/**
 * 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.apache.hadoop.hive.ql.parse;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map.Entry;

/**
 * Internal representation of the join tree.
 *
 */
public class QBJoinTree implements Serializable{
  private static final long serialVersionUID = 1L;
  private String leftAlias;
  private String[] rightAliases;
  private String[] leftAliases;
  private QBJoinTree joinSrc;
  private String[] baseSrc;
  private int nextTag;
  private JoinCond[] joinCond;
  private boolean noOuterJoin;
  private boolean noSemiJoin;

  // keeps track of the right-hand-side table name of the left-semi-join, and
  // its list of join keys
  private final HashMap<String, ArrayList<ASTNode>> rhsSemijoin;

  // join conditions
  private ArrayList<ArrayList<ASTNode>> expressions;

  // key index to nullsafe join flag
  private ArrayList<Boolean> nullsafes;

  // filters
  private ArrayList<ArrayList<ASTNode>> filters;

  // filters for pushing
  private ArrayList<ArrayList<ASTNode>> filtersForPushing;

  // user asked for map-side join
  private boolean mapSideJoin;
  private List<String> mapAliases;

  // big tables that should be streamed
  private List<String> streamAliases;

  /**
   * constructor.
   */
  public QBJoinTree() {
    nextTag = 0;
    noOuterJoin = true;
    noSemiJoin = true;
    rhsSemijoin = new HashMap<String, ArrayList<ASTNode>>();
  }

  /**
   * returns left alias if any - this is used for merging later on.
   *
   * @return left alias if any
   */
  public String getLeftAlias() {
    return leftAlias;
  }

  /**
   * set left alias for the join expression.
   *
   * @param leftAlias
   *          String
   */
  public void setLeftAlias(String leftAlias) {
    this.leftAlias = leftAlias;
  }

  public String[] getRightAliases() {
    return rightAliases;
  }

  public void setRightAliases(String[] rightAliases) {
    this.rightAliases = rightAliases;
  }

  public String[] getLeftAliases() {
    return leftAliases;
  }

  public void setLeftAliases(String[] leftAliases) {
    this.leftAliases = leftAliases;
  }

  public ArrayList<ArrayList<ASTNode>> getExpressions() {
    return expressions;
  }

  public void setExpressions(ArrayList<ArrayList<ASTNode>> expressions) {
    this.expressions = expressions;
  }

  public String[] getBaseSrc() {
    return baseSrc;
  }

  public void setBaseSrc(String[] baseSrc) {
    this.baseSrc = baseSrc;
  }

  public QBJoinTree getJoinSrc() {
    return joinSrc;
  }

  public void setJoinSrc(QBJoinTree joinSrc) {
    this.joinSrc = joinSrc;
  }

  public int getNextTag() {
    return nextTag++;
  }

  public String getJoinStreamDesc() {
    return "$INTNAME";
  }

  public JoinCond[] getJoinCond() {
    return joinCond;
  }

  public void setJoinCond(JoinCond[] joinCond) {
    this.joinCond = joinCond;
  }

  public boolean getNoOuterJoin() {
    return noOuterJoin;
  }

  public void setNoOuterJoin(boolean noOuterJoin) {
    this.noOuterJoin = noOuterJoin;
  }

  public boolean getNoSemiJoin() {
    return noSemiJoin;
  }

  public void setNoSemiJoin(boolean semi) {
    noSemiJoin = semi;
  }

  /**
   * @return the filters
   */
  public ArrayList<ArrayList<ASTNode>> getFilters() {
    return filters;
  }

  /**
   * @param filters
   *          the filters to set
   */
  public void setFilters(ArrayList<ArrayList<ASTNode>> filters) {
    this.filters = filters;
  }

  /**
   * @return the filters for pushing
   */
  public ArrayList<ArrayList<ASTNode>> getFiltersForPushing() {
    return filtersForPushing;
  }

  /**
   * @param filters for pushing
   *          the filters to set
   */
  public void setFiltersForPushing(ArrayList<ArrayList<ASTNode>> filters) {
    this.filtersForPushing = filters;
  }

  /**
   * @return the mapSidejoin
   */
  public boolean isMapSideJoin() {
    return mapSideJoin;
  }

  /**
   * @param mapSideJoin
   *          the mapSidejoin to set
   */
  public void setMapSideJoin(boolean mapSideJoin) {
    this.mapSideJoin = mapSideJoin;
  }

  /**
   * @return the mapAliases
   */
  public List<String> getMapAliases() {
    return mapAliases;
  }

  /**
   * @param mapAliases
   *          the mapAliases to set
   */
  public void setMapAliases(List<String> mapAliases) {
    this.mapAliases = mapAliases;
  }

  public List<String> getStreamAliases() {
    return streamAliases;
  }

  public void setStreamAliases(List<String> streamAliases) {
    this.streamAliases = streamAliases;
  }

  /**
   * Insert only a key to the semijoin table name to column names map.
   *
   * @param alias
   *          table name alias.
   */
  public void addRHSSemijoin(String alias) {
    if (!rhsSemijoin.containsKey(alias)) {
      rhsSemijoin.put(alias, null);
    }
  }

  /**
   * Remeber the mapping of table alias to set of columns.
   *
   * @param alias
   * @param columns
   */
  public void addRHSSemijoinColumns(String alias, ArrayList<ASTNode> columns) {
    ArrayList<ASTNode> cols = rhsSemijoin.get(alias);
    if (cols == null) {
      rhsSemijoin.put(alias, columns);
    } else {
      cols.addAll(columns);
    }
  }

  /**
   * Remeber the mapping of table alias to set of columns.
   *
   * @param alias
   * @param column
   */
  public void addRHSSemijoinColumns(String alias, ASTNode column) {
    ArrayList<ASTNode> cols = rhsSemijoin.get(alias);
    if (cols == null) {
      cols = new ArrayList<ASTNode>();
      cols.add(column);
      rhsSemijoin.put(alias, cols);
    } else {
      cols.add(column);
    }
  }

  public ArrayList<ASTNode> getRHSSemijoinColumns(String alias) {
    return rhsSemijoin.get(alias);
  }

  /**
   * Merge the rhs tables from another join tree.
   *
   * @param src
   *          the source join tree
   */
  public void mergeRHSSemijoin(QBJoinTree src) {
    for (Entry<String, ArrayList<ASTNode>> e : src.rhsSemijoin.entrySet()) {
      String key = e.getKey();
      ArrayList<ASTNode> value = rhsSemijoin.get(key);
      if (value == null) {
        rhsSemijoin.put(key, e.getValue());
      } else {
        value.addAll(e.getValue());
      }
    }
  }

  public ArrayList<Boolean> getNullSafes() {
    return nullsafes;
  }

  public void setNullSafes(ArrayList<Boolean> nullSafes) {
    this.nullsafes = nullSafes;
  }
}