// Copyright (c) 2016-2018 Kiwano - Nomango
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include <kiwano/core/Director.h>
#include <kiwano/core/Logger.h>
#include <kiwano/platform/Application.h>
#include <kiwano/platform/Input.h>
#include <kiwano/render/TextureCache.h>
#include <kiwano/utils/ResourceCache.h>
#include <mutex>

namespace kiwano
{
namespace
{

using FunctionToPerform = Function<void()>;

std::mutex               perform_mutex_;
Queue<FunctionToPerform> functions_to_perform_;

}  // namespace

Application::Application()
    : time_scale_(1.f)
{
    Use(&Renderer::Instance());
    Use(&Input::Instance());
    Use(&Director::Instance());
}

Application::~Application()
{
    Destroy();
}

void Application::Run(bool debug)
{
    // Setup all components
    for (auto c : comps_)
    {
        c->SetupComponent();
    }

    if (debug)
    {
        Director::Instance().ShowDebugInfo(true);
        Renderer::Instance().GetContext().SetCollectingStatus(true);
    }

    // Everything is ready
    OnReady();

    last_update_time_ = Time::Now();

    Window& window = Window::Instance();
    while (!window.ShouldClose())
    {
        while (EventPtr evt = window.PollEvent())
        {
            DispatchEvent(evt.get());
        }

        Update();
        Render();
    }
}

void Application::Quit()
{
    Window::Instance().Destroy();
}

void Application::Destroy()
{
    // Clear all resources
    Director::Instance().ClearStages();
    ResourceCache::Instance().Clear();
    TextureCache::Instance().Clear();

    for (auto iter = comps_.rbegin(); iter != comps_.rend(); ++iter)
    {
        (*iter)->DestroyComponent();
    }
    render_comps_.clear();
    update_comps_.clear();
    event_comps_.clear();
    comps_.clear();
}

void Application::Use(ComponentBase* component)
{
    if (component)
    {

#if defined(KGE_DEBUG)
        if (comps_.contains(component))
        {
            KGE_ASSERT(false && "Component already exists!");
        }
#endif

        comps_.push_back(component);

        if (component->Check(RenderComponent::flag))
            render_comps_.push_back(dynamic_cast<RenderComponent*>(component));

        if (component->Check(UpdateComponent::flag))
            update_comps_.push_back(dynamic_cast<UpdateComponent*>(component));

        if (component->Check(EventComponent::flag))
            event_comps_.push_back(dynamic_cast<EventComponent*>(component));
    }
}

void Application::SetTimeScale(float scale_factor)
{
    time_scale_ = scale_factor;
}

void Application::Update()
{
    // Before update
    for (auto c : update_comps_)
    {
        c->BeforeUpdate();
    }

    // perform functions
    {
        if (!functions_to_perform_.empty())
        {
            perform_mutex_.lock();
            auto functions = std::move(functions_to_perform_);
            perform_mutex_.unlock();

            while (!functions.empty())
            {
                auto& func = functions.front();
                if (func)
                {
                    func();
                }
                functions.pop();
            }
        }
    }

    // Updating
    {
        const Time     now = Time::Now();
        const Duration dt  = (now - last_update_time_) * time_scale_;

        last_update_time_ = now;

        for (auto c : update_comps_)
        {
            c->OnUpdate(dt);
        }
    }

    // After update
    for (auto rit = update_comps_.rbegin(); rit != update_comps_.rend(); ++rit)
    {
        (*rit)->AfterUpdate();
    }
}

void Application::Render()
{
    Renderer& renderer = Renderer::Instance();
    renderer.Clear();

    // Before render
    for (auto c : render_comps_)
    {
        c->BeforeRender();
    }

    // Rendering
    renderer.BeginDraw();
    for (auto c : render_comps_)
    {
        c->OnRender(renderer.GetContext());
    }
    renderer.EndDraw();

    // After render
    for (auto rit = render_comps_.rbegin(); rit != render_comps_.rend(); ++rit)
    {
        (*rit)->AfterRender();
    }

    renderer.Present();
}

void Application::DispatchEvent(Event* evt)
{
    for (auto c : event_comps_)
    {
        c->HandleEvent(evt);
    }
}

void Application::PreformInMainThread(Function<void()> func)
{
    std::lock_guard<std::mutex> lock(perform_mutex_);
    functions_to_perform_.push(func);
}

}  // namespace kiwano