#include "boost/mysql/connection.hpp"
#include <boost/asio/io_service.hpp>
#include <boost/system/system_error.hpp>
#include <iostream>

/**
 * For this example, we will be using the 'mysql_asio_examples' database.
 * You can get this database by running db_setup.sql.
 * This example assumes you are connecting to a localhost MySQL server.
 *
 * This example shows how to use the metadata contained in a resultset.
 *
 * This example assumes you are already familiar with the basic concepts
 * of mysql-asio (tcp_connection, resultset, rows, values). If you are not,
 * please have a look to the query_sync.cpp example.
 */

void main_impl(int argc, char** argv)
{
	if (argc != 3)
	{
		std::cerr << "Usage: " << argv[0] << " <username> <password>\n";
		exit(1);
	}

	// Connection params (host, port, user, password, database)
	boost::asio::ip::tcp::endpoint ep (boost::asio::ip::address_v4::loopback(), boost::mysql::default_port);
	boost::mysql::connection_params params (argv[1], argv[2], "mysql_asio_examples");

	// TCP and MySQL level connect
	boost::asio::io_context ctx;
	boost::mysql::tcp_connection conn (ctx);
	conn.next_layer().connect(ep);
	conn.handshake(params);

	// Issue the query
	const char* sql = R"(
		SELECT comp.name AS company_name, emp.id AS employee_id
		FROM employee emp
		JOIN company comp ON (comp.id = emp.company_id)
	)";
	boost::mysql::tcp_resultset result = conn.query(sql);

	/**
	 * Resultsets allow you to access metadata about the fields in the query
	 * using the fields() function, which returns a vector of field_metadata
	 * (one per field in the query, and in the same order as in the query).
	 * You can retrieve the field name, type, number of decimals,
	 * suggested display width, whether the field is part of a key...
	 */
	assert(result.fields().size() == 2);

	[[maybe_unused]] const boost::mysql::field_metadata& company_name = result.fields()[0];
	assert(company_name.database() == "mysql_asio_examples");  // database name
	assert(company_name.table() == "comp");                    // the alias we assigned to the table in the query
	assert(company_name.original_table() == "company");        // the original table name
	assert(company_name.field_name() == "company_name");       // the name of the field in the query
	assert(company_name.original_field_name() == "name");      // the name of the physical field in the table
	assert(company_name.type() == boost::mysql::field_type::varchar); // we created the field as a VARCHAR
	assert(!company_name.is_primary_key());                    // field is not a primary key
	assert(!company_name.is_auto_increment());                 // field is not AUTO_INCREMENT
	assert(company_name.is_not_null());                        // field may not be NULL

	[[maybe_unused]] const boost::mysql::field_metadata& employee_id = result.fields()[1];
	assert(employee_id.database() == "mysql_asio_examples");// database name
	assert(employee_id.table() == "emp");                   // the alias we assigned to the table in the query
	assert(employee_id.original_table() == "employee");     // the original table name
	assert(employee_id.field_name() == "employee_id");      // the name of the field in the query
	assert(employee_id.original_field_name() == "id");      // the name of the physical field in the table
	assert(employee_id.type() == boost::mysql::field_type::int_);  // we created the field as INT
	assert(employee_id.is_primary_key());                   // field is a primary key
	assert(employee_id.is_auto_increment());                // we declared the field as AUTO_INCREMENT
	assert(employee_id.is_not_null());                      // field cannot be NULL
}

int main(int argc, char** argv)
{
	try
	{
		main_impl(argc, argv);
	}
	catch (const boost::system::system_error& err)
	{
		std::cerr << "Error: " << err.what() << ", error code: " << err.code() << std::endl;
		return 1;
	}
	catch (const std::exception& err)
	{
		std::cerr << "Error: " << err.what() << std::endl;
		return 1;
	}
}