/**

 * vim: set ts=4 :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * 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/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#ifndef _INCLUDE_SOURCEMOD_INTERFACE_DBDRIVER_H_

#define _INCLUDE_SOURCEMOD_INTERFACE_DBDRIVER_H_

#include <IShareSys.h>

#include <IHandleSys.h>

#include <string.h>

/**

 * @file IDBDriver.h

 * @brief Defines interfaces for interacting with relational databases.

 */

#define SMINTERFACE_DBI_NAME		"IDBI"

#define SMINTERFACE_DBI_VERSION		7

namespace SourceMod

{

	/**

	 * @brief Describes a database field value.

	 */

	enum DBResult

	{

		DBVal_Error = 0,		/**< Column number/field is invalid */

		DBVal_TypeMismatch = 1,	/**< You cannot retrieve this data with this type */

		DBVal_Null = 2,			/**< Field has no data (NULL) */

		DBVal_Data = 3,			/**< Field has data */

	};

	/**

	 * @brief Describes a primitive database type.

	 */

	enum DBType

	{

		DBType_Unknown = 0,		/**< Type could not be inferred */

		DBType_String,			/**< NULL-terminated string (variable length) */

		DBType_Blob,			/**< Raw binary data (variable length) */

		DBType_Integer,			/**< 4-byte signed integer */

		DBType_Float,			/**< 4-byte floating point  */

		DBType_NULL,			/**< NULL (no data) */

		/* --------- */

		DBTypes_TOTAL,			/**< Total number of database types known */

	};

	/**

	 * @brief Represents a one database result row.

	 *

	 * Note that type mismatches will only occur when type safety is being

	 * enforced.  So far this is only the case for prepared statements in 

	 * MySQL and SQLite.

	 *

	 * Also, it is worth noting that retrieving as raw data will never cause a

	 * type mismatch.

	 */

	class IResultRow

	{

	public:

		/**

		 * @brief Retrieves a database field result as a string.

		 *

		 * For NULL values, the resulting string pointer will be non-NULL but 

		 * empty.  The pointer returned will become invalid after  advancing to

		 * the next row.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param pString		Pointer to store a pointer to the string.

		 * @param length		Optional pointer to store the string length.

		 * @return				A DBResult return code.

		 */

		virtual DBResult GetString(unsigned int columnId, const char **pString, size_t *length) =0;

		/**

		 * @brief Retrieves a database field result as a string, using a 

		 * user-supplied buffer.  If the field is NULL, an empty string

		 * will be copied.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param buffer		Buffer to store string in.

		 * @param maxlength		Maximum length of the buffer.

		 * @param written		Optional pointer to store the number of bytes 

		 *						written, excluding the null terminator.

		 * @return				A DBResult return code.

		 */

		virtual DBResult CopyString(unsigned int columnId, 

									char *buffer, 

									size_t maxlength, 

									size_t *written) =0;

		/**

		 * @brief Retrieves a database field result as a float.

		 *

		 * For NULL entries, the returned float value will be 0.0.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param pFloat		Pointer to a floating point number to set.

		 * @return				A DBResult return code.

		 */

		virtual DBResult GetFloat(unsigned int columnId, float *pFloat) =0;

		/**

		 * @brief Retrieves a database field result as an integer.

		 *

		 * For NULL entries, the returned integer value will be 0.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param pInt			Pointer to an integer number to set.

		 * @return				A DBResult return code.

		 */

		virtual DBResult GetInt(unsigned int columnId, int *pInt) =0;

		/**

		 * @brief Returns whether or not a field is NULL.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @return				True if field is NULL, false otherwise.

		 */

		virtual bool IsNull(unsigned int columnId) =0;

		/**

		 * @brief Returns the size of a field (text/raw/blob) in bytes.

		 * For strings, this returned size will not include the null

		 * terminator.

		 * 

		 * When used on fields that are not of variable length,

		 * the size returned will be the number of bytes required

		 * to store the internal data.  Note that the data size 

		 * will correspond to the ACTUAL data type, not the 

		 * COLUMN type.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @return				Number of bytes required to store

		 *						the data, or 0 on failure.

