package org.apache.samoa.instances;

import java.io.InputStream;

/*
 * #%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.Reader;
import java.io.Serializable;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;

public class Instances implements Serializable {

  /**
   * The keyword used to denote the start of an arff header
   */
  public final static String ARFF_RELATION = "@relation";

  /**
   * The keyword used to denote the start of the arff data section
   */
  public final static String ARFF_DATA = "@data";

  private static final long serialVersionUID = 8110510475535581577L;
  /**
   * The instance information.
   */
  protected InstanceInformation instanceInformation;
  /**
   * The instances.
   */
  protected List<Instance> instances;

  protected static enum AVRO_ENCODING_FORMAT {
    JSON, BINARY
  }

  protected int classAttribute;

  /**
   * A Hash that stores the indices of features.
   */
  protected HashMap<String, Integer> hsAttributesIndices;

  transient protected Loader loader;

  /**
   * Instantiates a new instances.
   *
   * @param chunk the chunk
   */
  public Instances(Instances chunk) {
    this(chunk, chunk.numInstances());
    chunk.copyInstances(0, this, chunk.numInstances());
  }

  /**
   * Instantiates a new instances.
   */
  public Instances() {
  }

  /**
   * Instantiates a new instances.
   *
   * @param reader the reader
   * @param size the size
   * @param classAttribute the class attribute
   */
  public Instances(Reader reader, int size, int classAttribute) {
    this.loader = new ArffLoader(reader, 0, classAttribute);
    this.instanceInformation = loader.getStructure();
    this.instances = new ArrayList<Instance>();
  }

  /**
   * Instantiates a new instances.
   *
   * @param reader the reader
   * @param range
   */
  public Instances(Reader reader, Range range) {
    this.loader = new ArffLoader(reader, 0, classAttribute);//new MultiTargetArffLoader(reader, range);
    this.instanceInformation = loader.getStructure();
    this.instances = new ArrayList<Instance>();
  }

  public Instances(InputStream inputStream, int classAttribute, String encodingFormat) {
    this.classAttribute = classAttribute;

    if (encodingFormat.equalsIgnoreCase(AVRO_ENCODING_FORMAT.BINARY.toString()))
      loader = new AvroBinaryLoader(inputStream, classAttribute);
    else
      loader = new AvroJsonLoader(inputStream, classAttribute);

    this.instanceInformation = loader.getStructure();
    this.instances = new ArrayList<>();
  }

  /**
   * Instantiates a new instances.
   *
   * @param chunk the chunk
   * @param capacity the capacity
   */
  public Instances(Instances chunk, int capacity) {
    this.instanceInformation = chunk.instanceInformation();
    if (capacity < 0) {
      capacity = 0;
    }
    this.instances = new ArrayList<Instance>(capacity);
  }

  /**
   * Instantiates a new instances.
   *
   * @param st the st
   * @param v the v
   * @param capacity the capacity
   */
  public Instances(String st, List<Attribute> v, int capacity) {
    this.instanceInformation = new InstanceInformation(st, v);
    this.instances = new ArrayList<Instance>(capacity);
  }

  /**
   * Instantiates a new instances.
   *
   * @param chunk the chunk
   * @param first the first instance
   * @param toCopy the j
   */
  public Instances(Instances chunk, int first, int toCopy) {

    this(chunk, toCopy);

    if ((first < 0) || ((first + toCopy) > chunk.numInstances())) {
      throw new IllegalArgumentException("Parameters first and/or toCopy out "
          + "of range");
    }
    chunk.copyInstances(first, this, toCopy);
  }

  /**
   * Instantiates a new instances.
   *
   * @param st the st
   * @param capacity the capacity
   */
  public Instances(StringReader st, int capacity) {
    this.instances = new ArrayList<Instance>(capacity);
  }

  //Information Instances
  /**
   * Sets the relation name.
   *
   * @param string the new relation name
   */
  public void setRelationName(String string) {
    this.instanceInformation.setRelationName(string);
  }

  /**
   * Gets the relation name.
   *
   * @return the relation name
   */
  public String getRelationName() {
    return this.instanceInformation.getRelationName();
  }

  /**
   * Class index.
   *
   * @return the int
   */
  public int classIndex() {
    return this.instanceInformation.classIndex();
  }

  /**
   * Sets the class index.
   *
   * @param classIndex the new class index
   */
  public void setClassIndex(int classIndex) {
    this.instanceInformation.setClassIndex(classIndex);
  }

  /**
   * Class attribute.
   *
   * @return the attribute
   */
  public Attribute classAttribute() {
    return this.instanceInformation.classAttribute();
  }

  /**
   * Num attributes.
   *
   * @return the int
   */
  public int numAttributes() {
    return this.instanceInformation.numAttributes();
  }

