#ifndef DICT_H
#define DICT_H

#define DICT_PATH_PRIVATE "priv/"
#define DICT_PATH_SHARED "shared/"

struct dict;

enum dict_iterate_flags {
	DICT_ITERATE_FLAG_RECURSE             = 0x01,
	DICT_ITERATE_FLAG_SORT_BY_KEY         = 0x02,
	DICT_ITERATE_FLAG_SORT_BY_VALUE       = 0x04
};

enum dict_data_type {
	DICT_DATA_TYPE_STRING,
	DICT_DATA_TYPE_UINT32
};

typedef void dict_transaction_commit_callback_t(int ret, void *context);

void dict_driver_register(struct dict *driver);
void dict_driver_unregister(struct dict *driver);

void dict_drivers_register_builtin(void);
void dict_drivers_unregister_builtin(void);

void dict_drivers_register_all(void);
void dict_drivers_unregister_all(void);

/* Open dictionary with given URI (type:data).
   If URI is invalid, returns NULL. */
struct dict *dict_init(const char *uri, enum dict_data_type value_type,
		       const char *username, const char *base_dir);
/* Close dictionary. */
void dict_deinit(struct dict **dict);
/* Wait for all pending asynchronous transaction commits to finish.
   Returns 0 if ok, -1 if error. */
int dict_wait(struct dict *dict);

/* Lookup value for key. Set it to NULL if it's not found.
   Returns 1 if found, 0 if not found and -1 if lookup failed. */
int dict_lookup(struct dict *dict, pool_t pool,
		const char *key, const char **value_r);

/* Iterate through all values in a path. flag indicates how iteration
   is carried out */
struct dict_iterate_context *
dict_iterate_init(struct dict *dict, const char *path, 
		  enum dict_iterate_flags flags);
/* Returns -1 = error, 0 = finished, 1 = key/value set */
int dict_iterate(struct dict_iterate_context *ctx,
		 const char **key_r, const char **value_r);
void dict_iterate_deinit(struct dict_iterate_context **ctx);

/* Start a new dictionary transaction. */
struct dict_transaction_context *dict_transaction_begin(struct dict *dict);
/* Commit the transaction. Returns 1 if ok, 0 if dict_atomic_inc() was used
   on a non-existing key, -1 if failed. */
int dict_transaction_commit(struct dict_transaction_context **ctx);
/* Commit the transaction, but don't wait to see if it finishes successfully.
   If callback isn't NULL, it's called eventually. If it's not called by the
   time you want to deinitialize dict, call dict_flush() to wait for the
   result. */
void dict_transaction_commit_async(struct dict_transaction_context **ctx,
				   dict_transaction_commit_callback_t *callback,
				   void *context);
/* Rollback all changes made in transaction. */
void dict_transaction_rollback(struct dict_transaction_context **ctx);

/* Set key=value in dictionary. */
void dict_set(struct dict_transaction_context *ctx,
	      const char *key, const char *value);
/* Unset a record in dictionary, identified by key*/
void dict_unset(struct dict_transaction_context *ctx,
		const char *key);
/* Increase/decrease a numeric value in dictionary. Note that the value is
   changed when transaction is being committed, so you can't know beforehand
   what the value will become. The value is updated only if it already exists,
   otherwise commit() will return 0. */
void dict_atomic_inc(struct dict_transaction_context *ctx,
		     const char *key, long long diff);

#endif