/**
**  abac_id.c
**/

#include <assert.h>
#include <err.h>
#include <time.h>

// include the GNU extension of asprintf
#define _GNU_SOURCE
#include <stdio.h>
#include <err.h>

#include "abac_internal.h"
#include "abac_util.h"

static int debug=0;
static int yes=1;

#define KEY_SUFFIX  "_private.pem"
#define CERT_SUFFIX "_ID.pem"

extern private_key_t *abac_key_private_key(abac_key_t *ptr);
extern abac_key_t *abac_key_file_new(char *filename, chunk_t potato);
extern abac_key_t *abac_key_chunk_new(chunk_t keyblob, chunk_t potato);
extern chunk_t abac_key_chunk(abac_key_t *);

static int _abac_id_set_cn(abac_id_t *id, char* cn);

//
// abac_id object
//
struct _abac_id_t {
    int idtype;    /* default to string 'keyid' for now */

    char *keyid; /* sha */
    char *cn;

    certificate_t *cert;
    abac_key_t *key;

    int refcount;
};

/****************************************************************/
//
// Helper functions below
//
static int _add_into_id_credentials(abac_id_t *id) 
{
    char *keyid=abac_id_keyid(id);
    abac_id_credential_t *idcred=abac_id_credential_lookup(keyid);
    if(idcred !=NULL) {
       if(debug) fprintf(stderr,"_add_into_id_credentials: something in there for %s\n",keyid);
       } else {
          if(debug) fprintf(stderr,"_add_into_id_credentials: adding %s\n",keyid);
          if(yes) {
             abac_verifier_add_id_credential(abac_id_dup(id));
          }
    }
}

static char *_get_keyid(certificate_t *cert) {
    // get the keyid
    x509_t *x509 = (x509_t *)cert;
    chunk_t keyid = x509->get_subjectKeyIdentifier(x509);
    chunk_t string = chunk_to_hex(keyid, NULL, 0);
    return (char *)string.ptr;
}

static char *_create_dn(char *cn) {

#define DN "cn="

    char *dn = abac_xmalloc(sizeof(DN) + strlen(cn));
    memcpy(dn, DN, sizeof(DN));
    strcat(dn, cn);

    return dn;
}

/**
 * Generate ID certificate.
 *
 * validity is measured in seconds (as of 0.2.0)
 */
static certificate_t *_generate_cert(abac_key_t *keyptr, char *cn, int validity) {
    // build the DN
    char *dn_string = _create_dn(cn);
    libabac_init();

    identification_t *id = identification_create_from_string(dn_string);
    if (id == NULL)
        errx(1, "couldn't create ID from DN %s", dn_string);
    free(dn_string);

    // get the private key
    private_key_t *private = abac_key_private_key(keyptr);
    if(private == NULL)
        errx(1, "couldn't create ID without private key");

    public_key_t *public = private->get_public_key(private);
    if (public == NULL)
        errx(1, "couldn't get public key from private key");

    // 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");

    // random serial
    chunk_t serial = abac_generate_serial();

    // validity period
    time_t not_before = time(NULL);
    time_t not_after = not_before + validity;

    // create!
    certificate_t *cert = lib->creds->create(lib->creds,
        CRED_CERTIFICATE, CERT_X509,
        BUILD_SIGNING_KEY, private,
        BUILD_PUBLIC_KEY, public,
        BUILD_SUBJECT, id,
        BUILD_NOT_BEFORE_TIME, not_before,
        BUILD_NOT_AFTER_TIME, not_after,
        BUILD_SERIAL, serial,
        BUILD_DIGEST_ALG, HASH_SHA1,
        BUILD_X509_FLAG, X509_CA,
        BUILD_PATHLEN, X509_NO_CONSTRAINT,
        BUILD_END
    );
    if (cert == NULL)
        errx(1, "couldn't build cert :(");

