#include <fstream>
#include <iostream>
#include <sstream>
#include <vector>

enum Cucumber {
    NONE,
    RIGHT,
    DOWN,
};

std::vector<std::vector<Cucumber>> getMap(const std::string &file_name) {
    std::ifstream file(file_name);
    std::vector<std::vector<Cucumber>> result{};
    int tmp = 0;
    std::string str;
    while (std::getline(file, str)) {
        result.emplace_back();
        for(auto &c : str) {
            switch(c) {
                case 'v':
                    result.back().push_back(DOWN);
                    break;
                case '>':
                    result.back().push_back(RIGHT);
                    break;
                default:
                    result.back().push_back(NONE);
                    break;
            }
        }
    }
    return result;
}

std::vector<std::vector<Cucumber>> createEmptyMap(size_t height, size_t width) {
    std::vector<std::vector<Cucumber>> res{};
    res.resize(height);
    for(size_t i = 0; i < height; i++) {
        res[i].resize(width);
        for(size_t j = 0; j < width; j++) {
            res[i][j] = NONE;
        }
    }
    return res;
}

bool mapsAreEqual(const std::vector<std::vector<Cucumber>> &a, const std::vector<std::vector<Cucumber>> &b) {
    for(size_t i = 0; i < a.size(); i++) {
        for(size_t j = 0; j < a[0].size(); j++) {
            if(a[i][j] != b[i][j]) {
                return false;
            }
        }
    }
    return true;
}

void printMap(const std::vector<std::vector<Cucumber>> &input) {
    for(size_t i = 0; i < input.size(); i++) {
        for(size_t j = 0; j < input[0].size(); j++) {
            char print = '.';
            switch(input[i][j]) {
                case DOWN:
                    print = 'v';
                    break;
                case RIGHT:
                    print = '>';
                default:
                    break;
            }
            std::cout << print;
        }
        std::cout << std::endl;
    }
    std::cout << std::endl;
}

uint64_t part1(const std::vector<std::vector<Cucumber>> &input) {
    auto cur_map = input;
    auto next_map = input;
    uint64_t rounds = 0;
    do {
        cur_map = next_map;
        next_map = createEmptyMap(cur_map.size(), cur_map[0].size());
        rounds++;
        for(size_t i = 0; i < input.size(); i++) {
            for(size_t j = 0; j < input[0].size(); j++) {
                size_t next_i = i;
                size_t next_j = j;
                switch(cur_map[i][j]) {
                    case RIGHT:
                        next_j += 1;
                        if(next_j >= cur_map[0].size()) {
                            next_j = 0;
                        }
                        break;
                    case DOWN:
                    default:
                        continue;
                        break;
                }
                if(cur_map[next_i][next_j] == NONE) {
                    next_map[next_i][next_j] = cur_map[i][j];
                } else {
                    next_map[i][j] = cur_map[i][j];
                }
            }
        }
        for(size_t i = 0; i < input.size(); i++) {
            for(size_t j = 0; j < input[0].size(); j++) {
                size_t next_i = i;
                size_t next_j = j;
                switch(cur_map[i][j]) {
                    case DOWN:
                        next_i += 1;
                        if(next_i >= cur_map.size()) {
                            next_i = 0;
                        }
                        break;
                    case RIGHT:
                    default:
                        continue;
                        break;
                }
                if(cur_map[next_i][next_j] != DOWN && next_map[next_i][next_j] == NONE) {
                    next_map[next_i][next_j] = cur_map[i][j];
                } else {
                    next_map[i][j] = cur_map[i][j];
                }
            }
        }
    } while(!mapsAreEqual(cur_map, next_map));
    return rounds;
}

int main(int argc, char **argv) {
    if (argc < 2) {
        std::cerr << "You must provide input file!" << std::endl;
        return 1;
    }
    auto map = getMap(argv[1]);
    std::cout << "The see cucumbers stop moving after \033[91;1m" << part1(map)
              << "\033[0m steps." << std::endl;
    return 0;
}