#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/ptrace.h>
#include <time.h>
#include <errno.h>
#include <limits.h>
#include <getopt.h>


void welcome() {
    printf("\n");
    printf("\n");
    printf("     .... NO! ...                  ... MNO! ...\n");
    printf("   ..... MNO!! ...................... MNNOO! ...\n");
    printf(" ..... MMNO! ......................... MNNOO!! .\n");
    printf("..... MNOONNOO!   MMMMMMMMMMPPPOII!   MNNO!!!! .\n");
    printf(" ... !O! NNO! MMMMMMMMMMMMMPPPOOOII!! NO! ....\n");
    printf("    ...... ! MMMMMMMMMMMMMPPPPOOOOIII! ! ...\n");
    printf("   ........ MMMMMMMMMMMMPPPPPOOOOOOII!! .....\n");
    printf("   ........ MMMMMOOOOOOPPPPPPPPOOOOMII! ...\n");
    printf("    ....... MMMMM..    OPPMMP    .,OMI! ....\n");
    printf("     ...... MMMM::   o.,OPMP,.o   ::I!! ...\n");
    printf("         .... NNM:::.,,OOPM!P,.::::!! ....\n");
    printf("          .. MMNNNNNOOOOPMO!!IIPPO!!O! .....\n");
    printf("         ... MMMMMNNNNOO:!!:!!IPPPPOO! ....\n");
    printf("           .. MMMMMNNOOMMNNIIIPPPOO!! ......\n");
    printf("          ...... MMMONNMMNNNIIIOO!..........\n");
    printf("       ....... MN MOMMMNNNIIIIIO! OO ..........\n");
    printf("    ......... MNO! IiiiiiiiiiiiI OOOO ...........\n");
    printf("  ...... NNN.MNO! . O!!!!!!!!!O . OONO NO! ........\n");
    printf("   .... MNNNNNO! ...OOOOOOOOOOO .  MMNNON!........\n");
    printf("   ...... MNNNNO! .. PPPPPPPPP .. MMNON!........\n");
    printf("      ...... OO! ................. ON! .......\n");
    printf("         ................................\n\n");
}

void randompass(char* s, const int len) {
    static const char alphanum[] =
        "0123456789"
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        "abcdefghijklmnopqrstuvwxyz";
    int i;

    for (i = 0; i < len; ++i) {
        s[i] = alphanum[rand() % (sizeof(alphanum) - 1)];
    }

    s[len] = 0;
}

unsigned int BKDRHash(char *str){
    unsigned int seed = 131;
    unsigned int hash = 0;
    unsigned int i = 0;
    char buff[60];
    unsigned int len = 0;
    strcpy(buff, str);
    len = strlen(buff);
    if(len >40)
        len = 40;

    for(i = 0; i < len; (*buff)++, i++)
    {
        hash = (hash * seed) + (*buff);
    }
    return hash;
}

void help_() {
    printf("--hash password : hashes a password with the BKDR hash, eg: ./psst --hash qwerty\n");
    printf("--password len : generates a random password, eg: ./psst --password 10\n");
    printf("--help : prints this information\n");
}


void handle(int argc, char** argv) {
    char line[124];
    int option = 0;
    int long_index = 0;
    int password = -1;
    char *endptr;
    int hv=-1, pv=-1, tv=-1;

    static struct option long_options[] = {
        {"help",      no_argument,       0,  'h' },
        {"password",  required_argument, 0,  'p' },
        {"hash",      required_argument, 0,  't' },
        {0,           0,                 0,  0   }
    };

    while((option = getopt_long(argc, argv, "hp:t:", long_options, &long_index)) != -1) {
        switch (option) {
            case 'h' :
                hv=0;
                break;
            case 'p' :
                password = strtol(optarg, &endptr, 10);
                if ((errno == ERANGE && (password == LONG_MAX || password == LONG_MIN)) || (errno != 0 && password == 0)) {
                    printf("error\n");
                    exit(EXIT_FAILURE);
                }

                if (endptr == optarg) {
                    printf("error\n");
                    exit(EXIT_FAILURE);
                }
                if (password>1337) {
                    printf("you are too paranoid for me\n");
                    exit(EXIT_FAILURE);
                }
                pv=0;
                break;
            case 't' :
                strncpy(line, optarg, sizeof(line));
                tv=0;
                break;
            default:
                printf("invalid command\n");
                exit(EXIT_FAILURE);
        }
    }

    if (!hv) {
        welcome();
        help_();
    } else if(!pv) {
        char *s = malloc(sizeof(char)*password);
        if(s!= NULL) {
            randompass(s,password);
            printf("%s\n", s);
            free(s);
        } else {
            printf("internal error");
        }
    } else if(!tv) {
        printf("%d\n",BKDRHash(line));
    } else {
        welcome();
        help_();
    }

}

int main(int argc, char** argv){
    srand(time(NULL));
    handle(argc, argv);
    return EXIT_SUCCESS;
}