    DESTROY_IF(id);
    DESTROY_IF(public);
    DESTROY_IF(private);
    free(serial.ptr);

    return cert;
}

#define BYTES_PER_LINE 64

// thx libstrongswan
static void _encode_base64(FILE *out, chunk_t encoding) {
    int start;

    chunk_t b64 = chunk_to_base64(encoding, NULL);

    fprintf(out, "-----BEGIN CERTIFICATE-----\n");

    for (start = 0; start < b64.len; start += BYTES_PER_LINE) {
        int left = b64.len - start;
        int len = left < BYTES_PER_LINE ? left : BYTES_PER_LINE;
        fwrite(b64.ptr + start, len, 1, out);
        fprintf(out, "\n");
    }

    fprintf(out, "-----END CERTIFICATE-----\n");

    free(b64.ptr);
}
/****************************************************************/
int abac_id_idtype(abac_id_t *id)
{
    assert(id != NULL);
    return id->idtype;
}

char* abac_id_idtype_string(abac_id_t *id)
{
    assert(id != NULL);
    return abac_idtype_string(id->idtype);
}

char *abac_id_keyid(abac_id_t *id) {
    assert(id != NULL);
    return id->keyid;
}

char *abac_id_cn(abac_id_t *id) {
    assert(id != NULL);
    return id->cn;
}

static int _abac_id_set_cn(abac_id_t *id, char* cn) {
    if(cn) {
        if(id->cn != NULL)
            free(id->cn);
        id->cn = abac_xstrdup(cn);
    }
    return 0;
}


char *abac_id_name(abac_id_t *id)
{
    assert(id != NULL);
    if(USE("ABAC_CN"))
        return abac_id_cn(id);
    else return abac_id_keyid(id);
}

char *abac_id_string(abac_id_t *id) 
{
    char *tmp=NULL;
    if(abac_id_has_privkey(id)) 
        asprintf(&tmp,"(%s,%s,y)",abac_id_name(id),abac_id_idtype_string(id));
        else asprintf(&tmp,"(%s,%s,n)",abac_id_name(id),abac_id_idtype_string(id));
    return tmp;
}

/**
 * Get the issuer of an ID cert.
 * Returns a malloc'd string that must be free'd.
 */
char *abac_id_issuer(abac_id_t *id) {
    char *ret;
    int rv = asprintf(&ret, "%Y", id->cert->get_issuer(id->cert));

    if (rv < 0)
        err(1, "couldn't malloc string for issuer\n");

    return ret;
}

int abac_id_lastone(abac_id_t *ptr)
{
    assert(ptr);
    if(ptr->refcount == 1)
        return 1;
    return 0;
}


/**
 * Gets the subject DN of an ID cert.
 * Returns a malloc'd string that must be free'd.
 */
char *abac_id_subject(abac_id_t *id) {
    char *ret;
    int rv = asprintf(&ret, "%Y", id->cert->get_subject(id->cert));

    if (rv < 0)
        err(1, "couldn't malloc string for subject\n");

    return ret;
}

/**
 * Get the validity period.
 */
void abac_id_validity(abac_id_t *id, time_t *not_before, time_t *not_after) {
    id->cert->get_validity(id->cert, NULL, not_before, not_after);
}

certificate_t *abac_id_cert(abac_id_t *id) {
    assert(id != NULL);
    return id->cert;
}

private_key_t *abac_id_privkey(abac_id_t *id) {
    assert(id != NULL);
    if(id->key !=0)
        return abac_key_private_key(id->key);
    return NULL;
}

abac_key_t *abac_id_keyptr(abac_id_t *id)
{
    return id->key;
}

int abac_id_has_privkey(abac_id_t *id) {
    if(id && id->key !=0)
       return 1;
    return 0;
}


/**
 * Write the ID cert to an open file pointer.
 */
void abac_id_write_cert(abac_id_t *id, FILE *out) {
    assert(id != NULL);

    chunk_t encoding = chunk_empty;
    int rc=id->cert->get_encoding(id->cert,CERT_ASN1_DER,&encoding);
    if(rc) {
        _encode_base64(out, encoding);
        free(encoding.ptr);
    }
}

/**
 * Write the private key to a file.
 * Returns false if there's no private key loaded
 */
int abac_id_write_privkey(abac_id_t *id, FILE *out)
{
    return abac_key_write_privkey(id->key, out);
}

/**
 * Get a DER-encoded chunk representing the cert.
 */
abac_chunk_t abac_id_cert_chunk(abac_id_t *id) {
    assert(id->cert);
    chunk_t encoding = chunk_empty;
    int rc= id->cert->get_encoding(id->cert, CERT_ASN1_DER, &encoding);
    abac_chunk_t ret= { encoding.ptr, encoding.len };
    return ret;
}

/**
 * Get a PEM-encoded chunk representing the private key 
 */
abac_chunk_t abac_id_privkey_chunk(abac_id_t *id) 
{
    chunk_t tmp=chunk_empty;
    if(id->key)
         tmp=abac_key_chunk(id->key);
    abac_chunk_t ret= {tmp.ptr, tmp.len};
    return ret;
}

void abac_id_print_key_chunk(abac_id_t *id)
{
   if(id->key)
       print_abac_key("abac_id_print_key_chunk",id->key);
}

