# Author:  James Tam
# Version: March 15, 2018


# CONSTANTS
SIZE = 4
EMPTY = " "
PERSON = "*"
START = (1,1)

'''
   @ initialize()
   @ no parameters
   @ returns a fully initialized world

'''
def initialize():
    world = []
    r = -1
    c = -1

    for r in range (0,SIZE,1):
        world.append([])  # Add in new empty row
        for c in range (0,SIZE,1):
            world[r].append(EMPTY) # Add new element to row end
    # Add the 'person' character to default start location
    sRow = START[0]
    sColumn = START[1]
    world[sRow][sColumn] = PERSON
    return(sRow,sColumn,world)

'''
   @ display()
   @ argument: 2D list of char(length 1 string), simulated game
     world
   @ return value: none
   @ 
   @ Shows the current state of the world
   
'''
def display(world):
   r = -1
   c = -1
   for r in range (0,SIZE,1):
      for c in range (0,SIZE,1):
         print(world[r][c], end="")
      print()
   print()

'''
   @ getDestination()
   @ argument: None
   @ return value: the point (row,column) to move the person
   @    
'''
def getDestination():
    dRow = int(input("Destination row: "))
    dColumn = int(input("Destination column: "))
    return(dRow,dColumn)

'''
   @ isDestinationValid()
   @ argument: two points P1(current row/column), 
   @   P2(destination row/column)  
   @ return value: boolean 
   @ Valid moves: one of the 4 cardinal compass directions
   @ (N,S,W,E) of an adjacent square   
   @    
'''
def isDestinationValid(cRow,cColumn,dRow,dColumn):
    isValid = False
    # Write your solution here
    return(isValid)

# MAIN EXECUTION POINT
def start():
    cRow,cColumn,world = initialize()
    print("Initial world")
    display(world)
    dRow,dColumn = getDestination()
    input("Hit enter to continue")
    valid = isDestinationValid(cRow,cColumn,dRow,dColumn)
    print("From: (%d/%d) " %(cRow,cColumn))
    print("To: (%d/%d) " %(dRow,dColumn))
    print("Can move?", str(valid))

start()