/*
 * Licensed 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 edu.stanford.futuredata.macrobase.sql.tree;

import static com.google.common.base.MoreObjects.toStringHelper;
import static java.util.Objects.requireNonNull;

import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.Objects;
import java.util.Optional;

public class AliasedRelation extends Relation {

    private final Relation relation;
    private final Identifier alias;
    private final List<Identifier> columnNames;

    public AliasedRelation(Relation relation, Identifier alias, List<Identifier> columnNames) {
        this(Optional.empty(), relation, alias, columnNames);
    }

    public AliasedRelation(NodeLocation location, Relation relation, Identifier alias,
        List<Identifier> columnNames) {
        this(Optional.of(location), relation, alias, columnNames);
    }

    private AliasedRelation(Optional<NodeLocation> location, Relation relation, Identifier alias,
        List<Identifier> columnNames) {
        super(location);
        requireNonNull(relation, "relation is null");
        requireNonNull(alias, " is null");

        this.relation = relation;
        this.alias = alias;
        this.columnNames = columnNames;
    }

    public Relation getRelation() {
        return relation;
    }

    public Identifier getAlias() {
        return alias;
    }

    public List<Identifier> getColumnNames() {
        return columnNames;
    }

    @Override
    public <R, C> R accept(AstVisitor<R, C> visitor, C context) {
        return visitor.visitAliasedRelation(this, context);
    }

    @Override
    public List<Node> getChildren() {
        return ImmutableList.of(relation);
    }

    @Override
    public String toString() {
        return toStringHelper(this)
            .add("relation", relation)
            .add("alias", alias)
            .add("columnNames", columnNames)
            .omitNullValues()
            .toString();
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }

        AliasedRelation that = (AliasedRelation) o;
        return Objects.equals(relation, that.relation) &&
            Objects.equals(alias, that.alias) &&
            Objects.equals(columnNames, that.columnNames);
    }

    @Override
    public int hashCode() {
        return Objects.hash(relation, alias, columnNames);
    }
}
