package net.messagevortex.router;

// ************************************************************************************
// * Copyright (c) 2018 Martin Gwerder (martin@gwerder.net)
// *
// * Permission is hereby granted, free of charge, to any person obtaining a copy
// * of this software and associated documentation files (the "Software"), to deal
// * in the Software without restriction, including without limitation the rights
// * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// * copies of the Software, and to permit persons to whom the Software is
// * furnished to do so, subject to the following conditions:
// *
// * The above copyright notice and this permission notice shall be included in all
// * copies or substantial portions of the Software.
// *
// * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// * SOFTWARE.
// ************************************************************************************

import net.messagevortex.asn1.IdentityStoreBlock;

/**
 * <p>Represents a graph between two identity blocks inclusive senders operation and time.</p>
 */
public class Edge {

  private static final long serialVersionUID = 9070431563L;

  private final IdentityStoreBlock from;
  private final IdentityStoreBlock to;
  private long startTime = 0;
  private long maxDelay = 10000;

  /***
   * <p>Represents a router graph during sending.</p>
   *
   * @param  from       The starting point of the graph
   * @param  to         The ending point of the graph
   * @param  startTime  The starting time relative to the GraphSet start (in ms)
   * @param  maxDelay   The maximum delay after the start of this graph (in ms)
   * @throws IllegalArgumentException if from and two are equal
   * @throws NullPointerException if one of the parameters is null
   */
  public Edge(IdentityStoreBlock from, IdentityStoreBlock to, long startTime, long maxDelay) {

    if (from == null) {
      throw new NullPointerException("from may not be null in an edge");
    }

    if (to == null) {
      throw new NullPointerException("from may not be null in an edge");
    }

    if (from == to || from.equals(to)) {
      throw new IllegalArgumentException("an edge may not have the same start and ending point");
    }

    this.from = from;
    this.to = to;
    this.startTime = startTime;
    this.maxDelay = maxDelay;
  }

  /***
   * <p>Get the sending entity.</p>
   *
   * @return The sending entity
   */
  public IdentityStoreBlock getFrom() {
    return from;
  }

  /***
   * <p>Get the receiving entity.</p>
   *
   * @return The receiving entity
   */
  public IdentityStoreBlock getTo() {
    return to;
  }

  /***
   * <p>Gets the start time of the edge relative to the graphsets start.</p>
   *
   * @return the currently set start time
   */
  public long getStartTime() {
    return startTime;
  }

  /***
   * <p>Sets the start time of the edge relative to the start time of the graph set.</p>
   *
   * @param newStartTime the time to be set in millis
   * @return the previously set time
   */
  public long setStartTime(long newStartTime) {
    long old = startTime;
    this.startTime = newStartTime;
    return old;
  }

  /***
   * <p>Gets the maximum delay time a router may choose to delay the edge starting at the
   * start time.</p>
   *
   * @return the currently set maximum delay time
   */
  public long getDelayTime() {
    return maxDelay;
  }

  /***
   * <p>Sets the maximum delay time a router may choose to delay the edge starting at the
   * start time.</p>
   *
   * @param newMaxDelay the new maximum time to be set
   * @return the previously set maximum delay time
   */
  public long setDelayTime(long newMaxDelay) {
    long old = maxDelay;
    this.maxDelay = newMaxDelay;
    return old;
  }

  @Override
  public boolean equals(Object t) {
    if (t == null) {
      return false;
    }
    if (t.getClass() != this.getClass()) {
      return false;
    }
    Edge g = (Edge) t;
    return (g.startTime == this.startTime) && (g.maxDelay == this.maxDelay)
        && g.to.equals(this.to) && g.from.equals(this.from);
  }

  @Override
  public int hashCode() {
    return toString().hashCode();
  }

  @Override
  public String toString() {
    return from + " -" + startTime + "/" + maxDelay + "-> " + to;
  }
}