/*
 * Copyright (C) Marius Gripsgard <marius@ubports.com>
 * Copyright (C) Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 or 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef MIR_FRONTEND_XWAYLAND_CONNECTOR_H
#define MIR_FRONTEND_XWAYLAND_CONNECTOR_H

#include <mir/frontend/connector.h>

#include <memory>
#include <mutex>

namespace mir
{
class Executor;
namespace dispatch
{
class ReadableFd;
class ThreadedDispatcher;
}
namespace frontend
{
class WaylandConnector;
class XWaylandServer;
class XWaylandSpawner;
class XWaylandWM;
class XWaylandConnector : public Connector, public std::enable_shared_from_this<XWaylandConnector>
{
public:
    /// Scale is a little complicated. It controls how big apps appear but *probably* not the scale they render at
    /// (unless they respect the X11 DPI, which most don't). For sharp, correctly sized apps the output scale, XWayland
    /// scale and the scale the application uses should all match. Application scale needs to be configured on a per-app
    /// or even per-toolkit basis. GDK_SCALE is used by default for XWayland scale because many apps respect it, so it's
    /// generally as correct as anything.
    XWaylandConnector(
        std::shared_ptr<Executor> const& main_loop,
        std::shared_ptr<WaylandConnector> const& wayland_connector,
        std::string const& xwayland_path,
        float scale);
    ~XWaylandConnector();

    void start() override;
    void stop() override;

    int client_socket_fd() const override;
    int client_socket_fd(
        std::function<void(std::shared_ptr<scene::Session> const& session)> const& connect_handler) const override;

    auto socket_name() const -> std::optional<std::string> override;

private:
    std::shared_ptr<Executor> const main_loop;
    std::shared_ptr<WaylandConnector> const wayland_connector;
    std::string const xwayland_path;
    float const scale;

    /// Creates the spawner if it doesn't already exist and is_started is true, given lock must be locked
    void maybe_create_spawner(std::unique_lock<std::mutex> const& lock);
    /// Destroyes all objects including the spawner, given lock must be locked
    void clean_up(std::unique_lock<std::mutex> lock);
    /// Called the first time a client attempts to connect. Creates the server (which forks the XWayland process), wm
    /// and wm_event_thread.
    void spawn();

    std::mutex mutable mutex;
    /// Set in start() and stop(), should always reflect the state Mir has requested this object to be in
    bool is_started{false};
    std::unique_ptr<XWaylandSpawner> spawner;
    std::unique_ptr<XWaylandServer> server;
    std::unique_ptr<XWaylandWM> wm;
    std::unique_ptr<dispatch::ThreadedDispatcher> wm_event_thread;
};
} /* frontend */
} /* mir */

#endif /* end of include guard: MIR_FRONTEND_XWAYLAND_CONNECTOR_H */
