/*
 * This file is a part of Winix
 * and is not publicly distributed
 * 
 * Copyright (c) 2010, Tomasz Sowa
 * All rights reserved.
 * 
 */
 
#include <stdlib.h>
#include <limits.h>
#include <limits>
#include "dbbase.h"
#include "core/log.h"
#include "core/error.h"
#include "utf8.h"


DbBase::DbBase()
{
	db_conn = 0;
	log_queries = false;
}



void DbBase::SetConn(DbConn * conn)
{
	db_conn = conn;
}



void DbBase::SetConn(DbConn & conn)
{
	db_conn = &conn;
}


DbConn * DbBase::GetConn()
{
	return db_conn;
}



void DbBase::LogQueries(bool log_q)
{
	log_queries = log_q;
}



PGresult * DbBase::AssertQuery(const char * q)
{
	if( log_queries )
		log << log1 << "Db: executing query: " << q << logend;

	bool bad_query = false;
	PGresult * r = PQexec(db_conn->GetPgConn(), q);
	
	if( !r )
	{
		bad_query = true;

		if( PQstatus(db_conn->GetPgConn()) != CONNECTION_OK )
		{
			db_conn->AssertConnection();
			r = PQexec(db_conn->GetPgConn(), q);

			if( r )
				bad_query = false;
		}
	}


	if( bad_query )
	{
		log << log1 << "Db: Problem with this query: \"" << q << '\"' << logend;
		log << log1 << "Db: " << PQerrorMessage(db_conn->GetPgConn()) << logend;

		throw Error(WINIX_ERR_DB_INCORRECT_QUERY);
	}

return r;
}


PGresult * DbBase::AssertQuery(const std::wstring & q)
{
	return AssertQuery(q.c_str());
}


PGresult * DbBase::AssertQuery(const DbTextStream & query)
{
	return AssertQuery(query.CStr());
}


void DbBase::AssertResult(PGresult * r, ExecStatusType t)
{
	if( PQresultStatus(r) != t )
	{
		log << "Db: Incorrect result status: " << PQerrorMessage(db_conn->GetPgConn()) << logend;
		
		throw Error(WINIX_ERR_DB_INCORRENT_RESULT_STATUS);
	}	
}



int DbBase::AssertColumn(PGresult * r, const char * column_name)
{
	int c = PQfnumber(r, column_name);
	
	if( c == -1 )
	{
		log << log1 << "Db: there is no column: " << column_name << logend;
		throw Error(WINIX_ERR_DB_NO_COLUMN);
	}
		
return c;
}


const char * DbBase::AssertValue(PGresult * r, int row, int col)
{
	const char * res = PQgetvalue(r, row, col);
	
	if( !res )
	{
		log << log1 << "Db: there is no such an item in the result, row:" << row << ", col:" << col << logend;
		throw Error(WINIX_ERR_NO_ITEM);
	}
	
return res;
}


const std::wstring & DbBase::AssertValueWide(PGresult * r, int row, int col)
{
	const char * res = AssertValue(r, row, col);
	static std::wstring temp_wide_value;	

	Ezc::UTF8ToWide(res, temp_wide_value);
	
return temp_wide_value;
}


void DbBase::AssertValueWide(PGresult * r, int row, int col, std::wstring & result)
{
	const char * res = AssertValue(r, row, col);
	Ezc::UTF8ToWide(res, result);
}


long DbBase::AssertValueLong(PGresult * r, int row, int col)
{
	return strtol( AssertValue(r, row, col), 0, 10 );
}


int DbBase::AssertValueInt(PGresult * r, int row, int col)
{
	return (int)strtol( AssertValue(r, row, col), 0, 10 );
}


bool DbBase::AssertValueBool(PGresult * r, int row, int col)
{
	return strtol( AssertValue(r, row, col), 0, 10 ) != 0;
}


unsigned long DbBase::AssertValueULong(PGresult * r, int row, int col)
{
	return strtoul( AssertValue(r, row, col), 0, 10 );
}


unsigned int DbBase::AssertValueUInt(PGresult * r, int row, int col)
{
	return (unsigned int)strtoul( AssertValue(r, row, col), 0, 10 );
}


tm DbBase::AssertValueTm(PGresult * r, int row, int col)
{
	return ConvertTime(AssertValue(r, row, col));
}



void DbBase::ClearResult(PGresult * r)
{
	if( r )
		PQclear(r);
}


bool DbBase::IsNull(PGresult * r, int row, int col)
{
	return PQgetisnull(r, row, col) == 1;
}


