/** @file
	Parser ODBC driver.

	Copyright(c) 2001, 2002 ArtLebedev Group (http://www.artlebedev.com)

	Author: Alexandr Petrosian <paf@design.ru> (http://paf.design.ru)
*/
static const char *RCSId="$Id: parser3odbc.C,v 1.9 2002/05/15 14:06:07 paf Exp $"; 

#ifndef _MSC_VER
#	error compile ISAPI module with MSVC [no urge for now to make it autoconf-ed (PAF)]
#endif

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>

#include "pa_sql_driver.h"

#include <AFXDB.H>

#define MAX_STRING 0x400
#define MAX_NUMBER 40

// MSSQL2000
#ifndef SQL_NVARCHAR
#define SQL_NVARCHAR (-9)
#endif
#ifndef SQL_NTEXT 
#define SQL_NTEXT (-10)
#endif
#ifndef SQL_SMALLDATETIME
#define SQL_SMALLDATETIME 11
#endif
// create table test (id int, a smalldatetime, b ntext, c nvarchar(100))

#define snprintf _snprintf
#ifndef strncasecmp
#	define strncasecmp _strnicmp
#endif

static char *lsplit(char *string, char delim) {
    if(string) {
		char *v=strchr(string, delim);
		if(v) {
			*v=0;
			return v+1;
		}
    }
    return 0;
}

/**
	ODBC server driver
*/
class ODBC_Driver : public SQL_Driver {
public:

	ODBC_Driver() : SQL_Driver() {
	}

	/// get api version
	int api_version() { return SQL_DRIVER_API_VERSION; }
	const char *initialize(char *dlopen_file_spec) { return 0; }
	/**	connect
		@param used_only_in_connect_url
			format: @b DSN=dsn;UID=user;PWD=password (ODBC connect string)
			WARNING: must be used only to connect, for buffer doesn't live long
	*/
	void connect(
		char *used_only_in_connect_url, 
		SQL_Driver_services& services, 
		void **connection ///< output: CDatabase *
		) {
	//	_asm int 3;
		CDatabase *db;
		TRY {
			db=new CDatabase();
			db->OpenEx(used_only_in_connect_url, CDatabase::noOdbcDialog);
			db->BeginTrans();
		} 
		CATCH_ALL (e) {
			_throw(services, e);
			db=0; // calm, compiler
		}
		END_CATCH_ALL

		*(CDatabase **)connection=db;
	}
	void disconnect(void *connection) {
		CDatabase *db=static_cast<CDatabase *>(connection);
		TRY
			delete db;
		CATCH_ALL (e) {
			// nothing
		}
		END_CATCH_ALL
	}
	void commit(SQL_Driver_services& services, void *connection) {
		CDatabase *db=static_cast<CDatabase *>(connection);
		TRY
			db->CommitTrans();
			db->BeginTrans();
		CATCH_ALL (e) {
			_throw(services, e);
		}
		END_CATCH_ALL
	}
	void rollback(SQL_Driver_services& services, void *connection) {
		CDatabase *db=static_cast<CDatabase *>(connection);
		TRY
			db->Rollback();
			db->BeginTrans();
		CATCH_ALL (e) {
			_throw(services, e);
		}
		END_CATCH_ALL
	}

	bool ping(SQL_Driver_services&, void *connection) {
		return true;
	}

	unsigned int quote(
		SQL_Driver_services&, void *connection,
		char *to, const char *from, unsigned int length) {
		if(to) { // store mode
			unsigned int result=length;
			while(length--) {
				if(*from=='\'') { // ' -> ''
					*to++='\''; result++;
				}
				*to++=*from++;
			}
			return result;
		} else // estimate mode
			return length*2;
	}
	void query(
		SQL_Driver_services& services, void *connection, 
		const char *statement, unsigned long offset, unsigned long limit,
		SQL_Driver_query_event_handlers& handlers) {

		CDatabase *db=static_cast<CDatabase *>(connection);

		while(isspace(*statement)) 
			statement++;
		
		TRY {
			// mk:@MSITStore:C:\Program%20Files\Microsoft%20SQL%20Server\80\Tools\Books\adosql.chm::/adoprg02_4g33.htm
			// Server cursors are created only for statements that begin with: 
			// SELECT
			// EXEC[ute] procedure_name
			// call procedure_name
			// mk:@MSITStore:C:\Program%20Files\Microsoft%20SQL%20Server\80\Tools\Books\odbcsql.chm::/od_6_035_5dnp.htm
			// The ODBC CALL escape sequence for calling a procedure is:
			// {[?=]call procedure_name[([parameter][,[parameter]]...)]}
			if(strncasecmp(statement, "select", 6)==0
				|| strncasecmp(statement, "EXEC", 4)==0
				|| strncasecmp(statement, "call", 4)==0
				|| strncasecmp(statement, "{", 1)==0) {
				CRecordset rs(db); 
				TRY {
					rs.Open(
						CRecordset::forwardOnly, 
						statement,
						CRecordset::executeDirect   
						);
				} CATCH_ALL (e) {
					// could not fetch a table
					TRY {
						// then try resultless query
						db->ExecuteSQL(statement);
						// OK then
						return;
					} CATCH_ALL (e2) {
						// still nothing good
						_throw(services, e); // throw ORIGINAL exception
					} END_CATCH_ALL
				} END_CATCH_ALL

