/**
 * This file is part of Hercules.
 * http://herc.ws - http://github.com/HerculesWS/Hercules
 *
 * Copyright (C) 2012-2020 Hercules Dev Team
 * Copyright (C) Athena Dev Teams
 *
 * Hercules 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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, see <http://www.gnu.org/licenses/>.
 */
#ifndef COMMON_SQL_H
#define COMMON_SQL_H

#include "common/hercules.h"

#include <stdarg.h>// va_list

// Return codes
#define SQL_ERROR (-1)
#define SQL_SUCCESS 0
#define SQL_NO_DATA 100

// macro definition to determine whether the mySQL engine is running on InnoDB (rather than MyISAM)
// uncomment this line if the your mySQL tables have been changed to run on InnoDB
// this macro will adjust how logs are recorded in the database to accommodate the change
//#define SQL_INNODB

/// Data type identifier.
/// String, enum and blob data types need the buffer length specified.
enum SqlDataType {
	SQLDT_NULL,
	// fixed size
	SQLDT_INT8,
	SQLDT_INT16,
	SQLDT_INT32,
	SQLDT_INT64,
	SQLDT_UINT8,
	SQLDT_UINT16,
	SQLDT_UINT32,
	SQLDT_UINT64,
	// platform dependent size
	SQLDT_CHAR,
	SQLDT_SHORT,
	SQLDT_INT,
	SQLDT_LONG,
	SQLDT_LONGLONG,
	SQLDT_UCHAR,
	SQLDT_USHORT,
	SQLDT_UINT,
	SQLDT_ULONG,
	SQLDT_ULONGLONG,
	SQLDT_BOOL,
	SQLDT_TIME,
	// floating point
	SQLDT_FLOAT,
	SQLDT_DOUBLE,
	// other
	SQLDT_STRING,
	SQLDT_ENUM,
	// Note: An ENUM is a string with restricted values. When an invalid value
	//       is inserted, it is saved as an empty string (numerical value 0).
	SQLDT_BLOB,
	SQLDT_LASTID
};

struct Sql;     ///< Sql handle (private access)
struct SqlStmt; ///< Sql statement (private access)

struct sql_interface {
	/// Establishes a connection.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*Connect) (struct Sql *self, const char *user, const char *passwd, const char *host, uint16 port, const char *db);
	/// Retrieves the timeout of the connection.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*GetTimeout) (struct Sql *self, uint32 *out_timeout);
	/// Retrieves the name of the columns of a table into out_buf, with the separator after each name.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*GetColumnNames) (struct Sql *self, const char *table, char *out_buf, size_t buf_len, char sep);
	/// Changes the encoding of the connection.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*SetEncoding) (struct Sql *self, const char *encoding);
	/// Pings the connection.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*Ping) (struct Sql *self);
	/// Escapes a string.
	/// The output buffer must be at least strlen(from)*2+1 in size.
	///
	/// @return The size of the escaped string
	size_t (*EscapeString) (struct Sql *self, char *out_to, const char *from);
	/// Escapes a string.
	/// The output buffer must be at least from_len*2+1 in size.
	///
	/// @return The size of the escaped string
	size_t (*EscapeStringLen) (struct Sql *self, char *out_to, const char *from, size_t from_len);
	/// Executes a query.
	/// Any previous result is freed.
	/// The query is constructed as if it was sprintf.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*Query) (struct Sql *self, const char *query, ...) __attribute__((format(printf, 2, 3)));
	/// Executes a query.
	/// Any previous result is freed.
	/// The query is constructed as if it was svprintf.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*QueryV) (struct Sql *self, const char *query, va_list args);
	/// Executes a query.
	/// Any previous result is freed.
	/// The query is used directly.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*QueryStr) (struct Sql *self, const char *query);
	/// Returns the number of the AUTO_INCREMENT column of the last INSERT/UPDATE query.
	///
	/// @return Value of the auto-increment column
	uint64 (*LastInsertId) (struct Sql *self);
	/// Returns the number of columns in each row of the result.
	///
	/// @return Number of columns
	uint32 (*NumColumns) (struct Sql *self);
	/// Returns the number of rows in the result.
	///
	/// @return Number of rows
	uint64 (*NumRows) (struct Sql *self);
	/// Fetches the next row.
	/// The data of the previous row is no longer valid.
	///
	/// @return SQL_SUCCESS, SQL_ERROR or SQL_NO_DATA
	int (*NextRow) (struct Sql *self);
	/// Gets the data of a column.
	/// The data remains valid until the next row is fetched or the result is freed.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*GetData) (struct Sql *self, size_t col, char **out_buf, size_t *out_len);
	/// Frees the result of the query.
	void (*FreeResult) (struct Sql *self);
	/// Shows debug information (last query).
	void (*ShowDebug_) (struct Sql *self, const char *debug_file, const unsigned long debug_line);
	/// Frees a Sql handle returned by Sql_Malloc.
	void (*Free) (struct Sql *self);
	/// Allocates and initializes a new Sql handle.
	struct Sql *(*Malloc) (void);

