#include <psemek/util/pixmap.hpp>

#include <iostream>

namespace psemek::util
{

	pixmap_monochrome read_pgm(std::istream & is)
	{
		auto fail = [](std::string str)
		{
			throw std::runtime_error("Error loading PGM image: " + str);
		};

		std::string line;
		std::getline(is, line);

		bool binary = true;

		if (line == "P2")
		{
			binary = false;
		}
		else if (line == "P5")
		{
			binary = true;
		}
		else
			fail("unknown format " + line);

		std::size_t width, height;
		std::size_t max;
		pixmap_monochrome pixmap;

		is >> width >> height >> max;

		if (max != 255)
			fail("max value " + std::to_string(max) + " is not supported");

		pixmap.resize(width, height);

		if (binary)
			is.read(reinterpret_cast<char *>(pixmap.data()), width * height * sizeof(pixmap.data()[0]));
		else
			fail("P2 format is not supported");

		if (!is)
			fail("stream error");

		return pixmap;
	}

	pixmap_rgb load_ppm(std::istream & is)
	{
		auto fail = [](std::string str)
		{
			throw std::runtime_error("Error loading PPM image: " + str);
		};

		std::string line;
		std::getline(is, line);

		bool binary = true;

		if (line == "P3")
		{
			binary = false;
		}
		else if (line == "P6")
		{
			binary = true;
		}
		else
			fail("unknown format " + line);

		std::size_t width, height;
		std::size_t max;
		pixmap_rgb pixmap;

		is >> width >> height >> max;

		if (max != 255)
			fail("max value " + std::to_string(max) + " is not supported");

		pixmap.resize(width, height);

		if (binary)
			is.read(reinterpret_cast<char *>(pixmap.data()), width * height * sizeof(pixmap.data()[0]));
		else
			fail("P3 format is not supported");

		if (!is)
			fail("stream error");

		return pixmap;
	}

	void write_pgm(pixmap_monochrome const & p, std::ostream & os)
	{
		os << "P5\n" << p.width() << " " << p.height() << "\n255\n";
		os.write(reinterpret_cast<char const *>(p.data()), p.width() * p.height() * sizeof(p.data()[0]));
	}

	void write_ppm(pixmap_rgb const & p, std::ostream & os)
	{
		os << "P6\n" << p.width() << " " << p.height() << "\n255\n";
		os.write(reinterpret_cast<char const *>(p.data()), p.width() * p.height() * sizeof(p.data()[0]));
	}

}