/*
 * Copyright (C) 2001-2003 FhG Fokus
 * Copyright (C) 2007-2008 1&1 Internet AG
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version
 *
 * Kamailio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/**
 * \file lib/srdb1/db.h
 * \ingroup db1
 * \ref db.c
 * \brief Generic Database Interface
 *
 * This is a generic database interface for modules that need to utilize a
 * database. The interface should be used by all modules that access database.
 * The interface will be independent of the underlying database server.
 * Notes:
 * If possible, use the predefined macros if you need to access any structure
 * attributes.
 * For additional description, see the comments in the sources of mysql module.
 *
 * If you want to see more complicated examples of how the API could be used,
 * take a look at the sources of the usrloc or auth modules.
 */

#ifndef DB1_H
#define DB1_H

#include "db_key.h"
#include "db_op.h"
#include "db_val.h"
#include "db_con.h"
#include "db_res.h"
#include "db_cap.h"
#include "db_con.h"
#include "db_row.h"
#include "db_pooling.h"
#include "db_locking.h"

/**
 * \brief Specify table name that will be used for subsequent operations.
 *
 * The function db_use_table takes a table name and stores it db1_con_t structure.
 * All subsequent operations (insert, delete, update, query) are performed on
 * that table.
 * \param _h database connection handle
 * \param _t table name
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_use_table_f)(db1_con_t *_h, const str *_t);

/**
 * \brief Initialize database connection and obtain the connection handle.
 *
 * This function initializes the database API and opens a new database
 * connection. This function must be called after bind_dbmod but before any
 * other database API function is called.
 *
 * The function takes one parameter, the parameter must contain the database
 * connection URL. The URL is of the form
 * mysql://username:password\@host:port/database where:
 *
 * username: Username to use when logging into database (optional).
 * password: password if it was set (optional)
 * host:     Hosname or IP address of the host where database server lives (mandatory)
 * port:     Port number of the server if the port differs from default value (optional)
 * database: If the database server supports multiple databases, you must specify the
 * name of the database (optional).
 * \see bind_dbmod
 * \param _sqlurl database connection URL
 * \return returns a pointer to the db1_con_t representing the connection if it was
 * successful, otherwise 0 is returned
 */
typedef db1_con_t *(*db_init_f)(const str *_sqlurl);

/**
 * \brief Initialize database connection and obtain the connection handle.
 *
 * This function initializes the database API and opens a new database
 * connection. This function must be called after bind_dbmod but before any
 * other database API function is called.
 *
 * The function takes one parameter, the parameter must contain the database
 * connection URL. The URL is of the form
 * mysql://username:password\@host:port/database where:
 *
 * username: Username to use when logging into database (optional).
 * password: password if it was set (optional)
 * host:     Hosname or IP address of the host where database server lives (mandatory)
 * port:     Port number of the server if the port differs from default value (optional)
 * database: If the database server supports multiple databases, you must specify the
 * name of the database (optional).
 * \see bind_dbmod
 * \param _sqlurl database connection URL
 * \param _pooling whether or not to use a pooled connection
 * \return returns a pointer to the db1_con_t representing the connection if it was
 * successful, otherwise 0 is returned
 */
typedef db1_con_t *(*db_init2_f)(const str *_sqlurl, db_pooling_t _pooling);

/**
 * \brief Close a database connection and free all memory used.
 *
 * The function closes previously open connection and frees all previously
 * allocated memory. The function db_close must be the very last function called.
 * \param _h db1_con_t structure representing the database connection
 */
typedef void (*db_close_f)(db1_con_t *_h);