int DbBase::Rows(PGresult * r)
{
	// PQntuples - Returns the number of rows (tuples) in the query result. Because it returns
	// an integer result, large result sets might overflow the return value on 32-bit operating systems. 
	return PQntuples(r);
}


int DbBase::Cols(PGresult * r)
{
	// PQnfields - Returns the number of columns (fields) in each row of the query result. 
	return PQnfields(r);
}


long DbBase::AffectedRows(PGresult * r)
{
	// PQcmdTuples - This function returns a string containing the number of rows affected by the SQL
	// statement that generated the PGresult. This function can only be used following the execution
	// of an INSERT, UPDATE, DELETE, MOVE, FETCH, or COPY statement, or [...]
	char * rows_str = PQcmdTuples(r); // can be an empty string
	long rows = 0;

	if( rows_str )
	{
		rows = strtol(rows_str, 0, 10);
		// strtol - If an overflow or underflow occurs, errno is set to ERANGE
		// and the function return value is clamped according to the following table:
		//   Function       underflow    overflow
		//   strtol()       LONG_MIN     LONG_MAX

		if( rows < 0 )
			rows = 0;
	}

return rows;
}


long DbBase::AssertCurrval(const char * table)
{
	PGresult * r;

	bquery.Clear();
	bquery << R("select currval(")
		   << table
		   << R(");");
	
	r = AssertQuery(bquery);
	AssertResult(r, PGRES_TUPLES_OK);

	if( Rows(r) != 1 )
	{
		log << log1 << "Db: error (currval) for table: " << table << ", " << PQerrorMessage(db_conn->GetPgConn()) << logend;
		throw Error(WINIX_ERR_DB_ERR_CURRVAL);
	}
	
return AssertValueLong(r, 0, 0);
}




tm DbBase::ConvertTime(const char * str)
{
tm t;

	memset(&t, 0, sizeof(t));

	if( !str )
		return t;
	
	size_t len = strlen(str);
	
	if( len != 19 )
	{
		// the format must be like this: 2008-12-31 22:30:00
		log << log1 << "DbBase: ConvertTime: unknown time format: \"" << str << "\"";
		return t;
	}

	t.tm_year = Toi(str + 0) - 1900;     /* year - 1900 */
	t.tm_mon  = Toi(str + 5) - 1;        /* month of year (0 - 11) */
	t.tm_mday = Toi(str + 8);            /* day of month (1 - 31) */
	t.tm_hour = Toi(str + 11);           /* hours (0 - 23) */
	t.tm_min  = Toi(str + 14);           /* minutes (0 - 59) */
	t.tm_sec  = Toi(str + 17);           /* seconds (0 - 60) */
	
	// t.tm_wday  = 0;   /* day of week (Sunday = 0) */
	// t.tm_yday  = 0;   /* day of year (0 - 365) */
	// t.tm_isdst = 0;   /* is summer time in effect? */
	// t.tm_zone  = 0;   // const_cast<char*>("");  /* abbreviation of timezone name */

return t;
}


const char * DbBase::ConvertTime(const tm & t)
{
// not thread safe
static char buffer[100];

	sprintf(buffer, "%04d-%02d-%02d %02d:%02d:%02d",
		t.tm_year + 1900,
		t.tm_mon + 1,
		t.tm_mday,
		t.tm_hour,
		t.tm_min,
		t.tm_sec);

return buffer;
}



void DbBase::CreateIdList(const std::vector<long> & id_tab, std::wstring & list, bool add_parentheses)
{
wchar_t buffer[50];
size_t buffer_len = sizeof(buffer) / sizeof(wchar_t);

	list.clear();

	if( add_parentheses )
		list += '(';

	for(size_t i=0 ; i<id_tab.size() ; ++i)
	{
		swprintf(buffer, buffer_len, L"%lu", (unsigned long)id_tab[i]);
		list += buffer;

		if( i+1 < id_tab.size() )
			list += ',';
	}

	if( add_parentheses )
		list += ')';
}



Error DbBase::DoCommand(const char * command)
{
	PGresult * r = 0;
	Error status = WINIX_ERR_OK;

	try
	{
		bquery.Clear();
		bquery << R(command);
		r = AssertQuery(bquery);
		AssertResult(r, PGRES_COMMAND_OK);
	}
	catch(const Error & e)
	{
		status = e;
	}
	
	ClearResult(r);

return status;
}



Error DbBase::BeginTrans()
{
	return DoCommand("BEGIN;");
}



Error DbBase::RollbackTrans()
{
	return DoCommand("ROLLBACK;");
}



Error DbBase::CommitTrans()
{
	return DoCommand("COMMIT;");
}