				int column_count=rs.GetODBCFieldCount();
				if(!column_count)
					services._throw("result contains no columns");

				for(int i=0; i<column_count; i++){
					CString string;
					CODBCFieldInfo fieldinfo;
					rs.GetODBCFieldInfo(i, fieldinfo);
					size_t size=fieldinfo.m_strName.GetLength();
					void *ptr=0;
					if(size) {
						ptr=services.malloc(size);
						memcpy(ptr, (char *)LPCTSTR(fieldinfo.m_strName), size);
					}
					handlers.add_column(ptr, size);
				}

				handlers.before_rows();

				unsigned long row=0;
				while(!rs.IsEOF() && (!limit||(row<offset+limit))) {
					if(row>=offset) {
						handlers.add_row();
						for(int i=0; i<column_count; i++) 						{
							CODBCFieldInfo fieldinfo;
							rs.GetODBCFieldInfo(i, fieldinfo);
							size_t size;
							void *ptr;
							switch(fieldinfo.m_nSQLType) {
							//case xBOOL:
//							case SQL_INTEGER: // serg@design.ru did that in parser2. test first!
							//case SQL_DATETIME:
							case SQL_SMALLDATETIME:
								{
									CDBVariant v;
									rs.GetFieldValue(i, v);
									getFromDBVariant(services, v, ptr, size);
									break;
								}
							default:
								{
									CString s;
									rs.GetFieldValue(i, s);
									getFromString(services, s, ptr, size);
									break;
								}
							}
							handlers.add_row_cell(ptr, size);
						}
					}
					rs.MoveNext();  row++;
				}
				
				rs.Close();
			} else {
				db->ExecuteSQL(statement);
			}
		} CATCH_ALL (e) {
			_throw(services, e);
		} END_CATCH_ALL
	}

	void getFromDBVariant(SQL_Driver_services& services, CDBVariant& v, void *& ptr, size_t& size) {
		switch(v.m_dwType) {
		case DBVT_NULL: // No union member is valid for access. 
			ptr=0;
			size=0;
			break;
/*		case DBVT_BOOL:
			ptr=v.m_boolVal?"1":"0";
			size=1;
			break;*/
/*							case DBVT_UCHAR:
			size=strlen(ptr=v.m_chVal);
			break;
		case DBVT_SHORT:
			char buf[MAX_NUMBER];
			size=snprintf(HEAPIZE buf, "%d", v.m_iVal);
			break;*/
/*		case DBVT_LONG: 
			{
				char local_buf[MAX_NUMBER];
				size=snprintf(local_buf, MAX_NUMBER, "%ld", v.m_lVal);
				ptr=services.malloc(size);
				memcpy(ptr, local_buf, size);
				break;
			}*/
		/*case DBVT_SINGLE:
			m_fltVal 
			break;
	case DBVT_DOUBLE m_dblVal 
	case DBVT_STRING m_pstring 
	case DBVT_BINARY m_pbinary */
		case DBVT_DATE:
			{
				char local_buf[MAX_STRING];
				size=snprintf(local_buf, MAX_STRING, 
					"%04d-%02d-%02d %02d:%02d:%02d.%03d",
					v.m_pdate->year, 
					v.m_pdate->month,
					v.m_pdate->day,
					v.m_pdate->hour,
					v.m_pdate->minute,
					v.m_pdate->second,
					v.m_pdate->fraction);
				ptr=services.malloc(size);
				memcpy(ptr, local_buf, size);
				break;
			}
		default:
			char msg[MAX_STRING];
			snprintf(msg, MAX_STRING, "unknown column return variant type (%d)",
				v.m_dwType);
			services._throw(msg);
		}
	}

	void getFromString(SQL_Driver_services& services, CString& s, void *& ptr, size_t& size) {
		if(s.IsEmpty()) {
			ptr=0;
			size=0;
		} else {
			const char *cstr=LPCTSTR(s);
			size=strlen(cstr); //string.GetLength() works wrong with non-string types: 
			ptr=services.malloc(size);
			memcpy(ptr, cstr, size);
		}
	}

	void _throw(SQL_Driver_services& services, CException *e) {
		char szCause[MAX_STRING]; szCause[0]=0;
		e->GetErrorMessage(szCause, MAX_STRING);
		char msg[MAX_STRING];
		snprintf(msg, MAX_STRING, "%s: %s",
			e->GetRuntimeClass()->m_lpszClassName,
			*szCause?szCause:"unknown");
		services._throw(msg);
	}

};

extern "C" SQL_Driver *SQL_DRIVER_CREATE() {
	return new ODBC_Driver();
}