#include "lua/bitmap.hpp"
#include "library/zip.hpp"
#include <limits>

namespace
{
	inline uint64_t tocolor(unsigned r, unsigned g, unsigned b, unsigned a)
	{
		if(!a)
			return -1;
		else
			return (static_cast<int64_t>(256 - a) << 24) | (static_cast<int64_t>(r) << 16) |
				(static_cast<int64_t>(g) << 8) | static_cast<int64_t>(b);
	}
}

struct lua_loaded_bitmap lua_loaded_bitmap::load(const std::string& name)
{
	struct lua_loaded_bitmap b;
	std::istream* file = NULL;
	try {
		std::string magic;
		unsigned pcolors;
		unsigned R;
		unsigned G;
		unsigned B;
		unsigned A;
		file = &open_file_relative(name, "");
		*file >> magic;
		if(magic != "LSNES-BITMAP")
			throw std::runtime_error("Bitmap load: Wrong magic");
		*file >> b.w;
		*file >> b.h;
		if(b.h >= std::numeric_limits<size_t>::max() / b.w)
			throw std::runtime_error("Bitmap load: Bitmap too large");
		b.bitmap.resize(b.w * b.h);
		*file >> pcolors;
		if(pcolors > 65536)
			throw std::runtime_error("Bitmap load: Palette too big");
		if(pcolors > 0) {
			//Paletted.
			b.d = false;
			b.palette.resize(pcolors);
			for(size_t i = 0; i < pcolors; i++) {
				*file >> R;
				*file >> G;
				*file >> B;
				*file >> A;
				if(R > 255 || G > 255 || B > 255 || A > 256)	//Yes, a can be 256.
					throw std::runtime_error("Bitmap load: Palette entry out of range");
				b.palette[i] = tocolor(R, G, B, A);
			}
			for(size_t i = 0; i < b.w * b.h; i++) {
				*file >> R;
				if(R >= pcolors)
					throw std::runtime_error("Bitmap load: color index out of range");
				b.bitmap[i] = R;
			}
		} else {
			//Direct.
			b.d = true;
			for(size_t i = 0; i < b.w * b.h; i++) {
				*file >> R;
				*file >> G;
				*file >> B;
				*file >> A;
				if(R > 255 || G > 255 || B > 255 || A > 256)	//Yes, a can be 256.
					throw std::runtime_error("Bitmap load: Color out of range");
				b.bitmap[i] = tocolor(R, G, B, A);
			}
		}
		if(!*file)
			throw std::runtime_error("Bitmap load: Error reading bitmap");
	} catch(...) {
		delete file;
		throw;
	}
	delete file;
	return b;
}