/*
 * 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.uima.cas.impl;

import java.util.ArrayList;
import java.util.List;

import org.apache.uima.internal.util.rb_trees.Int2IntRBT;
import org.apache.uima.jcas.cas.TOP;

/**
 * Used by Binary serialization form 4 and 6
 * 
 * Manage the conversion of FSs to relative sequential index number, and back Manage the difference
 * in two type systems both size of the FSs and handling excluded types
 * 
 * During serialization, these maps are constructed before serialization. During deserialization,
 * these maps are constructed while things are being deserialized, and then used in a "fixup" call
 * at the end. This allows for forward references.
 * 
 * For delta deserialization, the base part of these maps (for below-the-line) is constructed by
 * scanning up to the mark.
 */
public class CasSeqAddrMaps {

  /**
   * map from a target FS sequence nbr to a source id. value is 0 if the target instance doesn't
   * exist in the source (this doesn't occur for receiving remote CASes back (because src ts is
   * always a superset of tgt ts), but can occur while deserializing from Disk.)
   * <p>
   * index 0 is reserved for null
   */
  private final List<TOP> tgtId2SrcFs; // the key is the index

  // /**
  // * (Not Used, currently)
  // * map from a source seq number to a target seq number.
  // * value is -1 if the source FS is not in the target
  // */
  // final private IntVector srcSeq2TgtSeq = new IntVector();

  // /**
  // * (Not Used, currently)
  // * map from a target seq number to a target address.
  // */
  // final private IntVector tgtSeq2TgtAddr = new IntVector(); // used for comparing

  /**
   * map from source id to target id. if source is not in target, value = -1;
   */
  private final Int2IntRBT srcId2TgtId;

  private int nextTgt = 0;

  public CasSeqAddrMaps() {
    // this call makes the first real seq number == 1.
    // seq 0 refers to the NULL fs value.
    tgtId2SrcFs = new ArrayList<>();
    srcId2TgtId = new Int2IntRBT();
    addItemId(null, 0, true);
  }

  // copy constructor
  public CasSeqAddrMaps(List<TOP> tgtSeq2SrcFs, Int2IntRBT srcAddr2TgtSeq) {
    tgtId2SrcFs = tgtSeq2SrcFs;
    srcId2TgtId = srcAddr2TgtSeq;
  }

  /**
   * Add a new FS id - done during prescan of source during serialization Must call in heap scan
   * order
   * 
   * @param srcFs
   *          -
   * @param tgtId
   *          -
   * @param inTarget
   *          true if this type is in the target
   */
  public void addItemId(TOP srcFs, int tgtId, boolean inTarget) {
    if (inTarget) {
      tgtId2SrcFs.add(srcFs);
    }
    srcId2TgtId.put((null == srcFs) ? 0 : srcFs._id, inTarget ? nextTgt++ : -1);
  }

  /**
   * Called during deserialize to incrementally add
   * 
   * @param srcFs
   *          -
   * @param inSrc
   *          -
   */
  public void addSrcFsForTgt(TOP srcFs, boolean inSrc) {
    if (inSrc) {
      srcId2TgtId.put(srcFs._id, nextTgt);
      tgtId2SrcFs.add(srcFs);
    } else {
      tgtId2SrcFs.add(null);
    }
    nextTgt++;
  }

  // public void addSrcFsForTgtId(TOP srcFS, boolean isInSrc) {
  // if (isInSrc) {
  // tgtId2SrcFs.add(srcFS);
  // } else {
  // tgtId2SrcFs.add(null);
  // }
  // }

  /**
   * 
   * @param seq
   *          -
   * @return 0 means target seq doesn't exist in source CAS
   */
  public TOP getSrcFsFromTgtSeq(int seq) {
    if (seq >= tgtId2SrcFs.size()) {
      return null;
    }
    return tgtId2SrcFs.get(seq);
  }

  /**
   * @param itemAddr
   *          -
   * @return -1 if src addr not in target seq
   */
  public int getTgtSeqFromSrcAddr(int itemAddr) {
    return srcId2TgtId.getMostlyClose(itemAddr);
  }

  public int getNumberSrcFss() {
    return srcId2TgtId.size();
  }

  CasSeqAddrMaps copy() {
    CasSeqAddrMaps c = new CasSeqAddrMaps(new ArrayList<>(tgtId2SrcFs), srcId2TgtId.copy());
    c.nextTgt = nextTgt;
    return c;
  }

}
