#ifndef STATS_PREFIX_H

#define STATS_PREFIX_H

/* The stats prefix subsystem stores detailed statistics for each key prefix.

 * Simple statistics like total number of GETS are stored by the Stats

 * subsystem defined elsewhere.

 *

 * Suppose the prefix delimiter is ":", then "user:123" and "user:456" both

 * have the same prefix "user".

 */

/* Initialize the stats prefix subsystem. Should be called once before other

 * functions are called. The global hash initialization should be done before

 * using this subsystem.

 */

void stats_prefix_init(char prefix_delimiter);

/* Clear previously collected stats. Requires you to have the acquired

 * the STATS_LOCK() first.

 */

void stats_prefix_clear(void);

/* Record a GET for a key */

void stats_prefix_record_get(const char *key, const size_t nkey, const bool is_hit);

/* Record a DELETE for a key */

void stats_prefix_record_delete(const char *key, const size_t nkey);

/* Record a SET for a key */

void stats_prefix_record_set(const char *key, const size_t nkey);

/* Return the collected stats in a textual for suitable for writing to a client.

 * The size of the output text is stored in the length parameter.

 * Returns NULL on error

 */

char *stats_prefix_dump(int *length);

/* Visible for testing */

#define PREFIX_HASH_SIZE 256

typedef struct _prefix_stats PREFIX_STATS;

struct _prefix_stats {

    char *prefix;

    size_t prefix_len;

    uint64_t num_gets;

    uint64_t num_sets;

    uint64_t num_deletes;

    uint64_t num_hits;

    PREFIX_STATS *next;

};

/* Return the PREFIX_STATS structure for the specified key, creating it if

 * it does not already exist. Returns NULL if the key does not contain

 * prefix delimiter, or if there was an error. Requires you to have acquired

 * STATS_LOCK() first.

 */

PREFIX_STATS *stats_prefix_find(const char *key, const size_t nkey);

#endif