#include "lib.h"

#define DBG 1

#define RUN_PART1 1
#define RUN_PART2 1
#define RUN_TEST1 1
#define RUN_TEST2 1

#define TEST1_EXPECT 3
#define TEST2_EXPECT 6

static
char input[] = {
#embed "day1_input.txt"
};

static
char test[] = {
#embed "day1_test.txt"
};

static
unsigned long do_part1(size_t src_len, const char src[src_len]) {
    const char *s = src;
    unsigned long count = 0;
    unsigned long pos = 1'000'000'000'050;
    while (s < &src[src_len]) {
        const char *ns = s + 1;
        unsigned r = grabnum(ns, &ns);
        if (*s == 'L') {
            pos -= r;
        } else {
            pos += r;
        }
        count += pos % 100 == 0;
        s = ns + 1;
    }
    return count;
}

static
unsigned do_part2(size_t src_len, const char src[src_len]) {
    const char *s = src, *ns = s + 1;
    unsigned count = 0;
    unsigned pos = 50;
    for (;s < &src[src_len]; s = ns + 1, ns = s + 1) {
        unsigned r = grabnum(ns, &ns);
        if (*s == 'L') {
            if (pos == 0) pos = 100;
            unsigned to_zero = pos;
            if (r < to_zero) {
                pos -= r;
            } else {
                unsigned over = r - to_zero;
                unsigned rots = over / 100;
                unsigned adjust = over % 100;
                count += 1 + rots;
                pos = (100 - adjust) % 100;
            }
        } else {
            unsigned to_zero = 100 - pos;
            if (r < to_zero) {
                pos += r;
            } else {
                unsigned over = r - to_zero;
                unsigned rots = over / 100;
                unsigned adjust = over % 100;
                count += 1 + rots;
                pos = adjust;
            }
        }
    }
    return count;
}

void _start() {
#if RUN_TEST1
    print("PART 1 TEST: ");
    if (unsigned long v = do_part1(countof(test), test); v != TEST1_EXPECT) {
        print("FAILED (got ");
        printd(v);
        print(", expected " xstr(TEST1_EXPECT) ")\n");
    } else {
        print("PASSED\n");
    }
#endif

#if RUN_PART1
    print("PART 1 RESULT: ");
    printd(do_part1(countof(input), input));
    print("\n");
#endif

#if RUN_TEST2
    print("PART 2 TEST: ");
    if (unsigned v = do_part2(countof(test), test); v != TEST2_EXPECT) {
        print("FAILED (got ");
        printd(v);
        print(", expected " xstr(TEST2_EXPECT) ")\n");
    } else {
        print("PASSED\n");
    }
#endif

#if RUN_PART2
    print("PART 2 RESULT: ");
    printd(do_part2(countof(input), input));
    print("\n");
#endif

    syscall(SYS_exit_group, 0);
}