	///////////////////////////////////////////////////////////////////////////////
	// Prepared Statements
	///////////////////////////////////////////////////////////////////////////////
	// Parameters are placed in the statement by embedding question mark ('?')
	// characters into the query at the appropriate positions.
	// The markers are legal only in places where they represent data.
	// The markers cannot be inside quotes. Quotes will be added automatically
	// when they are required.
	//
	// example queries with parameters:
	// 1) SELECT col FROM table WHERE id=?
	// 2) INSERT INTO table(col1,col2) VALUES(?,?)

	/*=====================================
	SQL Statement interface [Susu]
	*-------------------------------------*/

	/// Allocates and initializes a new SqlStmt handle.
	/// It uses the connection of the parent Sql handle.
	/// Queries in Sql and SqlStmt are independent and don't affect each other.
	///
	/// @return SqlStmt handle or NULL if an error occurred
	struct SqlStmt* (*StmtMalloc)(struct Sql *sql);

	/// Prepares the statement.
	/// Any previous result is freed and all parameter bindings are removed.
	/// The query is constructed as if it was sprintf.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtPrepare) (struct SqlStmt *self, const char *query, ...) __attribute__((format(printf, 2, 3)));

	/// Prepares the statement.
	/// Any previous result is freed and all parameter bindings are removed.
	/// The query is constructed as if it was svprintf.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtPrepareV)(struct SqlStmt *self, const char *query, va_list args);

	/// Prepares the statement.
	/// Any previous result is freed and all parameter bindings are removed.
	/// The query is used directly.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtPrepareStr)(struct SqlStmt *self, const char *query);

	/// Returns the number of parameters in the prepared statement.
	///
	/// @return Number or parameters
	size_t (*StmtNumParams)(struct SqlStmt *self);

	/// Binds a parameter to a buffer.
	/// The buffer data will be used when the statement is executed.
	/// All parameters should have bindings.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtBindParam)(struct SqlStmt *self, size_t idx, enum SqlDataType buffer_type, const void *buffer, size_t buffer_len);

	/// Executes the prepared statement.
	/// Any previous result is freed and all column bindings are removed.
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtExecute)(struct SqlStmt *self);

	/// Returns the number of the AUTO_INCREMENT column of the last INSERT/UPDATE statement.
	///
	/// @return Value of the auto-increment column
	uint64 (*StmtLastInsertId)(struct SqlStmt *self);

	/// Returns the number of columns in each row of the result.
	///
	/// @return Number of columns
	size_t (*StmtNumColumns)(struct SqlStmt *self);

	/// Binds the result of a column to a buffer.
	/// The buffer will be filled with data when the next row is fetched.
	/// For string/enum buffer types there has to be enough space for the data
	/// and the null-terminator (an extra byte).
	///
	/// @return SQL_SUCCESS or SQL_ERROR
	int (*StmtBindColumn)(struct SqlStmt *self, size_t idx, enum SqlDataType buffer_type, void *buffer, size_t buffer_len, uint32 *out_length, int8 *out_is_null);

	/// Returns the number of rows in the result.
	///
	/// @return Number of rows
	uint64 (*StmtNumRows)(struct SqlStmt *self);

	/// Fetches the next row.
	/// All column bindings will be filled with data.
	///
	/// @return SQL_SUCCESS, SQL_ERROR or SQL_NO_DATA
	int (*StmtNextRow)(struct SqlStmt *self);

	/// Frees the result of the statement execution.
	void (*StmtFreeResult)(struct SqlStmt *self);

	/// Frees a SqlStmt returned by SqlStmt_Malloc.
	void (*StmtFree)(struct SqlStmt *self);

	void (*StmtShowDebug_)(struct SqlStmt *self, const char *debug_file, const unsigned long debug_line);

};

#ifdef HERCULES_CORE
void sql_defaults(void);

void Sql_Init(void);

void Sql_HerculesUpdateCheck(struct Sql *self);
void Sql_HerculesUpdateSkip(struct Sql *self, const char *filename);
#endif // HERCULES_CORE

HPShared struct sql_interface *SQL;

#if defined(SQL_REMOVE_SHOWDEBUG)
#define Sql_ShowDebug(self) (void)(self)
#else
#define Sql_ShowDebug(self) (SQL->ShowDebug_((self), __FILE__, __LINE__))
#endif

#if defined(SQL_REMOVE_SHOWDEBUG)
#define SqlStmt_ShowDebug(self) (void)(self)
#else
/// Shows debug information (with statement).
#define SqlStmt_ShowDebug(self) (SQL->StmtShowDebug_((self), __FILE__, __LINE__))
#endif

#endif /* COMMON_SQL_H */