package org.apache.samoa.instances;

/*
 * #%L
 * SAMOA
 * %%
 * Copyright (C) 2014 - 2015 Apache Software Foundation
 * %%
 * 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.
 * #L%
 */

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/**
 * Class for storing the information of the attributes.
 * It stores only information about discrete attributes and suppose that
 * the default attribute is numeric.
 */
public class AttributesInformation implements Serializable {

  /**
   * The attribute information.
   */
  protected Attribute[] attributes;

  protected int[] indexValues;
  /**
   * The number of attributes.
   */
  protected int numberAttributes;

  /**
   * The attribute used for default for numerical values
   */
  protected Attribute defaultNumericAttribute;

  public AttributesInformation(AttributesInformation chunk) {
    this.attributes = chunk.attributes.clone();
    this.indexValues = chunk.indexValues.clone();
    this.numberAttributes = chunk.numberAttributes;
  }

  public AttributesInformation(Attribute[] v, int[] i, int numberAttributes) {
    this.attributes = v;
    this.indexValues = i;
    this.numberAttributes = numberAttributes;
  }

  public AttributesInformation(Attribute[] v, int numberAttributes) {
    this.attributes = v;
    this.indexValues = new int[numberAttributes];
    for (int i = 0; i < numberAttributes; i++) {
      this.indexValues[i] = i;
    }
    this.numberAttributes = numberAttributes;
  }

  public AttributesInformation(List<Attribute> v, int numberAttributes) {
    this.attributes = new Attribute[numberAttributes];
    this.indexValues = new int[numberAttributes];
    for (int i = 0; i < numberAttributes; i++) {
      this.indexValues[i] = i;
      this.attributes[i] = v.get(i);
    }
    this.numberAttributes = numberAttributes;
  }

  public AttributesInformation() {
    this.attributes = null;
    this.indexValues = null;
    this.numberAttributes = 0;
    this.defaultNumericAttribute = null;
  }

  /**
   * Attribute.
   *
   * @param indexAttribute the index Attribute
   * @return the attribute
   */
  public Attribute attribute(int indexAttribute) {
    if (this.attributes == null) {
      //All attributes are numeric
      return defaultNumericAttribute();
    }
    int location = locateIndex(indexAttribute);
    if (location == -1) {
      //if there is not attribute information, it is numeric
      return defaultNumericAttribute();
    }
    return attributes[location];
  }

  /*public void add(Attribute attribute, int value) {
      this.attributes.add(attribute);
      this.indexValues.add(value);
  }*/

  /**
   * Sets the attribute information.
   *
   * @param v the new attribute information
   */
  public void setAttributes(Attribute[] v) {
    this.attributes = v;
    this.numberAttributes = v.length;
    this.indexValues = new int[numberAttributes];
    for (int i = 0; i < numberAttributes; i++) {
      this.indexValues[i] = i;
    }
  }

  /**
   * Locates the greatest index that is not greater than the given index.
   *
   * @return the internal index of the attribute index. Returns -1 if no index
   * with this property could be found
   */
  public int locateIndex(int index) {

    int min = 0;
    int max = this.indexValues.length - 1;

    if (max == -1) {
      return -1;
    }

    // Binary search
    while ((this.indexValues[min] <= index) && (this.indexValues[max] >= index)) {
      int current = (max + min) / 2;
      if (this.indexValues[current] > index) {
        max = current - 1;
      } else if (this.indexValues[current] < index) {
        min = current + 1;
      } else {
        return current;
      }
    }
    if (this.indexValues[max] < index) {
      return max;
    } else {
      return min - 1;
    }
  }

  private Attribute defaultNumericAttribute() {
    if (this.defaultNumericAttribute == null) {
      this.defaultNumericAttribute = new Attribute("default");
    }
    return this.defaultNumericAttribute;
  }

  public void setAttributes(Attribute[] v, int[] indexValues) {
    this.attributes = v;
    this.numberAttributes = v.length;
    this.indexValues = indexValues;
  }

  public void deleteAttributeAt(int position) {

    int index = locateIndex(position);

    this.numberAttributes--;
    if ((index >= 0) && (indexValues[index] == position)) {
      int[] tempIndices = new int[indexValues.length - 1];
      Attribute[] tempValues = new Attribute[attributes.length - 1];
      System.arraycopy(indexValues, 0, tempIndices, 0, index);
      System.arraycopy(attributes, 0, tempValues, 0, index);
      for (int i = index; i < indexValues.length - 1; i++) {
        tempIndices[i] = indexValues[i + 1] - 1;
        tempValues[i] = attributes[i + 1];
      }
      indexValues = tempIndices;
      attributes = tempValues;
    } else {
      int[] tempIndices = new int[indexValues.length];
      Attribute[] tempValues = new Attribute[attributes.length];
      System.arraycopy(indexValues, 0, tempIndices, 0, index + 1);
      System.arraycopy(attributes, 0, tempValues, 0, index + 1);
      for (int i = index + 1; i < indexValues.length; i++) {
        tempIndices[i] = indexValues[i] - 1;
        tempValues[i] = attributes[i];
      }
      indexValues = tempIndices;
      attributes = tempValues;
    }
  }

  public void insertAttributeAt(Attribute attribute, int position) {
    if ((position < 0) || (position > this.numberAttributes)) {
      throw new IllegalArgumentException("Can't insert attribute: index out "
              + "of range");
    }
    int index = locateIndex(position);

    this.numberAttributes++;
    if ((index >= 0) && (indexValues[index] == position)) {
      int[] tempIndices = new int[indexValues.length + 1];
      Attribute[] tempValues = new Attribute[attributes.length + 1];
      System.arraycopy(indexValues, 0, tempIndices, 0, index);
      System.arraycopy(attributes, 0, tempValues, 0, index);
      tempIndices[index] = position;
      tempValues[index] = attribute;
      for (int i = index; i < indexValues.length; i++) {
        tempIndices[i + 1] = indexValues[i] + 1;
        tempValues[i + 1] = attributes[i];
      }
      indexValues = tempIndices;
      attributes = tempValues;
    } else {
      int[] tempIndices = new int[indexValues.length + 1];
      Attribute[] tempValues = new Attribute[attributes.length + 1];
      System.arraycopy(indexValues, 0, tempIndices, 0, index + 1);
      System.arraycopy(attributes, 0, tempValues, 0, index + 1);
      tempIndices[index + 1] = position;
      tempValues[index + 1] = attribute;
      for (int i = index + 1; i < indexValues.length; i++) {
        tempIndices[i + 1] = indexValues[i] + 1;
        tempValues[i + 1] = attributes[i];
      }
      indexValues = tempIndices;
      attributes = tempValues;
    }
  }

}