#!/usr/bin/perl

my %infoProvider;
my @infoOrdering;

##
# Register an information provider with the current providers
#
# @param[in]  $name     The name of the provider
# @param[in]  %details  A hashref of the information required by the
#                       provider
#                         after   => any provider which this info is after
#                         before  => any provider which this info is before
#                         isa     => any provider which this is a member of
#                         func    => the function to call to provide info
#                         private => a private value to pass to the function
sub registerInfoProvider
{
	my ($name, %details) = @_;

	$details{'name'} = $name; # For diagnostic purposes
	if (!defined $details{'after'} &&
	    !defined $details{'before'} &&
	    !defined $details{'isa'})
	{
		# If they didn't say anything about where it goes,
		# place it in the middle.
		$details{'isa'} = 'middle';
	}
	$infoProvider{$name} = \%details;

	# Clear the array to force it to be rebuilt
	@infoOrdering = ();
}

##
# Deregister an information provider
#
# @param[in]  $name     The name of the provider
sub deregisterInfoProvider
{
	my ($name) = @_;
	delete $infoProvider{$name};

	# Clear the array to force it to be rebuilt
	@infoOrdering = ();
}

##
# Add information to the current list of items
#
# @param[in]  $client  The client this request is coming from
# @param[in]  $line    The line to add
# @param[in]  $content The operation to perform when this item is selected.
#                      May be a hashref of information to search for:
#                         'type' => a type of search:
#                                       ALBUM = album+track search
#                                       <role> = contributor role search
#                                       GENRE = genre+contrib+album+track search
#                                       YEAR  = year+album+track search
#                         'obj' => the value searched
#                     Or may be a code ref to execute the code in the form
#                         func($client);
#                     Or may be undef to never push right.
sub addInfo
{
	my $client = shift;
	my $line = shift;
	my $content = shift;
	
	print "Adding $line\n";
	push (@{$client->trackInfoLines}, $line);
	push (@{$client->trackInfoContent}, $content);
}


##
# Add the 'title' information to the information.
#
# Should call addInfo to add information to the menu.
#
# @param[in]  $client  The client this request is coming from
# @param[in]  $private A private value passed on registration
# @param[in]  $url     The URL to which this information refers
# @param[in]  $track   The track reference
sub infoTitle
{
	my ($client, $private, $url, $track) = @_;

	print "Title\n";
}

# The 'top', 'middle' and 'bottom' groups, so that we can add items in absolute
# positions
registerInfoProvider('top',    ('isa' => '') );
registerInfoProvider('middle', ('isa' => '') );
registerInfoProvider('bottom', ('isa' => '') );

registerInfoProvider('title', (
				'after'  => 'top',
				'func'   => \&infoTitle
			));

registerInfoProvider('audioscrobbler', (
				'before' => 'title',
				'func'   => sub { print "AScrobbler\n"; }
			));

registerInfoProvider('lyrics', (
				'after'  => 'top',
				'before' => 'title',
				'func'   => sub { print "LYRICS\n"; }
			));

registerInfoProvider('contributors', (
				'after' => 'title',
				'func'  => sub { print "Contribs\n"; }
			));

registerInfoProvider('album', (
				'after' => 'contributors',
				'func'  => sub { print "Album\n"; }
			));

registerInfoProvider('tracknum', (
				'after' => 'album',
				'func'  => sub { print "TrackNum\n"; }
			));

registerInfoProvider('year', (
				'after' => 'tracknum',
				'func'  => sub { print "Year\n"; }
			));

registerInfoProvider('genres', (
				'after' => 'year',
				'func'  => sub { print "Genres\n"; }
			));

registerInfoProvider('type', (
				'after' => 'genres',
				'func'  => sub { print "Type\n"; }
			));

registerInfoProvider('comment', (
				'after' => 'type',
				'func'  => sub { print "Comment\n"; }
			));

registerInfoProvider('duration', (
				'after' => 'comment',
				'func'  => sub { print "Duration\n"; }
			));

registerInfoProvider('replaygain', (
				'after' => 'duration',
				'func'  => sub { print "Replaygain\n"; }
			));

registerInfoProvider('rating', (
				'after' => 'replaygain',
				'func'  => sub { print "Rating\n"; }
			));

registerInfoProvider('formatinfo', (
				'after' => 'rating'
			));

registerInfoProvider('fileinfo', (
				'after' => 'formatinfo'
			));

registerInfoProvider('favorite', (
				'after' => 'fileinfo'
			));

