#include "Texture.h"
#include <fstream>

TextureTGA::TextureTGA(const char * filePath)
{
	// open the file
	std::fstream fsPicture(filePath, std::ios::in | std::ios::binary);

	if (!fsPicture.is_open())
		throw std::invalid_argument(std::string("file not found: ") += filePath);

	// read in the header
	std::uint8_t ui8x18Header[19] = { 0 };
	fsPicture.read(reinterpret_cast<char*>(&ui8x18Header), sizeof(ui8x18Header)-1);
	
	// extract all information from header
	ui32IDLength = ui8x18Header[0];
	bColorTabel = ui8x18Header[1] == 1;
	ui32PicType = ui8x18Header[2];
	ui32PaletteBegin = ui8x18Header[4] * 0x100 + ui8x18Header[3];
	ui32PaletteLength = ui8x18Header[6] * 0x100 + ui8x18Header[5];
	ui32PaletteBpP = ui8x18Header[7];
	ui32Width = ui8x18Header[13] * 0x100 + ui8x18Header[12];
	ui32Height = ui8x18Header[15] * 0x100 + ui8x18Header[14];
	ui32BpP = ui8x18Header[16];
	ui32Attribut = ui8x18Header[17];

	// calculate some more information
	ui32Size = ui32Width * ui32Height * ui32BpP/8;
	bCompressed = ui32PicType == 9 || ui32PicType == 10;
	vui8Pixels.resize(ui32Size);

	/* consol output of the header
	std::cout << "Header\n"
		<< "ID länge: " << ui32IDLength << std::endl
		<< "Farbtabelle: " << (int)bColorTabel << std::endl
		<< "Bildtype: " << ui32PicType << std::endl
		<< "Palletenbegin: " << ui32PaletteBegin << std::endl
		<< "Palletenlängen: " << ui32PaletteLength << std::endl
		<< "Bits pro Palleteneintrag: " << ui32PaletteBpP << std::endl
		<< "Breite: " << ui32Width << std::endl
		<< "Höhe: " << ui32Height << std::endl
		<< "Bit pro Pixel: " << ui32BpP << std::endl
		<< "Bild Attribute: " << ui32Attribut << std::endl;*/

	// jump to the data block
	fsPicture.seekg(ui32IDLength + ui32PaletteLength, std::ios_base::cur);

	// If not compressed 24 or 32 bit
	if (ui32PicType == 2 && (ui32BpP == 24 || ui32BpP == 32))
	{
		fsPicture.read(reinterpret_cast<char*>(vui8Pixels.data()), ui32Size);
	}
	// else if compressed 24 or 32 bit
	else if (ui32PicType == 10 && (ui32BpP == 24 || ui32BpP == 32))	// compressed
	{
		std::uint8_t tempChunkHeader;
		std::uint8_t tempData[5];
		unsigned int tempByteIndex = 0;
		std::size_t tempPixelIndex = 0;

		do {
			fsPicture.read(reinterpret_cast<char*>(&tempChunkHeader), sizeof(tempChunkHeader));

			if (tempChunkHeader >> 7)	// repeat count
			{
				// just use the first 7 bits
				tempChunkHeader = (uint8_t(tempChunkHeader << 1) >> 1);

				fsPicture.read(reinterpret_cast<char*>(&tempData), ui32BpP/8);

				for (int i = 0; i <= tempChunkHeader; i++)
				{
					vui8Pixels[tempByteIndex++] = tempData[0];
					vui8Pixels[tempByteIndex++] = tempData[1];
					vui8Pixels[tempByteIndex++] = tempData[2];
					if(ui32BpP == 32) vui8Pixels[tempByteIndex++] = tempData[3];
				}
			}
			else						// data count
			{
				// just use the first 7 bits
				tempChunkHeader = (uint8_t(tempChunkHeader << 1) >> 1);

				for (int i = 0; i <= tempChunkHeader; i++)
				{
					fsPicture.read(reinterpret_cast<char*>(&tempData), ui32BpP/8);

					vui8Pixels[tempByteIndex++] = tempData[0];
					vui8Pixels[tempByteIndex++] = tempData[1];
					vui8Pixels[tempByteIndex++] = tempData[2];
					if (ui32BpP == 32) vui8Pixels[tempByteIndex++] = tempData[3];
				}
			}
		} while (tempByteIndex < ui32Size);
	}
	// not useable format
	else
	{
		fsPicture.close();
		throw std::invalid_argument("Invaild File Format! Required 24 or 31 Bit Image.");
	}

	fsPicture.close();
}

TextureTGA::~TextureTGA()
{
	vui8Pixels.clear();
}

std::vector<std::uint8_t> TextureTGA::getData() const
{
	return vui8Pixels;
}

bool TextureTGA::hasAlpha() const
{
	return ui32BpP == 32;
}

std::uint32_t TextureTGA::getWidth() const
{
	return ui32Width;
}

std::uint32_t TextureTGA::getHeight() const
{
	return ui32Height;
}