// yabridge: a Wine plugin bridge
// Copyright (C) 2020-2022 Robbert van der Helm
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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 <https://www.gnu.org/licenses/>.

#include <iostream>
#include <thread>

// Generated inside of the build directory
#include <config.h>
#include <version.h>

#include "../common/utils.h"
#ifdef WITH_CLAP
#include "bridges/clap.h"
#endif
#include "bridges/group.h"
#include "bridges/vst2.h"
#ifdef WITH_VST3
#include "bridges/vst3.h"
#endif

static const std::string host_name = "yabridge host version " +
                                     std::string(yabridge_git_version)
#ifdef __i386__
                                     + " (32-bit compatibility mode)"
#endif
    ;

/**
 * This is the universal plugin host application. This can either load an
 * individual plugin, or spawn a group host server This can either load a
 * plugin, or spawn a group host server.
 *
 * For the individual plugin situation this process will load the specified
 * plugin plugin, and then connect back to the `libyabridge-{clap,vst2,vst3}.so`
 * instance that spawned this over the socket.
 *
 * For the group host case this process will act as a daemon yabridge plugin
 * binaries can connect to and request it to host plugins for them. After this
 * host request everything works exactly the same as with individually hosted
 * plugins.
 */
int YABRIDGE_EXPORT
#ifdef WINE_USE_CDECL
    __cdecl
#endif
    main(int argc, char* argv[]) {
    // For individually hosted plugins we'll pass along the plugin format, the
    // name of the VST2 plugin .dll file or VST3 bundle to load, the base
    // directory for the Unix domain socket endpoints to connect to and the
    // process ID of the process the native plugin is being hosted in as
    // arguments for yabridge-host.exe. Group host processes receive only a unix
    // domain socket it should listen on.
    const bool is_group_host = (argc >= 3 && strcmp(argv[1], "group") == 0);
    if (!(is_group_host || argc >= 5)) {
        std::cerr << host_name << std::endl;
        std::cerr << "Usage: "
#ifdef __i386__
                  << yabridge_host_name_32bit
#else
                  << yabridge_host_name
#endif
                  << " <plugin_type> <plugin_location> "
                     "<endpoint_base_directory> <parent_pid>"
                  << std::endl;
        std::cerr << "       "
#ifdef __i386__
                  << yabridge_host_name_32bit
#else
                  << yabridge_host_name
#endif
                  << " group <unix_domain_socket>" << std::endl;

        return 1;
    }

    std::cerr << "Initializing " << host_name << std::endl;

    // NOTE: Some plugins use Microsoft COM, but don't initialize it first and
    //       just pray the host does it for them. Examples of this are
    //       PSPaudioware's InfiniStrip and Shattered Glass Audio Code Red Free.
    OleInitialize(nullptr);

    // The first argument is either a plugin type or 'group', in which case
    // we'll spawn a plugin group host process. In the past this was a separate
    // binary, but they have been merged since they share 95% of the same code.
    if (is_group_host) {
        const std::string group_socket_endpoint_path(argv[2]);

        try {
            GroupBridge bridge(group_socket_endpoint_path);

            // Blocks the main thread until all plugins have exited
            bridge.handle_incoming_connections();
        } catch (const std::system_error& error) {
            // If another process is already listening on the socket, we'll just
            // print a message and exit quietly. This could happen if the host
            // starts multiple yabridge instances that all use the same plugin
            // group at the same time. The same error is also used if we could
            // not create a pipe. Since that error is so rare, we'll just print
            // to STDERR before that happens to differentiate the two cases.
            std::cerr << "Another process is already listening on this group's "
                         "socket, connecting to the existing process:"
                      << std::endl;
            std::cerr << error.what() << std::endl;

            return 0;
        }

        // This shouldn't be needed, but sometimes with Wine background threads
        // will be kept alive while this process exits
        TerminateProcess(GetCurrentProcess(), 0);
    } else {
        const std::string plugin_type_str(argv[1]);
        const PluginType plugin_type = plugin_type_from_string(plugin_type_str);
        const std::string plugin_location(argv[2]);
        const std::string socket_endpoint_path(argv[3]);
        const pid_t parent_pid = std::stoi(argv[4]);

        std::cerr << "Preparing to load " << plugin_type_to_string(plugin_type)
                  << " plugin at '" << plugin_location << "'" << std::endl;

        // As explained in `Vst2Bridge`, the plugin has to be initialized in the
        // same thread as the one that calls `io_context.run()`. This setup is
        // slightly more convoluted than it has to be, but doing it this way we
        // don't need to differentiate between individually hosted plugins and
        // plugin groups when it comes to event handling.
        MainContext main_context{};
        std::unique_ptr<HostBridge> bridge;
        try {
            switch (plugin_type) {
                case PluginType::clap:
#ifdef WITH_CLAP
                    bridge = std::make_unique<ClapBridge>(
                        main_context, plugin_location, socket_endpoint_path,
                        parent_pid);
#else
                    std::cerr
                        << "This version of yabridge has not been compiled "
                           "with CLAP support"
                        << std::endl;
                    return 1;
#endif
                    break;
                case PluginType::vst2:
                    bridge = std::make_unique<Vst2Bridge>(
                        main_context, plugin_location, socket_endpoint_path,
                        parent_pid);
                    break;
                case PluginType::vst3:
#ifdef WITH_VST3
                    bridge = std::make_unique<Vst3Bridge>(
                        main_context, plugin_location, socket_endpoint_path,
                        parent_pid);
#else
                    std::cerr
                        << "This version of yabridge has not been compiled "
                           "with VST3 support"
                        << std::endl;
                    return 1;
#endif
                    break;
                case PluginType::unknown:
                    std::cerr << "Unknown plugin type '" << plugin_type_str
                              << "'" << std::endl;
                    return 1;
                    break;
            };
        } catch (const std::exception& error) {
            std::cerr << "Error while initializing the Wine plugin host:"
                      << std::endl;
            std::cerr << error.what() << std::endl;

            // See below, just returning from `main()` isn't enough to terminate
            // the process
            TerminateProcess(GetCurrentProcess(), 0);

            return 1;
        }

        // Let the plugin receive and handle its events on its own thread. Some
        // potentially unsafe events that should always be run from the UI
        // thread will be posted to `main_context`.
        Win32Thread worker_thread([&]() {
            pthread_setname_np(pthread_self(), "worker");

            bridge->run();

            // // When the sockets get closed, this application should
            // // terminate gracefully
            // main_context.stop();
            // FIXME: So some of the background threads spawned by the plugin
            //        may get stuck if the host got terminated abruptly. After
            //        an entire day of debugging I still have no idea whether
            //        this is a bug in yabridge, Wine, or those plugins, but
            //        just killing off this process and all of its threads
            //        'fixes' the issue.
            //
            //        https://github.com/robbert-vdh/yabridge/issues/69
            TerminateProcess(GetCurrentProcess(), 0);
        });

        std::cerr << "Finished initializing '" << plugin_location << "'"
                  << std::endl;

        // Handle Win32 messages and X11 events on a timer, just like in
        // `GroupBridge::async_handle_events()``
        main_context.async_handle_events(
            [&]() { bridge->handle_events(); },
            [&]() { return !bridge->inhibits_event_loop(); });
        main_context.run();
    }
}