package Reaction::UI::LayoutSet;

use Reaction::Class;
use File::Spec;

use namespace::clean -except => [ qw(meta) ];


has 'layouts' => (is => 'ro', default => sub { {} });

has 'name' => (is => 'ro', required => 1);

has 'source_file' => (is => 'ro', required => 1);

has 'widget_class' => (
  is => 'rw', lazy_fail => 1, predicate => 'has_widget_class'
);

has 'widget_type' => (is => 'rw', lazy_build => 1);

has 'super' => (is => 'rw', predicate => 'has_super');
sub BUILD {
  my ($self, $args) = @_;
  my @path = @{$args->{search_path}||[]};
  confess "No skin object provided" unless $args->{skin};
  confess "No top skin object provided" unless $args->{top_skin};
  $self->_load_file($self->source_file, $args);
  unless ($self->has_widget_class) {
    $self->widget_class($args->{skin}->widget_class_for($self));
  }
};
sub widget_order_for {
  my ($self, $name) = @_;
  return (
    ($self->has_layout($name)
      ? ([ $self->widget_class, $self ]) #;
      : ()),
    ($self->has_super
      ? ($self->super->widget_order_for($name))
      : ()),
  );
};
sub layout_names {
  my ($self) = @_;
  my %seen;
  return [
    grep { !$seen{$_}++ }
      keys %{shift->layouts},
      ($self->has_super
        ? (@{$self->super->layout_names})
        : ())
  ];
};
sub has_layout { exists $_[0]->layouts->{$_[1]} };
sub _load_file {
  my ($self, $file, $build_args) = @_;
  my $data = $file->slurp;
  utf8::decode($data)
    unless utf8::is_utf8($data);
  my $layouts = $self->layouts;
  # cheesy match for "=for layout name ... =something"
  # final split group also handles last in file, (?==) is lookahead
  # assertion for '=' so "=for layout name1 ... =for layout name2"
  # doesn't have the match pos go past the latter = and lose name2
  while ($data =~ m/=(.*?)\n(.*?)(?:\n(?==)|$)/sg) {
    my ($data, $text) = ($1, $2);
    if ($data =~ /^for layout (\S+)/) {
      my $fname = $1;
      $text =~ s/^(?:\s*\r?\n)+//; #remove leading empty lines
      $text =~ s/[\s\r\n]+$//;     #remove trailing whitespace
      $layouts->{$fname} = $text;
    } elsif ($data =~ /^extends (\S+)/) {
      my $super_name = $1;
      my $skin;
      if ($super_name eq 'NEXT') {
        confess "No next skin and layout extends NEXT"
          unless $build_args->{next_skin};
        $skin = $build_args->{next_skin};
        $super_name = $self->name;
      } else {
        $skin = $build_args->{top_skin};
      }
      $self->super($skin->create_layout_set($super_name));
    } elsif ($data =~ /^widget (\S+)/) {
      my $widget_type = $1;
      $self->widget_type($1);
    } elsif ($data =~ /^cut/) {
      # no-op
    } else {
      confess "Unparseable directive ${data} in ${file}";
    }
  }
};
sub _build_widget_type {
  my ($self) = @_;
  my $widget = join('',   map { ucfirst($_) } split('_', $self->name));
  $widget    = join('::', map { ucfirst($_) } split('/', $widget));

  #print STDERR "--- ", $self->name, " maps to widget $widget \n";

  return $widget;
};

__PACKAGE__->meta->make_immutable;


1;