package client

import (
	"fmt"
	"net"

	"git.lang-dieter.de/rs2322tcp/internal/transport"
)

///////////////////////////////////////////////////////////////////////////////
// Data connection
///////////////////////////////////////////////////////////////////////////////

// OpenDataConnection opens the TCP data connection for the specified
// remote device.
//
// The DataPort is supplied by the server as part of the device information.
func (c *Client) OpenDataConnection(
	device transport.RemoteDeviceInfo,
) (net.Conn, error) {
	if c == nil || c.conn == nil {
		return nil, fmt.Errorf("client is not connected")
	}

	if device.DataPort == 0 {
		return nil, fmt.Errorf(
			"device %q has no data port",
			device.ID,
		)
	}

	serverAddr := c.conn.RemoteAddr()
	if serverAddr == nil {
		return nil, fmt.Errorf("control connection has no remote address")
	}

	host, _, err := net.SplitHostPort(serverAddr.String())
	if err != nil {
		return nil, fmt.Errorf(
			"invalid control server address %q: %w",
			serverAddr.String(),
			err,
		)
	}

	dataAddr := net.JoinHostPort(
		host,
		fmt.Sprintf("%d", device.DataPort),
	)

	conn, err := net.Dial("tcp", dataAddr)
	if err != nil {
		return nil, fmt.Errorf(
			"connect data port %d for device %q: %w",
			device.DataPort,
			device.ID,
			err,
		)
	}

	return conn, nil
}