#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#ifdef __linux__
    #include <crypt.h>
#elif __APPLE__
    #include <unistd.h>
#endif
#include "mycrypt.h"

#define DEBUG

int main(int argc, char* argv[]) {
    char *pw1, *pw2, *entry;
    char linebuf[MAXLINE];
    FILE *pwfile;
    int ret;

    // Check number of arguments.
    if (argc<2) {
        printf("Usage: %s <cmd>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    // Check, whether file exists.
    pwfile = fopen(PWFILE, "r");
    if (pwfile == NULL) {
        perror("open pwfile");
        exit(EXIT_FAILURE);
    }

    // Search for user in passwords.txt.
    while (!feof(pwfile)) {
        fgets(linebuf, MAXLINE, pwfile);
        ret = memcmp(linebuf, argv[1], strlen(argv[1]));
        if (ret == 0) {
            // Quit, if user already exists.
            printf("User already exists.\n");
            exit(EXIT_FAILURE);
        }
    }
    fclose(pwfile);

    // Continue, if user name is unique.
    if (ret != 0) {
        printf("User not found\n\n");
    }

    // Get user password and hash it immediatly.
    pw1 = strdup(crypt(getpass("Enter your password: "), "ab"));
    pw2 = strdup(crypt(getpass("Re-enter your password: "), "ab"));

    // Compare user passwords and compare them.
    if (strcmp(pw1, pw2) != 0) {
        printf("\nYour provided passwords didn't match.\n");
        exit(EXIT_FAILURE);
    }

    // Concatenate user:hash(password) to char.
    entry = (char *)malloc((strlen(argv[1]) + strlen(pw1) + 1)*sizeof(char));
    strcpy(entry, argv[1]);
    strcat(entry, ":");
    strcat(entry, pw1);
    strcat(entry, "\n");

    // Append char to file.
    pwfile = fopen(PWFILE, "a");
    fprintf(pwfile, "%s", entry);

    fclose(pwfile);
    free(pw1);
    free(pw2);
    free(entry);

    exit(EXIT_SUCCESS);
}