// Chapter 4, Exercise Set 2, Question 6
// A turning slow fish may turn right or left even if it doesn't move
// outside its own cell.

import java.awt.Color;
import java.util.ArrayList;
import java.util.Random;

/**
 * Marine Biology Simulation:
 * The TurningSlowFish class represents a fish in the MBS that moves
 * very slowly. It moves so slowly that it only has a 1 in 5 chance
 * of moving out of its current cell into an adjacent cell in any
 * given timestep in the simulation. When it does move beyond its
 * own cell,its behavior is the same as for objects of the Fish
 * class. If it doesn't move beyond its cell, the fish may still
 * turn left or right.
 *
 * TurningSlowFish objects inherit instance variables and much of
 * their behavior from the SlowFish class.
 *
 **/
public class TurningSlowFish extends SlowFish
{
  // Instance Variables: Encapsulated data for EACH slow fish
  private double probOfMoving;
          // defines likelihood in each timestep
  private double probOfTurning;
          // defines likelihood of turning in place
  private double probOfRight;
          // defines likelihood of turning right

  // constructors

  /** Constructs a turning slow fish at the specified location in a
   *  given environment. This slow fish is colored green.
   *  (Precondition: parameters are non-null; <code>loc</code> is
   *  valid for <code>env</code>.)
   *  @param env	environment in which fish will live
   *  @param loc	location of the new fish in <code>env</code>
   **/
  public TurningSlowFish(Environment env, Location loc)
  {
    // Construct and initialize the attributes inherited from SlowFish.
    super(env, loc, env.randomDirection(), Color.green);

    // Define the likelihood that a turning slow fish will move in any
    // given timestep. This is the same value for all slow fish.
    probOfMoving = 1.0/5.0;  // 1 in 5 chance in each timestep
    probOfTurning = 0.1;     // 1 in 10 chance of turning in place
    probOfRight = 0.5;       // chance of turning right is one-half
  }

  /** Constructs a turning slow fish at the specified location and
   *  direction in a given environment.
   *  This slow fish is colored green.
   *  (Precondition: parameters are non-null; <code>loc</code> and
   *  <code>dir</code> are valid for <code>env</code>.)
   *  @param env	environment in which fish will live
   *  @param loc	location of the new fish in <code>env</code>
   *  @param dir	direction the new fish is facing
   **/
  public TurningSlowFish(Environment env, Location loc, Direction dir)
  {
    // Construct and initialize the attributes inherited from SlowFish.
    super(env, loc, dir, Color.green);

    // Define the likelihood that a turning slow fish will move in any
    // given timestep. This is the same value for all slow fish.
    probOfMoving = 1.0/5.0; // 1 in 5 chance in each timestep
    probOfTurning = 0.1; // 1 in 10 chance of turning in place
    probOfRight = 0.5; // chance of turning right is one-half
  }

  /** Constructs a turning slow fish of the specified color at the
   *  specified location and direction.
   *  (Precondition: parameters are non-null; <code>loc</code> and
   *  <code>dir</code> are valid for <code>env</code>.)
   *  @param env	environment in which fish will live
   *  @param loc	location of the new fish in <code>env</code>
   *  @param dir	direction the new fish is facing
   *  @param col	color of the new fish
   **/
  public TurningSlowFish(Environment env, Location loc, Direction dir,
                         Color col)
  {
    // Construct and initialize the attributes inherited from SlowFish.
    super(env, loc, dir, col);

    // Define the likelihood that a turning slow fish will move in any
    // given timestep. This is the same value for all slow fish.
    probOfMoving = 1.0/5.0;  // 1 in 5 chance in each timestep
    probOfTurning = 0.1;     // 1 in 10 chance of turning in place
    probOfRight = 0.5;       // chance of turning right is one-half
  }

// redefined methods

  /** Returns a string representing key information about this
   *  turning slow fish.
   *  @return	a string indicating the fish's ID and location
   **/
  public String toString()
  {
    return "TurningSlowFish " + super.toString();
  }

  /** Creates a new turning slow fish.
   *  @param loc	location of the new fish
   **/
  protected void generateChild(Location loc)
  {
    // Create a new fish, which adds itself to the environment.
    TurningSlowFish child = new TurningSlowFish(environment(), loc,
                            environment().randomDirection(), color());
    Debug.println(" Newly created: " + child.toString());
  }

  protected void move()
  {
    Location currentLoc = location();

    super.move();

    if (currentLoc.equals(location()))   // Have we not moved?
    {
      Random randNumGen = RandNumGenerator.getInstance();

      // If this is the probOfTurning chance of turning,
      // turn left or right.
      if (randNumGen.nextDouble() < probOfTurning)
      {
        turnRightOrLeft(direction());
        Debug.println(" Turned and now facing " + direction());
        return location();
      }
    }
  }

  /** Turns this fish right or left
   **/
  protected void turnRightOrLeft(Direction dir)
  {
    Random randNumGen = RandNumGenerator.getInstance();
    if (randNumGen.nextDouble() < probOfRight)
    {
      changeDirection(dir.toRight());
    }
    else
    {
      changeDirection(dir.toLeft());
    }
  }
}