//go:build windows

/*
 * ============================================================================
 * Projekt.....: rs2322tcp
 * Datei.......: internal/client/virtual_port_open_windows.go
 * Copyright (C) 2026 Dieter Lang
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * Beschreibung:
 * Windows-spezifische Erzeugung eines verwalteten virtuellen rs2322tcp-Ports.
 *
 * Der konfigurierte virtuelle COM-Port wird einmal geöffnet und anschließend
 * über dasselbe Handle für Lese- und Schreiboperationen verwendet.
 * ============================================================================
 */

package client

import (
	"fmt"

	bugserial "go.bug.st/serial"
)

///////////////////////////////////////////////////////////////////////////////
// Open virtual port
///////////////////////////////////////////////////////////////////////////////

// openVirtualPort creates and initializes a Windows virtual serial port.
//
// The port number must already have been reserved by the
// VirtualPortManager.
//
// The visible COM port is provided by the platform-specific PortPath()
// implementation. The actual COM-port pair configuration is managed
// externally by the Windows virtual COM-port driver.
//
// The COM port is opened exactly once. The resulting handle is used for
// parallel read and write operations.
func openVirtualPort(
	manager *VirtualPortManager,
	number int,
) (*ManagedVirtualPort, error) {
	if manager == nil {
		return nil, fmt.Errorf("virtual port manager is nil")
	}

	portPath := manager.PortPath(number)
	if portPath == "" {
		return nil, fmt.Errorf(
			"virtual port path is empty for port %d",
			number,
		)
	}

	mode := &bugserial.Mode{
		BaudRate: 9600,
		DataBits: 8,
		Parity:   bugserial.NoParity,
		StopBits: bugserial.OneStopBit,
	}

	port, err := bugserial.Open(portPath, mode)
	if err != nil {
		return nil, fmt.Errorf(
			"open virtual serial port %s: %w",
			portPath,
			err,
		)
	}

	virtualPort := NewVirtualPort(
		portPath,
		&windowsSerial{
			port: port,
			path: portPath,
		},
	)

	return &ManagedVirtualPort{
		port:    virtualPort,
		manager: manager,
		number:  number,
	}, nil
}