// Copyright (c) 2017-2021, The Khronos Group Inc.
//
// SPDX-License-Identifier: Apache-2.0

#include "pch.h"
#include "common.h"
#include "options.h"
#include "platformdata.h"
#include "platformplugin.h"
#include "graphicsplugin.h"
#include "openxr_program.h"

namespace {

#ifdef XR_USE_PLATFORM_ANDROID
void ShowHelp() { Log::Write(Log::Level::Info, "adb shell setprop debug.xr.graphicsPlugin OpenGLES|Vulkan"); }

bool UpdateOptionsFromSystemProperties(Options& options) {
    char value[PROP_VALUE_MAX] = {};
    if (__system_property_get("debug.xr.graphicsPlugin", value) != 0) {
        options.GraphicsPlugin = value;
    }

    // Check for required parameters.
    if (options.GraphicsPlugin.empty()) {
        Log::Write(Log::Level::Error, "GraphicsPlugin parameter is required");
        ShowHelp();
        return false;
    }

    return true;
}
#else
void ShowHelp() {
    // TODO: Improve/update when things are more settled.
    Log::Write(Log::Level::Info,
               "HelloXr --graphics|-g <Graphics API> [--formfactor|-ff <Form factor>] [--viewconfig|-vc <View config>] "
               "[--blendmode|-bm <Blend mode>] [--space|-s <Space>] [--verbose|-v]");
    Log::Write(Log::Level::Info, "Graphics APIs:            D3D11, D3D12, OpenGLES, OpenGL, Vulkan2, Vulkan");
    Log::Write(Log::Level::Info, "Form factors:             Hmd, Handheld");
    Log::Write(Log::Level::Info, "View configurations:      Mono, Stereo");
    Log::Write(Log::Level::Info, "Environment blend modes:  Opaque, Additive, AlphaBlend");
    Log::Write(Log::Level::Info, "Spaces:                   View, Local, Stage");
}

bool UpdateOptionsFromCommandLine(Options& options, int argc, char* argv[]) {
    int i = 1;  // Index 0 is the program name and is skipped.

    auto getNextArg = [&] {
        if (i >= argc) {
            throw std::invalid_argument("Argument parameter missing");
        }

        return std::string(argv[i++]);
    };

    while (i < argc) {
        const std::string arg = getNextArg();
        if (EqualsIgnoreCase(arg, "--graphics") || EqualsIgnoreCase(arg, "-g")) {
            options.GraphicsPlugin = getNextArg();
        } else if (EqualsIgnoreCase(arg, "--formfactor") || EqualsIgnoreCase(arg, "-ff")) {
            options.FormFactor = getNextArg();
        } else if (EqualsIgnoreCase(arg, "--viewconfig") || EqualsIgnoreCase(arg, "-vc")) {
            options.ViewConfiguration = getNextArg();
        } else if (EqualsIgnoreCase(arg, "--blendmode") || EqualsIgnoreCase(arg, "-bm")) {
            options.EnvironmentBlendMode = getNextArg();
        } else if (EqualsIgnoreCase(arg, "--space") || EqualsIgnoreCase(arg, "-s")) {
            options.AppSpace = getNextArg();
        } else if (EqualsIgnoreCase(arg, "--verbose") || EqualsIgnoreCase(arg, "-v")) {
            Log::SetLevel(Log::Level::Verbose);
        } else if (EqualsIgnoreCase(arg, "--help") || EqualsIgnoreCase(arg, "-h")) {
            ShowHelp();
            return false;
        } else {
            throw std::invalid_argument(Fmt("Unknown argument: %s", arg.c_str()));
        }
    }

    // Check for required parameters.
    if (options.GraphicsPlugin.empty()) {
        Log::Write(Log::Level::Error, "GraphicsPlugin parameter is required");
        ShowHelp();
        return false;
    }

    return true;
}
#endif
}  // namespace

#ifdef XR_USE_PLATFORM_ANDROID

struct AndroidAppState {
    ANativeWindow* NativeWindow = nullptr;
    bool Resumed = false;
};

/**
 * Process the next main command.
 */
static void app_handle_cmd(struct android_app* app, int32_t cmd) {
    AndroidAppState* appState = (AndroidAppState*)app->userData;

    switch (cmd) {
        // There is no APP_CMD_CREATE. The ANativeActivity creates the
        // application thread from onCreate(). The application thread
        // then calls android_main().
        case APP_CMD_START: {
            Log::Write(Log::Level::Info, "    APP_CMD_START");
            Log::Write(Log::Level::Info, "onStart()");
            break;
        }
        case APP_CMD_RESUME: {
            Log::Write(Log::Level::Info, "onResume()");
            Log::Write(Log::Level::Info, "    APP_CMD_RESUME");
            appState->Resumed = true;
            break;
        }
        case APP_CMD_PAUSE: {
            Log::Write(Log::Level::Info, "onPause()");
            Log::Write(Log::Level::Info, "    APP_CMD_PAUSE");
            appState->Resumed = false;
            break;
        }
        case APP_CMD_STOP: {
            Log::Write(Log::Level::Info, "onStop()");
            Log::Write(Log::Level::Info, "    APP_CMD_STOP");
            break;
        }
        case APP_CMD_DESTROY: {
            Log::Write(Log::Level::Info, "onDestroy()");
            Log::Write(Log::Level::Info, "    APP_CMD_DESTROY");
            appState->NativeWindow = NULL;
            break;
        }
        case APP_CMD_INIT_WINDOW: {
            Log::Write(Log::Level::Info, "surfaceCreated()");
            Log::Write(Log::Level::Info, "    APP_CMD_INIT_WINDOW");
            appState->NativeWindow = app->window;
            break;
        }
        case APP_CMD_TERM_WINDOW: {
            Log::Write(Log::Level::Info, "surfaceDestroyed()");
            Log::Write(Log::Level::Info, "    APP_CMD_TERM_WINDOW");
            appState->NativeWindow = NULL;
            break;
        }
    }
}

