#include <errno.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>

#include "lmdb.h"
#include "volksdata/core.h"


bool VOLK_env_is_init = false;

/** @brief Warning messages.
 *
 * The message corresponding to the rc is found by
 * warning_msg[rc - VOLK_MIN_WARNING]. #VOLK_strerror() facilitates this.
 */
char *warning_msg[] = {
    "VOLK_NOACTION: No action or change of state occurred.",
    "VOLK_NORESULT: No result.",
    "VOLK_END: End of the loop reached.",
    "VOLK_CONFLICT: A conflict prevented a resource from being updated.",
};

/** @brief error messages.
 *
 * Note that all error values are < 0 so it is possible to set conditions to
 * be triggered only by error return values.
 *
 * The message corresponding to the rc is found by
 * err_msg[rc - VOLK_MIN_ERROR]. #VOLK_strerror() facilitates this.
 */
char *err_msg[] = {
    "VOLK_ERROR: Runtime error.",
    "VOLK_PARSE_ERR: Error parsing input.",
    "VOLK_VALUE_ERR: Invalid input.",
    "VOLK_TXN_ERR: MDB transaction error.",
    "VOLK_DB_ERR: Database error.",
    "VOLK_NOT_IMPL_ERR: Feature is not implemented.",
    "VOLK_IO_ERR: Input/Output error.",
    "VOLK_MEM_ERR: Memory error.",
    "VOLK_CONFLICT_ERR: A resource conflict interrupted the operation.",
    "VOLK_ENV_ERR: Environment not initialized. Did you call VOLK_init()?",
};

char *VOLK_root_path = __FILE__; // This is trimmed to root path on init.


VOLK_rc
mkdir_p (const char *_path, mode_t mode)
{
    char *path = strdup (_path);
    char *p;

    // Trim any trailing slash(es).
    for (p = path + strlen (path) - 1; p > path; p--)
        if (*p == '/') *p = '\0';
        else break;

    errno = 0;
    VOLK_rc rc = VOLK_NOACTION;

    /* Iterate the string */
    for (p = path + 1; *p; p++) {
        if (*p == '/') {
            /* Temporarily truncate */
            *p = '\0';

            if (mkdir (path, mode) != 0 && errno != EEXIST) goto finally;

            *p = '/';
        }
    }
    if (mkdir (path, mode) != 0) {
        if (errno != EEXIST) rc = errno;
    } else {
        rc = VOLK_OK;
    }

finally:

    LOG_TRACE("Path: %s", path);
    LOG_TRACE("errno: %d", errno);
    LOG_TRACE("rc: %d", rc);
    free (path);

    return rc;
}


char *
strndup (const char *src, size_t max)
{
    size_t len = strlen (src);
    if (len > max) len = max;

    char *dup;
    dup = malloc (len + 1);
    if (dup) {
        memcpy (dup, src, len);
        dup[len] = '\0';
    }

    return dup;
}


char *
strdup (const char *src)
{
   char *dup;
   dup = malloc (strlen (src) + 1);
   if (dup) strcpy(dup, src);

   return dup;
}


/** @brief Remove a directory recursively (POSIX compatible).
 *
 * Adapted from
 * https://stackoverflow.com/questions/5467725/how-to-delete-a-directory-and-its-contents-in-posix-c/42596507#42596507
 */
VOLK_rc rm_r (const char *path)
{
    size_t path_len;
    char *full_path;
    DIR *dir;
    struct stat stat_path, stat_entry;
    struct dirent *entry;

    // stat for the path
    stat(path, &stat_path);

    // if path does not exists or is not dir - exit with status -1
    if (S_ISDIR(stat_path.st_mode) == 0) {
        log_error ("%s: %s\n", "Is not directory", path);
        return VOLK_IO_ERR;
    }

    // if not possible to read the directory for this user
    if ((dir = opendir(path)) == NULL) {
        log_error ("%s: %s\n", "Can`t open directory", path);
        return VOLK_IO_ERR;
    }

    // the length of the path
    path_len = strlen(path);

    // iteration through entries in the directory
    while ((entry = readdir(dir)) != NULL) {

        // skip entries "." and ".."
        if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, ".."))
            continue;

        // determine a full path of an entry
        full_path = calloc(
                path_len + 1 + strlen(entry->d_name) + 1, sizeof(char));
        strcpy(full_path, path);
        strcat(full_path, "/");
        strcat(full_path, entry->d_name);

        // stat for the entry
        stat(full_path, &stat_entry);

        // recursively remove a nested directory
        if (S_ISDIR(stat_entry.st_mode) != 0) {
            rm_r (full_path);
            free (full_path);
            continue;
        }

        // remove a file object
        if (unlink(full_path) == 0)
            LOG_DEBUG ("Removed a file:\t%s\n", full_path);
        else
            log_error ("Can't remove a file:\t%s\n", full_path);
        free(full_path);
    }

    // remove the devastated directory and close the object of it
    if (rmdir(path) == 0)
        LOG_DEBUG ("Removed a directory:\t%s\n", path);
    else
        log_error ("Can't remove a directory:\t%s\n", path);

    closedir(dir);

    return VOLK_OK;
}


const char *
VOLK_strerror (VOLK_rc rc)
{
    if (rc >= VOLK_MIN_ERROR && rc <= VOLK_MAX_ERROR)
        return err_msg[rc - VOLK_MIN_ERROR];

    if (rc >= VOLK_MIN_WARNING && rc <= VOLK_MAX_WARNING)
        return warning_msg[rc - VOLK_MIN_WARNING];

    return mdb_strerror (rc);
}


/* Inline extern functions. */

int utf8_encode (const uint32_t utf, unsigned char *out);