/**
 * Copy an abac ID. Actually just increases its reference count.
 */
abac_id_t *abac_id_dup(abac_id_t *id) {
    if(id)
        ++id->refcount;
    return id;
}

void abac_id_free(abac_id_t *id) {
    if (id == NULL)
        return;

    --id->refcount;
    if (id->refcount > 0)
        return;

    if(debug)
        fprintf(stderr,"making abac_id_free call on (%s)!!!\n", id->cn);
    // free once the reference count reaches 0
    DESTROY_IF(id->cert);

    if(id->key) abac_key_free(id->key);

    free(id->keyid);
    free(id->cn);
    free(id);
}

/****************************************************************/
/**
 * Default private key filename. Value must be freed by caller.
 */
char *abac_id_privkey_filename(abac_id_t *id) {
    assert(id != NULL);
    assert(id->cn != NULL);

    /* this cn has pCN attached to it */
    char *filename = NULL;
    char* ptr=id->cn;
    asprintf(&filename, "%s%s",(ptr+1),KEY_SUFFIX);
    return filename;
}

/**
 * Get the default filename for the cert. Value must be freed by caller.
 */
char *abac_id_cert_filename(abac_id_t *id) {
    assert(id != NULL);
    assert(id->cn != NULL);

    /* this cn has pCN attached to it */
    char *filename = NULL;
    char* ptr=id->cn;
    asprintf(&filename, "%s%s",(ptr+1),CERT_SUFFIX);
    return filename;
}

/****************************************************************/

/*
** Create an ID from tidbits info
*/
abac_id_t *abac_id_new(int idtype,char *keyid, char *cn, 
certificate_t *cert)
{
    abac_id_t *id = abac_xmalloc(sizeof(abac_id_t));
    id->idtype = idtype;
    id->keyid = abac_xstrdup(keyid);
    id->cn = abac_xstrdup(cn);
    id->cert = cert;
    id->key = NULL;
    id->refcount = 1;
    if(debug) fprintf(stderr,"abac_id_new: made a new id, %ld\n",(long) id);
    _add_into_id_credentials(id);
    return id;
}

abac_id_t *abac_id_keyid_new(char *keyid, char *cn, certificate_t *cert)
{
    return abac_id_new(e_KEYID,keyid,cn,cert); 
}

static abac_id_t *_abac_id_from_cert(certificate_t *cert) {
    abac_id_t *id = abac_xmalloc(sizeof(abac_id_t));
    id->idtype = e_KEYID;
    id->keyid = NULL;
    id->cn = NULL;
    id->cert = cert;
    id->key = NULL;

    id->keyid = _get_keyid(id->cert);
    // get the CN from the cert
    id_part_t type;
    chunk_t data;

    identification_t *cert_id = id->cert->get_subject(id->cert);
    enumerator_t *id_enum = cert_id->create_part_enumerator(cert_id);
    while (id_enum->enumerate(id_enum, &type, &data))
        if (type == ID_PART_RDN_CN) {
            id->cn = abac_xmalloc(data.len + 2);
            id->cn[0]='p';
            memcpy(&id->cn[1], data.ptr, data.len);
            id->cn[data.len+1] = 0;
        }
    id_enum->destroy(id_enum);

    if(id->cn != NULL) {
        if(debug) fprintf(stderr, "_abac_id_from_cert, found cn (%s)\n", id->cn);
        } else { /* have to prepend a p */
            char *tmp=NULL;
            asprintf(&tmp,"p%s",id->keyid);
            _abac_id_set_cn(id,tmp);
            free(tmp);
            if(debug) fprintf(stderr,"_abac_id_from_cert, did not find cn, set it to (%s)\n", id->cn);
    }

    id->refcount = 1;
    _add_into_id_credentials(id);
    return id;
}

/**
 * Create an ID cert from a file.
 * this one does not add id into id hash list
 */
abac_id_t *abac_id_from_file(char *filename) {

