//#include<iostream>
//#include<fstream>
//
//using namespace std;
//
//void main()
//{
//	//dynamic memory allocation
//	//dynamic - changing - at runtime
//	//memory - memory for variables, normally arrays
//	//allocation - to set aside something
//
//	int* p = NULL;
//
//	// ...
//	int size;
//	cin >> size;
//
//	while(true)
//	{
//		p = new int[size];
//
//		//...
//		delete []p;
//	}
//
//	for(int i = 0; i < size; i++)
//	{
//		cin >> p[i];
//	}
//	for(int i = 0; i < size; i++)
//	{
//		cout << p[i] << endl;
//	}
//}


#include<iostream>
#include<fstream>

using namespace std;

const unsigned int HEADER_SIZE = 54;
const unsigned int BYTES_PER_PIXEL = 3;

struct FileHeader
{
	char bfType[3];
	unsigned int bfSize;
	unsigned short bfReserved1;
	unsigned short bfReserved2;
	unsigned int bfOffBits;
};

struct InfoHeader
{
	unsigned int biSize;
	unsigned int biWidth;
	unsigned int biHeight;
	unsigned short biPlanes;
	unsigned short biBitCount;
	unsigned int biCompression;
	unsigned int biSizeImage;
	unsigned int biXPelsPerMeter;
	unsigned int biYPelsPerMeter;
	unsigned int biClrUsed;
	unsigned int biClrImportant;
};

struct Pixel
{
	unsigned char blue;
	unsigned char green;
	unsigned char red;
};

struct BitmapFile
{
	FileHeader fileHeader;
	InfoHeader infoHeader;
	Pixel* pixels;
};

int paddingBytesNeededPerRow(int width);
int bytesPerRow(int width);


void writeFileHeader(ofstream& fout, const FileHeader& fileHeader)
{
	fout.write(fileHeader.bfType, 2); // this should read BM
	fout.write((char*)&fileHeader.bfSize,4);
	fout.write((char*)&fileHeader.bfReserved1,2);
	fout.write((char*)&fileHeader.bfReserved2,2);
	fout.write((char*)&fileHeader.bfOffBits,4);
}

void writeInfoHeader(ofstream& fout, const InfoHeader& infoHeader)
{
	fout.write((char*)&infoHeader.biSize,4);
	fout.write((char*)&infoHeader.biWidth,4);
	fout.write((char*)&infoHeader.biHeight,4);
	fout.write((char*)&infoHeader.biPlanes,2);
	fout.write((char*)&infoHeader.biBitCount,2);
	fout.write((char*)&infoHeader.biCompression,4);
	fout.write((char*)&infoHeader.biSizeImage,4);
	fout.write((char*)&infoHeader.biXPelsPerMeter,4);
	fout.write((char*)&infoHeader.biYPelsPerMeter,4);
	fout.write((char*)&infoHeader.biClrUsed,4);
	fout.write((char*)&infoHeader.biClrImportant,4);
}
void writePixels(ofstream& fout, const Pixel* pixels, const InfoHeader& infoHeader)
{
	int i = 0;
	unsigned int padding = 0;
	int paddingBytes = paddingBytesNeededPerRow(infoHeader.biWidth);

	for(int row = 0; row < infoHeader.biHeight; row++)
	{
		for(int column = 0;column < infoHeader.biWidth; column++)
		{
			fout.write((char*)&pixels[i].blue, 1);
			fout.write((char*)&pixels[i].green, 1);
			fout.write((char*)&pixels[i].red, 1);
			i++;
		}
		//may need to write extra bytes
		fout.write((char*)&padding,paddingBytes);
	}
}

void writeBitmapFile(char fileName[], const BitmapFile& bitmapFile)
{
	ofstream fout(fileName,ios::binary);

	writeFileHeader(fout,bitmapFile.fileHeader);
	writeInfoHeader(fout,bitmapFile.infoHeader);
	writePixels(fout, bitmapFile.pixels, bitmapFile.infoHeader);

