package de.lmu.ifi.dbs.elki.utilities.optionhandling.parameters;

/*
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2015
 Ludwig-Maximilians-Universität München
 Lehr- und Forschungseinheit für Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import de.lmu.ifi.dbs.elki.math.random.RandomFactory;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.OptionID;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.ParameterException;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.WrongParameterValueException;

/**
 * Parameter for random generators and/or random seeds.
 * 
 * @author Erich Schubert
 */
public class RandomParameter extends AbstractParameter<RandomParameter, RandomFactory> {
  /**
   * Seed value, if used
   */
  Long seed = null;

  /**
   * Constructor without default.
   * 
   * @param optionID Option ID
   */
  public RandomParameter(OptionID optionID) {
    super(optionID, RandomFactory.DEFAULT);
  }

  /**
   * Constructor with default value. The default value may be {@code null},
   * which means a new random will be generated.
   * 
   * @param optionID Option ID
   * @param defaultValue Default value. If {@code null}, a new random object
   *        will be created.
   */
  public RandomParameter(OptionID optionID, RandomFactory defaultValue) {
    super(optionID, defaultValue);
  }

  /**
   * Constructor with default seed value.
   * 
   * @param optionID Option ID
   * @param seed Default seed.
   */
  public RandomParameter(OptionID optionID, long seed) {
    super(optionID, true);
    this.seed = Long.valueOf(seed);
  }

  @Override
  public String getSyntax() {
    return "<long|Random>";
  }

  @Override
  public void setValue(Object obj) throws ParameterException {
    // This is a bit hackish. Set both seed and random (via super.setValue())
    if (obj instanceof RandomFactory) {
      seed = null;
    } else if (obj instanceof Long) {
      seed = (Long) obj;
      obj = RandomFactory.get(seed);
    } else if (obj instanceof Number) {
      seed = Long.valueOf(((Number) obj).longValue());
      obj = RandomFactory.get(seed);
    } else if ("global random".equals(obj)) {
      obj = RandomFactory.DEFAULT;
    } else {
      try {
        seed = Long.valueOf(obj.toString());
        obj = RandomFactory.get(seed);
      } catch (NullPointerException e) {
        throw new WrongParameterValueException("Wrong parameter format! Parameter \"" + getName() + "\" requires a long seed value or a random generator factory, read: " + obj + "!\n");
      } catch (NumberFormatException e) {
        throw new WrongParameterValueException("Wrong parameter format! Parameter \"" + getName() + "\" requires a long seed value or a random generator factory, read: " + obj + "!\n");
      }
    }
    super.setValue(obj);
  }

  @Override
  protected RandomFactory parseValue(Object obj) throws ParameterException {
    if (obj instanceof RandomFactory) {
      return (RandomFactory) obj;
    }
    if (obj instanceof Long) {
      return RandomFactory.get((Long) obj);
    }
    if (obj instanceof Number) {
      return RandomFactory.get(Long.valueOf(((Number) obj).longValue()));
    }
    try {
      return RandomFactory.get(Long.valueOf(obj.toString()));
    } catch (NullPointerException e) {
      throw new WrongParameterValueException("Wrong parameter format! Parameter \"" + getName() + "\" requires a long seed value or a random generator factory, read: " + obj + "!\n");
    } catch (NumberFormatException e) {
      throw new WrongParameterValueException("Wrong parameter format! Parameter \"" + getName() + "\" requires a long seed value or a random generator factory, read: " + obj + "!\n");
    }
  }

  @Override
  public Object getGivenValue() {
    Object r = super.getGivenValue();
    if (r != null && seed != null) {
      super.givenValue = RandomFactory.get(seed);
      r = super.givenValue;
    }
    return r;
  }

  @Override
  public String getValueAsString() {
    return (seed != null) ? seed.toString() : "null";
  }

  @Override
  public String getDefaultValueAsString() {
    if (defaultValue == RandomFactory.DEFAULT) {
      return "global random";
    }
    return super.getDefaultValueAsString();
  }
}