package App::CLI;
our $VERSION = 0.08;
use strict;
use warnings;

=head1 NAME

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

=head1 SYNOPSIS

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

  package main;

  MyApp->dispatch;

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

  sub options {
    ('verbose' => 'verbose');
  }

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

=head1 DESCRIPTION

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

=cut

use Getopt::Long ();

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

sub new {
    my $class = shift;
    my $self = bless {}, $class;
    %$self = @_;
    return $self;
}

sub prepare {
    my $class = shift;
    my $data = {};
    $class->_getopt( [qw(no_ignore_case bundling pass_through)],
		     _opt_map($data, $class->global_options));
    my $cmd = shift @ARGV;
    $cmd = $class->get_cmd($cmd, @_, %$data);

    $class->_getopt( [qw(no_ignore_case bundling)],
		     _opt_map($cmd, $cmd->command_options) );
    return $cmd;
}

sub _getopt {
    my $class = shift;
    my $config = shift;
    my $p = Getopt::Long::Parser->new;
    $p->configure(@$config);
    my $err = '';
    local $SIG{__WARN__} = sub { my $msg = shift; $err .= "$msg" };
    die $class->error_opt ($err)
	unless $p->getoptions(@_);
}

sub dispatch {
    my $class = shift;
    my $cmd = $class->prepare(@_);
    $cmd->subcommand;
    $cmd->run_command(@ARGV);
}

sub _cmd_map {
    my ($pkg, $cmd) = @_;
    my %alias = $pkg->alias;
    $cmd = $alias{$cmd} if exists $alias{$cmd};
    return ucfirst($cmd);
}

sub error_cmd {
    "Command not recognized, try $0 --help.\n";
}

sub error_opt { $_[1] }

sub command_class { $_[0] }

sub get_cmd {
    my ($class, $cmd, @arg) = @_;
    die $class->error_cmd
	unless $cmd && $cmd =~ m/^[?a-z]+$/;
    my $pkg = join('::', $class->command_class, $class->_cmd_map ($cmd));
    my $file = "$pkg.pm";
    $file =~ s!::!/!g;
    eval {require $file; };

    unless ($pkg->can('run')) {
	warn $@ if $@ and exists $INC{$file};
	die $class->error_cmd;
    }
    $cmd = $pkg->new (@arg);
    $cmd->app ($class);
    return $cmd;
}

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

sub commands {
    my $class = shift;
    $class =~ s{::}{/}g;
    my $dir = $INC{$class.'.pm'};
    $dir =~ s/\.pm$//;
    return sort map { ($_) = m{^\Q$dir\E/(.*)\.pm}; lc($_) } $class->files;
}

sub files {
    my $class = shift;
    $class =~ s{::}{/}g;
    my $dir = $INC{$class.'.pm'};
    $dir =~ s/\.pm$//;
    return sort glob("$dir/*.pm");
}

=head1 TODO

More documentation

=head1 SEE ALSO

L<App::CLI::Command>

=head1 AUTHORS

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

=head1 COPYRIGHT

Copyright 2005-2006 by Chia-liang Kao E<lt>clkao@clkao.orgE<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;