/**
 * \brief Query table for specified rows.
 *
 * This function implements the SELECT SQL directive.
 * If _k and _v parameters are NULL and _n is zero, you will get the whole table.
 *
 * if _c is NULL and _nc is zero, you will get all table columns in the result.
 * _r will point to a dynamically allocated structure, it is necessary to call
 * db_free_result function once you are finished with the result.
 *
 * If _op is 0, equal (=) will be used for all key-value pairs comparisons.
 *
 * Strings in the result are not duplicated, they will be discarded if you call
 * db_free_result, make a copy yourself if you need to keep it after db_free_result.
 *
 * You must call db_free_result before you can call db_query again!
 * \see db_free_result
 *
 * \param _h database connection handle
 * \param _k array of column names that will be compared and their values must match
 * \param _op array of operators to be used with key-value pairs
 * \param _v array of values, columns specified in _k parameter must match these values
 * \param _c array of column names that you are interested in
 * \param _n number of key-value pairs to match in _k and _v parameters
 * \param _nc number of columns in _c parameter
 * \param _o order by statement for query
 * \param _r address of variable where pointer to the result will be stored
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_query_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_op_t *_op, const db_val_t *_v, const db_key_t *_c,
		const int _n, const int _nc, const db_key_t _o, db1_res_t **_r);

/**
 * \brief Gets a partial result set, fetch rows from a result
 *
 * Gets a partial result set, fetch a number of rows from a database result.
 * This function initializes the given result structure on the first run, and
 * fetches the nrows number of rows. On subsequenting runs, it uses the
 * existing result and fetches more rows, until it reaches the end of the
 * result set. Because of this the result needs to be null in the first
 * invocation of the function. If the number of wanted rows is zero, the
 * function returns anything with a result of zero.
 * \param _h structure representing database connection
 * \param _r structure for the result
 * \param _n the number of rows that should be fetched
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_fetch_result_f)(
		const db1_con_t *_h, db1_res_t **_r, const int _n);


/**
 * \brief Raw SQL query.
 *
 * This function can be used to do database specific queries. Please
 * use this function only if needed, as this creates portability issues
 * for the different databases. Also keep in mind that you need to
 * escape all external data sources that you use. You could use the
 * escape_common and unescape_common functions in the core for this task.
 * \see escape_common
 * \see unescape_common
 * \param _h structure representing database connection
 * \param _s the SQL query
 * \param _r structure for the result
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_raw_query_f)(
		const db1_con_t *_h, const str *_s, db1_res_t **_r);


/**
 * \brief Raw SQL query via async framework.
 *
 * This function can be used to do database specific queries. Please
 * use this function only if needed, as this creates portability issues
 * for the different databases. Also keep in mind that you need to
 * escape all external data sources that you use. You could use the
 * escape_common and unescape_common functions in the core for this task.
 * \see escape_common
 * \see unescape_common
 * \param _h structure representing database connection
 * \param _s the SQL query
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_raw_query_async_f)(const db1_con_t *_h, const str *_s);


/**
 * \brief Free a result allocated by db_query.
 *
 * This function frees all memory allocated previously in db_query. Its
 * necessary to call this function on a db1_res_t structure if you don't need the
 * structure anymore. You must call this function before you call db_query again!
 * \param _h database connection handle
 * \param _r pointer to db1_res_t structure to destroy
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_free_result_f)(db1_con_t *_h, db1_res_t *_r);


/**
 * \brief Insert a row into the specified table.
 *
 * This function implements INSERT SQL directive, you can insert one or more
 * rows in a table using this function.
 * \param _h database connection handle
 * \param _k array of keys (column names)
 * \param _v array of values for keys specified in _k parameter
 * \param _n number of keys-value pairs int _k and _v parameters
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_insert_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_val_t *_v, const int _n);


/**
 * \brief Delete a row from the specified table.
 *
 * This function implements DELETE SQL directive, it is possible to delete one or
 * more rows from a table.
 * If _k is NULL and _v is NULL and _n is zero, all rows are deleted, the
 * resulting table will be empty.
 * If _o is NULL, the equal operator "=" will be used for the comparison.
 *
 * \param _h database connection handle
 * \param _k array of keys (column names) that will be matched
 * \param _o array of operators to be used with key-value pairs
 * \param _v array of values that the row must match to be deleted
 * \param _n number of keys-value parameters in _k and _v parameters
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_delete_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_op_t *_o, const db_val_t *_v, const int _n);


