package Catalyst::Dispatcher;

use strict;
use base 'Class::Accessor::Fast';
use Catalyst::Exception;
use Catalyst::Utils;
use Catalyst::Action;
use Catalyst::ActionContainer;
use Catalyst::DispatchType::Default;
use Catalyst::DispatchType::Index;
use Text::SimpleTable;
use Tree::Simple;
use Tree::Simple::Visitor::FindByPath;

# Stringify to class
use overload '""' => sub { return ref shift }, fallback => 1;

__PACKAGE__->mk_accessors(
    qw/tree dispatch_types registered_dispatch_types
      method_action_class action_container_class/
);

# Preload these action types
our @PRELOAD = qw/Path Regex/;

# Postload these action types
our @POSTLOAD = qw/Index Default/;

=head1 NAME

Catalyst::Dispatcher - The Catalyst Dispatcher

=head1 SYNOPSIS

See L<Catalyst>.

=head1 DESCRIPTION

=head1 METHODS

=over 4

=item $self->detach( $c, $command [, \@arguments ] )

=cut

sub detach {
    my ( $self, $c, $command, @args ) = @_;
    $c->forward( $command, @args ) if $command;
    die $Catalyst::DETACH;
}

=item $self->dispatch($c)

=cut

sub dispatch {
    my ( $self, $c ) = @_;

    if ( $c->action ) {
        $c->forward( join( '/', '', $c->namespace, '_DISPATCH' ) );
    }

    else {
        my $path  = $c->req->path;
        my $error = $path
          ? qq/Unknown resource "$path"/
          : "No default action defined";
        $c->log->error($error) if $c->debug;
        $c->error($error);
    }
}

=item $self->forward( $c, $command [, \@arguments ] )

=cut

sub forward {
    my $self    = shift;
    my $c       = shift;
    my $command = shift;

    unless ($command) {
        $c->log->debug('Nothing to forward to') if $c->debug;
        return 0;
    }

    my $arguments = ( ref( $_[-1] ) eq 'ARRAY' ) ? pop(@_) : $c->req->args;

    my $result;

    unless ( ref $command ) {
        my $command_copy = $command;

        unless ( $command_copy =~ s/^\/// ) {
            my $namespace = $c->namespace;
            $command_copy = "${namespace}/${command}";
        }

        unless ( $command_copy =~ /\// ) {
            $result = $c->get_action( $command_copy, '/' );
        }
        else {
            my @extra_args;
          DESCEND: while ( $command_copy =~ s/^(.*)\/(\w+)$/$1/ ) {
                my $tail = $2;
                $result = $c->get_action( $tail, $1 );
                if ($result) {
                    $command = $tail;
                    push( @{$arguments}, @extra_args );
                    last DESCEND;
                }
                unshift( @extra_args, $tail );
            }
        }
    }

    unless ($result) {

        my $class  = ref($command) || ref( $c->component($command) );
        my $method = shift         || 'process';

        unless ($class) {
            my $error =
qq/Couldn't forward to command "$command". Invalid action or component./;
            $c->error($error);
            $c->log->debug($error) if $c->debug;
            return 0;
        }

        if ( my $code = $class->can($method) ) {
            my $action = $self->method_action_class->new(
                {
                    name      => $method,
                    code      => $code,
                    reverse   => "$class->$method",
                    class     => $class,
                    namespace => $class,
                }
            );
            $result = $action;
        }

        else {
            my $error =
              qq/Couldn't forward to "$class". Does not implement "$method"/;
            $c->error($error);
            $c->log->debug($error)
              if $c->debug;
            return 0;
        }

    }

    local $c->request->{arguments} = [ @{$arguments} ];

    $result->execute($c);

    return $c->state;
}

=item $self->prepare_action($c)

=cut

sub prepare_action {
    my ( $self, $c ) = @_;
    my $path = $c->req->path;
    my @path = split /\//, $c->req->path;
    $c->req->args( \my @args );

    push( @path, '/' ) unless @path;    # Root action

  DESCEND: while (@path) {
        $path = join '/', @path;

        $path = '' if $path eq '/';     # Root action

        # Check out dispatch types to see if any will handle the path at
        # this level

        foreach my $type ( @{ $self->dispatch_types } ) {
            last DESCEND if $type->match( $c, $path );
        }

        # If not, move the last part path to args

        unshift @args, pop @path;
    }

    $c->log->debug( 'Arguments are "' . join( '/', @args ) . '"' )
      if ( $c->debug && @args );
}

=item $self->get_action( $c, $action, $namespace )

=cut

sub get_action {
    my ( $self, $c, $name, $namespace ) = @_;
    return unless $name;
    $namespace ||= '';
    $namespace = '' if $namespace eq '/';

    my @match = $self->get_containers($namespace);

    return unless @match;

    if ( my $action = $match[-1]->get_action( $c, $name ) ) {
        return $action if $action->namespace eq $namespace;
    }
}

=item $self->get_actions( $c, $action, $namespace )

=cut

sub get_actions {
    my ( $self, $c, $action, $namespace ) = @_;
    return [] unless $action;
    $namespace ||= '';
    $namespace = '' if $namespace eq '/';

    my @match = $self->get_containers($namespace);

    return map { $_->get_action( $c, $action ) } @match;
}

=item $self->get_containers( $namespace )