		 */

		virtual size_t GetDataSize(unsigned int columnId) =0;

		/**

		 * @brief Retrieves field data as a raw bitstream.  The pointer returned

		 * will become invalid after advancing to the next row.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param pData			Pointer to store the raw bit stream.  If the 

		 *						data is NULL, a NULL pointer will be returned.

		 * @param length		Pointer to store the data length.

		 * @return				A DBResult return code.

		 */

		virtual DBResult GetBlob(unsigned int columnId, const void **pData, size_t *length) =0;

		/**

		 * @brief Copies field data as a raw bitstream.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @param buffer		Pointer to copy the data to.  If the data is

		 *						NULL, no data will be copied.

		 * @param maxlength		Maximum length of the buffer.

		 * @param written		Optional pointer to store the number of bytes 

		 *						written.

		 * @return				A DBResult return code.

		 */

		virtual DBResult CopyBlob(unsigned int columnId, void *buffer, size_t maxlength, size_t *written) =0;

	};

	/**

	 * @brief Describes a set of database results.

	 */

	class IResultSet

	{

	public:

		/**

		 * @brief Returns the number of rows in the set.

		 *

		 * @return				Number of rows in the set.

		 */

		virtual unsigned int GetRowCount() =0;

		/**

		 * @brief Returns the number of fields in the set.

		 *

		 * @return				Number of fields in the set.

		 */

		virtual unsigned int GetFieldCount() =0;

		/**

		 * @brief Converts a column number to a column name.

		 *

		 * @param columnId		Column to use, starting from 0.

		 * @return				Pointer to column name, or NULL if not found.

		 */

		virtual const char *FieldNumToName(unsigned int columnId) =0;

		/**

		 * @brief Converts a column name to a column id.

		 *

		 * @param name			Column name (case sensitive).

		 * @param columnId		Pointer to store the column id.  If the

		 *						name is not found, the value will be

		 *						undefined.

		 * @return				True on success, false if not found.

		 */

		virtual bool FieldNameToNum(const char *name, unsigned int *columnId) =0;

		/**

		 * @brief Returns if there is still data in the result set.

		 *

		 * @return				False if there is more data to be read, 

		 *						true, otherwise.

		 */

		virtual bool MoreRows() =0;

		/**

		 * @brief Returns a pointer to the current row and advances

		 * the internal row pointer/counter to the next row available.

		 *

		 * @return				IResultRow pointer to the current row,

		 *						or NULL if there is no more data.

		 */

		virtual IResultRow *FetchRow() =0;

		/**

		 * @brief Returns a pointer to the current row.

		 *

		 * @return				IResultRow pointer to the current row,

		 *						or NULL if the current row is invalid.

		 */

		virtual IResultRow *CurrentRow() =0;

		/**

		 * @brief Rewinds back to the beginning of the row iteration.

		 * 

		 * @return				True on success, false otherwise.

		 */

		virtual bool Rewind() =0;

		/**

		 * @brief Returns a field's type as it should be interpreted

		 * by the user.

		 *

		 * @param field			Field number (starting from 0).

		 * @return				A DBType value.

		 */

		virtual DBType GetFieldType(unsigned int field) =0;

		/**

		 * @brief Returns a field's type as it will be interpreted

		 * by the GetDataSize() function.  For example, MySQL

		 * for non-prepared queries will store all results as

		 * strings internally.

		 *

		 * @param field			Field number (starting from 0).

		 * @return				A DBType value.

		 */

		virtual DBType GetFieldDataType(unsigned int field) =0;

	};

	class IDBDriver;

	class IQuery

	{

	public:

		/**

		 * @brief Returns a pointer to the current result set, if any.  

		 *

		 * @return				An IResultSet pointer on success,

		 *						NULL if no result set exists.

		 */

		virtual IResultSet *GetResultSet() =0;

		/**

		 * @brief Advances to the next result set if one exists.  This

		 * is for checking for MORE result sets, and should not be used

		 * on the first result set.

