#!/usr/bin/env python

import re
import argparse
import copy

DIRECTIONS = [
    {'dir': 'N', 'V': 1, "H": 0 },
    {'dir': 'W', 'V': 0, "H": -1 },
    {'dir': 'S', 'V': -1, "H": 0 },
    {'dir': 'E', 'V': 0, "H": 1 }
]
DIRECTION_CHANGE = {
    'L': -1,
    'R': 1
}

MAPS_VISITED = []

def load_file(filename):
    with open(filename) as f:
        data = f.read()
    return data

def main(args):
    DIRECTION_INDEX = 0
    MAP_POSITION_B = [0, 0]
    MAP_POSITION_A = None 
    TWICE = None

    MAPS_VISITED = {0: [0]}

    for INDICE in load_file(args.input).split(','):
        INDICE = INDICE.strip()
        TURN = INDICE[0]
        STEP = int(INDICE[1:].strip())
        DIRECTION_INDEX = DIRECTION_INDEX + DIRECTION_CHANGE[TURN]
        if DIRECTION_INDEX < 0:
            DIRECTION_INDEX = len(DIRECTIONS) - 1 
        if DIRECTION_INDEX >= len(DIRECTIONS):
            DIRECTION_INDEX = 0
        MAP_POSITION_A = copy.copy(MAP_POSITION_B)
        MAP_POSITION_B[0] = MAP_POSITION_A[0] + DIRECTIONS[DIRECTION_INDEX]['V']*STEP 
        MAP_POSITION_B[1] = MAP_POSITION_A[1] + DIRECTIONS[DIRECTION_INDEX]['H']*STEP

        if bool(DIRECTIONS[DIRECTION_INDEX]['V']):
            step =  DIRECTIONS[DIRECTION_INDEX]['V']
            for x in range(MAP_POSITION_A[0]+step, MAP_POSITION_B[0]+step, step):
                if x not in MAPS_VISITED:
                    MAPS_VISITED[x] = []
                if MAP_POSITION_A[1] in MAPS_VISITED[x]:
                    TWICE = [x, MAP_POSITION_A[1]]
                    break
                MAPS_VISITED[x].append(MAP_POSITION_A[1])
        if TWICE:
            break

        if bool(DIRECTIONS[DIRECTION_INDEX]['H']):
            step =  DIRECTIONS[DIRECTION_INDEX]['H']
            for y in range(MAP_POSITION_A[1]+step, MAP_POSITION_B[1]+step, step):
                if MAP_POSITION_A[0] not in MAPS_VISITED:
                    MAPS_VISITED[MAP_POSITION_A[0]] = []
                if y in MAPS_VISITED[MAP_POSITION_A[0]]:
                    TWICE = [MAP_POSITION_A[0], y]
                    break
                MAPS_VISITED[MAP_POSITION_A[0]].append(y)
        if TWICE:
            break

    if TWICE:
        print("%d" % (abs(TWICE[0]) + abs(TWICE[1])))

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='AdventOfCode 2016 Day 01')
    parser.add_argument('--input', '-i', action='store',  required=True, help='input file')
    args = parser.parse_args()

    main(args)