	fout.close();
}

void readFileHeader(ifstream& fin, FileHeader& fileHeader)
{
	fin.read(fileHeader.bfType, 2); // this should read BM
	fin.read((char*)&fileHeader.bfSize,4);
	fin.read((char*)&fileHeader.bfReserved1,2);
	fin.read((char*)&fileHeader.bfReserved2,2);
	fin.read((char*)&fileHeader.bfOffBits,4);
}

void readInfoHeader(ifstream& fin, InfoHeader& infoHeader)
{
	fin.read((char*)&infoHeader.biSize,4);
	fin.read((char*)&infoHeader.biWidth,4);
	fin.read((char*)&infoHeader.biHeight,4);
	fin.read((char*)&infoHeader.biPlanes,2);
	fin.read((char*)&infoHeader.biBitCount,2);
	fin.read((char*)&infoHeader.biCompression,4);
	fin.read((char*)&infoHeader.biSizeImage,4);
	fin.read((char*)&infoHeader.biXPelsPerMeter,4);
	fin.read((char*)&infoHeader.biYPelsPerMeter,4);
	fin.read((char*)&infoHeader.biClrUsed,4);
	fin.read((char*)&infoHeader.biClrImportant,4);
}
void readPixels(ifstream& fin, Pixel* pixels, InfoHeader& infoHeader)
{
	int i = 0;
	unsigned int padding = 0;
	int paddingBytes = paddingBytesNeededPerRow(infoHeader.biWidth);

	for(int row = 0; row < infoHeader.biHeight; row++)
	{
		for(int column = 0;column < infoHeader.biWidth; column++)
		{
			fin.read((char*)&pixels[i].blue, 1);
			fin.read((char*)&pixels[i].green, 1);
			fin.read((char*)&pixels[i].red, 1);
			i++;
		}
		//may need to read extra bytes
		fin.read((char*)&padding,paddingBytes);
	}
}

void readBitmapFile(char fileName[], BitmapFile& bitmapFile)
{
	ifstream fin(fileName,ios_base::binary);

	readFileHeader(fin,bitmapFile.fileHeader);
	readInfoHeader(fin,bitmapFile.infoHeader);

	//asking form memory at runtime (dynamic memeory allocation)
	bitmapFile.pixels = new Pixel[bitmapFile.infoHeader.biWidth * bitmapFile.infoHeader.biHeight];
	
	readPixels(fin, bitmapFile.pixels, bitmapFile.infoHeader);

	fin.close();
}


int bytesPerRow(int width)
{
	int result = width * 3;
	
	while(result % 4 != 0)
	{
		result ++;
	}

	return result;
}


int paddingBytesNeededPerRow(int width)
{
	return ( bytesPerRow(width) - (width * 3));
}

void rotate90(BitmapFile& bitmapFile)
{
	Pixel* newPixels = new Pixel[bitmapFile.infoHeader.biWidth * bitmapFile.infoHeader.biHeight];
	for(int row =0; row < bitmapFile.infoHeader.biHeight; row++)
	{
		for(int column =0; column < bitmapFile.infoHeader.biWidth; column++)
		{
			newPixels[(bitmapFile.infoHeader.biWidth - column - 1)*bitmapFile.infoHeader.biHeight + row] = 
				bitmapFile.pixels[row * bitmapFile.infoHeader.biWidth + column];
		}
	}
	delete []bitmapFile.pixels;
	bitmapFile.pixels = newPixels;

	unsigned int temp = bitmapFile.infoHeader.biWidth;
	bitmapFile.infoHeader.biWidth = bitmapFile.infoHeader.biHeight;
	bitmapFile.infoHeader.biHeight = temp;
	bitmapFile.infoHeader.biSizeImage = bytesPerRow(bitmapFile.infoHeader.biWidth) * 
		bitmapFile.infoHeader.biHeight;

	bitmapFile.fileHeader.bfSize = bitmapFile.infoHeader.biSizeImage + HEADER_SIZE;
}

void main()
{
	char fileName[100];
	cout << "Enter the name of the bitmap file you want to edit\n";
	cin.getline(fileName,100);

	BitmapFile bitmapFile;
	readBitmapFile(fileName, bitmapFile);

	//do the menu stuff if the file was there

	rotate90(bitmapFile);


	writeBitmapFile(fileName,bitmapFile);
}