#include <ctype.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "aocdailies.h"
#include "aocutils.h"

/* === aoc202407 =======================================================
   Part one looks easy
===================================================================== */

static bool canbetrue(unsigned v, unsigned *a, size_t n) {
    // for startes let's assume no overflowing
    if (n == 1) return (v == *a);
    unsigned tmp = a[1];
    a[1] = a[0] + tmp;
    if (canbetrue(v, a+1, n-1)) return true;
    a[1] = a[0] * tmp;
    if (canbetrue(v, a+1, n-1)) return true;
    a[1] = tmp;
    return false;
}

void aoc202407(char *data, size_t len) {
    (void)len; // unused argument
    unsigned calibrationtotal = 0;
    char *line = strtok(data, "\n");
    unsigned number[50], nnumber, maxn = 0;
    while (line) {
        char *err;
        unsigned testvalue = strtoul(line, &err, 10);
        err += 1; // skip ':'
        nnumber = 0;
        while (*err == ' ') {
            number[nnumber++] = strtoul(err, &err, 10);
        }
        if (canbetrue(testvalue, number, nnumber)) calibrationtotal += testvalue;
        if (nnumber > maxn) { maxn = nnumber; printf("max: %u\n", maxn); }
        line = strtok(NULL, "\n");
    }
    printf("The calibration total is {%u}.\n", calibrationtotal);
}

/* === aoc202406 =======================================================
   Hmmm, I've done something like this already this year... on day 4
   I need rcmap() moved to aocutils ... done; now it's called `linearize2d`
Part Two: brute force? It likely is faster than coming up with an algo
   Let's go: save map, for every available position put in an obstacle,
   loop around until some place is visited 4? times or area is exited

#include <stddef.h>
#include "aocdailies.h"

aocfunc *aocselect(unsigned y, unsigned d) {
    aocfunc *p;
    switch (y * 100 + d) {
        default: p = NULL; break;

        //   YYYYdd ==>  aocYYYYdd
        case 202407: p = aoc202407; break;
        case 202406: p = aoc202406; break;
        case 202405: p = aoc202405; break;
        case 202404: p = aoc202404; break;
        case 202403: p = aoc202403; break;
        case 202402: p = aoc202402; break;
        case 202401: p = aoc202401; break;

#ifndef AOCDAILIES_H_INCLUDED
#define AOCDAILIES_H_INCLUDED

#include <stddef.h>

typedef void aocfunc(char *, size_t);
aocfunc *aocselect(unsigned, unsigned);

aocfunc aoc202407;
aocfunc aoc202406;
aocfunc aoc202405;
aocfunc aoc202404;
aocfunc aoc202403;
aocfunc aoc202402;
aocfunc aoc202401;