		 *

		 * Multiple results only happen in certain cases, such as CALLing

		 * stored procedure that have a SELECTs, where MySQL will return 

		 * both the CALL status and one or more SELECT result sets.  If

		 * you do not process these results, they will be automatically

		 * processed for you.  However, the behaviour of creating a new

		 * query from the same connection while results are left 

		 * unprocessed is undefined, and may result in a dropped 

		 * connection.  Therefore, process all extra results or destroy the

		 * IQuery pointer before starting a new query.

		 *

		 * Again, this only happens in very specific cases, so there is

		 * no need to call this for normal queries.

		 *

		 * After calling this function, GetResultSet() must be called

		 * again to return the result set.  The previous result set

		 * is automatically destroyed and will be unusable.

		 *

		 * @return				True if another result set is

		 *						available, false otherwise.

		 */

		virtual bool FetchMoreResults() =0;

		/**

		 * @brief Frees resources created by this query.

		 */

		virtual void Destroy() =0;

	};

	class IPreparedQuery : public IQuery

	{

	public:

		/** 

		 * @brief Binds an integer parameter.

		 *

		 * @param param			Parameter index, starting from 0.

		 * @param num			Number to bind as a value.

		 * @param signd			True to write as signed, false to write as 

		 *						unsigned.

		 * @return				True on success, false otherwise.

		 */

		virtual bool BindParamInt(unsigned int param, int num, bool signd=true) =0;

		/**

		 * @brief Binds a float parameter.

		 *

		 * @param param			Parameter index, starting from 0.

		 * @param f				Float to bind as a value.

		 * @return				True on success, false otherwise.

		 */

		virtual bool BindParamFloat(unsigned int param, float f) =0;

		/**

		 * @brief Binds an SQL NULL type as a parameter.

		 *

		 * @param param			Parameter index, starting from 0.

		 * @return				True on success, false otherwise.

		 */

		virtual bool BindParamNull(unsigned int param) =0;

		/**

		 * @brief Binds a string as a parameter.

		 *

		 * @param param			Parameter index, starting from 0.

		 * @param text			Pointer to a null-terminated string.

		 * @param copy			If true, the pointer is assumed to be

		 *						volatile and a temporary copy may be

		 *						made for safety.

		 * @return				True on success, false otherwise.

		 */

		virtual bool BindParamString(unsigned int param, const char *text, bool copy) =0;

		/**

		 * @brief Binds a blob of raw data as a parameter.

		 *

		 * @param param			Parameter index, starting from 0.

		 * @param data			Pointer to a blob of memory.

		 * @param length		Number of bytes to copy.

		 * @param copy			If true, the pointer is assumed to be

		 *						volatile and a temporary copy may be

		 *						made for safety.

		 * @return				True on success, false otherwise.

		 */

		virtual bool BindParamBlob(unsigned int param, 

									const void *data, 

									size_t length, 

									bool copy) =0;

		/**

		 * @brief Executes the query with the currently bound parameters.

		 * @return				True on success, false otherwise.

		 */

		virtual bool Execute() =0;

		/**

		 * @brief Returns the last error message from this statement.

		 *

		 * @param errCode		Optional pointer to store the driver-specific

		 *						error code.

		 * @return				Error message string.

		 */

		virtual const char *GetError(int *errCode=NULL) =0;

		/**

		 * @brief Number of rows affected by the last execute.

		 *

		 * @return				Number of rows affected by the last execute.

		 */

		virtual unsigned int GetAffectedRows() =0;

		/**

		 * @brief Retrieves the last insert ID on this database connection.

		 *

		 * @return				Row insertion ID of the last execute, if any.

		 */

		virtual unsigned int GetInsertID() =0;

	};

	class IDBDriver;

	/**

	 * @brief Encapsulates a database connection.

	 */

	class IDatabase

	{

	public:

		/**

		 * @brief Disconnects the database and frees its associated memory.

		 * Note that the actual object will not be freed until all open 

		 * references have been closed.

		 *

		 * It is guaranteed that an IDatabase pointer won't be destroyed until

		 * all open IQuery or IPreparedQuery pointers are closed.

		 *

		 * This function is thread safe.

		 * 

		 * @return				True if object was destroyed, false if 

		 *						references are remaining.

		 */

		virtual bool Close() =0;

		/**

		 * @brief Error code and string returned by the last operation on this

		 * connection.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param errorCode		Optional pointer to retrieve an error code.

