#include <erl_driver.h>
#include <ei.h>
#include <stdio.h>
#include <string.h>
#include <sqlite3.h>
#include <erl_interface.h>

// Path to file where data will be stored. 
// It will be created if it doesn't exist
#define DB_PATH "./store.db"

// Binary commands between Erlang VM and Driver
#define CMD_SQL_EXEC 2
// #define CMD_DEL 3

// Number of bytes for each key
// (160 bits for SHA1 hash)
#define KEY_SIZE 20

// Define struct to hold state across calls
typedef struct _bdb_drv_t {
  ErlDrvPort port;
 
  struct sqlite3 *db;
} sqlite3_drv_t;


static ErlDrvData start(ErlDrvPort port, char* cmd);
static void stop(ErlDrvData handle);
static int control(ErlDrvData drv_data, unsigned int command, char *buf, 
                   int len, char **rbuf, int rlen);
static void ready_async(ErlDrvData drv_data, ErlDrvThreadData thread_data);
static int sql_exec(sqlite3_drv_t *drv, char *buf, int len);
// static void get(bdb_drv_t *bdb_drv, ErlIOVec *ev);
// static void del(bdb_drv_t *bdb_drv, ErlIOVec *ev);
static int unknown(sqlite3_drv_t *bdb_drv, char *buf, int len);