#!/usr/bin/perl

use strict;
use warnings;

use XML::Parser;
use Getopt::Lucid qw/:all/;
use LWP::Simple;
use Data::Dumper;
use Heap::Simple;
use POSIX qw/strftime/;

my @friends;

sub fparse_start {
    my $expat = shift;
    my $elt = shift;

    if ($elt eq 'user')
    {
        my %attr = @_;
        push @friends, $attr{username};
    }
}

my @tracks;
my $insertpoint = -1;

sub tparse_start {
    my $expat = shift;
    my $elt = shift;
    my %attr = @_;

    if ($elt eq 'track')
    {
        push @tracks, [];
    } elsif ($elt eq 'artist')
    {
        $insertpoint = 0;
    } elsif ($elt eq 'name')
    {
        $insertpoint = 1;
    } elsif ($elt eq 'url')
    {
        $insertpoint = 2;
    } elsif ($elt eq 'date')
    {
        $tracks[$#tracks]->[3] = $attr{uts};
        $insertpoint = 4;
    }
}

sub tparse_char {
    my $expat = shift;
    my $string = shift;
    if ($insertpoint > -1)
    {
        $tracks[$#tracks]->[$insertpoint] = $string;
        $insertpoint = -1;
    }
}

my @opts = (
            Param('user|u')->required,
            Param('mode|m')->default('text')
           );

my $opt = Getopt::Lucid->getopt( \@opts );

my $user = $opt->get_user();
my $mode = $opt->get_mode();

my $xp = new XML::Parser(Handlers => {Start => \&fparse_start});
my $content = get("http://ws.audioscrobbler.com/1.0/user/${user}/friends.xml");
if ($content)
{
    $xp->parse($content);
    my $alltracks = new Heap::Simple(elements => [Array => 4],
                                     order => '>');
    foreach my $fr(@friends)
    {
        my $content = get("http://ws.audioscrobbler.com/1.0/user/${fr}/recenttracks.xml");
        if ($content)
        {
            my $xp = new XML::Parser(Handlers => {
                                                  Start => \&tparse_start,
                                                  Char => \&tparse_char
                                                 });
            $xp->parse($content);
            foreach my $t(@tracks)
            {
                $alltracks->insert([ $fr, @$t ]);
            }
            @tracks = ();
        } else
        {
            print "error getting tracks for $fr\n";
        }
    }
    if ($mode eq 'dump')
    {
        for (1..$alltracks->count())
        {
            my $tr = $alltracks->extract_top();
            print Dumper(\$tr);
        }
    } elsif ($mode eq 'text')
    {
        for (1..$alltracks->count())
        {
            my $tr = $alltracks->extract_top();
            print "User: $tr->[0]\n";
            print "Track: $tr->[1] - $tr->[2]\nDate: $tr->[5]\n";
        }
    } elsif ($mode eq 'rss')
    {
        print "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n";
        print "<rss version=\"2.0\">\n";
        print "<channel>\n";

        print "<language>en</language>\n";
        print "<pubDate>", scalar localtime, "</pubDate>\n";
        print "<ttl>10</ttl>\n";
        print "<title>${user}'s Friends' Recent Tracks</title>\n";

        for (1..$alltracks->count())
        {
            print "<item>\n";
            my $tr = $alltracks->extract_top();
            my $title = "$tr->[0] - $tr->[1] - $tr->[2]";
            my $date = strftime '%a, %d %b %Y %H:%M:%S %z', localtime $tr->[4];
            print "<title>$title</title>\n";
            print "<link>$tr->[3]</link>\n";
            print "<pubDate>$date</pubDate>\n";
            print "</item>\n";
        }

        print "</channel>\n";
        print "</rss>\n";
    } else
    {
        print "Undefined output mode $mode\n";
    }
} else
{
    die "Badness!";
}