/**
** abac_util.c
**/

#include <err.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <stdarg.h>
#include <sys/stat.h>

#include "abac_util.h"

static int debug=0;

#define SHA1_LENGTH 40
#define ABAC_VERSION "0.2.1"

char *abac_version()
{
   return ABAC_VERSION;
}

void abac_errx(int eval, const char *msg)
{
   errx(eval,"%s",msg);
}

/**
 * Malloc, fatal on error.
 */
void *abac_xmalloc(size_t size) {
    void *ret;
    
    ret = malloc(size);
    if (ret == NULL)
        err(1, "malloc");

    return ret;
}

void *abac_xrealloc(void *ptr, size_t size) {
    void *ret = realloc(ptr, size);
    if (ret == NULL)
        err(1, "couldn't realloc %d bytes\n", size);
    return ret;
}


/**
 * strdup fatal on error
 */
char *abac_xstrdup(char *source) {
    char *ret;

    if (source == NULL) {
        return NULL;
    }

    ret = strdup(source);
    if (ret == NULL)
        err(1, "strdup");

    return ret;
}

/* make a brand new string with or without being trimmed */
char *abac_trim_quotes(char *string) {
    char *tmp=abac_xstrdup(string);
    int len=strlen(tmp);
    if( (tmp[len-1] == '\'' || tmp[len-1] == '"') &&
                       (tmp[0] == '\'' || tmp[0] == '"')) {
       tmp[len-1]='\0';
       char *ntmp=abac_xstrdup(&tmp[1]);
       free(tmp);
       return ntmp;
    }
    return tmp;
}

/**
 * Split a string based on the given delimiter.
 */
void abac_split(char *string, char *delim, char **ret, int *num) {
    int len = strlen(delim);
    char *start = string;
    int count = 0;

    // split the string by the delim
    while ((start = strstr(string, delim)) != NULL) {
        *start = 0;
        ret[count++] = string;
        string = start + len;
    }
    ret[count++] = string;

    *num = count;
}

int abac_validate_clean_name(char *string) {
    int i;

    assert(string != NULL);

    // must start with a letter/number
    if (!isalnum(string[0])) return 0;

    // Name must be alphanumeric or - 
    for (i = 1; string[i] != '\0'; ++i)
        if (!isalnum(string[i]) && string[i] != '-')
            return 0;

    return 1;
}

/* check up to first ( if its there.. 
   a.role(this)
   a.role(?,?Year:[100..200],?Value:[one,two,three])
   a.role(isi)
*/
int abac_validate_clean_aspect_name(char *string) {
    int i;

    assert(string != NULL);

    // must start with a letter/number
    if (!isalnum(string[0])) return 0;

    // Name must be alphanumeric or - or _ up to the ( if there is one
    for (i = 1; string[i] != '\0' && string[i] != '(' ; ++i)
        if (!isalnum(string[i]) && string[i] != '-' && 
                    string[i] != '_' )
            return 0;
    return 1;
}

chunk_t abac_generate_serial() {
    chunk_t serial = chunk_empty;

    // create a serial (stolen from strongswan pki)
    rng_t *rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
    if (!rng)
        errx(1, "no random number generator");

    rng->allocate_bytes(rng, 8, &serial);
    while (serial.ptr[0] == 0) {
        // don't get leading 0's
        rng->get_bytes(rng, 1, serial.ptr);
    }
    rng->destroy(rng);

    if(debug)
        printf( "abac_generate_serial, serial generated is %#B\n", &serial);
    return serial;
}

// validate a princpal's name
// makes sure it's a valid SHA1 identifier
// return values:
//  success: malloc'd copy with all hex digits lowercase
//  fail: NULL
char *abac_validate_principal(char *keyid) {
    int i;
    char *copy = NULL;

    if (strlen(keyid) != SHA1_LENGTH)
        return NULL;

    int len = strlen(keyid) + 1;
    copy = abac_xmalloc(len);
    sprintf(copy, "%s", keyid);

    i=0;
    for (; i < SHA1_LENGTH; ++i) {
        copy[i] = tolower(copy[i]);
        if (!isxdigit(copy[i]))
            goto error;
    }
    return copy;
error:
    free(copy);
    return NULL;
}

// parse&validate the validity
int abac_validate_validity_string(char *validity_str)
{
    int validity=0;
    if (validity_str != NULL) {
        char suffix = 'd'; // default suffix is days
        int multiplier;

        int len = strlen(validity_str);
        assert(len > 0);

        // get the suffix char if it's alphabetical
        if (isalpha(validity_str[len - 1])) {
            suffix = validity_str[len - 1];

           // truncate
            validity_str[len - 1] = '\0';
            --len;

            // make sure it's not only a suffix
            if (len == 0) {
                errx(1,"Invalid validity\n");
            }
        }

        // convert the suffix to a multiplier
        switch(suffix) {
            case 's': multiplier =        1; break;
            case 'm': multiplier =       60; break;
            case 'h': multiplier =     3600; break;
            case 'd': multiplier =    86400; break;
            case 'y': multiplier = 31536000; break;
            default:
                errx(1,"Invalid suffix, must be s m h d y\n");
        }

        // ascii to int
        char *end;
        validity = strtol(validity_str, &end, 10);
        if (end - validity_str < len) {
            errx(1,"Invalid validity\n");
        }

        if (validity <= 0) {
            errx(1,"Invalid validity: must be > 0\n");
        }

        // multiply!
        validity *= multiplier;
    }
    return validity;
}


int file_exist(char *filename)
{
   struct stat stbuf;
   if(stat(filename,&stbuf) == -1)
       return 0;
   return 1;
}