/*
 * DriverPostgres.cpp -- PostgreSQL driver
 *
 * Copyright (c) 2013, David Demelier <markand@malikania.fr>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sstream>

#include "DriverPostgres.h"

/* --------------------------------------------------------
 * Query PostgreSQL (protected methods)
 * -------------------------------------------------------- */

bool QueryPostgres::getBoolean(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());
	std::string code = PQgetvalue(m_result.get(), row, idx);

	return code[0] == 't';
}

Date QueryPostgres::getDate(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());
	long timestamp = static_cast<long>(time(0));

	try
	{
		std::ostringstream oss;
		std::string value, req;

		value = PQgetvalue(m_result.get(), row, idx);

		/*
		 * Convert the date using the SQL function so that user does
		 * not require any explicit conversion itself.
		 */
		oss << "Select EXTRACT(EPOCH FROM TIMESTAMP '";
		oss << value;
		oss << "') AS RESULT";
		req = oss.str();

		Query::Ptr result = m_driver->query(req);
		timestamp = result->get<double>(0, "RESULT");
	}
	catch (...) { }

	return Date(static_cast<time_t>(timestamp));
}

double QueryPostgres::getDouble(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());

	return std::stod(PQgetvalue(m_result.get(), row, idx));
}

int QueryPostgres::getInt(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());

	return std::stoi(PQgetvalue(m_result.get(), row, idx));

}

std::string QueryPostgres::getString(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());

	return std::string(PQgetvalue(m_result.get(), row, idx));
}

/* --------------------------------------------------------
 * Query PostgreSQL (public methods)
 * -------------------------------------------------------- */

QueryPostgres::QueryPostgres(Driver::Ptr driver, PostgresResult result)
{
	m_driver = driver;
	m_result = std::move(result);
}

QueryPostgres::~QueryPostgres()
{
}

ColumnType QueryPostgres::type(const std::string &column) const
{
	ColumnType type;
	int pqType, index;
	
	index = PQfnumber(m_result.get(), column.c_str());
	pqType = PQftype(m_result.get(), index);
	switch (pqType)
	{
	case 16:
		type = ColumnType::Boolean;
		break;
	case 1082:
	case 1083:
	case 1114:
		type = ColumnType::Date;
		break;
	case 1700:
	case 700:
	case 701:
		type = ColumnType::Double;
		break;
	case 20:
	case 21:
	case 23:
		type = ColumnType::Integer;
		break;
	case 25:
	case 1042:
	case 1043:
		type = ColumnType::String;
		break;
	default:
		type = ColumnType::Invalid;
	}

	return type;
}

int QueryPostgres::countRows()
{
	return PQntuples(m_result.get());
}

int QueryPostgres::countColumns()
{
	return PQnfields(m_result.get());
}

bool QueryPostgres::isNull(int row, const std::string &column)
{
	int idx = PQfnumber(m_result.get(), column.c_str());

	return PQgetisnull(m_result.get(), row, idx) == 1;
}

void QueryPostgres::dump(void)
{
	std::cout << "Dumping PostgreSQL result, ";
	std::cout << countRows() << " rows, ";
	std::cout << countColumns() << " columns" << std::endl;

	for (int r = 0; r < countRows(); ++r)
	{
		std::cout << "Dumping row " << r << std::endl;
		std::cout << "==============================" << std::endl;

		for (int c = 0; c < countColumns(); ++c)
		{
			std::cout << "\t" << PQfname(m_result.get(), c);
			std::cout << " = " << PQgetvalue(m_result.get(), r, c) << std::endl;
		}
	}
}

/* --------------------------------------------------------
 * Driver PostgreSQL
 * -------------------------------------------------------- */

DriverPostgres::DriverPostgres()
{
}

DriverPostgres::~DriverPostgres()
{
}

std::string DriverPostgres::convert(Params &params)
{
	std::ostringstream oss;

	oss << "host = " << params["host"] << " ";
	oss << "port = " << params["port"] << " ";
	oss << "user = " << params["user"] << " ";
	oss << "dbname = " << params["database"] << " ";
	oss << "password = " << params["password"];

	return oss.str();
}

bool DriverPostgres::connect(const Params &params)
{
	Params copy = params;
	PGconn *conn = PQconnectdb(convert(copy).c_str());

	if (conn == nullptr)
	{
		m_error = strerror(ENOMEM);
		return false;
	}

	if (PQstatus(conn) == CONNECTION_BAD)
	{
		m_error = PQerrorMessage(conn);
		PQfinish(conn);

		return false;
	}

	m_connection = PostgresConn(conn);

	return true;
}

Query::Ptr DriverPostgres::query(const std::string &cmd)
{
	PGresult *info;

	// If NULL, the libpq said no memory
	info = PQexec(m_connection.get(), cmd.c_str());
	if (info == nullptr)
		throw Query::Error(strerror(ENOMEM));

	// If an error occured
	int errorCode = PQresultStatus(info);
	if (errorCode != PGRES_COMMAND_OK && errorCode != PGRES_TUPLES_OK)
	{
		std::string error = PQresultErrorMessage(info);
		PQclear(info);
		throw Query::Error(error);
	}

	return std::unique_ptr<Query>(new QueryPostgres(shared_from_this(),
				      QueryPostgres::PostgresResult(info)));
}

std::string DriverPostgres::description() const
{
	std::ostringstream oss;

	oss << "Connected on PostgreSQL database: " << std::endl;
	oss << "  host: " << PQhost(m_connection.get()) << std::endl;
	oss << "  port: " << PQport(m_connection.get()) << std::endl;
	oss << "  user: " << PQuser(m_connection.get()) << std::endl;
	oss << "  database: " << PQdb(m_connection.get()) << std::endl;

	return oss.str();
}

std::string DriverPostgres::version() const
{
	std::ostringstream oss;

	// TODO: ADD VERSION

	oss << "PostgreSQL driver";

	return oss.str();
}