  /**
   * Attribute.
   *
   * @param w the w
   * @return the attribute
   */
  public Attribute attribute(int w) {
    return this.instanceInformation.attribute(w);
  }

  /**
   * Num classes.
   *
   * @return the int
   */
  public int numClasses() {
    return this.instanceInformation.numClasses();
  }

  /**
   * Delete attribute at.
   *
   * @param integer the integer
   */
  public void deleteAttributeAt(Integer integer) {
    this.instanceInformation.deleteAttributeAt(integer);
  }

  /**
   * Insert attribute at.
   *
   * @param attribute the attribute
   * @param i the i
   */
  public void insertAttributeAt(Attribute attribute, int i) {
    if (this.instanceInformation == null) {
      this.instanceInformation = new InstanceInformation();
    }
    this.instanceInformation.insertAttributeAt(attribute, i);
  }

  //List of Instances
  /**
   * Instance.
   *
   * @param num the num
   * @return the instance
   */
  public Instance instance(int num) {
    return this.instances.get(num);
  }

  /**
   * Num instances.
   *
   * @return the int
   */
  public int numInstances() {
    return this.instances.size();
  }

  /**
   * Adds the.
   *
   * @param inst the inst
   */
  public void add(Instance inst) {
    this.instances.add(inst);
  }

  /**
   * Randomize.
   *
   * @param random the random
   */
  public void randomize(Random random) {
    for (int j = numInstances() - 1; j > 0; j--) {
      swap(j, random.nextInt(j + 1));
    }
  }

  /**
   * Stratify.
   *
   * @param numFolds the num folds
   */
  public void stratify(int numFolds) {

    if (classAttribute().isNominal()) {

      // sort by class
      int index = 1;
      while (index < numInstances()) {
        Instance instance1 = instance(index - 1);
        for (int j = index; j < numInstances(); j++) {
          Instance instance2 = instance(j);
          if ((instance1.classValue() == instance2.classValue())
              || (instance1.classIsMissing()
                  && instance2.classIsMissing())) {
            swap(index, j);
            index++;
          }
        }
        index++;
      }
      stratStep(numFolds);
    }
  }

  protected void stratStep(int numFolds) {
    ArrayList<Instance> newVec = new ArrayList<Instance>(this.instances.size());
    int start = 0, j;

    // create stratified batch
    while (newVec.size() < numInstances()) {
      j = start;
      while (j < numInstances()) {
        newVec.add(instance(j));
        j = j + numFolds;
      }
      start++;
    }
    this.instances = newVec;
  }

  /**
   * Train cv.
   *
   * @param numFolds the num folds
   * @param numFold
   * @param random the random
   * @return the instances
   */
  public Instances trainCV(int numFolds, int numFold, Random random) {
    Instances train = trainCV(numFolds, numFold);
    train.randomize(random);
    return train;
  }

  public Instances trainCV(int numFolds, int numFold) {
    int numInstForFold, first, offset;
    Instances train;

    numInstForFold = numInstances() / numFolds;
    if (numFold < numInstances() % numFolds) {
      numInstForFold++;
      offset = numFold;
    } else {
      offset = numInstances() % numFolds;
    }
    train = new Instances(this, numInstances() - numInstForFold);
    first = numFold * (numInstances() / numFolds) + offset;
    copyInstances(0, train, first);
    copyInstances(first + numInstForFold, train,
        numInstances() - first - numInstForFold);
    return train;
  }

  protected void copyInstances(int from, Instances dest, int num) {
    for (int i = 0; i < num; i++) {
      dest.add(instance(from + i));
    }
  }

  /**
   * Test cv.
   *
   * @param numFolds the num folds
   * @param numFold the num fold
   * @return the instances
   */
  public Instances testCV(int numFolds, int numFold) {

    int numInstForFold, first, offset;
    Instances test;

    numInstForFold = numInstances() / numFolds;
    if (numFold < numInstances() % numFolds) {
      numInstForFold++;
      offset = numFold;
    } else {
      offset = numInstances() % numFolds;
    }
    test = new Instances(this, numInstForFold);
    first = numFold * (numInstances() / numFolds) + offset;
    copyInstances(first, test, numInstForFold);
    return test;
  }

  /*  public Instances dataset() {
     throw new UnsupportedOperationException("Not yet implemented");
     }*/
  /**
   * Mean or mode.
   *
   * @param j the j
   * @return the double
   */
  public double meanOrMode(int j) {
    throw new UnsupportedOperationException("Not yet implemented"); //CobWeb
  }

  /**
   * Read instance.
   *
   * @param fileReader the file reader
   * @return true, if successful
   */
  public boolean readInstance(Reader fileReader) {

