/* Copyright 2015, Michele Santullo
 * This file is part of "dindexer".
 *
 * "dindexer" 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.
 *
 * "dindexer" 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 "dindexer".  If not, see <http://www.gnu.org/licenses/>.
 */

#include "connection.hpp"
#include "pq/databaseexception.hpp"
#include "resultinfo.hpp"
#include <libpq-fe.h>
#include <algorithm>
#include <ciso646>
#include <memory>
#include <boost/lexical_cast.hpp>
#include <sstream>
#include <cstring>
#include "libpqtypes.h"
#include <cstdlib>
#include <ctime>
#include <cassert>

using sc = std::chrono::system_clock;

namespace pq {
	namespace implem {
		template <> const char* type_to_pqtypes_name<std::string>() { return "%text"; }
		template <> const char* type_to_pqtypes_name<boost::string_ref>() { return "%text"; }
		template <> const char* type_to_pqtypes_name<bool>() { return "%bool"; }
		template <> const char* type_to_pqtypes_name<float>() { return "%float4"; }
		template <> const char* type_to_pqtypes_name<double>() { return "%float8"; }
		template <> const char* type_to_pqtypes_name<int16_t>() { return "%int2"; }
		template <> const char* type_to_pqtypes_name<int32_t>() { return "%int4"; }
		template <> const char* type_to_pqtypes_name<int64_t>() { return "%int8"; }
		template <> const char* type_to_pqtypes_name<uint16_t>() { return "%int2"; }
		template <> const char* type_to_pqtypes_name<uint32_t>() { return "%int4"; }
		template <> const char* type_to_pqtypes_name<uint64_t>() { return "%int8"; }
		template <> const char* type_to_pqtypes_name<sc::time_point>() { return "%timestamptz"; }

		template const char* type_to_pqtypes_name<std::string> ( void );
		template const char* type_to_pqtypes_name<boost::string_ref> ( void );
		template const char* type_to_pqtypes_name<bool> ( void );
		template const char* type_to_pqtypes_name<float> ( void );
		template const char* type_to_pqtypes_name<double> ( void );
		template const char* type_to_pqtypes_name<int16_t> ( void );
		template const char* type_to_pqtypes_name<int32_t> ( void );
		template const char* type_to_pqtypes_name<int64_t> ( void );
		template const char* type_to_pqtypes_name<uint16_t> ( void );
		template const char* type_to_pqtypes_name<uint32_t> ( void );
		template const char* type_to_pqtypes_name<uint64_t> ( void );

		auto get_pqlib_c_type_struct<std::chrono::system_clock::time_point>::conv (const std::chrono::system_clock::time_point& parParam) -> type {
			static_assert(sizeof(storage) == sizeof(PGtimestamp), "Wrong size for timestamp, please update DATA_SIZE");
			static_assert(alignof(storage) == alignof(PGtimestamp), "Wrong alignment for timestamp, please update type");

			using std::chrono::system_clock;

			PGtimestamp ts;

			std::memset(&ts, 0, sizeof(PGtimestamp));

			auto t = system_clock::to_time_t(parParam);
			ts.epoch = t;
			auto tm = std::localtime(&t);
			ts.time.hour = tm->tm_hour;
			ts.time.min = tm->tm_min;
			ts.time.sec = tm->tm_sec;
			ts.time.usec = 0;
			ts.time.withtz = 1;
			ts.date.isbc = 0;
			ts.date.year = tm->tm_year + 1900;
			ts.date.mon = tm->tm_mon;
			ts.date.mday = tm->tm_mday;
			char* tzn;
			PQlocalTZInfo(&t, &ts.time.gmtoff, &ts.time.isdst, &tzn);
			std::strcpy(ts.time.tzabbr, tzn);

			std::copy(reinterpret_cast<const char*>(&ts), reinterpret_cast<const char*>(&ts) + sizeof(ts), reinterpret_cast<char*>(&m_storage));
			return &m_storage;
		}

		get_pqlib_c_type_struct<std::chrono::system_clock::time_point>::~get_pqlib_c_type_struct ( void ) noexcept {
			return;
		}
	} //namespace implem

	namespace {
		int call_PQputf (PGparam* parParam, const std::string* parTypes, va_list parArgp) {
			return PQputvf(parParam, nullptr, 0, parTypes->c_str(), parArgp);
		}
	} //unnamed namespace

	struct Connection::LocalData {
		PGconn* connection;
	};

