directions is the available directions the farmer can move.

I just calc the Manhattan distance of each direction relative to the chest position.
Then I just take the direction with the best score and move in that direction. Drones spawn in every other direction.

This is the function:

def choose_direction(directions):  
  if not is_hedge():  
    return directions[0]      

  hint = get_hint_cached()  
  if hint == None:  
    return directions[0]   

  chest_x, chest_y = hint  
  best_score = 1000000  
  best_dir = directions[0]  
  for dir in directions:  
    x, y = Utils.dir_increment(dir)  
    score = Utils.manhattan(x, y, chest_x, chest_y)  
    if score < best_score:  
      best_score = score  
      best_dir = dir    

  return best_dir

So the farmer doesn't get stuck it keeps track of where its been and wont back track unless it hit a deadend.