// 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 <mutex>

#include <kiwano/platform/Application.h>
#include <kiwano/platform/modules.h>
#include <kiwano/core/win32/helper.h>
#include <kiwano/platform/Input.h>
#include <kiwano/core/Director.h>
#include <kiwano/renderer/TextureCache.h>
#include <kiwano/utils/ResourceCache.h>

#include <windowsx.h>  // GET_X_LPARAM, GET_Y_LPARAM
#include <imm.h>  // ImmAssociateContext

#pragma comment(lib, "imm32.lib")

namespace kiwano
{
	namespace
	{
		using FunctionToPerform = Function<void()>;

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

	Config::Config(String const& title, uint32_t width, uint32_t height, uint32_t icon)
		: debug(false)
	{
		window.title = title;
		window.width = width;
		window.height = height;
		window.icon = icon;
	}

	Config::Config(WindowConfig const& wnd_config, RenderConfig const& render_config)
		: debug(false)
	{
		window = wnd_config;
		render = render_config;
	}
}

namespace kiwano
{
	Application::Application()
		: end_(true)
		, inited_(false)
		, time_scale_(1.f)
	{
		ThrowIfFailed(::CoInitialize(nullptr));

		Use(Renderer::GetInstance());
		Use(Input::GetInstance());
		Use(Director::GetInstance());
	}

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

		::CoUninitialize();
	}

	void Application::Init(const Config& config)
	{
		Window::GetInstance()->Init(config.window, Application::WndProc);
		Renderer::GetInstance()->Init(config.render);

		// Setup all components
		for (auto c : comps_)
		{
			c->SetupComponent();
		}

		if (config.debug)
		{
			Director::GetInstance()->ShowDebugInfo(true);
			Renderer::GetInstance()->SetCollectingStatus(true);
		}

		// Everything is ready
		OnReady();

		HWND hwnd = Window::GetInstance()->GetHandle();

		// disable imm
		::ImmAssociateContext(hwnd, nullptr);

		// use Application instance in message loop
		::SetWindowLongPtr(hwnd, GWLP_USERDATA, LONG_PTR(this));

		inited_ = true;
	}

	void Application::Run()
	{
		KGE_ASSERT(inited_ && "Calling Application::Run before Application::Init");

		end_ = false;

		Window::GetInstance()->Prepare();
		while (!end_)
		{
			Window::GetInstance()->PollEvents();
		}
	}

	void Application::Quit()
	{
		end_ = true;
	}

	void Application::Destroy()
	{
		// Clear all resources
		Director::GetInstance()->ClearStages();
		ResourceCache::GetInstance()->Clear();
		TextureCache::GetInstance()->Clear();

		if (inited_)
		{
			inited_ = false;

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

		// Destroy all instances
		Director::DestroyInstance();
		ResourceCache::DestroyInstance();
		TextureCache::DestroyInstance();
		Input::DestroyInstance();
		Renderer::DestroyInstance();
		Window::DestroyInstance();

		// DO NOT destroy Logger instance manually
		// Logger::DestroyInstance();
	}

	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
		{
			static auto last = Time::Now();

			const auto now = Time::Now();
			const auto dt = (now - last) * time_scale_;
			last = 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()
	{
		// Before render
		for (auto c : render_comps_)
		{
			c->BeforeRender();
		}

		// Rendering
		Renderer* renderer = Renderer::GetInstance();
		for (auto c : render_comps_)
		{
			c->OnRender(renderer);
		}

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

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

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

	LRESULT CALLBACK Application::WndProc(HWND hwnd, UINT32 msg, WPARAM wparam, LPARAM lparam)
	{
		Application* app = reinterpret_cast<Application*>(static_cast<LONG_PTR>(::GetWindowLongPtrW(hwnd, GWLP_USERDATA)));
		if (app == nullptr)
		{
			return ::DefWindowProcW(hwnd, msg, wparam, lparam);
		}

		// Handle Message
		for (auto c : app->event_comps_)
		{
			c->HandleMessage(hwnd, msg, wparam, lparam);
		}

		switch (msg)
		{
		case WM_PAINT:
		{
			app->Update();
			app->Render();

			::InvalidateRect(hwnd, NULL, FALSE);
			return 0;
		}
		break;

		case WM_KEYDOWN:
		case WM_SYSKEYDOWN:
		case WM_KEYUP:
		case WM_SYSKEYUP:
		{
			bool down = msg == WM_KEYDOWN || msg == WM_SYSKEYDOWN;
			if (down)
			{
				KeyDownEvent evt;
				evt.code = static_cast<int>(wparam);
				evt.count = static_cast<int>(lparam & 0xFF);
				app->DispatchEvent(&evt);
			}
			else
			{
				KeyUpEvent evt;
				evt.code = static_cast<int>(wparam);
				evt.count = static_cast<int>(lparam & 0xFF);
				app->DispatchEvent(&evt);
			}
		}
		break;

