/**
 * @file statfile.h
 * Describes common methods for accessing statistics files and caching them in memory
 */

#ifndef RSPAMD_STATFILE_H
#define RSPAMD_STATFILE_H

#include "config.h"
#include "mem_pool.h"
#include "hash.h"

#define CHAIN_LENGTH 128

/* Section types */
#define STATFILE_SECTION_COMMON 1
#define STATFILE_SECTION_HEADERS 2
#define STATFILE_SECTION_URLS 3
#define STATFILE_SECTION_REGEXP 4

#define DEFAULT_STATFILE_INVALIDATE_TIME 30
#define DEFAULT_STATFILE_INVALIDATE_JITTER 30

/**
 * Common statfile header
 */
struct stat_file_header {
	u_char magic[3];						/**< magic signature ('r' 's' 'd') 		*/
	u_char version[2];						/**< version of statfile				*/
	u_char padding[3];						/**< padding							*/
	guint64 create_time;					/**< create time (time_t->guint64)		*/
	guint64 revision;						/**< revision number					*/
	guint64 rev_time;						/**< revision time						*/
	guint64 used_blocks;					/**< used blocks number					*/
	guint64 total_blocks;					/**< total number of blocks				*/
	u_char unused[239];						/**< some bytes that can be used in future */
};

/**
 * Section header
 */
struct stat_file_section {
	guint64 code;							/**< section's code						*/
	guint64 length;						/**< section's length in blocks			*/
};

/**
 * Block of data in statfile
 */
struct stat_file_block {
	guint32 hash1;							/**< hash1 (also acts as index)			*/				
	guint32 hash2;							/**< hash2								*/
	double value; 							/**< double value 						*/
};

/**
 * Statistic file
 */
struct stat_file {
	struct stat_file_header header;			/**< header								*/
	struct stat_file_section section;		/**< first section						*/
	struct stat_file_block blocks[1];		/**< first block of data				*/
};

/**
 * Common view of statfile object
 */
typedef struct stat_file_s {
#ifdef HAVE_PATH_MAX
	gchar filename[PATH_MAX];				/**< name of file						*/
#else
	gchar filename[MAXPATHLEN];				/**< name of file						*/
#endif
	gint fd;									/**< descriptor							*/
	void *map;								/**< mmaped area						*/
	off_t seek_pos;							/**< current seek position				*/
	struct stat_file_section cur_section;	/**< current section					*/
	time_t open_time;						/**< time when file was opened			*/
	time_t access_time;						/**< last access time					*/
	size_t len;								/**< length of file(in bytes)			*/
	memory_pool_mutex_t *lock;				/**< mutex								*/
} stat_file_t;

/**
 * Statfiles pool
 */
typedef struct statfile_pool_s {
	stat_file_t *files;						/**< hash table of opened files indexed by name	*/
	void **maps;							/**< shared hash table of mmaped areas indexed by name	*/
	gint opened;								/**< number of opened files				*/
	size_t max;								/**< maximum size						*/
	size_t occupied;						/**< current size						*/
	memory_pool_t *pool;					/**< memory pool object					*/
	memory_pool_mutex_t *lock;				/**< mutex								*/
	struct event  *invalidate_event;        /**< event for pool invalidation        */
	struct timeval invalidate_tv;
	gboolean mlock_ok;						/**< whether it is possible to use mlock (2) to avoid statfiles unloading */
} statfile_pool_t;

/* Forwarded declarations */
struct classifier_config;
struct statfile;

/**
 * Create new statfile pool
 * @param max_size maximum size
 * @return statfile pool object
 */
statfile_pool_t* statfile_pool_new (memory_pool_t *pool, size_t max_size, gboolean use_mlock);

/**
 * Open statfile and attach it to pool
 * @param pool statfile pool object
 * @param filename name of statfile to open
 * @return 0 if specified statfile is attached and -1 in case of error
 */
stat_file_t* statfile_pool_open (statfile_pool_t *pool, gchar *filename, size_t len, gboolean forced);

/**
 * Create new statfile but DOES NOT attach it to pool, use @see statfile_pool_open for attaching
 * @param pool statfile pool object
 * @param filename name of statfile to create
 * @param len length of new statfile
 * @return 0 if file was created and -1 in case of error
 */
gint statfile_pool_create (statfile_pool_t *pool, gchar *filename, size_t len);

/**
 * Close specified statfile
 * @param pool statfile pool object
 * @param filename name of statfile to close
 * @param remove_hash remove filename from opened files hash also
 * @return 0 if file was closed and -1 if statfile was not opened
 */
gint statfile_pool_close (statfile_pool_t *pool, stat_file_t *file, gboolean keep_sorted);