/**
 * \brief Update some rows in the specified table.
 *
 * The function implements UPDATE SQL directive. It is possible to modify one
 * or more rows in a table using this function.
 * \param _h database connection handle
 * \param _k array of keys (column names) that will be matched
 * \param _o array of operators to be used with key-value pairs
 * \param _v array of values that the row must match to be modified
 * \param _uk array of keys (column names) that will be modified
 * \param _uv new values for keys specified in _k parameter
 * \param _n number of key-value pairs in _k and _v parameters
 * \param _un number of key-value pairs in _uk and _uv parameters
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_update_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_op_t *_o, const db_val_t *_v, const db_key_t *_uk,
		const db_val_t *_uv, const int _n, const int _un);


/**
 * \brief Insert a row and replace if one already exists.
 *
 * The function implements the REPLACE SQL directive. It is possible to insert
 * a row and replace if one already exists. The old row will be deleted before
 * the insertion of the new data.
 * \param _h structure representing database connection
 * \param _k key names
 * \param _v values of the keys
 * \param _n number of key=value pairs
 * \param _un number of keys to build the unique key, starting from first _k
 * \param _m mode - first update, then insert, or first insert, then update
 * \note the last two parameters are used only if the DB server does not
 * have native replace command (like postgres - the module doing an internal
 * implementation using synchronized update/affected rows/insert mechanism)
 * \return returns 0 if everything is OK, otherwise returns value < 0
*/
typedef int (*db_replace_f)(const db1_con_t *handle, const db_key_t *keys,
		const db_val_t *vals, const int n, const int _un, const int _m);


/**
 * \brief Retrieve the last inserted ID in a table.
 *
 * The function returns the value generated for an AUTO_INCREMENT column by the
 * previous INSERT or UPDATE  statement. Use this function after you have
 * performed an INSERT statement into a table that contains an AUTO_INCREMENT
 * field.
 * \param _h structure representing database connection
 * \return returns the ID as integer or returns 0 if the previous statement
 * does not use an AUTO_INCREMENT value.
 */
typedef int (*db_last_inserted_id_f)(const db1_con_t *_h);


/**
 * \brief Insert a row into specified table, update on duplicate key.
 *
 * The function implements the INSERT ON DUPLICATE KEY UPDATE SQL directive.
 * It is possible to insert a row and update if one already exists.
 * The old row will not deleted before the insertion of the new data.
 * \param _h structure representing database connection
 * \param _k key names
 * \param _v values of the keys
 * \param _n number of key=value pairs
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_insert_update_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_val_t *_v, const int _n);


/**
 * \brief Insert delayed a row into the specified table.
 *
 * This function implements INSERT DELAYED SQL directive. It is possible to
 * insert one or more rows in a table with delay using this function.
 * \param _h database connection handle
 * \param _k array of keys (column names)
 * \param _v array of values for keys specified in _k parameter
 * \param _n number of keys-value pairs int _k and _v parameters
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_insert_delayed_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_val_t *_v, const int _n);

/**
 * \brief Insert a row into the specified table via async framework.
 *
 * This function implements INSERT DELAYED SQL directive. It is possible to
 * insert one or more rows in a table with delay using this function.
 * \param _h database connection handle
 * \param _k array of keys (column names)
 * \param _v array of values for keys specified in _k parameter
 * \param _n number of keys-value pairs int _k and _v parameters
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
typedef int (*db_insert_async_f)(const db1_con_t *_h, const db_key_t *_k,
		const db_val_t *_v, const int _n);


/**
 * \brief Retrieve the number of affected rows for the last query.
 *
 * The function returns the rows affected by the last query.
 * If any other type of query was the last, it returns null.
 * \param _h structure representing database connection
 * \return returns the number of rows as integer or returns -1 on error
 */
typedef int (*db_affected_rows_f)(const db1_con_t *_h);

/**
 * \brief Start a single transaction that will consist of one or more queries.
 *
 * \param _h structure representing database connection
 * \return 0 if everything is OK, otherwise returns < 0
 */
typedef int (*db_start_transaction_f)(db1_con_t *_h, db_locking_t _l);