	Connection::Connection (std::string&& parUsername, std::string&& parPasswd, std::string&& parDatabase, std::string&& parAddress, uint16_t parPort) :
		m_username(std::move(parUsername)),
		m_passwd(std::move(parPasswd)),
		m_database(std::move(parDatabase)),
		m_address(std::move(parAddress)),
		m_port(parPort),
		m_localData(new LocalData)
	{
		m_localData->connection = nullptr;
	}

	Connection::~Connection() noexcept {
		disconnect();
	}

	bool Connection::is_connected() const noexcept {
		return m_localData->connection != nullptr;
	}

	void Connection::connect() {
		assert(not is_connected());

		std::unique_ptr<const char*[]> names(new const char*[6]);
		names[0] = "host";
		names[1] = "port";
		names[2] = "dbname";
		names[3] = "user";
		names[4] = "password";
		names[5] = nullptr;

		std::unique_ptr<const char*[]> keywords(new const char*[6]);
		const std::string port(boost::lexical_cast<std::string>(m_port));
		keywords[0] = m_address.c_str();
		keywords[1] = port.c_str();
		keywords[2] = m_database.c_str();
		keywords[3] = m_username.c_str();
		keywords[4] = m_passwd.c_str();
		keywords[5] = nullptr;

		m_localData->connection = PQconnectdbParams(names.get(), keywords.get(), 0);
		if (not m_localData->connection)
			throw DatabaseException("", "Error allocatinng connection object", __FILE__, __LINE__);
		if (PQstatus(m_localData->connection) != CONNECTION_OK) {
			std::string err = error_message();
			disconnect();

			std::ostringstream oss;
			oss << "Unable to connect to database " << m_address << ':' << m_port << " as user \"" << m_username << '"';
			throw DatabaseException(oss.str(), std::move(err), __FILE__, __LINE__);
		}
		this->query("SET NAMES 'utf8'");

		PQinitTypes(m_localData->connection); //Init libpqtypes
	}

	void Connection::disconnect() {
		if (is_connected()) {
			PQclearTypes(m_localData->connection); //clear libpqtypes
			PQfinish(m_localData->connection);
			m_localData->connection = nullptr;
		}
	}

	std::string Connection::error_message() const {
		assert(is_connected());
		return PQerrorMessage(m_localData->connection);
	}

	ResultSet Connection::query (const std::string& parQuery) {
		ResultInfo info(PQexec(m_localData->connection, parQuery.c_str()));
		if (not info.result)
			throw DatabaseException("Error running query", "Error allocating result object", __FILE__, __LINE__);
		const int ress = PQresultStatus(info.result.get());
		if (ress != PGRES_TUPLES_OK && ress != PGRES_COMMAND_OK) {
			throw DatabaseException("Error running query", error_message(), __FILE__, __LINE__);
		}

		return ResultSet(std::move(info));
	}

	std::string Connection::escaped_literal (const std::string& parString) {
		return this->escaped_literal(boost::string_ref(parString));
	}

	std::string Connection::escaped_literal (boost::string_ref parString) {
		typedef std::unique_ptr<char[], void(*)(void*)> PQArrayType;

		PQArrayType clean_str(PQescapeLiteral(m_localData->connection, parString.data(), parString.size()), &PQfreemem);
		return std::string(clean_str.get());
	}

	ResultSet Connection::query_params (const std::string& parQuery, PGParams& parParams) {
		//TODO: make result_format parametric
		int result_format = 0;
		assert(parParams.get());
		ResultInfo info(
			PQparamExec(
				m_localData->connection,
				parParams.get(),
				parQuery.c_str(),
				result_format
			)
		);
		if (not info.result) {
			std::ostringstream oss;
			oss << "Error allocating result object while running \"" << parQuery << "\": " << PQgeterror();
			throw DatabaseException("Error running query", oss.str(), __FILE__, __LINE__);
		}
		const int ress = PQresultStatus(info.result.get());
		if (ress != PGRES_TUPLES_OK && ress != PGRES_COMMAND_OK) {
			throw DatabaseException("Error running query", error_message(), __FILE__, __LINE__);
		}

		return ResultSet(std::move(info));
	}

	auto Connection::make_params (const std::string* parTypes, ...) -> PGParams {
		PGParams retval(PQparamCreate(m_localData->connection), &PQparamClear);
		va_list argp;

		va_start(argp, parTypes);
		call_PQputf(retval.get(), parTypes, argp);
		va_end(argp);

		return std::move(retval);
	}
} //namespace pq