#pragma once

#include <functional>
#include <string>
#include <pgsql/libpq-fe.h>
#include <cassert>
#include <QString>

#include <vector>
#include <codecvt>
#include <memory>

#include <fmt/format.h>

#include "Pgsql_Result.h"

namespace Pgsql {

	class Connection;
	/*
	This library has multiple layers.

	Layer 1 delivers lowlevel C++ wrappers for the basic libpq functionality. Adding
	automatic resource management.

	*/

//	class ConnectionParams {
//	public:
//		std::string host;
//		std::string hostaddr;
//		unsigned short port = 5432;
//		std::string dbname;
//		std::string user;
//		std::string password;
//		int connect_timeout = -1; ///< -1 omit (ie uses default)
//		std::string application_name;

//	};



	class Result;





	/** \brief Wrapper for a cancel object from libpq.
	 */
	class Canceller {
	public:
		Canceller() = default;
		Canceller(PGcancel *c);
		Canceller(const Canceller&) = delete;
		Canceller& operator=(const Canceller&) = delete;
		Canceller(Canceller&& rhs);
		Canceller& operator=(Canceller&& rhs);
		~Canceller();

		bool cancel(std::string *error);
	private:
		PGcancel *m_cancel = nullptr;
	};

	/** \brief Class for connecting to the database.
	 *
	 * The class isolates the programmer from the worst C style parts
	 * of the libpq API but is mostly a very thin wrapper.
	 */
	class Connection {
	public:
		Connection();
		~Connection();

		Connection(const Connection &rhs) = delete;
		Connection& operator=(const Connection &rhs) = delete;

		Connection(Connection &&rhs);
		Connection& operator=(Connection &&rhs);

//		void connect(const ConnectionParams &params);
		bool connect(const char *params);
		bool connect(const QString &params)
		{
			return connect(params.toUtf8().data());
		}
		bool connect(const char *const * keywords, const char* const * values, int expand_dbname);

		bool connectStart(const char *params);

		bool connectStart(const std::string &params)
		{
			return connectStart(params.c_str());
		}

		bool connectStart(const QString &params)
		{
			return connectStart(params.toUtf8().data());
		}
		bool connectStart(const char * const *keywords,
						  const char * const *values);

		PostgresPollingStatusType connectPoll();
		ConnStatusType status();
		int socket();

		void close();
		Canceller getCancel();

		std::string getErrorMessage() const;

		Result query(const char * command);
		Result query(const QString &command)
		{
			return query(command.toUtf8().data());
		}

		bool sendQuery(const char * query);
		bool sendQuery(const std::string &command)
		{
			return sendQuery(command.c_str());
		}
		bool sendQuery(const QString &command)
		{
			return sendQuery(command.toUtf8().data());
		}

		std::shared_ptr<Result> getResult();

		bool consumeInput();
		bool isBusy();

		void setNoticeReceiver(std::function<void(const PGresult *)> callback);
	private:
		PGconn *conn = nullptr;
		std::function<void(const PGresult *)> notifyReceiver;

		static void notifyReceiveFunc(void *arg, const PGresult *result);
	};




//	class Field {
//	public:

//		std::string getName() const;

//	private:
//		//Tuples tuples;
//		int field;
//		//

//	};

//	class Tuples {
//	public:
//		int getRowCount() const;
//		int getColCount() const;

//		Field getField(const std::string &fname);
//		Field getField(const int idx);

//		class const_iterator {
//		public:
//            const_iterator& operator++();
//		};

//		void rewind();


//	};

//	class OkResult: public Result {
//	public:
//		/** If the result is a data result then returns an interface for processing this data.

//		The returned interface remains valid as long as this OkResult exists.
//		*/
//		Tuples* hasTuples();
//	};

//	class ErrorResult: public Result {
//
//	};

//	class ITransaction {
//	public:
//
//		Canceller Query(std::string query,
//			std::function<void(OkResult)> on_success,
//			std::function<void()> on_cancelled,
//			std::function<void(ErrorResult)> on_error);
//
//		Canceller Query(std::string query,
//			std::function<void(OkResult)> on_success,
//			std::function<void()> on_cancelled,
//			std::function<void(ErrorResult)> on_error);
//
//
//		void Rollback(
//			std::function<void(OkResult)> on_success,
//			std::function<void(ErrorResult)> on_error);
//		void Commit(
//			std::function<void(OkResult)> on_success,
//			std::function<void()> on_cancelled,
//			std::function<void(ErrorResult)> on_error);
//
//	};
}