/**
 * \brief End a transaction.
 *
 * \param _h structure representing database connection
 * \return 0 if everything is OK, otherwise returns < 0
 */
typedef int (*db_end_transaction_f)(db1_con_t *_h);

/**
 * \brief Abort a transaction.
 *
 * Use this function if you have an error after having started a transaction
 * and you want to rollback any uncommitted changes before continuing.
 * \param _h structure representing database connection
 * \return 1 if there was something to rollbak, 0 if not, negative on failure
 */
typedef int (*db_abort_transaction_f)(db1_con_t *_h);

/**
 * \brief Database module callbacks
 *
 * This structure holds function pointer to all database functions. Before this
 * structure can be used it must be initialized with bind_dbmod.
 * \see bind_dbmod
 */
typedef struct db_func
{
	unsigned int cap;		  /* Capability vector of the database transport */
	db_use_table_f use_table; /* Specify table name */
	db_init_f init;			  /* Initialize database connection */
	db_init2_f init2;		  /* Initialize database connection */
	db_close_f close;		  /* Close database connection */
	db_query_f query;		  /* query a table */
	db_fetch_result_f fetch_result;			/* fetch result */
	db_raw_query_f raw_query;				/* Raw query - SQL */
	db_free_result_f free_result;			/* Free a query result */
	db_insert_f insert;						/* Insert into table */
	db_delete_f delete;						/* Delete from table */
	db_update_f update;						/* Update table */
	db_replace_f replace;					/* Replace row in a table */
	db_last_inserted_id_f last_inserted_id; /* Retrieve the last inserted ID
	                                            in a table */
	db_insert_update_f
			insert_update; /* Insert into table, update on duplicate key */
	db_insert_delayed_f insert_delayed; /* Insert delayed into table */
	db_insert_async_f insert_async;		/* Insert async into table */
	db_affected_rows_f
			affected_rows; /* Number of affected rows for last query */
	db_start_transaction_f
			start_transaction; /* Start a single transaction consisting of multiple queries */
	db_end_transaction_f end_transaction;	  /* End a transaction */
	db_abort_transaction_f abort_transaction; /* Abort a transaction */
	db_query_f query_lock; /* query a table and lock rows for update */
	db_raw_query_async_f raw_query_async; /* Raw query - SQL */
} db_func_t;


/**
 * \brief Bind database module functions
 *
 * This function is special, it's only purpose is to call find_export function in
 * the core and find the addresses of all other database related functions. The
 * db_func_t callback given as parameter is updated with the found addresses.
 *
 * This function must be called before any other database API call!
 *
 * The database URL is of the form "mysql://username:password@host:port/database" or
 * "mysql" (database module name).
 * In the case of a database connection URL, this function looks only at the first
 * token (the database protocol). In the example above that would be "mysql":
 * \see db_func_t
 * \param mod database connection URL or a database module name
 * \param dbf database module callbacks
 * \return returns 0 if everything is OK, otherwise returns value < 0
 */
int db_bind_mod(const str *mod, db_func_t *dbf);


/**
 * \brief Helper for db_init function.
 *
 * This helper method do the actual work for the database specific db_init
 * functions.
 * \param url database connection URL
 * \param (*new_connection)() Pointer to the db specific connection creation method
 * \return returns a pointer to the db1_con_t representing the connection if it was
   successful, otherwise 0 is returned.
 */
db1_con_t *db_do_init(const str *url, void *(*new_connection)());


/**
 * \brief Helper for db_init2 function.
 *
 * This helper method do the actual work for the database specific db_init
 * functions.
 * \param url database connection URL
 * \param (*new_connection)() Pointer to the db specific connection creation method
 * \param pooling whether or not to use a pooled connection
 * \return returns a pointer to the db1_con_t representing the connection if it was
   successful, otherwise 0 is returned.
 */
db1_con_t *db_do_init2(
		const str *url, void *(*new_connection)(), db_pooling_t pooling);


