// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include "RemoteDisplayMode.h"

#include <QGuiApplication>

static bool DetectRemoteDisplay() {
    const QByteArray env = qgetenv("JFJOCH_VIEWER_REMOTE");
    if (!env.isEmpty())
        return env != "0" && env.compare("false", Qt::CaseInsensitive) != 0;

    // Wayland, Windows and macOS sessions are local by construction.
    if (QGuiApplication::platformName() != QLatin1String("xcb"))
        return false;

    // A DISPLAY with a host part goes over a socket that carries every pixel:
    // "localhost:10.0" is SSH forwarding, "host:0" is raw remote X. A local display
    // is ":0"-style ("unix:0" is a legacy spelling of the same thing).
    const QByteArray display = qgetenv("DISPLAY");
    const auto colon = display.indexOf(':');
    if (colon <= 0)
        return false;
    return display.left(colon) != "unix";
}

static bool &ActiveFlag() {
    static bool active = DetectRemoteDisplay();
    return active;
}

bool RemoteDisplayMode() {
    return ActiveFlag();
}

void SetRemoteDisplayMode(bool active) {
    ActiveFlag() = active;
}