#include "aoc.h"
#include <limits.h>
#include <ctype.h>

typedef struct Vec2i {
    i64 x;
    i64 y;
} Vec2i;

static Vec2i
parse_numbers(str line, Arena *arena) {
    bool x_set = false;
    Vec2i result = {0};
    for (isize i = 0; i < line.len; i++) {
        if (isdigit(line.data[i])) {
            isize end = i + 1;
            while (end < line.len && isdigit(line.data[end])) {
                end++;
            }
            str num_str = str_sub(line, i, end);
            if (!x_set) {
                result.x = (i32) parse_i64(num_str, *arena);
                x_set = true;
            }
            else {
                result.y = (i32) parse_i64(num_str, *arena);
                return result;
            }
            i = end;
        }
    }
    NOT_REACHABLE();
}

static bool 
solve(Vec2i a, Vec2i b, Vec2i p, Vec2i *solution) {
    i64 det = a.x * b.y - a.y * b.x;
    ASSERT(det != 0);

    i64 numerator_a = p.x * b.y - p.y * b.x;
    i64 numerator_b = p.y * a.x - p.x * a.y;
    bool solved = false;
    if ((numerator_a % det == 0) && (numerator_b % det == 0)) {
        i64 n_a = numerator_a / det;
        i64 n_b = numerator_b / det;
        if (n_a >= 0 && n_b >= 0) {
            solution->x = n_a;
            solution->y = n_b;
            solved = true;
        }
    }
    else {
        // no integer solution
    }
    return solved;
}

int main(int argc, char **argv) {
    Arena *arena = make_arena(Megabytes(1));
    str input = read_file(arena, argv[1]);

    str line;
    i64 part_1 = 0;
    i64 part_2 = 0;
    while (input.len > 0) {
        str a_line = str_next_token(&input, STR("\n"));
        str b_line = str_next_token(&input, STR("\n"));
        str prize_line = str_next_token(&input, STR("\n"));
        str empty_line = str_next_token(&input, STR("\n"));
        ASSERT(str_trim(empty_line).len == 0);

        Vec2i a = parse_numbers(a_line, arena);
        Vec2i b = parse_numbers(b_line, arena);
        Vec2i p = parse_numbers(prize_line, arena);
        Vec2i p_ = { p.x + 10000000000000ull, p.y + 10000000000000ull };

#if 0
        printf("a: %ld %ld\n", a.x, a.y);
        printf("b: %ld %ld\n", b.x, b.y);
        printf("p: %ld %ld\n", p.x, p.y);
        printf("\n");
#endif
        Vec2i n;
        if (solve(a, b, p, &n)) {
            part_1 += n.x * 3 + n.y;
        }

        if (solve(a, b, p_, &n)) {
            part_2 += n.x * 3 + n.y;
        }
    }
    printf("%ld\n", part_1);
    printf("%ld\n", part_2);
}