		case WM_CHAR:
		{
			KeyCharEvent evt;
			evt.value = static_cast<char>(wparam);
			evt.count = static_cast<int>(lparam & 0xFF);
			app->DispatchEvent(&evt);
		}
		break;

		case WM_LBUTTONUP:
		case WM_LBUTTONDOWN:
		//case WM_LBUTTONDBLCLK:
		case WM_MBUTTONUP:
		case WM_MBUTTONDOWN:
		//case WM_MBUTTONDBLCLK:
		case WM_RBUTTONUP:
		case WM_RBUTTONDOWN:
		//case WM_RBUTTONDBLCLK:
		case WM_MOUSEMOVE:
		case WM_MOUSEWHEEL:
		{
			auto UpdateMouseData = [&](MouseEvent* evt)
			{
				evt->pos = Point(static_cast<float>(GET_X_LPARAM(lparam)), static_cast<float>(GET_Y_LPARAM(lparam)));
				evt->left_btn_down = !!(wparam & MK_LBUTTON);
				evt->left_btn_down = !!(wparam & MK_RBUTTON);
			};

			if (msg == WM_MOUSEMOVE)
			{
				MouseMoveEvent evt;
				UpdateMouseData(&evt);
				app->DispatchEvent(&evt);
			}
			else if	(msg == WM_LBUTTONDOWN || msg == WM_RBUTTONDOWN || msg == WM_MBUTTONDOWN)
			{
				MouseDownEvent evt;
				UpdateMouseData(&evt);
				if		(msg == WM_LBUTTONDOWN)	{ evt.button = MouseButton::Left; }
				else if	(msg == WM_RBUTTONDOWN)	{ evt.button = MouseButton::Right; }
				else if	(msg == WM_MBUTTONDOWN)	{ evt.button = MouseButton::Middle; }
				app->DispatchEvent(&evt);
			}
			else if (msg == WM_LBUTTONUP || msg == WM_RBUTTONUP || msg == WM_MBUTTONUP)
			{
				MouseDownEvent evt;
				UpdateMouseData(&evt);
				if		(msg == WM_LBUTTONUP)	{ evt.button = MouseButton::Left; }
				else if	(msg == WM_RBUTTONUP)	{ evt.button = MouseButton::Right; }
				else if	(msg == WM_MBUTTONUP)	{ evt.button = MouseButton::Middle; }
				app->DispatchEvent(&evt);
			}
			else if	(msg == WM_MOUSEWHEEL)
			{
				MouseWheelEvent evt;
				UpdateMouseData(&evt);
				evt.wheel = GET_WHEEL_DELTA_WPARAM(wparam) / (float)WHEEL_DELTA;
				app->DispatchEvent(&evt);
			}
		}
		break;

		case WM_SIZE:
		{
			if (SIZE_MAXHIDE == wparam || SIZE_MINIMIZED == wparam)
			{
				// KGE_LOG(L"Window minimized");
			}
			else
			{
				// KGE_LOG(L"Window resized");

				Window::GetInstance()->UpdateWindowRect();

				WindowResizedEvent evt;
				evt.width = LOWORD(lparam);
				evt.height = HIWORD(lparam);
				app->DispatchEvent(&evt);
			}
		}
		break;

		case WM_MOVE:
		{
			int x = (int)(short)LOWORD(lparam);
			int y = (int)(short)HIWORD(lparam);

			WindowMovedEvent evt;
			evt.x = x;
			evt.y = y;
			app->DispatchEvent(&evt);
		}
		break;

		case WM_ACTIVATE:
		{
			bool active = (LOWORD(wparam) != WA_INACTIVE);

			Window::GetInstance()->SetActive(active);

			WindowFocusChangedEvent evt;
			evt.focus = active;
			app->DispatchEvent(&evt);
		}
		break;

		case WM_SETTEXT:
		{
			// KGE_LOG(L"Window title changed");

			WindowTitleChangedEvent evt;
			evt.title = reinterpret_cast<const wchar_t*>(lparam);
			app->DispatchEvent(&evt);
		}
		break;

		case WM_SETICON:
		{
			// KGE_LOG(L"Window icon changed");
		}
		break;

		case WM_DISPLAYCHANGE:
		{
			// KGE_LOG(L"The display resolution has changed");

			::InvalidateRect(hwnd, nullptr, FALSE);
		}
		break;

		case WM_SETCURSOR:
		{
			Window::GetInstance()->UpdateCursor();
		}
		break;

		case WM_CLOSE:
		{
			// KGE_LOG(L"Window is closing");

			if (!app->OnClosing())
			{
				WindowClosedEvent evt;
				app->DispatchEvent(&evt);
				return 0;
			}
		}
		break;

		case WM_DESTROY:
		{
			KGE_LOG(L"Window was destroyed");

			app->Quit();
			app->OnDestroy();

			::PostQuitMessage(0);
			return 0;
		}
		break;
		}

		return ::DefWindowProcW(hwnd, msg, wparam, lparam);
	}
}