#!/usr/bin/env python3

import sys, math
import numpy as np

def dijkstra(graph, s, v, a):
    Q = [n for n in graph.keys()]
    lq = len(Q)
    while len(Q) > 0:
        u = min([u for u in Q], key=lambda x: a[x])
        Q.remove(u)
        for vo in graph[u]:
            if vo in Q:
                distance_update(graph, u,vo,a,v)
    return v, a

def distance_update(g, u, vo, a, v):
    dist = 1 if vo[2] == u[2] else 1000
    alt = a[u] + dist
    if alt <= a[vo]:
        v[vo].add(u)
        v[vo] = v[vo].union(set(v[u]))
    if alt < a[vo]:
        a[vo] = alt

def count_set(edges):
    edg = set([])
    for e in edges:
        edg.add((e[0], e[1]))
    return len(edg)

if __name__ == '__main__':
    lab = [list(line.strip('\n')) for line in open(sys.argv[1])]
    rot90 = {(0,-1): [(-1,0),(1,0)], (1,0): [(0,-1),(0,1)], (0,1): [(1,0),(-1, 0)], (-1,0): [(0,1),(0,-1)]}

    start = (1, len(lab)-2, (1,0))
    end = (len(lab[0])-2, 1)
    graph = {}
    distance = {}
    pred = {}
    for y, l in enumerate(lab):
        for x, f in enumerate(lab[y]):
            if f == '#': continue
            for d in [(0,1), (0,-1), (1,0), (-1,0)]:
                distance[(x,y,d)] = math.inf
                pred[(x,y,d)] = set([])
                graph[(x,y,d)] = []
                for d1 in rot90[d]:
                    graph[(x,y,d)].append((x,y,d1))
                if lab[y+d[1]][x+d[0]] == '.' or lab[y+d[1]][x+d[0]] == 'E':
                    graph[(x,y,d)].append((x+d[0], y+d[1], d))
    distance[start] = 0
    v, a = dijkstra(graph, start, pred, distance)
    print([a[end[0], end[1], d] for d in [(0,1), (0,-1), (1,0), (-1,0)]], [1+count_set(v[end[0], end[1], d]) for d in [(0,1), (0,-1), (1,0), (-1,0)]])

    # challenge 1
    res1 = min([a[end[0], end[1], d] for d in [(0,1), (0,-1), (1,0), (-1,0)]])
    print(f"challenge 1:\n{res1}\n")

    # challenge 2
    ind = [a[end[0], end[1], d] for d in [(0,1), (0,-1), (1,0), (-1,0)]].index(res1)
    d = [(0,1), (0,-1), (1,0), (-1,0)][ind]
    res2 = 1+count_set(v[end[0], end[1], d])
    print(f"challenge 2:\n{res2}")