import becker.robots.*;

/** A class of robot that can harvest a field of Things.
 *  The field can be any rectangular size
 *  BUT the field must be solid with things
 *  AND the robot must be positioned on the Thing at the upper left corner of the field.
 *
 *  The robot moves east, picking up dots, as long as there is no blank intersection.
 *  When the robot gets to an intersection with no dots, it turns around, returns
 *  to where it started, and then moves down to position itself for picking up another row.
 *  The robot stops when it gets positioned to a blank intersection.
 * @author Duncan Buell
**/

public class Harvester extends RobotSE
{
/** Construct a new Harvester robot.
 *  @param aCity The city where the robot will be created.
 *  @param str The robot's initial street.
 *  @param ave The robot's initial avenue.
 *  @param dir The robot's initial direction, one of {Direction.NORTH, SOUTH, EAST, WEST}.
**/
  public Harvester(City aCity, int str, int ave, Direction dir)
  {
    super(aCity,str,ave,dir);
  }
   
/*******************************************************************************/
/** Harvest a field of things.  The robot is assumed to start on the north-west
 *  corner of the field and to be positioned on top of a Thing that can be
 *  picked up.
**/
  public void harvestField()
  {
    while(this.canPickThing())
    {
      this.harvestOneRow();
      this.positionForNextRow();
    }
  } // public void harvestField()

/*******************************************************************************/
/** Harvest one row of things, then turn around and return to the starting
 *  position.  The robot is assumed to start at the east end of a row of Things
 *  and to be positioned over a Thing that can be picked up.
**/
  private void harvestOneRow()
  {
    int moveCount;

    moveCount = 0;
    while(this.canPickThing())
    {
      this.pickThing();
      this.move();
      moveCount = moveCount + 1;
    }

    this.turnAround();

    while(moveCount > 0)
    {
      this.move();
      moveCount = moveCount - 1;
    }

  } // public void harvestOneRow()

/*******************************************************************************/
/** Position for the next row.  That is, from a position facing west at the
 *  west edge of a row just harvested, move down one row and turn to face east.
**/
  private void positionForNextRow()
  {
    this.turnLeft();
    this.move();
    this.turnLeft();
  } // private void positionForNextRow()

/*******************************************************************************/
/**
 *  Harvest one intersection.
**/
  public void harvestIntersection()
  {
    while (this.canPickThing())
    {
      this.pickThing();
    }
  } // public void harvestIntersection()

}