// ConsoleApplication1.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <windows.h>
#include <stdio.h>
#include <conio.h>

inline WORD ifw(WORD w)
{
	return (rand() % 2 == 1) ? w : 0;
}

int main()
{
	srand(time(NULL));   // Initialization, should only be called once.
	//int r = rand();      // Returns a pseudo-random integer between 0 and RAND_MAX.

	CHAR_INFO* chiBuffer;
	HANDLE hStdout, hNewScreenBuffer;
	SMALL_RECT srctWriteRect;
	COORD coordBufSize;
	COORD coordBufCoord;
	BOOL fSuccess;

	hStdout = GetStdHandle(STD_OUTPUT_HANDLE);

	CONSOLE_SCREEN_BUFFER_INFO scrBuffInfo;
	if (!GetConsoleScreenBufferInfo(hStdout, &scrBuffInfo))
	{
		printf("GetConsoleScreenBufferInfo failed - (%d)\n", GetLastError());
		return 1;
	}

	size_t scrBuffLen;
	COORD scrBuffDim; // window size, not actual buffer, no point drawing off screen
	scrBuffDim.X = scrBuffInfo.srWindow.Right - scrBuffInfo.srWindow.Left;
	scrBuffDim.Y = scrBuffInfo.srWindow.Bottom - scrBuffInfo.srWindow.Top;
	scrBuffLen = scrBuffDim.X * scrBuffDim.Y;

	chiBuffer = new CHAR_INFO[scrBuffLen];
	for (size_t i = 0; i < scrBuffLen; i++)
	{
		chiBuffer[i].Char.AsciiChar = rand() % 91 + 32;
		chiBuffer[i].Attributes = ifw(FOREGROUND_BLUE) | ifw(FOREGROUND_GREEN) | ifw(FOREGROUND_RED) |
			ifw(BACKGROUND_RED) | ifw(BACKGROUND_BLUE) | ifw(BACKGROUND_GREEN) |
			ifw(BACKGROUND_INTENSITY) | ifw(FOREGROUND_INTENSITY);
	}

	hNewScreenBuffer = CreateConsoleScreenBuffer(
		GENERIC_READ |           // read/write access
		GENERIC_WRITE,
		FILE_SHARE_READ |
		FILE_SHARE_WRITE,        // shared
		NULL,                    // default security attributes
		CONSOLE_TEXTMODE_BUFFER, // must be TEXTMODE
		NULL);                   // reserved; must be NULL
	if (hStdout == INVALID_HANDLE_VALUE ||
		hNewScreenBuffer == INVALID_HANDLE_VALUE)
	{
		printf("CreateConsoleScreenBuffer failed - (%d)\n", GetLastError());
		return 1;
	}

	if (!SetConsoleActiveScreenBuffer(hNewScreenBuffer))
	{
		printf("SetConsoleActiveScreenBuffer failed - (%d)\n", GetLastError());
		return 1;
	}

	coordBufSize = scrBuffDim;

	coordBufCoord.X = 0;
	coordBufCoord.Y = 0;

	srctWriteRect.Left = 1; // 1 char wide border all around
	srctWriteRect.Top = 1;
	srctWriteRect.Right = scrBuffDim.X - 2;
	srctWriteRect.Bottom = scrBuffDim.Y - 2;

	// better timer resolution
	if (timeBeginPeriod(1) != TIMERR_NOERROR)
	{
		printf("timeBeginPeriod failed - (%d)\n", GetLastError());
		return 1;
	}
	DWORD t1 = timeGetTime();

	fSuccess = WriteConsoleOutput(
		hNewScreenBuffer, // screen buffer to write to
		chiBuffer,        // buffer to copy from
		coordBufSize,     // col-row size of chiBuffer
		coordBufCoord,    // top left src cell in chiBuffer
		&srctWriteRect);  // dest. screen buffer rectangle
	if (!fSuccess)
	{
		printf("WriteConsoleOutput failed - (%d)\n", GetLastError());
		return 1;
	}

	DWORD t2 = timeGetTime();
	timeEndPeriod(1);
	delete chiBuffer;

	_getch();
	std::cout << "\nTook " << t2 - t1 << " ms\n";

}

// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file