		 * @return				Error string pointer (empty if none).

		 */

		virtual const char *GetError(int *errorCode=NULL) =0;

		/**

		 * @brief Prepares and executes a query in one step, and discards

		 * any return data.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param query			Query string.

		 * @return				True on success, false otherwise.

		 */

		virtual bool DoSimpleQuery(const char *query) =0;

		/**

		 * @brief Prepares and executes a query in one step, and returns

		 * the resultant data set.

		 *

		 * Note: If a query contains more than one result set, each

		 * result set must be processed before a new query is started.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param query			Query string.

		 * @return				IQuery pointer on success, NULL otherwise.

		 */

		virtual IQuery *DoQuery(const char *query) =0;

		/** 

		 * @brief Prepares a query statement for multiple executions and/or

		 * binding marked parameters (? in MySQL/sqLite, $n in PostgreSQL).

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param query			Query string.

		 * @param error			Error buffer.

		 * @param maxlength		Maximum length of the error buffer.

		 * @param errCode		Optional pointer to store a driver-specific error code.

		 * @return				IPreparedQuery pointer on success, NULL

		 *						otherwise.

		 */

		virtual IPreparedQuery *PrepareQuery(const char *query, char *error, size_t maxlength, int *errCode=NULL) =0;

		/**

		 * Quotes a string for insertion into a query.

		 *

		 * @param str			Source string.

		 * @param buffer		Buffer to store new string (should not overlap source string).

		 * @param maxlen		Maximum length of the output buffer.

		 * @param newSize		Pointer to store the output size.

		 * @return				True on success, false if the output buffer is not big enough.

		 *						If not big enough, the required buffer size is passed through

		 *						newSize.

		 */

		virtual bool QuoteString(const char *str, char buffer[], size_t maxlen, size_t *newSize) =0;

		/**

		 * @brief Number of rows affected by the last execute.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @return				Number of rows affected by the last execute.

		 */

		virtual unsigned int GetAffectedRows() =0;

		/**

		 * @brief Retrieves the last insert ID on this database connection.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @return				Row insertion ID of the last execute, if any.

		 */

		virtual unsigned int GetInsertID() =0;

		/**

		 * @brief Locks the database for an atomic query+retrieval operation.

		 *

		 * @return				True on success, false if not supported.

		 */

		virtual bool LockForFullAtomicOperation() =0;

		/**

		 * @brief Unlocks a locked atomic fetch.

		 */

		virtual void UnlockFromFullAtomicOperation() =0;

		/**

		 * @brief Increases the reference count on the database.

		 *

		 * This function is thread safe.

		 */

		virtual void IncReferenceCount() =0;

		/**

		 * @brief Returns the parent driver.

		 *

		 * This function is thread safe.

		 */

		virtual IDBDriver *GetDriver() =0;

		/**

		 * @brief Prepares and executes a binary query in one step, and discards

		 * any return data.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param query			Query string.

		 * @param length		Length of query string.

		 * @return				True on success, false otherwise.

		 */

		virtual bool DoSimpleQueryEx(const char *query, size_t len) =0;

		/**

		 * @brief Prepares and executes a binary query in one step, and returns

		 * the resultant data set.

		 *

		 * Note: If a query contains more than one result set, each

		 * result set must be processed before a new query is started.

		 *

		 * This function is not thread safe and must be included in any locks.

		 *

		 * @param query			Query string.

		 * @return				IQuery pointer on success, NULL otherwise.

		 */

		virtual IQuery *DoQueryEx(const char *query, size_t len) =0;

	};

	/** 

	 * @brief Describes database connection info.

	 */

	struct DatabaseInfo

	{

		DatabaseInfo()

		{

			dbiVersion = SMINTERFACE_DBI_VERSION;

			port = 0;

			maxTimeout = 0;

		}

		unsigned int dbiVersion;		/**< DBI Version for backwards compatibility */

		const char *host;				/**< Host string */

		const char *database;			/**< Database name string */

		const char *user;				/**< User to authenticate as */

		const char *pass;				/**< Password to authenticate with */

		const char *driver;				/**< Driver to use */

		unsigned int port;				/**< Port to use, 0=default */

		unsigned int maxTimeout;		/**< Maximum timeout, 0=default */

	};

	/**

	 * @brief Describes an SQL driver.