    /* make sure file exists */
    if(!file_exist(filename)) return NULL;

    libabac_init();
    certificate_t *cert = lib->creds->create(lib->creds,
        CRED_CERTIFICATE, CERT_X509,
        BUILD_FROM_FILE, filename,
        BUILD_X509_FLAG, X509_AA,
        BUILD_END
    );

    if (cert == NULL)
        return NULL;

    return _abac_id_from_cert(cert);
}

/**
 * Create an ID cert from a chunk.
 */
abac_id_t *abac_id_from_chunk(abac_chunk_t achunk) {
    chunk_t chunk = { .ptr = achunk.ptr, .len = achunk.len };

    certificate_t *cert = lib->creds->create(lib->creds,
        CRED_CERTIFICATE, CERT_X509,
        BUILD_BLOB_ASN1_DER, chunk,
        BUILD_X509_FLAG, X509_AA,
        BUILD_END
    );

    if (cert == NULL)
        return NULL;

    return _abac_id_from_cert(cert);
}

/**
 * Generate an ID with the specified CN and validity.
 *
 * validity is measured in seconds (as of 0.2.0)
 */
int abac_id_generate(abac_id_t **ret, char *cn, int validity)
{
    if (cn == NULL || !abac_validate_clean_name(cn))
        return ABAC_ID_GENERATE_INVALID_CN;

    if(debug) fprintf(stderr,"abac_id_generate: generating id with cn(%s)\n",cn);

    if (validity < 0)
        return ABAC_ID_GENERATE_INVALID_VALIDITY;

    if (validity == 0) validity = 1080 * 86400;

    abac_id_t *id = abac_xmalloc(sizeof(abac_id_t));

    /* add p to cn here */
    char *tmp=NULL;
    asprintf(&tmp,"p%s",cn);
    id->idtype = e_KEYID;
    id->cn = tmp;
    id->key = abac_key_generate();
    id->cert = _generate_cert(id->key, cn, validity);
    id->keyid = _get_keyid(id->cert);

    id->refcount = 1;
    _add_into_id_credentials(id);

    *ret = id;
    return ABAC_ID_SUCCESS;
}


/**
 * Generate an ID with the specified CN and validity and a passphrase.
 *
 * validity is measured in seconds (as of 0.2.0)
 */
int abac_id_generate_with_key(abac_id_t **ret, char *cn, int validity, char *filename, char *pfile) {
    if (cn == NULL || !abac_validate_clean_name(cn))
        return ABAC_ID_GENERATE_INVALID_CN;

    if(debug) {
        fprintf(stderr,"abac_id_generate: generating id with cn(%s) and privkey(%s)",
                                                    cn, filename);
        if(pfile) fprintf(stderr,"pfile(%s)\n",pfile);
            else fprintf(stderr,"\n");
    }

    if (validity < 0)
        return ABAC_ID_GENERATE_INVALID_VALIDITY;

    if (validity == 0) validity = 1080 * 86400;

    chunk_t pp=chunk_empty;
    if(pfile && strlen(pfile)!=0) {
        if(!file_exist(pfile))
            errx(1, "passphrase file does not exist!!\n");
        pp=extract_potato(filename,pfile);
    }

    abac_id_t *id = abac_xmalloc(sizeof(abac_id_t));
    char *tmp=NULL;
    asprintf(&tmp,"p%s",cn);
    id->idtype = e_KEYID;
    id->cn = tmp;
    id->key = abac_key_file_new(filename,pp);
    id->cert = _generate_cert(id->key, cn, validity);
    id->keyid = _get_keyid(id->cert);

    id->refcount = 1;
    _add_into_id_credentials(id);

    *ret = id;
    return ABAC_ID_SUCCESS;
}

int abac_id_load_privkey_file(abac_id_t *ptr, char *keyfile)
{
    assert(ptr);
    ptr->key=abac_key_file_new(keyfile, chunk_empty);
    return 1;
}

int abac_id_load_enc_privkey_file(abac_id_t *ptr, char *keyfile, char *pfile)
{
    assert(ptr);
    chunk_t pp=extract_potato(keyfile,pfile);
    ptr->key=abac_key_file_new(keyfile, pp);
    return 1;
}

int abac_id_load_privkey_chunk(abac_id_t *ptr, chunk_t keychunk)
{
    assert(ptr);
    ptr->key=abac_key_chunk_new(keychunk, chunk_empty);
    if(debug)
        print_abac_key("after abac_id_load_privkey_chunk", ptr->key);
    return 1;
}

int abac_id_load_enc_privkey_chunk(abac_id_t *ptr, chunk_t keychunk, char *pfile)
{
    assert(ptr);
    chunk_t pp=extract_potato(NULL,pfile);
    ptr->key=abac_key_chunk_new(keychunk, pp);
    return 1;
}