/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsIServiceManager.h"
#include "nsCOMPtr.h"
#include "nsCNativeApp.h"
#include "nsIEventLoop.h"
#include <windows.h>

static NS_DEFINE_CID(kNativeAppCID, NS_NATIVE_APP_CID);

LRESULT CALLBACK WndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam);

void ErrorBox(LPSTR text)
{
	MessageBox(nullptr, text, "XP Event Loop", MB_OK | MB_ICONSTOP);
}

void InfoBox(LPSTR text)
{
	MessageBox(nullptr, text, "XP Event Loop", MB_OK | MB_ICONINFORMATION);
}

int WINAPI WinMain(HINSTANCE inst, 
                   HINSTANCE prevInstance, 
                   LPSTR lpszCmdLine,
                   int nShowCmd)
{
	char* lpszAppName = "HelloWorld";
	HWND wnd;
	WNDCLASSEX wndclass;
	int retCode;

    {	//  Needed to scope all nsCOMPtr within XPCOM Init and Shutdown
      nsresult rv;
      nsCOMPtr<nsIServiceManager> servMan;
      rv = NS_InitXPCOM2(getter_AddRefs(servMan), nullptr, nullptr);
      if(NS_FAILED(rv))
      {
        ErrorBox("Failed to initialize xpcom.");
        return -1;
      }
      
      nsCOMPtr<nsIComponentRegistrar> registrar = do_QueryInterface(servMan);
      NS_ASSERTION(registrar, "Null nsIComponentRegistrar");
      registrar->AutoRegister(nullptr);
      
      nsCOMPtr<nsINativeApp> nativeAppService(do_GetService(kNativeAppCID, &rv));

      if(NS_FAILED(rv))
      {
        ErrorBox("Failed to get nativeAppService");
        return -1;
      }
      wndclass.cbSize        = sizeof(wndclass);
      wndclass.style         = CS_HREDRAW | CS_VREDRAW;
      wndclass.lpfnWndProc   = WndProc;
      wndclass.cbClsExtra    = 0;
      wndclass.cbWndExtra    = 0;
      wndclass.hInstance     = inst;
      wndclass.hIcon         = LoadIcon(nullptr, IDI_APPLICATION);
      wndclass.hCursor       = LoadCursor(nullptr, IDC_ARROW);
      wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
      wndclass.lpszMenuName  = nullptr;
      wndclass.lpszClassName = lpszAppName;
      wndclass.hIconSm       = LoadIcon(nullptr, IDI_APPLICATION);

      RegisterClassEx(&wndclass) ;
      
      wnd = CreateWindow(lpszAppName, "The Hello World",
                         WS_OVERLAPPEDWINDOW,
                         CW_USEDEFAULT, CW_USEDEFAULT,
                         CW_USEDEFAULT, CW_USEDEFAULT,
                         nullptr, nullptr, inst, nullptr);		     
      
      ShowWindow(wnd, nShowCmd);
      UpdateWindow(wnd);
      
      nsCOMPtr<nsIEventLoop> eventLoop;
      
      if(NS_FAILED(nativeAppService->CreateEventLoop(L"_MainLoop", 
                                                     nsEventLoopTypes::MainAppLoop, getter_AddRefs(eventLoop))))
        {
          ErrorBox("Failed to create event Loop");
          return 0;
        } 
      
      eventLoop->Run(nullptr, nullptr, nullptr, &retCode);
      eventLoop = nullptr; // Clear out before Shutting down XPCOM
      
      InfoBox("Hello World app is out of loop");
    }
	NS_ShutdownXPCOM(nullptr);
	InfoBox("Hello World app is exiting");
	return retCode;
}

LRESULT CALLBACK WndProc(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	HDC         hdc;
	PAINTSTRUCT ps;
	RECT        rect;

	switch(msg)
		{
		case WM_PAINT:
			hdc = BeginPaint(wnd, &ps);

			GetClientRect(wnd, &rect);

			DrawText(hdc, "Hello, XP Event Loop!", -1, &rect,
					 DT_SINGLELINE | DT_CENTER | DT_VCENTER);

			EndPaint(wnd, &ps);
			return 0;

		case WM_DESTROY:
			{
			nsresult rv;
			nsCOMPtr<nsINativeApp> nativeAppService = 
			         do_GetService(kNativeAppCID, &rv);
			if(NS_FAILED(rv))
				{
				ErrorBox("Could not get NativeAppService");
				return 0;
				}
			nsCOMPtr<nsIEventLoop> eventLoop;

			if(NS_FAILED(nativeAppService->FindEventLoop(L"_MainLoop", 
				getter_AddRefs(eventLoop))))
				{
				ErrorBox("Failed to find event Loop");
				return 0;
				}
			eventLoop->Exit(0);
			}
			return 0;
		}

	return DefWindowProc(wnd, msg, wParam, lParam);
}
