#ifndef DB_CONNECTIONPOOL_H
#define DB_CONNECTIONPOOL_H

#include "connection.h"
#include "connection_fwd.h" // for ConnectionPtr
#include "resourcePool.impl.h" // for ResourcePool<>::InUse, ResourcePool
#include <map> // for operator!=
#include <memory>
#include <string>
#include <visibility.h>

namespace DB {
	/// Specialisation of AdHoc::ResourcePool for database connections.
	class DLL_PUBLIC BasicConnectionPool : public AdHoc::ResourcePool<Connection> {
	public:
		/// Create a new connection pool.
		/// @param max Maximum number of concurrent database connections.
		/// @param keep Number of connections to keep open after use.
		BasicConnectionPool(unsigned int max, unsigned int keep);

	protected:
		/// Ping a connection.
		void returnTestResource(Connection const *) const override;
		/// Ping a connection.
		void testResource(Connection const *) const override;
	};

	/// Standard specialisation of AdHoc::ResourcePool for database connections given a type and connection string.
	class DLL_PUBLIC ConnectionPool : public BasicConnectionPool {
	public:
		/// Create a new connection pool.
		/// @param max Maximum number of concurrent database connections.
		/// @param keep Number of connections to keep open after use.
		/// @param type Database connection factory name.
		/// @param connectionString Connection string to pass to the connection factory.
		ConnectionPool(unsigned int max, unsigned int keep, const std::string & type, std::string connectionString);

	protected:
		/// Create a new connection.
		ConnectionPtr createResource() const override;

	private:
		const ConnectionFactoryCPtr factory;
		const std::string connectionString;
	};

	using ConnectionPoolPtr = std::shared_ptr<BasicConnectionPool>;
}

#endif