/*
 * This file is part of GumTree.
 *
 * GumTree is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * GumTree 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with GumTree.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2011-2015 Jean-Rémy Falleri <jr.falleri@gmail.com>
 * Copyright 2011-2015 Floréal Morandat <florealm@gmail.com>
 */

package com.github.gumtreediff.matchers;

import com.github.gumtreediff.tree.ITree;

import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.logging.Logger;

public abstract class Matcher {

    public static final Logger LOGGER = Logger.getLogger("com.github.gumtreediff.matchers");

    protected final ITree src;

    protected final ITree dst;

    protected final MappingStore mappings;

    public Matcher(ITree src, ITree dst, MappingStore mappings) {
        this.src = src;
        this.dst = dst;
        this.mappings = mappings;
    }

    public abstract void match();

    public MappingStore getMappings() {
        return mappings;
    }

    public Set<Mapping> getMappingSet() {
        return mappings.asSet();
    }

    public ITree getSrc() {
        return src;
    }

    public ITree getDst() {
        return dst;
    }

    protected void addMapping(ITree src, ITree dst) {
        mappings.link(src, dst);
    }

    protected void addMappingRecursively(ITree src, ITree dst) {
        List<ITree> srcTrees = src.getTrees();
        List<ITree> dstTrees = dst.getTrees();
        for (int i = 0; i < srcTrees.size(); i++) {
            ITree currentSrcTree = srcTrees.get(i);
            ITree currentDstTree = dstTrees.get(i);
            addMapping(currentSrcTree, currentDstTree);
        }
    }

    public double chawatheSimilarity(ITree src, ITree dst) {
        int max = Math.max(src.getDescendants().size(), dst.getDescendants().size());
        return (double) numberOfCommonDescendants(src, dst) / (double) max;
    }

    public double diceSimilarity(ITree src, ITree dst) {
        double c = (double) numberOfCommonDescendants(src, dst);
        return (2D * c) / ((double) src.getDescendants().size() + (double) dst.getDescendants().size());
    }

    public double jaccardSimilarity(ITree src, ITree dst) {
        double num = (double) numberOfCommonDescendants(src, dst);
        double den = (double) src.getDescendants().size() + (double) dst.getDescendants().size() - num;
        return num / den;
    }

    protected int numberOfCommonDescendants(ITree src, ITree dst) {
        Set<ITree> dstDescandants = new HashSet<>(dst.getDescendants());
        int common = 0;

        for (ITree t : src.getDescendants()) {
            ITree m = mappings.getDst(t);
            if (m != null && dstDescandants.contains(m))
                common++;
        }

        return common;
    }

    public boolean isMappingAllowed(ITree src, ITree dst) {
        return src.hasSameType(dst) && !(mappings.hasSrc(src) || mappings.hasDst(dst));
    }
}
