEE ALSO

=over 4

=item *

L<App::CLI::Command>

=item *

L<Getopt::Long>

=back

=head1 AUTHORS

=over 4

=item *

Chia-liang Kao E<lt>clkao@clkao.orgE<gt>

=item *

Alex Vandiver  E<lt>alexmv@bestpractical.comE<gt>

=item *

Yo-An Lin      E<lt>cornelius.howl@gmail.comE<gt>

=item *

Shelling       E<lt>navyblueshellingford@gmail.comE<gt>

=item *

Paul Cochrane  E<lt>paul@liekut.deE<gt> (current maintainer)

=back

=head1 CONTRIBUTORS

The following people have contributed patches to the project:

=over 4

=item *

José Joaquín Atria E<lt>jjatria@gmail.comE<gt>

=item *

sunnavy            E<lt>sunnavy@gmail.comE<gt>

=back

=head1 COPYRIGHT

Copyright 2005-2010 by Chia-liang Kao E<lt>clkao@clkao.orgE<gt>.
Copyright 2010 by Yo-An Lin E<lt>cornelius.howl@gmail.comE<gt>
and Shelling E<lt>navyblueshellingford@gmail.comE<gt>.
Copyright 2017 by Paul Cochrane E<lt>paul@liekut.deE<gt>

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

See L<http://www.perl.com/perl/misc/Artistic.html>

=cut

1;