=cut

sub get_containers {
    my ( $self, $namespace ) = @_;

    # If the namespace is / just return the root ActionContainer

    return ( $self->tree->getNodeValue )
      if ( !$namespace || ( $namespace eq '/' ) );

    # Use a visitor to recurse down the tree finding the ActionContainers
    # for each namespace in the chain.

    my $visitor = Tree::Simple::Visitor::FindByPath->new;
    my @path = split( '/', $namespace );
    $visitor->setSearchPath(@path);
    $self->tree->accept($visitor);

    my @match = $visitor->getResults;
    @match = ( $self->tree ) unless @match;

    if ( !defined $visitor->getResult ) {

        # If we don't manage to match, the visitor doesn't return the last
        # node is matched, so foo/bar/baz would only find the 'foo' node,
        # not the foo and foo/bar nodes as it should. This does another
        # single-level search to see if that's the case, and the 'last unless'
        # should catch any failures - or short-circuit this if this *is* a
        # bug in the visitor and gets fixed.

        if ( my $extra = $path[ ( scalar @match ) - 1 ] ) {
            $visitor->setSearchPath($extra);
            $match[-1]->accept($visitor);
            push( @match, $visitor->getResult ) if defined $visitor->getResult;
        }
    }

    return map { $_->getNodeValue } @match;
}

sub register {
    my ( $self, $c, $action ) = @_;

    my $namespace = $action->namespace;
    my $parent    = $self->tree;
    my $visitor   = Tree::Simple::Visitor::FindByPath->new;

    if ($namespace) {
        for my $part ( split '/', $namespace ) {
            $visitor->setSearchPath($part);
            $parent->accept($visitor);
            my $child = $visitor->getResult;

            unless ($child) {

                # Create a new tree node and an ActionContainer to form
                # its value.

                my $container =
                  Catalyst::ActionContainer->new(
                    { part => $part, actions => {} } );
                $child = $parent->addChild( Tree::Simple->new($container) );
                $visitor->setSearchPath($part);
                $parent->accept($visitor);
                $child = $visitor->getResult;
            }

            $parent = $child;
        }
    }

    # Set the method value
    $parent->getNodeValue->actions->{ $action->name } = $action;

    my $registered = $self->registered_dispatch_types;

    foreach my $key ( keys %{ $action->attributes } ) {
        my $class = "Catalyst::DispatchType::$key";
        unless ( $registered->{$class} ) {
            eval "require $class";
            push( @{ $self->dispatch_types }, $class->new ) unless $@;
            $registered->{$class} = 1;
        }
    }

    # Pass the action to our dispatch types so they can register it if reqd.
    foreach my $type ( @{ $self->dispatch_types } ) {
        $type->register( $c, $action );
    }
}

=item $self->setup_actions( $class, $component )

=cut

sub setup_actions {
    my ( $self, $c ) = @_;

    $self->dispatch_types( [] );
    $self->registered_dispatch_types( {} );
    $self->method_action_class('Catalyst::Action');
    $self->action_container_class('Catalyst::ActionContainer');

    # Preload action types
    for my $type (@PRELOAD) {
        my $class = "Catalyst::DispatchType::$type";
        eval "require $class";
        Catalyst::Exception->throw( message => qq/Couldn't load "$class"/ )
          if $@;
        push @{ $self->dispatch_types }, $class->new;
        $self->registered_dispatch_types->{$class} = 1;
    }

    # We use a tree
    my $container =
      Catalyst::ActionContainer->new( { part => '/', actions => {} } );
    $self->tree( Tree::Simple->new( $container, Tree::Simple->ROOT ) );

    foreach my $comp ( values %{ $c->components } ) {
        $comp->register_actions($c) if $comp->can('register_actions');
    }

    # Postload action types
    for my $type (@POSTLOAD) {
        my $class = "Catalyst::DispatchType::$type";
        eval "require $class";
        Catalyst::Exception->throw( message => qq/Couldn't load "$class"/ )
          if $@;
        push @{ $self->dispatch_types }, $class->new;
    }

    return unless $c->debug;

    my $privates = Text::SimpleTable->new( [ 36, 'Private' ], [ 37, 'Class' ] );

    my $has_private = 0;
    my $walker = sub {
        my ( $walker, $parent, $prefix ) = @_;
        $prefix .= $parent->getNodeValue || '';
        $prefix .= '/' unless $prefix =~ /\/$/;
        my $node = $parent->getNodeValue->actions;

        for my $action ( keys %{$node} ) {
            my $action_obj = $node->{$action};
            next
              if ( ( $action =~ /^_.*/ )
                && ( !$c->config->{show_internal_actions} ) );
            $privates->row( "$prefix$action", $action_obj->class );
            $has_private = 1;
        }

        $walker->( $walker, $_, $prefix ) for $parent->getAllChildren;
    };

    $walker->( $walker, $self->tree, '' );
    $c->log->debug( "Loaded Private actions:\n" . $privates->draw )
      if ($has_private);

    # List all public actions
    $_->list($c) for @{ $self->dispatch_types };
}

=back

=head1 AUTHOR

Sebastian Riedel, C<sri@cpan.org>
Matt S Trout, C<mst@shadowcatsystems.co.uk>

=head1 COPYRIGHT

This program is free software, you can redistribute it and/or modify it under
the same terms as Perl itself.

=cut

1;
