#!/usr/bin/env python3

import pprint
import sys

input_file = sys.argv[1]

with open(input_file) as fd:
    lines = [line.rstrip() for line in fd.readlines()]

height = len(lines)
width = len(lines[0])

vec = tuple[int, int]

directions = [
    (-1, 0),  # ^ North
    (0, 1),  # > East
    (1, 0),  # v South
    (0, -1),  # < West
]

directions_keys = ("^", ">", "v", "<")

min_scores: list[list[list[None | int]]] = list()
for _ in range(height):
    line: list[list[None | int]] = list()
    for _ in range(width):
        cell: list[None | int] = [None] * len(directions)
        line.append(cell)
    min_scores.append(line)

start = height - 2, 1

valid_paths: list[tuple[int, set[vec]]] = list()


def walk(pos: vec, dir: int, score: int, path: list[vec]) -> int | None:
    i, j = pos
    char = lines[i][j]

    depth = len(path)
    path = path + [pos]

    if depth > 1000:
        return None

    # print("-" * depth, 28, pos, char, directions_keys[dir], score)
    if char == "E":
        valid_paths.append((score, set(path)))
        return score
    elif char == "#":
        return None

    min_score = min_scores[i][j][dir]
    if min_score is not None and score > min_score:
        # print("-" * depth, f" 32 already taken {score} >= {min_score}")
        return None
    min_scores[i][j][dir] = score

    mscore = None
    for ndir, direction in enumerate(directions):
        ii, jj = i + direction[0], j + direction[1]
        price = 1 if dir == ndir else 1001
        nscore = walk((ii, jj), ndir, score + price, path)
        if nscore is None:
            continue
        if mscore is None or nscore < mscore:
            mscore = nscore
    return mscore


sys.setrecursionlimit(9000)
tot_score = walk(start, 1, 0, [])

print(76, len(valid_paths))
all_best: set[vec] = set()
for s, path in valid_paths:
    if s != tot_score:
        continue
    print(81, "BEST")
    all_best |= path

# Viz
for i in range(height):
    cline = ""
    for j in range(width):
        char = lines[i][j]
        pos = i, j
        if pos in all_best:
            min_score = None
            for d in range(len(directions)):
                score = min_scores[i][j][d]
                if score is None:
                    continue
                if min_score is None or score < min_score:
                    char = directions_keys[d]
                    min_score = score
        cline += char
    print(cline)
print()


print(tot_score)
print(len(all_best))