/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.eclipse.aether.util.filter;

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.eclipse.aether.graph.DependencyFilter;
import org.eclipse.aether.graph.DependencyNode;

import static java.util.Objects.requireNonNull;

/**
 * A dependency filter that combines zero or more other filters using a logical {@code AND}. The resulting filter
 * accepts a given dependency node if and only if all constituent filters accept it.
 */
public final class AndDependencyFilter implements DependencyFilter {

    private final Set<DependencyFilter> filters = new LinkedHashSet<>();

    /**
     * Creates a new filter from the specified filters. Prefer {@link #newInstance(DependencyFilter, DependencyFilter)}
     * if any of the input filters might be {@code null}.
     *
     * @param filters the filters to combine, may be {@code null} but must not contain {@code null} elements
     */
    public AndDependencyFilter(DependencyFilter... filters) {
        if (filters != null) {
            Collections.addAll(this.filters, filters);
        }
    }

    /**
     * Creates a new filter from the specified filters.
     *
     * @param filters the filters to combine, may be {@code null} but must not contain {@code null} elements
     */
    public AndDependencyFilter(Collection<DependencyFilter> filters) {
        if (filters != null) {
            this.filters.addAll(filters);
        }
    }

    /**
     * Creates a new filter from the specified filters.
     *
     * @param filter1 the first filter to combine, may be {@code null}
     * @param filter2 the second filter to combine, may be {@code null}
     * @return the combined filter or {@code null} if both filter were {@code null}
     */
    public static DependencyFilter newInstance(DependencyFilter filter1, DependencyFilter filter2) {
        if (filter1 == null) {
            return filter2;
        } else if (filter2 == null) {
            return filter1;
        }
        return new AndDependencyFilter(filter1, filter2);
    }

    public boolean accept(DependencyNode node, List<DependencyNode> parents) {
        requireNonNull(node, "node cannot be null");
        requireNonNull(parents, "parents cannot be null");
        for (DependencyFilter filter : filters) {
            if (!filter.accept(node, parents)) {
                return false;
            }
        }
        return true;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj == null || !getClass().equals(obj.getClass())) {
            return false;
        }

        AndDependencyFilter that = (AndDependencyFilter) obj;

        return this.filters.equals(that.filters);
    }

    @Override
    public int hashCode() {
        int hash = getClass().hashCode();
        hash = hash * 31 + filters.hashCode();
        return hash;
    }
}