/**
 * Delete statfile pool and close all attached statfiles
 * @param pool statfile pool object
 */
void statfile_pool_delete (statfile_pool_t *pool);

/**
 * Try to lock all statfiles in memory
 * @param pool statfile pool object
 */
void statfile_pool_lockall (statfile_pool_t *pool);

/**
 * Lock specified file for exclusive use (eg. learning)
 * @param pool statfile pool object
 * @param filename name of statfile
 */
void statfile_pool_lock_file (statfile_pool_t *pool, stat_file_t *file);

/**
 * Unlock specified file
 * @param pool statfile pool object
 * @param filename name of statfile
 */
void statfile_pool_unlock_file (statfile_pool_t *pool, stat_file_t *file);

/**
 * Get block from statfile with h1 and h2 values, use time argument for current time
 * @param pool statfile pool object
 * @param filename name of statfile
 * @param h1 h1 in file
 * @param h2 h2 in file
 * @param now current time
 * @return block value or 0 if block is not found
 */
double statfile_pool_get_block (statfile_pool_t *pool, stat_file_t *file, guint32 h1, guint32 h2, time_t now);

/**
 * Set specified block in statfile
 * @param pool statfile pool object
 * @param filename name of statfile
 * @param h1 h1 in file
 * @param h2 h2 in file
 * @param now current time
 * @param value value of block
 */
void statfile_pool_set_block (statfile_pool_t *pool, stat_file_t *file, guint32 h1, guint32 h2, time_t now, double value);

/**
 * Check whether statfile is opened
 * @param pool statfile pool object
 * @param filename name of statfile
 * @return TRUE if specified statfile is opened and FALSE otherwise
 */
stat_file_t* statfile_pool_is_open (statfile_pool_t *pool, gchar *filename);

/**
 * Returns current statfile section
 * @param pool statfile pool object
 * @param filename name of statfile
 * @return code of section or 0 if file is not opened
 */
guint32 statfile_pool_get_section (statfile_pool_t *pool, stat_file_t *file);

/**
 * Go to other section of statfile
 * @param pool statfile pool object
 * @param filename name of statfile
 * @param code code of section to seek to
 * @param from_begin search for section from begin of file if true
 * @return TRUE if section was set and FALSE otherwise
 */
gboolean statfile_pool_set_section (statfile_pool_t *pool, stat_file_t *file, guint32 code, gboolean from_begin);

/**
 * Add new section to statfile
 * @param pool statfile pool object
 * @param filename name of statfile
 * @param code code of section to seek to
 * @param length length in blocks of new section
 * @return TRUE if section was successfully added and FALSE in case of error
 */
gboolean statfile_pool_add_section (statfile_pool_t *pool, stat_file_t *file, guint32 code, guint64 length);


/**
 * Return code of section identified by name
 * @param name name of section
 * @return code of section or 0 if name of section is unknown
 */
guint32 statfile_get_section_by_name (const gchar *name);

/**
 * Set statfile revision and revision time
 * @param filename name of statfile
 * @param revision number of revision
 * @param time time of revision
 * @return TRUE if revision was set
 */
gboolean statfile_set_revision (stat_file_t *file, guint64 rev, time_t time);

/**
 * Increment statfile revision and revision time
 * @param filename name of statfile
 * @param time time of revision
 * @return TRUE if revision was set
 */
gboolean statfile_inc_revision (stat_file_t *file);

/**
 * Set statfile revision and revision time
 * @param filename name of statfile
 * @param revision saved number of revision
 * @param time saved time of revision
 * @return TRUE if revision was saved in rev and time
 */
gboolean statfile_get_revision (stat_file_t *file, guint64 *rev, time_t *time);

/**
 * Get statfile used blocks
 * @param file file to get number of used blocks
 * @return number of used blocks or (guint64)-1 in case of error
 */
guint64 statfile_get_used_blocks (stat_file_t *file);

/**
 * Get statfile total blocks
 * @param file file to get number of used blocks
 * @return number of used blocks or (guint64)-1 in case of error
 */
guint64 statfile_get_total_blocks (stat_file_t *file);


/**
 * Plan statfile pool invalidation
 */
void statfile_pool_plan_invalidate (statfile_pool_t *pool, time_t seconds, time_t jitter);

/**
 * Get a statfile by symbol
 * @param pool pool object
 * @param ccf ccf classifier config
 * @param symbol symbol to search
 * @param st statfile to get
 * @param try_create whether we need to create statfile if it is absent
 */
stat_file_t* get_statfile_by_symbol (statfile_pool_t *pool, struct classifier_config *ccf,
		const gchar *symbol, struct statfile **st, gboolean try_create);

#endif