package Net::LastFM;
use Moose;
use MooseX::StrictConstructor;
use Digest::MD5 qw(md5_hex);
use JSON::XS::VersionOneAndTwo;
use LWP::UserAgent;
use URI::QueryParam;
our $VERSION = '0.34';

has 'api_key' => (
    is       => 'rw',
    isa      => 'Str',
    required => 1,
);

has 'api_secret' => (
    is       => 'rw',
    isa      => 'Str',
    required => 1,
);

has 'ua' => (
    is       => 'rw',
    isa      => 'LWP::UserAgent',
    required => 0,
    default  => sub {
        my $ua = LWP::UserAgent->new;
        $ua->agent( 'Net::LastFM/' . $VERSION );
        $ua->env_proxy;
        return $ua;
    }
);

my $ROOT = 'http://ws.audioscrobbler.com/2.0/';

sub create_http_request {
    my ( $self, %conf ) = @_;

    $conf{api_key} = $self->api_key;
    my $uri = URI->new('http://ws.audioscrobbler.com/2.0/');

    foreach my $key ( keys %conf ) {
        my $value = $conf{$key};
        $uri->query_param( $key, $value );
    }
    $uri->query_param( 'format', 'json' );

    return HTTP::Request->new( 'GET', $uri );
}

sub create_http_request_signed {
    my ( $self, %conf ) = @_;
    $conf{api_key} = $self->api_key;

    my $to_hash = '';
    foreach my $key ( sort keys %conf ) {
        my $value = $conf{$key};
        $to_hash .= $key . $value;
    }
    $to_hash .= $self->api_secret;
    $conf{api_sig} = md5_hex($to_hash);

    return $self->create_http_request(%conf);
}

sub request {
    my ( $self, %conf ) = @_;
    my $request = $self->create_http_request(%conf);
    return $self->_make_request($request);
}

sub request_signed {
    my ( $self, %conf ) = @_;
    my $request = $self->create_http_request_signed(%conf);
    return $self->_make_request($request);
}

sub _make_request {
    my ( $self, $request ) = @_;
    my $ua = $self->ua;

    my $response = $ua->request($request);
    my $data     = from_json( $response->content );

    if ( defined $data->{error} ) {
        my $code    = $data->{error};
        my $message = $data->{message};
        confess "$code: $message";
    } else {
        return $data;
    }
}

1;

__END__

=head1 NAME

Net::LastFM - A simple interface to the Last.fm API

=head1 SYNOPSIS

  my $lastfm = Net::LastFM->new(
      api_key    => 'XXX',
      api_secret => 'YYY',
  );
  my $data = $lastfm->request_signed(
      method => 'user.getRecentTracks',
      user   => 'lglb',
  );

=head1 DESCRIPTION

The module provides a simple interface to the Last.fm API. To use
this module, you must first sign up at L<http://www.last.fm/api>
to receive an API key and secret.

You can then make requests on the API - most of the requests
are signed. You pass in a hash of paramters and a data structure
mirroring the response is returned.

This module confesses if there is an error.

=head1 METHODS

=head2 request

This makes an unsigned request:

  my $data = $lastfm->request( method => 'auth.gettoken' );

=head2 request_signed

This makes a signed request:

  my $data = $lastfm->request_signed(
      method => 'user.getRecentTracks',
      user   => 'lglb',
  );

=head2 create_http_request

If you want to integrate this module into another HTTP framework, this 
method will simple create an unsigned L<HTTP::Request> object:

  my $http_request = $lastfm->create_http_request(
      method => 'auth.gettoken'
  );

=head2 create_http_request_signed

If you want to integrate this module into another HTTP framework, this 
method will simple create a signed L<HTTP::Request> object:

  my $http_request = $lastfm->create_http_request_signed(
      method => 'user.getRecentTracks',
      user   => 'lglb',
  );

=head1 AUTHOR

Leon Brocard <acme@astray.com>

=head1 COPYRIGHT

Copyright (C) 2008-9, Leon Brocard.

=head1 LICENSE

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