package WWW::CPAN;

use 5.006;
use strict;
use warnings;

our $VERSION = '0.012';

use Class::Lego::Constructor 0.004 ();
use parent qw( Class::Accessor Class::Lego::Constructor );

my $FIELDS = {
  host     => 'search.cpan.org',
  ua       => sub { # default useragent
                my %options = ( agent => 'www-cpan/' . $VERSION, );
#                require LWP::UserAgent;
#                return LWP::UserAgent->new( %options );
                require LWP::UserAgent::Determined;
                return LWP::UserAgent::Determined->new( %options );
              },
  j_loader => sub { # json loader sub
                require JSON::Any;
                JSON::Any->import; # XXX JSON::Any needs this
                my $j = JSON::Any->new;
                return sub { $j->Load(shift); }
              },
  x_loader => sub { # xml loader sub
                require XML::Simple;
                my %options = (
                  ForceArray => [qw( module dist match )],
                  KeyAttr    => [],
                );
                my $x = XML::Simple->new( %options );
                return sub { $x->XMLin(shift); }
              },
};

__PACKAGE__->mk_constructor0( $FIELDS );
__PACKAGE__->mk_accessors( keys %$FIELDS );

use Class::Lego::Myself;
__PACKAGE__->give_my_self;

use Carp qw( carp );

sub _build_distmeta_uri {
  my $self = shift;
  my $params = shift;

  if ( ! ref $params ) {
    $params = { dist => $params };
  }
  require URI;
  my $uri = URI->new();
  $uri->scheme('http');
  $uri->authority( $self->host );
  my @path = qw( meta );
  if ( $params->{author} ) {
    push @path, $params->{author};
  }

  my $dist = $params->{dist};
  if ( $params->{version} ) {
    $dist .= '-' . $params->{version};
  }
  push @path, $dist;

  push @path, 'META.json'; # XXX support YAML as well
  $uri->path_segments(@path);

  return $uri;
}

sub fetch_distmeta {
  (my $self, @_) = &find_my_self;
  my $uri = $self->_build_distmeta_uri(@_);
  my $r = $self->ua->get($uri);
  if ( $r->is_success ) {

    my $content = $r->decoded_content;

    # Back to UTF8 (if needed)
    utf8::encode($content)
     unless utf8::is_utf8($content);

    return $self->j_loader->( $content );
  } else {
    carp $r->status_line; # FIXME needs more convincing error handling
    return;
  }
}

# http://search.cpan.org/search?query=Archive&mode=all&format=xml
sub _build_query_uri {
  my $self = shift;
  my $params = shift;

  if ( ! ref $params ) {
    $params = { query => $params, mode => 'all', format => 'xml', };
  }
  require URI;
  my $uri = URI->new();
  $uri->scheme('http');
  $uri->authority( $self->host );
  my @path = qw( search );
  $uri->path_segments(@path);

  $params->{mode}   ||= 'all';
  $params->{format} ||= 'xml';
  $uri->query_form( $params );

  return $uri;
}
# other params: s (start), n (page size, should be <= 100)

sub _basic_query {
  my $self = shift;
  my $uri = $self->_build_query_uri(@_);
  my $r = $self->ua->get($uri);
  if ( $r->is_success ) {
    return $self->x_loader->( $r->content );
  } else {
    carp $r->status_line; # FIXME needs more convincing error handling
    return;
  }
}

sub search {
  my $self = &find_my_self;
  return $self->_basic_query(@_);
}
# TODO fetch the entire result by default

# &query is an alias to &search (see Method::Alias for the rationale)
sub query { 
  goto &{ $_[0]->can('search') }; 
}

"I didn't do it! -- Bart Simpson";