#include "Game.hpp"

#include <numeric>

#include <SFML/System.hpp>
#include <SFML/Window/ContextSettings.hpp>
#include <SFML/Window/Event.hpp>

#include "Engine/Utils/Perfs.hpp"
#include "Engine/Utils/Timers.hpp"

using std::make_shared;
using std::make_unique;

#define TARGET_FPS  (1000/60)


std::unique_ptr<SysTimer> mPerfsTimer;

Game::Game(bool dbg) : gbDbgModeEnabled(dbg) {
    InitWindows();
    if (gbDbgModeEnabled) {
        gDbgUI = make_unique<DebugUI>();
        mPerfsTimer = make_unique<SysTimer>();
        mPerfsTimer->Reset();
    }
}

void Game::InitWindows() {
    // Create default game window
    sf::ContextSettings sWindowSettings;
    sWindowSettings.depthBits = 0;
    sWindowSettings.stencilBits = 0;
    sWindowSettings.antialiasingLevel = 8;
    sWindowSettings.sRgbCapable = true;

    gMainWindow = make_shared<sf::RenderWindow>(
        sf::VideoMode(1080, 720), "ProtoTank", 
        (sf::Style::Close | sf::Style::Titlebar), 
        sWindowSettings
    );
    gMainWindow->setVerticalSyncEnabled(false);
    gMainWindow->setFramerateLimit(60);
    gMainWindow->setKeyRepeatEnabled(false);
    gMainWindow->setMouseCursorVisible(true);
}

GAME_STATUS Game::Tick(SysTimer& time) {
    static std::vector<double> msTicksMonitoring;
    static double mPrevdelta = 0;
    static int mFrameCnt = 0;
    double mDelta = time.GetDeltaTime();

    if (gDbgUI != nullptr && mPerfsTimer != nullptr) {
        msTicksMonitoring.push_back((mDelta - mPrevdelta) / TARGET_FPS);
        if (mPerfsTimer->GetDeltaTime() >= 1000) {   // Re-evaluate CPU usage every seconds (for FP'S')
            double cpuUsage = std::accumulate(msTicksMonitoring.begin(), msTicksMonitoring.end(), 0) / msTicksMonitoring.size();

            gDbgUI->UpdateDebugData(cpuUsage, (mDelta - mPrevdelta), mFrameCnt, (PerfsGetVirtMem() / 1000), (PerfsGetPhysMem() / 1000));

            mFrameCnt = -1;     // Minus one to compensate the direct next frame
            msTicksMonitoring.clear();
            mPerfsTimer->Reset();
        }
    }

    sf::Event event;
    while (gMainWindow->pollEvent(event)) {     // Wait for next frame (fixed FPS)
        if (event.type == sf::Event::Closed)
            gMainWindow->close();
    }

    if (mDelta >= TARGET_FPS) {      //TODO: Replace with global var and use dynamic window loader
        Update();
        Render();

        mFrameCnt++;
        time.Reset();
        mPrevdelta = -mDelta;
    } else {
        mPrevdelta = mDelta;
    }

    sf::sleep(sf::milliseconds(TARGET_FPS - (mDelta - mPrevdelta)));

    if (gMainWindow->isOpen())
        return GAME_RUNNING;
    else
        return GAME_QUIT;
}

void Game::Update() {

}

void Game::Render() {
    // Clear the draw buffer
    gMainWindow->clear();

    // Draw the arena view
    //3DRenderer::draw()
    // Draw the UI above
    //UI::draw()
    // Draw the debug informations if enabled
    if (gDbgUI != nullptr) gDbgUI->DrawDebugData(gMainWindow);
    
    // Present the draw buffer
    gMainWindow->display();
}