/**
 * This is the main entry point of a native application that is using
 * android_native_app_glue.  It runs in its own thread, with its own
 * event loop for receiving input events and doing other things.
 */
void android_main(struct android_app* app) {
    try {
        JNIEnv* Env;
        app->activity->vm->AttachCurrentThread(&Env, nullptr);

        AndroidAppState appState = {};

        app->userData = &appState;
        app->onAppCmd = app_handle_cmd;

        std::shared_ptr<Options> options = std::make_shared<Options>();
        if (!UpdateOptionsFromSystemProperties(*options)) {
            return;
        }

        std::shared_ptr<PlatformData> data = std::make_shared<PlatformData>();
        data->applicationVM = app->activity->vm;
        data->applicationActivity = app->activity->clazz;

        bool requestRestart = false;
        bool exitRenderLoop = false;

        // Create platform-specific implementation.
        std::shared_ptr<IPlatformPlugin> platformPlugin = CreatePlatformPlugin(options, data);
        // Create graphics API implementation.
        std::shared_ptr<IGraphicsPlugin> graphicsPlugin = CreateGraphicsPlugin(options, platformPlugin);

        // Initialize the OpenXR program.
        std::shared_ptr<IOpenXrProgram> program = CreateOpenXrProgram(options, platformPlugin, graphicsPlugin);

        // Initialize the loader for this platform
        PFN_xrInitializeLoaderKHR initializeLoader = nullptr;
        if (XR_SUCCEEDED(
                xrGetInstanceProcAddr(XR_NULL_HANDLE, "xrInitializeLoaderKHR", (PFN_xrVoidFunction*)(&initializeLoader)))) {
            XrLoaderInitInfoAndroidKHR loaderInitInfoAndroid;
            memset(&loaderInitInfoAndroid, 0, sizeof(loaderInitInfoAndroid));
            loaderInitInfoAndroid.type = XR_TYPE_LOADER_INIT_INFO_ANDROID_KHR;
            loaderInitInfoAndroid.next = NULL;
            loaderInitInfoAndroid.applicationVM = app->activity->vm;
            loaderInitInfoAndroid.applicationContext = app->activity->clazz;
            initializeLoader((const XrLoaderInitInfoBaseHeaderKHR*)&loaderInitInfoAndroid);
        }

        program->CreateInstance();
        program->InitializeSystem();
        program->InitializeSession();
        program->CreateSwapchains();

        while (app->destroyRequested == 0) {
            // Read all pending events.
            for (;;) {
                int events;
                struct android_poll_source* source;
                // If the timeout is zero, returns immediately without blocking.
                // If the timeout is negative, waits indefinitely until an event appears.
                const int timeoutMilliseconds =
                    (!appState.Resumed && !program->IsSessionRunning() && app->destroyRequested == 0) ? -1 : 0;
                if (ALooper_pollAll(timeoutMilliseconds, nullptr, &events, (void**)&source) < 0) {
                    break;
                }

                // Process this event.
                if (source != nullptr) {
                    source->process(app, source);
                }
            }

            program->PollEvents(&exitRenderLoop, &requestRestart);
            if (!program->IsSessionRunning()) {
                continue;
            }

            program->PollActions();
            program->RenderFrame();
        }

        app->activity->vm->DetachCurrentThread();
    } catch (const std::exception& ex) {
        Log::Write(Log::Level::Error, ex.what());
    } catch (...) {
        Log::Write(Log::Level::Error, "Unknown Error");
    }
}
#else
int main(int argc, char* argv[]) {
    try {
        // Parse command-line arguments into Options.
        std::shared_ptr<Options> options = std::make_shared<Options>();
        if (!UpdateOptionsFromCommandLine(*options, argc, argv)) {
            return 1;
        }

        std::shared_ptr<PlatformData> data = std::make_shared<PlatformData>();

        // Spawn a thread to wait for a keypress
        static bool quitKeyPressed = false;
        auto exitPollingThread = std::thread{[] {
            Log::Write(Log::Level::Info, "Press any key to shutdown...");
            (void)getchar();
            quitKeyPressed = true;
        }};
        exitPollingThread.detach();

        bool requestRestart = false;
        do {
            // Create platform-specific implementation.
            std::shared_ptr<IPlatformPlugin> platformPlugin = CreatePlatformPlugin(options, data);

            // Create graphics API implementation.
            std::shared_ptr<IGraphicsPlugin> graphicsPlugin = CreateGraphicsPlugin(options, platformPlugin);

            // Initialize the OpenXR program.
            std::shared_ptr<IOpenXrProgram> program = CreateOpenXrProgram(options, platformPlugin, graphicsPlugin);

            program->CreateInstance();
            program->InitializeSystem();
            program->InitializeSession();
            program->CreateSwapchains();

            while (!quitKeyPressed) {
                bool exitRenderLoop = false;
                program->PollEvents(&exitRenderLoop, &requestRestart);
                if (exitRenderLoop) {
                    break;
                }

                if (program->IsSessionRunning()) {
                    program->PollActions();
                    program->RenderFrame();
                } else {
                    // Throttle loop since xrWaitFrame won't be called.
                    std::this_thread::sleep_for(std::chrono::milliseconds(250));
                }
            }

        } while (!quitKeyPressed && requestRestart);

        return 0;
    } catch (const std::exception& ex) {
        Log::Write(Log::Level::Error, ex.what());
        return 1;
    } catch (...) {
        Log::Write(Log::Level::Error, "Unknown Error");
        return 1;
    }
}
#endif
