/*
 * Copyright (C) 2016 Google, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <cassert>
#include <dlfcn.h>
#include <time.h>
#include <android/log.h>

#include "Helpers.h"
#include "Game.h"
#include "ShellAndroid.h"

namespace {

// copied from ShellXCB.cpp
class PosixTimer {
   public:
    PosixTimer() { reset(); }

    void reset() { clock_gettime(CLOCK_MONOTONIC, &start_); }

    double get() const {
        struct timespec now;
        clock_gettime(CLOCK_MONOTONIC, &now);

        constexpr long one_s_in_ns = 1000 * 1000 * 1000;
        constexpr double one_s_in_ns_d = static_cast<double>(one_s_in_ns);

        time_t s = now.tv_sec - start_.tv_sec;
        long ns;
        if (now.tv_nsec > start_.tv_nsec) {
            ns = now.tv_nsec - start_.tv_nsec;
        } else {
            assert(s > 0);
            s--;
            ns = one_s_in_ns - (start_.tv_nsec - now.tv_nsec);
        }

        return static_cast<double>(s) + static_cast<double>(ns) / one_s_in_ns_d;
    }

   private:
    struct timespec start_;
};

}  // namespace

std::vector<std::string> ShellAndroid::get_args(android_app &app) {
    const char intent_extra_data_key[] = "args";
    std::vector<std::string> args;

    JavaVM &vm = *app.activity->vm;
    JNIEnv *p_env;
    if (vm.AttachCurrentThread(&p_env, nullptr) != JNI_OK) return args;

    JNIEnv &env = *p_env;
    jobject activity = app.activity->clazz;
    jmethodID get_intent_method = env.GetMethodID(env.GetObjectClass(activity), "getIntent", "()Landroid/content/Intent;");
    jobject intent = env.CallObjectMethod(activity, get_intent_method);

    jmethodID get_string_extra_method =
        env.GetMethodID(env.GetObjectClass(intent), "getStringExtra", "(Ljava/lang/String;)Ljava/lang/String;");
    jvalue get_string_extra_args;
    get_string_extra_args.l = env.NewStringUTF(intent_extra_data_key);
    jstring extra_str = static_cast<jstring>(env.CallObjectMethodA(intent, get_string_extra_method, &get_string_extra_args));

    std::string args_str;
    if (extra_str) {
        const char *extra_utf = env.GetStringUTFChars(extra_str, nullptr);
        args_str = extra_utf;
        env.ReleaseStringUTFChars(extra_str, extra_utf);

        env.DeleteLocalRef(extra_str);
    }

    env.DeleteLocalRef(get_string_extra_args.l);
    env.DeleteLocalRef(intent);

    vm.DetachCurrentThread();

    // split args_str
    std::stringstream ss(args_str);
    std::string arg;
    while (std::getline(ss, arg, ' ')) {
        if (!arg.empty()) args.push_back(arg);
    }

    return args;
}

ShellAndroid::ShellAndroid(android_app &app, Game &game) : Shell(game), app_(app) {
    if (game.settings().validate) {
        instance_layers_.push_back("VK_LAYER_GOOGLE_threading");
        instance_layers_.push_back("VK_LAYER_LUNARG_parameter_validation");
        instance_layers_.push_back("VK_LAYER_LUNARG_object_tracker");
        instance_layers_.push_back("VK_LAYER_LUNARG_core_validation");
        instance_layers_.push_back("VK_LAYER_GOOGLE_unique_objects");
    }

    instance_extensions_.push_back(VK_KHR_ANDROID_SURFACE_EXTENSION_NAME);

    app_dummy();
    app_.userData = this;
    app_.onAppCmd = on_app_cmd;
    app_.onInputEvent = on_input_event;

    init_vk();
}

ShellAndroid::~ShellAndroid() {
    cleanup_vk();
    dlclose(lib_handle_);
}

void ShellAndroid::log(LogPriority priority, const char *msg) {
    int prio;

    switch (priority) {
        case LOG_DEBUG:
            prio = ANDROID_LOG_DEBUG;
            break;
        case LOG_INFO:
            prio = ANDROID_LOG_INFO;
            break;
        case LOG_WARN:
            prio = ANDROID_LOG_WARN;
            break;
        case LOG_ERR:
            prio = ANDROID_LOG_ERROR;
            break;
        default:
            prio = ANDROID_LOG_UNKNOWN;
            break;
    }

    __android_log_write(prio, settings_.name.c_str(), msg);
}

PFN_vkGetInstanceProcAddr ShellAndroid::load_vk() {
    const char filename[] = "libvulkan.so";
    void *handle = nullptr, *symbol = nullptr;

    handle = dlopen(filename, RTLD_LAZY);
    if (handle) symbol = dlsym(handle, "vkGetInstanceProcAddr");
    if (!symbol) {
        if (handle) dlclose(handle);

        throw std::runtime_error(dlerror());
    }

    lib_handle_ = handle;

    return reinterpret_cast<PFN_vkGetInstanceProcAddr>(symbol);
}

VkSurfaceKHR ShellAndroid::create_surface(VkInstance instance) {
    VkAndroidSurfaceCreateInfoKHR surface_info = {};
    surface_info.sType = VK_STRUCTURE_TYPE_ANDROID_SURFACE_CREATE_INFO_KHR;
    surface_info.window = app_.window;

    VkSurfaceKHR surface;
    vk::assert_success(vk::CreateAndroidSurfaceKHR(instance, &surface_info, nullptr, &surface));

    return surface;
}

void ShellAndroid::on_app_cmd(int32_t cmd) {
    switch (cmd) {
        case APP_CMD_INIT_WINDOW:
            create_context();
            resize_swapchain(0, 0);
            break;
        case APP_CMD_TERM_WINDOW:
            destroy_context();
            break;
        case APP_CMD_WINDOW_RESIZED:
            resize_swapchain(0, 0);
            break;
        case APP_CMD_STOP:
            ANativeActivity_finish(app_.activity);
            break;
        default:
            break;
    }
}

int32_t ShellAndroid::on_input_event(const AInputEvent *event) {
    if (AInputEvent_getType(event) != AINPUT_EVENT_TYPE_MOTION) return false;

    bool handled = false;

    switch (AMotionEvent_getAction(event) & AMOTION_EVENT_ACTION_MASK) {
        case AMOTION_EVENT_ACTION_UP:
            game_.on_key(Game::KEY_SPACE);
            handled = true;
            break;
        default:
            break;
    }

    return handled;
}

void ShellAndroid::quit() { ANativeActivity_finish(app_.activity); }

void ShellAndroid::run() {
    PosixTimer timer;

    double current_time = timer.get();

    while (true) {
        struct android_poll_source *source;
        while (true) {
            int timeout = (settings_.animate && app_.window) ? 0 : -1;
            if (ALooper_pollAll(timeout, nullptr, nullptr, reinterpret_cast<void **>(&source)) < 0) break;

            if (source) source->process(&app_, source);
        }

        if (app_.destroyRequested) break;

        if (!app_.window) continue;

        acquire_back_buffer();

        double t = timer.get();
        add_game_time(static_cast<float>(t - current_time));

        present_back_buffer();

        current_time = t;
    }
}