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/*
 * Copyright (c) 2002-2016 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */
package org.neo4j.graphmatching;

import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.neo4j.graphdb.Node;
import org.neo4j.graphmatching.filter.AbstractFilterExpression;
import org.neo4j.graphmatching.filter.FilterBinaryNode;
import org.neo4j.graphmatching.filter.FilterExpression;
import org.neo4j.graphmatching.filter.FilterValueGetter;
import org.neo4j.helpers.collection.FilteringIterable;

/**
 * The PatternMatcher is the engine that performs the matching of a graph
 * pattern with the actual graph.
 */
@Deprecated
public class PatternMatcher
{
    private static PatternMatcher matcher = new PatternMatcher();

    private PatternMatcher()
    {
    }

    /**
     * Get the sole instance of the {@link PatternMatcher}.
     *
     * @return the instance of {@link PatternMatcher}.
     */
    public static PatternMatcher getMatcher()
    {
        return matcher;
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param startNode the {@link Node} to start matching at.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
        Node startNode )
    {
        return match( start, startNode, null );
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param startNode the {@link Node} to start matching at.
     * @param objectVariables mapping from names to {@link PatternNode}s.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
        Node startNode, Map objectVariables )
    {
        return match( start, startNode, objectVariables,
            ( Collection ) null );
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param objectVariables mapping from names to {@link PatternNode}s.
     * @param optional nodes that form sub-patterns connected to this pattern.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
            Map objectVariables,
            PatternNode... optional )
    {
        return match( start, objectVariables,
            Arrays.asList( optional ) );
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param objectVariables mapping from names to {@link PatternNode}s.
     * @param optional nodes that form sub-patterns connected to this pattern.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
            Map objectVariables,
            Collection optional )
    {
        Node startNode = start.getAssociation();
        if ( startNode == null )
        {
            throw new IllegalStateException(
                    "Associating node for start pattern node is null" );
        }
        return match( start, startNode, objectVariables, optional );
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param startNode the {@link Node} to start matching at.
     * @param objectVariables mapping from names to {@link PatternNode}s.
     * @param optional nodes that form sub-patterns connected to this pattern.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
        Node startNode, Map objectVariables,
        Collection optional )
    {
        Node currentStartNode = start.getAssociation();
        if ( currentStartNode != null && !currentStartNode.equals( startNode ) )
        {
            throw new IllegalStateException(
                    "Start patter node already has associated " +
                    currentStartNode + ", can not start with " + startNode );
        }
        Iterable result = null;
        if ( optional == null || optional.size() < 1 )
        {
            result = new PatternFinder( this, start, startNode );
        }
        else
        {
            result = new PatternFinder( this, start, startNode, false,
                optional );
        }

        if ( objectVariables != null )
        {
            // Uses the FILTER expressions
            result = new FilteredPatternFinder( result, objectVariables );
        }
        return result;
    }

    /**
     * Find occurrences of the pattern defined by the given {@link PatternNode}
     * where the given {@link PatternNode} starts matching at the given
     * {@link Node}.
     *
     * @param start the {@link PatternNode} to start matching at.
     * @param startNode the {@link Node} to start matching at.
     * @param objectVariables mapping from names to {@link PatternNode}s.
     * @param optional nodes that form sub-patterns connected to this pattern.
     * @return all matching instances of the pattern.
     */
    public Iterable match( PatternNode start,
        Node startNode, Map objectVariables,
        PatternNode... optional )
    {
        return match( start, startNode, objectVariables,
            Arrays.asList( optional ) );
    }

    private static class SimpleRegexValueGetter implements FilterValueGetter
    {
        private PatternMatch match;
        private Map labelToNode =
            new HashMap();
        private Map labelToProperty =
            new HashMap();

        SimpleRegexValueGetter( Map objectVariables,
            PatternMatch match, FilterExpression[] expressions )
        {
            this.match = match;
            for ( FilterExpression expression : expressions )
            {
                mapFromExpression( expression );
            }
            this.labelToNode = objectVariables;
        }

        private void mapFromExpression( FilterExpression expression )
        {
            if ( expression instanceof FilterBinaryNode )
            {
                FilterBinaryNode node = ( FilterBinaryNode ) expression;
                mapFromExpression( node.getLeftExpression() );
                mapFromExpression( node.getRightExpression() );
            }
            else
            {
                AbstractFilterExpression pattern =
                    ( AbstractFilterExpression ) expression;
                labelToProperty.put( pattern.getLabel(),
                    pattern.getProperty() );
            }
        }

        public String[] getValues( String label )
        {
            PatternNode pNode = labelToNode.get( label );
            if ( pNode == null )
            {
                throw new RuntimeException( "No node for label '" + label +
                    "'" );
            }
            Node node = this.match.getNodeFor( pNode );

            String propertyKey = labelToProperty.get( label );
            if ( propertyKey == null )
            {
                throw new RuntimeException( "No property key for label '" +
                    label + "'" );
            }

            Object rawValue = node.getProperty( propertyKey, null );
            if ( rawValue == null )
            {
                return new String[ 0 ];
            }

            Collection