# File information
registerInfoProvider('filesize', (
				'isa' => 'fileinfo',
				'func'  => sub { print "Filesize\n"; }
			));

registerInfoProvider('modtime', (
				'isa' => 'fileinfo',
				'func'  => sub { print "ModTime\n"; }
			));

registerInfoProvider('url', (
				'isa' => 'fileinfo',
				'func'  => sub { print "URL\n"; }
			));

# Format information
registerInfoProvider('bitrate', (
				'isa'   => 'formatinfo',
				'func'  => sub { print "Bitrate\n"; }
			));
registerInfoProvider('samplerate', (
				'isa'   => 'formatinfo',
				'func'  => sub { print "Samplerate\n"; }
			));
registerInfoProvider('samplesize', (
				'isa'   => 'formatinfo',
				'func'  => sub { print "Samplesize\n"; }
			));
registerInfoProvider('drm', (
				'isa'   => 'formatinfo',
				'func'  => sub { print "DRM\n"; }
			));

registerInfoProvider('lastthing', (
				'before' => 'bottom',
				'func'  => sub { print "LAST\n"; }
			));



my %thing;
$client = \%thing;
@{$client->{'trackInfoLines'}} = ();
@{$client->{'trackInfoContent'}} = ();

# If we don't have a ordering, generate one
if (scalar(@infoOrdering) == 0)
{
	# We don't know what order the entries should be in,
	# so work that out.
	generateInfoOrderingItem($client, 'top', undef);
	generateInfoOrderingItem($client, 'middle', undef);
	generateInfoOrderingItem($client, 'bottom', undef);
}

print "\nUnordered:\n";
for $ref (values %infoProvider)
{
	print "$ref->{'name'} [$ref->{'before'} > $ref->{'after'}]\n";
}

print "\nOrdered:\n";
for $ref (@infoOrdering)
{
	print "$ref->{'name'}\n";
}

# print "\nRun the ordering:\n";
# for my $ref (@infoOrdering)
# {
	# if (defined $ref->{'func'})
	# {
		# $ref->{'func'}($client, $ref->{'private'}, $url, $track);
	# }
# }

##
# Adds an item to the ordering list, following any
# 'after', 'before' and 'isa' requirements that the
# registered providers have requested.
#
# @param[in]  $client   The client we're ordering for
# @param[in]  $name     The name of the item to add
# @param[in]  $previous The item before this one, for 'before' processing
sub generateInfoOrderingItem
{
	my $client = shift;
	my $name = shift;
	my $previous = shift;
	my $item;
	
	# Check for the 'before' items which are 'after' the last item
	if (defined $previous)
	{
		for $item (sort { $a cmp $b }
				grep {
					defined $infoProvider{$_}->{'after'} &&
					$infoProvider{$_}->{'after'} eq $previous &&
					defined $infoProvider{$_}->{'before'} &&
					$infoProvider{$_}->{'before'} eq $name
				} keys %infoProvider)
		{
			&generateInfoOrderingItem($client, $item, $previous);
		}
	}
	
	# Now the before items which are just before this item
	for $item (sort { $a cmp $b }
			grep {
				!defined $infoProvider{$_}->{'after'} &&
				defined $infoProvider{$_}->{'before'} &&
				$infoProvider{$_}->{'before'} eq $name
			} keys %infoProvider)
	{
		&generateInfoOrderingItem($client, $item, $previous);
	}

	# Add the item itself
	push @infoOrdering, $infoProvider{$name};
	
	# Now any items that are members of the group
	for $item (sort { $a cmp $b }
			grep {
				defined $infoProvider{$_}->{'isa'} &&
				$infoProvider{$_}->{'isa'} eq $name
			} keys %infoProvider)
	{
		&generateInfoOrderingItem($client, $item, undef);
	}
	
	# Any 'after' items
	for $item (sort { $a cmp $b }
			grep {
				defined $infoProvider{$_}->{'after'} &&
				$infoProvider{$_}->{'after'} eq $name &&
				!defined $infoProvider{$_}->{'before'}
			} keys %infoProvider)
	{
		&generateInfoOrderingItem($client, $item, $name);
	}
}