#include <Windows.h>
#include <stdlib.h>
#include <stdio.h>

//typedef struct _BITMAPFILEHEADER
//{
//    WORD bfType;  //specifies the file type
//    DWORD bfSize;  //specifies the size in bytes of the bitmap file
//    WORD bfReserved1;  //reserved; must be 0
//    WORD bfReserved2;  //reserved; must be 0
//    DWORD bfOffBits;  //species the offset in bytes from the bitmapfileheader to the bitmap bits
//}BITMAPFILEHEADER, *PBITMAPFILEHEADER;
//
//typedef struct _BITMAPINFOHEADER
//{
//    DWORD biSize;  //specifies the number of bytes required by the struct
//    LONG biWidth;  //specifies width in pixels
//    LONG biHeight;  //species height in pixels
//    WORD biPlanes; //specifies the number of color planes, must be 1
//    WORD biBitCount; //specifies the number of bit per pixel
//    DWORD biCompression;//spcifies the type of compression
//    DWORD biSizeImage;  //size of image in bytes
//    LONG biXPelsPerMeter;  //number of pixels per meter in x axis
//    LONG biYPelsPerMeter;  //number of pixels per meter in y axis
//    DWORD biClrUsed;  //number of colors used by th ebitmap
//    DWORD biClrImportant;  //number of colors that are important
//}BITMAPINFOHEADER, *PBITMAPINFOHEADER;

typedef struct _RGB {
	BYTE Red;
	BYTE Green;
	BYTE Blue;
} RGB, *PRGB;

#define FILE_NAME "pr19.bmp"
#define SIGNATURE 0x4D42

HANDLE getDataPointer(
	PBYTE copyFileName,
	int *width,
	int *height,
	PRGB *startingPixel
)
{
	HANDLE fileHandle = INVALID_HANDLE_VALUE;
	HANDLE fileMappingHandle = INVALID_HANDLE_VALUE;
	PBITMAPFILEHEADER data = NULL;
	PBITMAPINFOHEADER bitmapInfoHeader = NULL;
	DWORD fileSize = 0;

	BOOL copied = CopyFileA(
		FILE_NAME,
		copyFileName,
		FALSE
	);

	if (copied == FALSE)
	{
		printf("Could not copy file %s", copyFileName);
		return INVALID_HANDLE_VALUE;
	}

	fileHandle = CreateFileA(
		copyFileName,                       //lpFileName
		GENERIC_READ | GENERIC_WRITE,       //dwDesiredAccess
		0,                                  //dwShareMode
		NULL,                               //lpSecurityAttributes
		OPEN_EXISTING,                      //dwCreationDisposition
		FILE_ATTRIBUTE_NORMAL,              //dwFlagsAndAttributes
		NULL                                //hTemplateFile
	);
	if (INVALID_HANDLE_VALUE == fileHandle)
	{
		printf("Error: could not open file %d", GetLastError());
		system("pause");
		exit(1);
	}

	fileMappingHandle = CreateFileMappingA(
		fileHandle,                 //hFile
		NULL,                       //lpFileMappingAttributes
		PAGE_READWRITE,             //flProtect
		0,                          //dwMaximumSizeHigh
		0,                          //dwMaximumSizeLow
		NULL                        //lpName
	);
	if (NULL == fileMappingHandle)
	{
		printf("Error: mapping file %d", GetLastError());
		goto cleanup;
	}

	fileSize = GetFileSize(
		fileHandle,
		NULL
	);

	data = (PBITMAPFILEHEADER)MapViewOfFile(
		fileMappingHandle,              //hFileMappingObject
		FILE_MAP_WRITE,                 //dwDesiredAccess
		0,                              //dwFileOffsetHigh
		0,                              //dwFileOffsetLow
		fileSize                        //dwNumberOfBytesToMap
	);
	if (NULL == data)
	{
		printf("Error: mapping file %d", GetLastError());
		goto cleanup;
	}

	if (SIGNATURE != data->bfType)
	{
		printf("Error: signature");
		goto cleanup;
	}


	bitmapInfoHeader = (PBITMAPINFOHEADER)((PBYTE)data + sizeof(BITMAPFILEHEADER));
	*width = bitmapInfoHeader->biWidth;
	*height = bitmapInfoHeader->biHeight;

	*startingPixel = (PBYTE)data + data->bfOffBits;
	return fileHandle;

cleanup:
	if (NULL != data)
	{
		UnmapViewOfFile(data);
	}
	if (NULL != fileMappingHandle)
	{
		CloseHandle(fileMappingHandle);
	}

	return INVALID_HANDLE_VALUE;
}

void solveA()
{
	int width, height;
	PRGB pixel;

	HANDLE h = getDataPointer("pr191.bmp", &width, &height, &pixel);
	int pad = (4 - width * 3 % 4) % 4;
	if (INVALID_HANDLE_VALUE != h)
	{
		for (int j = 0; j < height; ++j)
		{
			for (int i = 0; i < width; ++i)
			{
				pixel->Red = 255 - pixel->Red;
				pixel->Green = 255 - pixel->Green;
				pixel->Blue = 255 - pixel->Blue;
				pixel += 1;
			}
			pixel = (PBYTE)pixel + pad;
		}
		CloseHandle(h);
	}
}

void solveB()
{
	int width, height;
	PRGB pixel;

	HANDLE h = getDataPointer("pr193.bmp", &width, &height, &pixel);
	int pad = (4 - width * 3 % 4) % 4;
	if (INVALID_HANDLE_VALUE != h)
	{
		for (int j = 0; j < height; ++j)
		{
			for (int i = 0; i < width; ++i)
			{
				int av = (pixel->Red + pixel->Green + pixel->Blue) / 3;
				pixel->Red = av;
				pixel->Green = av;
				pixel->Blue = av;
				pixel += 1;
			}
			pixel = (PBYTE)pixel + pad;
		}
		CloseHandle(h);
	}
}

void solveC()
{
	int width, height;
	PRGB pixel;
	PRGB pixelAux;
	RGB aux;

	HANDLE h = getDataPointer("pr192.bmp", &width, &height, &pixel);
	int pad = (4 - width * 3 % 4) % 4;
	pixelAux = pixel + width * (height - 1);
	pixelAux = (PBYTE)pixelAux + (height - 1) * pad;
	if (INVALID_HANDLE_VALUE != h)
	{
		for (int i = 0; i < height / 2; ++i)
		{
			for (int j = 0; j < width; ++j)
			{
				//swap
				//////////////////////////////////
				aux.Red = pixel->Red;
				aux.Blue = pixel->Blue;
				aux.Green = pixel->Green;

				pixel->Red = pixelAux->Red;
				pixel->Green = pixelAux->Green;
				pixel->Blue = pixelAux->Blue;

				pixelAux->Red = aux.Red;
				pixelAux->Green = aux.Green;
				pixelAux->Blue = aux.Blue;
				//////////////////////////////////
				pixel += 1;
				pixelAux += 1;
			}
			pixel = (PBYTE)pixel + pad;
			pixelAux -= width * 2;
			pixelAux = (PBYTE)pixelAux - pad;
		}
		CloseHandle(h);
	}
}

int main()
{
	solveA();
	solveB();
	solveC();
	system("pause");
	return 0;
}