/**
 * \brief Helper for db_close function.
 *
 * This helper method does some work for the closing of a database
 * connection. No function should be called after this
 * \param _h database connection handle
 * \param (*free_connection) Pointer to the db specific free_connection method
 */
void db_do_close(db1_con_t *_h, void (*free_connection)());


/**
 * \brief Get the version of a table.
 *
 * Returns the version number of a given table from the version table.
 * Instead of this function you should use db_check_table_version!
 * \see db_check_table_version
 * \param dbf database module callbacks
 * \param con database connection handle
 * \param table checked table
 * \return the version number if present, 0 if no version data available, < 0 on error
 */
int db_table_version(const db_func_t *dbf, db1_con_t *con, const str *table);

/**
 * \brief Check the table version
 *
 * Small helper function to check the table version.
 * \param dbf database module callbacks
 * \param dbh database connection handle
 * \param table checked table
 * \param version checked version
 * \return 0 means ok, -1 means an error occurred
 */
int db_check_table_version(db_func_t *dbf, db1_con_t *dbh, const str *table,
		const unsigned int version);

/**
 * \brief Stores the name of a table.
 *
 * Stores the name of the table that will be used by subsequent database
 * functions calls in a db1_con_t structure.
 * \param _h database connection handle
 * \param _t stored name
 * \return 0 if everything is ok, otherwise returns value < 0
 */
int db_use_table(db1_con_t *_h, const str *_t);

/**
 * \brief Bind the DB API exported by a module.
 *
 * The function links the functions implemented by the module to the members
 * of db_func_t structure
 * \param dbb db_func_t structure representing the variable where to bind
 * \return 0 if everything is ok, otherwise returns -1
 */

typedef int (*db_bind_api_f)(db_func_t *dbb);

/**
 * \brief Generic query helper for load bulk data
 *
 * Generic query helper method for load bulk data, e.g. lcr tables
 * \param binding database module binding
 * \param handle database connection
 * \param name database table name
 * \param cols queried columns
 * \param count number of queried columns
 * \param strict if set to 1 an error is returned when no data could be loaded,
    otherwise just a warning is logged
 * \param res database result, unchanged on failure and if no data could be found
 * \return 0 if the query was run successful, -1 otherwise
 */
int db_load_bulk_data(db_func_t *binding, db1_con_t *handle, str *name,
		db_key_t *cols, unsigned int count, unsigned int strict,
		db1_res_t *res);

/**
 * \brief DB API init function.
 *
 * This function must be executed by DB connector modules at load time to
 * initialize the internals of DB API library.
 * \return returns 0 on successful initialization, -1 on error.
 */
int db_api_init(void);

/**
 * \brief wrapper around db query to handle fetch capability
 * \return -1 error; 0 ok with no fetch capability; 1 ok with fetch capability
 */
int db_fetch_query(db_func_t *dbf, int frows, db1_con_t *_h, const db_key_t *_k,
		const db_op_t *_op, const db_val_t *_v, const db_key_t *_c,
		const int _n, const int _nc, const db_key_t _o, db1_res_t **_r);

/**
 * \brief wrapper around db query_lock to handle fetch capability
 * \return -1 error; 0 ok with no fetch capability; 1 ok with fetch capability
 */
int db_fetch_query_lock(db_func_t *dbf, int frows, db1_con_t *_h,
		const db_key_t *_k, const db_op_t *_op, const db_val_t *_v,
		const db_key_t *_c, const int _n, const int _nc, const db_key_t _o,
		db1_res_t **_r);

/**
 * \brief wrapper around db fetch to handle fetch capability
 * \return -1 error; 0 ok with no fetch capability; 1 ok with fetch capability
 */
int db_fetch_next(db_func_t *dbf, int frows, db1_con_t *_h, db1_res_t **_r);

/**
 * \brief Error logging helper for database version check error.
 * \param table database table name string
 */
#define DB_TABLE_VERSION_ERROR(table)                 \
	LM_ERR("Error during version check for db table:" \
		   " %.*s, check database structure.\n",      \
			table.len, table.s)

#endif /* DB1_H */