	 */

	class IDBDriver

	{

	public:

		virtual unsigned int GetDBIVersion()

		{

			return SMINTERFACE_DBI_VERSION;

		}

	public:

		/**

		 * @brief Initiates a database connection.

		 *

		 * Note: Persistent connections should never be created from a thread.

		 * 

		 * @param info			Database connection info pointer.

		 * @param persistent	If true, a previous persistent connection will

		 *						be re-used if possible.

		 * @param error			Buffer to store error message.

		 * @param maxlength		Maximum size of the error buffer.

		 * @return				A new IDatabase pointer, or NULL on failure.

		 */

		virtual IDatabase *Connect(const DatabaseInfo *info, bool persistent, char *error, size_t maxlength) =0;

		/**

		 * @brief Returns a case insensitive database identifier string.

		 *

		 * @return				String containing an identifier.

		 */

		virtual const char *GetIdentifier() =0;

		/**

		 * @brief Returns a case sensitive implementation name.

		 *

		 * @return				String containing an implementation name.

		 */

		virtual const char *GetProductName() =0;

		/**

		 * @brief Retrieves a Handle_t handle of the IDBDriver type.

		 *

		 * @return				A Handle_t handle.

		 */

		virtual Handle_t GetHandle() =0;

		/**

		 * @brief Returns the driver's controlling identity (must be the same 

		 * as from IExtension::GetIdentity).

		 *

		 * @return				An IdentityToken_t identity.

		 */

		virtual IdentityToken_t *GetIdentity() =0;

		/**

		 * @brief Returns whether the driver is thread safe.

		 *

		 * @return				True if thread safe, false otherwise.

		 */

		virtual bool IsThreadSafe() =0;

		/**

		 * @brief Initializes thread safety for the calling thread.

		 *

		 * @return				True on success, false otherwise.

		 */

		virtual bool InitializeThreadSafety() =0;

		/**

		 * @brief Shuts down thread safety for the calling thread.

		 */

		virtual void ShutdownThreadSafety() =0;

	};

	/**

	 * @brief Priority queue level.

	 */

	enum PrioQueueLevel

	{

		PrioQueue_High,			/**< High priority */

		PrioQueue_Normal,		/**< Normal priority */

		PrioQueue_Low			/**< Low priority */

	};

	/**

	 * Specification for a threaded database operation.

	 */

	class IDBThreadOperation

	{

	public:

		/**

		 * @brief Must return the driver this operation is using, or 

		 * NULL if not using any driver.  This is not never inside 

		 * the thread.

		 *

		 * @return			IDBDriver pointer.

		 */

		virtual IDBDriver *GetDriver() =0;

		/**

		 * @brief Must return the object owning this threaded operation.

		 * This is never called inside the thread.

		 *

		 * @return			IdentityToken_t pointer.

		 */

		virtual IdentityToken_t *GetOwner() =0;

		/**

		 * @brief Called inside the thread; this is where any blocking

		 * or threaded operations must occur.

		 */

		virtual void RunThreadPart() =0;

		/**

		 * @brief Called in a server frame after the thread operation 

		 * has completed.  This is the non-threaded completion callback,

		 * which although optional, is useful for pumping results back

		 * to normal game API.

		 */

		virtual void RunThinkPart() =0;

		/**

		 * @brief If RunThinkPart() is not called, this will be called

		 * instead.  Note that RunThreadPart() is ALWAYS called regardless,

		 * and this is only called when Core requests that the operation

		 * be scrapped (for example, the database driver might be unloading).

		 */

		virtual void CancelThinkPart() =0;

		/**

		 * @brief Called when the operation is finalized and any resources

		 * can be released.

		 */

		virtual void Destroy() =0;

	};

	/**

	 * @brief Database-related Handle types.

	 */

	enum DBHandleType

	{

		DBHandle_Driver = 0,		/**< Driver Handle */

		DBHandle_Database = 1,		/**< Database Handle */

	};