#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <ctype.h>

int two_char_two_interger(int a, int b)
{
    // int a is the 10's
    // int b is the 1's
    int num = (a * 10) + b;
    printf("Got number: %i\n", num);
    return num;
}

int main()
{
    const char *inputFile = "/home/ben/Documents/Projects/C/advent-of-code/day1/puzzle1/input";
    int fd = open(inputFile, O_RDONLY);

    if (fd < 0)
    {
        printf("\n\"%s \" could not open\n", inputFile);
        exit(1);
    }
    struct stat statbuf;
    int err = fstat(fd, &statbuf);
    if (err < 0)
    {
        printf("\n\"%s \" could not open\n", inputFile);
        exit(2);
    }

    char *ptr = mmap(NULL, statbuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
    if (ptr == MAP_FAILED)
    {
        printf("Mapping Failed\n");
        return 1;
    }
    int in_line = 0;
    int first_num = -1;
    int last_num;
    char cur_char;
    int total = 0;
    // int numbers[1000];
    int freePos = 0;

    for (int i = 0; i < statbuf.st_size; i++)
    {
        if (in_line == 0)
        {
            in_line = 1;
            for (i; i < __INT64_MAX__; i++)
            {
                cur_char = ptr[i];
                if isdigit (cur_char)
                {
                    if (first_num == -1)
                    {
                        // We have not set a first number yet
                        first_num = (int)cur_char - '0';
                        last_num = (int)cur_char - '0';
                        continue;
                    }

                    last_num = (int)cur_char - '0';
                }
                if (cur_char == 0x0A)
                {
                    if (last_num != -1)
                    {
                        // printf("First num = %i\t", first_num);
                        // printf("Last num = %i\n", last_num);
                        total += two_char_two_interger(first_num, last_num);
                    }
                    first_num = -1;
                    last_num = -1;
                    in_line = 0;
                    // printf("Line break\n");
                    break;
                }
            }
        }

        // printf("%X\n", ptr[i]);
    }
    printf("Total is: %i\n", total);
    // ssize_t n = write(1, ptr, statbuf.st_size);
    // if (n != statbuf.st_size)
    // {
    //     printf("Write Failed");
    // }

    err = munmap(ptr, statbuf.st_size);

    if (err != 0)
    {
        printf("Unmapping Failed\n");
        return 1;
    }

    close(fd);

    return 0;
}