/*
 * File: MidpointFindingKarel.java
 * -------------------------------
 * When you finish writing it, the MidpointFindingKarel class should
 * leave a beeper on the corner closest to the center of 1st Street
 * (or either of the two central corners if 1st Street has an even
 * number of corners).  Karel can put down additional beepers as it
 * looks for the midpoint, but must pick them up again before it
 * stops.  The world may be of any size, but you are allowed to
 * assume that it is at least as tall as it is wide.
 */

import stanford.karel.*;

public class MidpointFindingKarel extends SuperKarel {
		public void run () {
				makeDiagonalRight () ;
				putBeeper () ;
				setUpForNextDiagonal () ;
				makeDiagonalLeft () ;
				putBeeper () ;
				turnLeft () ;
				checkForLoneBeeper () ;
				cleanUpBeepers () ;
				}
		
		private void makeDiagonalRight () {
				while (frontIsClear()) {
						putBeeper () ;
						move () ;
						turnLeft () ;
						move () ;
						turnRight () ;
				}
		}
		
		private void setUpForNextDiagonal () {
				turnAround () ;
				while (frontIsClear()) {
						move () ;
				}
				turnAround () ;
		}
			

		private void makeDiagonalLeft () {
				while (frontIsClear()) {
						if (noBeepersPresent()) {
								putBeeper () ;
						}
						move () ;
						turnRight () ;
						move () ;
						turnLeft () ;
				}
		}
		
		private void checkForLoneBeeper () {
				while (leftIsClear()) {
						while (noBeepersPresent() && frontIsClear()) {
								move () ;
						}
						if (beepersPresent()) {
								move () ;
								}
						while (noBeepersPresent() && frontIsClear ()) {
								move () ;
						}
						checkForSecondBeeper () ;
						if (frontIsBlocked()) {
								placeMidpointBeeper () ;
						}
				}
		}
		
		private void checkForSecondBeeper () {
				if (beepersPresent() && facingNorth ()) {
						if (frontIsBlocked()) {
								turnLeft () ;
								move () ;
								turnLeft () ;
								move () ;
						}
						while (frontIsClear() && facingNorth ()) {
								move () ;
								if (beepersPresent()) {
										turnLeft () ;
										move () ;
										if (beepersPresent()) {
												turnAround () ;
												move () ;
												turnLeft () ;
												placeMidpointBeeper () ;
										}
										if (noBeepersPresent()) {
												turnAround () ;
												move () ;
												turnLeft () ;
										}
										if (frontIsBlocked()) {
												turnLeft () ;
												move () ;
												turnLeft () ;
												move () ;
										}
								}
						}
				}
				if (beepersPresent() && facingSouth ()) {
						if (frontIsBlocked()) {
								turnRight () ;
								move () ;
								turnRight () ;
								move () ;
						}
						while (frontIsClear() && facingSouth ()) {
								move () ;
								if (beepersPresent()) {
										turnRight () ;
										move () ;
										if (beepersPresent()) {
												turnAround () ;
												move () ;
												turnRight () ;
												placeMidpointBeeper () ;
										}
										if (noBeepersPresent()) {
												turnAround () ;
												move () ;
												turnRight () ;
										}
										if (frontIsBlocked()) {
												turnRight () ;
												move () ;
												turnRight () ;
												move () ;
										}
								}
						}
				}
		}
		
		private void placeMidpointBeeper () {
				turnAround () ;
				while (noBeepersPresent()) {
						move () ;
				}
				if (beepersPresent()) {
						pickBeeper () ;
				}
				if (facingNorth()) {
						turnAround () ;
				}
				while (frontIsClear()) {
						move () ;
				}
				if (frontIsBlocked()) {
						putBeeper () ;
						turnRight () ;
						move () ;
				}
		}
		
		private void cleanUpBeepers () {
				cleanRow () ;
				while (rightIsClear()) {
						repositionForRowToEast () ;
						cleanRow () ;
						if (leftIsClear()) {
								repositionForRowToWest () ;
								cleanRow () ;
						} else {
								turnAround () ;
						}
				}
				turnAround () ;
				cleanRow () ;
				turnRight () ;
				cleanRow () ;
				repositionToBeginning () ;
		}
						
		private void cleanRow () {				
				while (frontIsClear()) {
						move () ;
						if (beepersPresent()) {
								pickBeeper () ;
						}
				}
		}
		
		private void repositionForRowToWest () {
				turnLeft () ;
				move () ;
				turnLeft () ;
		}
		
		private void repositionForRowToEast () {
				turnRight () ;
				move () ;
				turnRight () ;
		}
		
		private void repositionToBeginning () {
				turnRight () ;
				while (frontIsClear()) {
						move () ;
				}
				turnAround () ;
		}
}