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package RT::Interface::Web::QueryBuilder::Tree;

use strict;
use warnings;

use Tree::Simple qw/use_weak_refs/;
use base qw/Tree::Simple/;

=head1 NAME

  RT::Interface::Web::QueryBuilder::Tree - subclass of Tree::Simple used in Query Builder

=head1 DESCRIPTION

This class provides support functionality for the Query Builder (Search/Build.html).
It is a subclass of L<Tree::Simple>.

=head1 METHODS

=head2 TraversePrePost PREFUNC POSTFUNC

Traverses the tree depth-first.  Before processing the node's children,
calls PREFUNC with the node as its argument; after processing all of the
children, calls POSTFUNC with the node as its argument.

(Note that unlike Tree::Simple's C<traverse>, it actually calls its functions
on the root node passed to it.)

=cut

sub TraversePrePost {
   my ($self, $prefunc, $postfunc) = @_;

   # XXX: if pre or post action changes siblings (delete or adds)
   # we could have problems
   $prefunc->($self) if $prefunc;

   foreach my $child ($self->getAllChildren()) { 
           $child->TraversePrePost($prefunc, $postfunc);
   }
   
   $postfunc->($self) if $postfunc;
}

=head2 GetReferencedQueues

Returns a hash reference; each queue referenced with an '=' operation
will appear as a key whose value is 1.

=cut

sub GetReferencedQueues {
    my $self = shift;

    my $queues = {};

    $self->traverse(
        sub {
            my $node = shift;

            return if $node->isRoot;
            return unless $node->isLeaf;

            my $clause = $node->getNodeValue();
            return unless $clause->{Key} eq 'Queue';
            return unless $clause->{Op} eq '=';

            $queues->{ $clause->{Value} } = 1;
        }
    );

    return $queues;
}

=head2 GetQueryAndOptionList SELECTED_NODES

Given an array reference of tree nodes that have been selected by the user,
traverses the tree and returns the equivalent SQL query and a list of hashes
representing the "clauses" select option list.  Each has contains the keys
TEXT, INDEX, SELECTED, and DEPTH.  TEXT is the displayed text of the option
(including parentheses, not including indentation); INDEX is the 0-based
index of the option in the list (also used as its CGI parameter); SELECTED
is either 'SELECTED' or '', depending on whether the node corresponding
to the select option was in the SELECTED_NODES list; and DEPTH is the
level of indentation for the option.

=cut 

sub GetQueryAndOptionList {
    my $self           = shift;
    my $selected_nodes = shift;

    my $list = $self->__LinearizeTree;
    foreach my $e( @$list ) {
        $e->{'DEPTH'}    = $e->{'NODE'}->getDepth;
        $e->{'SELECTED'} = (grep $_ == $e->{'NODE'}, @$selected_nodes)? qq[ selected="selected"] : '';
    }

    return (join ' ', map $_->{'TEXT'}, @$list), $list;
}

=head2 PruneChildLessAggregators

If tree manipulation has left it in a state where there are ANDs, ORs,
or parenthesizations with no children, get rid of them.

=cut

sub PruneChildlessAggregators {
    my $self = shift;

    $self->TraversePrePost(
        undef,
        sub {
            my $node = shift;
            return unless $node->isLeaf;

            # We're only looking for aggregators (AND/OR)
            return if ref $node->getNodeValue;

            return if $node->isRoot;

            # OK, this is a childless aggregator.  Remove self.
            $node->getParent->removeChild($node);
            $node->DESTROY;
        }
    );
}

=head2 GetDisplayedNodes

This function returns a list of the nodes of the tree in depth-first
order which correspond to options in the "clauses" multi-select box.
In fact, it's all of them but the root and its child.

=cut

sub GetDisplayedNodes {
    return map $_->{NODE}, @{ (shift)->__LinearizeTree };
}


sub __LinearizeTree {
    my $self = shift;

    my ($list, $i) = ([], 0);

    $self->TraversePrePost( sub {
        my $node = shift;
        return if $node->isRoot;

        my $str = '';
        if( $node->getIndex > 0 ) {
            $str .= " ". $node->getParent->getNodeValue ." ";
        }

        unless( $node->isLeaf ) {
            $str .= '( ';
        } else {

            my $clause = $node->getNodeValue;
            my $key = $clause->{Key};
            $key .= "." . $clause->{Subkey} if defined $clause->{Subkey};
            if ($key =~ s/(['\\])/\\$1/g or $key =~ /[^{}\w\.]/) {
                $key = "'$key'";
            }
            my $value = $clause->{Value};
            my $op = $clause->{Op};
            if ( $value =~ /^NULL$/i && $op =~ /^(!?)=$/  ) {
                $op = $1 ? 'IS NOT' : 'IS';
            }

            if ( $op =~ /^IS( NOT)?$/i ) {
                $value = 'NULL';
            } elsif ( $value !~ /^[+-]?[0-9]+$/ ) {
                $value =~ s/(['\\])/\\$1/g;
                $value = "'$value'";
            }

            $str .= $key ." ". $op . " " . $value;
        }
        $str =~ s/^\s+|\s+$//;

        push @$list, {
            NODE     => $node,
            TEXT     => $str,
            INDEX    => $i,
        };

        $i++;
    }, sub {
        my $node = shift;
        return if $node->isRoot;
        return if $node->isLeaf;
        $list->[-1]->{'TEXT'} .= ' )';
    });

    return $list;
}

sub ParseSQL {
    my $self = shift;
    my %args = (
        Query => '',
        CurrentUser => '', #XXX: Hack
        @_
    );
    my $string = $args{'Query'};

    my @results;

    my %field = %{ RT::Tickets->new( $args{'CurrentUser'} )->FIELDS };
    my %lcfield = map { ( lc($_) => $_ ) } keys %field;

    my $node =  $self;

    my %callback;
    $callback{'OpenParen'} = sub {
        $node = __PACKAGE__->new( 'AND', $node );
    };
    $callback{'CloseParen'} = sub { $node = $node->getParent };
    $callback{'EntryAggregator'} = sub { $node->setNodeValue( $_[0] ) };
    $callback{'Condition'} = sub {
        my ($key, $op, $value) = @_;

        my ($main_key, $subkey) = split /[.]/, $key, 2;

        unless( $lcfield{ lc $main_key} ) {
            push @results, [ $args{'CurrentUser'}->loc("Unknown field: [_1]", $key), -1 ]
        }
        $main_key = $lcfield{ lc $main_key };

        # Hardcode value for IS / IS NOT
        $value = 'NULL' if $op =~ /^IS( NOT)?$/i;

        my $clause = { Key => $main_key, Subkey => $subkey,
                       Meta => $field{ $main_key },
                       Op => $op, Value => $value };
        $node->addChild( __PACKAGE__->new( $clause ) );
    };
    $callback{'Error'} = sub { push @results, @_ };

    require RT::SQL;
    RT::SQL::Parse($string, \%callback);
    return @results;
}

RT::Base->_ImportOverlays();

1;
