// 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