    //ArffReader arff = new ArffReader(reader, this, m_Lines, 1);
    if (loader == null) {
      loader = new ArffLoader(fileReader, 0, this.classAttribute);
    }
    Instance inst = loader.readInstance();
    if (inst != null) {
      inst.setDataset(this);
      add(inst);
      return true;
    } else {
      return false;
    }
  }

  public boolean readInstance() {

    Instance inst = loader.readInstance();
    if (inst != null) {
      inst.setDataset(this);
      add(inst);
      return true;
    } else {
      return false;
    }
  }

  /**
   * Delete.
   */
  public void delete() {
    this.instances = new ArrayList<Instance>();
  }

  /**
   * Delete.
   */
  public void delete(int index) {
    this.instances.remove(index);
  }

  /**
   * Swap.
   *
   * @param i the i
   * @param j the j
   */
  public void swap(int i, int j) {
    Instance in = instances.get(i);
    instances.set(i, instances.get(j));
    instances.set(j, in);
  }

  /**
   * Instance information.
   *
   * @return the instance information
   */
  private InstanceInformation instanceInformation() {
    return this.instanceInformation;
  }

  public Attribute attribute(String name) {

    for (int i = 0; i < numAttributes(); i++) {
      if (attribute(i).name().equals(name)) {
        return attribute(i);
      }
    }
    return null;
  }

  public int size() {
    return this.numInstances();
  }

  public void set(int i, Instance inst) {
    this.instances.set(i, inst);
  }

  public Instance get(int k) {
    return this.instance(k);
  }

  public void setRangeOutputIndices(Range range) {
    this.instanceInformation.setRangeOutputIndices(range);

  }

  public void setAttributes(List<Attribute> v) {
    if (this.instanceInformation == null) {
      this.instanceInformation = new InstanceInformation();
    }
    this.instanceInformation.setAttributes(v);
  }

  public void setAttributes(List<Attribute> v, List<Integer> indexValues) {
    if (this.instanceInformation == null) {
      this.instanceInformation = new InstanceInformation();
    }
    this.instanceInformation.setAttributes(v, indexValues);
  }

  /**
   * Returns the dataset as a string in ARFF format. Strings are quoted if
   * they contain whitespace characters, or if they are a question mark.
   *
   * @return the dataset in ARFF format as a string
   */
  public String toString() {

    StringBuffer text = new StringBuffer();

    text.append(ARFF_RELATION).append(" ").
    append(Utils.quote(this.instanceInformation.getRelationName())).append("\n\n");
    for (int i = 0; i < numAttributes(); i++) {
      text.append(attribute(i).toString()).append("\n");
    }
    text.append("\n").append(ARFF_DATA).append("\n");

    text.append(stringWithoutHeader());
    return text.toString();
  }

  /**
   * Returns the dataset as a string in ARFF format. Strings are quoted if
   * they contain whitespace characters, or if they are a question mark.
   *
   * @return the dataset in ARFF format as a string
   */
  public String toStringArff() {

    StringBuffer text = new StringBuffer();

    text.append(ARFF_RELATION).append(" ").
    append(Utils.quote(this.instanceInformation.getRelationName())).append("\n\n");
    for (int i = 0; i < numAttributes(); i++) {
      text.append(attribute(i).toString()).append("\n");
    }
    text.append("\n").append(ARFF_DATA).append("\n");

    text.append(stringWithoutHeader());
    return text.toString();
  }

  /**
   * Returns the instances in the dataset as a string in ARFF format. Strings
   * are quoted if they contain whitespace characters, or if they are a
   * question mark.
   *
   * @return the dataset in ARFF format as a string
   */
  protected String stringWithoutHeader() {

    StringBuffer text = new StringBuffer();

    for (int i = 0; i < numInstances(); i++) {
      text.append(instance(i));
      if (i < numInstances() - 1) {
        text.append('\n');
      }
    }
    return text.toString();

  }

  /**
   * Returns the index of an Attribute.
   *
   * @param att, the attribute.
   */
  protected int indexOf(Attribute att) {
    if (this.hsAttributesIndices == null || !this.hsAttributesIndices.containsKey(att.name)) {
      computeAttributesIndices();
    }

    return this.hsAttributesIndices.get(att.name());
  }

  /**
   * Completes the hashset with attributes indices.
   */
  private void computeAttributesIndices() {
    this.hsAttributesIndices = new HashMap<String, Integer>();
    // iterates through all existing attributes
    // and sets an unique identifier for each one of them
    for (int i = 0; i < this.numAttributes(); i++) {
      hsAttributesIndices.put(this.attribute(i).name(), i);
    }
  }
}