#define _GNU_SOURCE

#include "encryption.h"
#include "shared.h"

#include <sodium.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <stdio.h>

#if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
void naclfaildefault(void *none) {
    none = none; // Makes gcc happy    
    error(1, ENOTSUP, "Couldn't initialize sodium for some reason. Quitting...");
}

int checksodiumcb(const vxgg_naclfailcb callback, void *data) {
    static vxgg_naclfailcb cb = naclfaildefault;
    static void *usr = NULL;

    if(callback != NULL) {
        cb = callback;
        usr = data;
        return 2;   // libsodium normally returns 1 if the library is already initialized, so this is to signal that the callback has been updated
    }

    int ret = sodium_init();
    if(ret < 0)
        cb(usr);

    return ret;
}

void vxgg_setsodiumfailcb(vxgg_naclfailcb cb, void *data) {
    checksodiumcb(cb, data);
}
#endif

void checksodium(void) {
    #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
        checksodiumcb(NULL, NULL);
    #else
        if(sodium_init() < 0)
            error(1, ENOTSUP, "Couldn't initialize sodium for some reason. Quitting...");
    #endif
    
    return;
}

// To encrypt:
// 1- Create a temp file with the correct name in the root folder of the partition being encrypted      -- 
    // 1.1- Detect the partition and find the root folder                                                   -- DONE || NOT NECESSARY
    // 1.2- Create the temp file                                                                            -- DONE
// 2- Encrypt the file's contents to the temp file                                                      -- 
    // 2.1- Open the file                                                                                   -- 
    // 2.2- Stream the file's contents into some encryption algo                                            -- 
    // 2.3- Pipe the output of the encryption into the temp file                                            -- 
// 3- Once the file has been encrypted, hard link it back to the original location, with the right name -- 
// 4- Delete the original file                                                                          -- 
// 5- Delete the temp file                                                                              --


int maketmp(const char *dest) {
    return open(dest, (O_TMPFILE | O_WRONLY | O_CLOEXEC | O_SYNC), (S_IRUSR | S_IWUSR));
}

int encrypttotmp(const char *toencrypt) {
    #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
        checksodium();
    #endif

    struct stat esb;
    int efd = -1;

    // Make sure the file is real and an actual file that can be encrypted
    if(stat(toencrypt, &esb) < 0)
        return -1;
    if(!S_ISREG(esb.st_mode))
        return -2;

    // Open the file as read-only
    if((efd = open(toencrypt, O_RDONLY)) < 0)
        return -3;

    // Need to get a secret key from a password and then set up cryptostream from libsodium

    return 0;
}

int genpassword(char **str, unsigned int words) {
    // Early returns
    if(words < 1)
        return 0;
    #if defined ___VXGG___ALWAYS_CHECK_LIBSODIUM___ && ___VXGG___ALWAYS_CHECK_LIBSODIUM___ > 0
        checksodium();
    #endif

    // Bootstrap the first word
    char *lstr = NULL, *tmp = NULL;
    if(asprintf(&lstr, "%s", PASSWORD_WORDS[randombytes_uniform(PASSWORD_WORDS_LEN)]) < 0)
        return -1;

    // Concat the rest of the words into the password (without leaking memory)
    int ret;
    for(unsigned int i = 1; i < words; i++) {    
        ret = asprintf(&tmp, "%s %s", lstr, PASSWORD_WORDS[randombytes_uniform(PASSWORD_WORDS_LEN)]);
        free(lstr);
        if(ret < 0)
            return -1;

        lstr = tmp;
    }

    *str = lstr;
    return words;

    // This function was exploding because of some weird conflict with using my buggy implementation of asprintf instead of the 
    // _GNU_SOURCE version. Don't know why it wasn't using the _GNU_SOURCE version, as I had a define macro put in place to 
    // prevent it from being compiled if _GNU_SOURCE was defined, but whatever
}


#define TESTING
#ifdef TESTING

#include <string.h>

int main(void) {
    /*// Example code for creating a temp file, writing to it, then linking it back into the fs
    const char *dir = ".", *testmsg = "we do a little testing\n";
    char *path = NULL;

    int fd = maketmp(dir);
    if(fd < 0)
        error(1, errno, "Couldn't make temp file at %s", dir);

    if(write(fd, testmsg, strlen(testmsg)) < 0)
        error(1, errno, "write broke");
    
    asprintf(&path, "/proc/self/fd/%d", fd);
    linkat(AT_FDCWD, path, AT_FDCWD, "./test", AT_SYMLINK_FOLLOW);
    free(path);

    // Apparently, I don't have the CAP_DAC_READ_SEARCH capibility. Thanks for the solution, linux man pages

    if(close(fd) < 0)
        error(1, errno, "close broke");
    //*///

    //*// Example code for getting a password using genpassword
    checksodium();

    char *password = NULL;
    genpassword(&password, 20);
    printf("%s\n", (password != NULL) ? password : "Couldn't get a password");
    free(password);
    //*///

    return 0;
}

#endif