#include <psemek/gfx/color.hpp>
#include <psemek/util/hash_table.hpp>

namespace psemek::gfx
{

	static util::hash_map<std::string_view, color_rgba> const named_colors
	{
		{"black", {0, 0, 0, 255}},
		{"white", {255, 255, 255, 255}},
		{"grey", {127, 127, 127, 255}},

		{"red", {255, 0, 0, 255}},
		{"green", {0, 255, 0, 255}},
		{"blue", {0, 0, 255, 255}},
		{"cyan", {0, 255, 255, 255}},
		{"magenta", {255, 0, 255, 255}},
		{"yellow", {255, 255, 0, 255}},

		{"dark_grey", {63, 63, 63, 255}},
		{"light_grey", {191, 191, 191, 255}},

		{"dark_red", {127, 0, 0, 255}},
		{"dark_green", {0, 127, 0, 255}},
		{"dark_blue", {0, 0, 127, 255}},
		{"dark_cyan", {0, 127, 127, 255}},
		{"dark_magenta", {127, 0, 127, 255}},
		{"dark_yellow", {127, 127, 0, 255}},

		{"light_red", {255, 127, 127, 255}},
		{"light_green", {127, 255, 127, 255}},
		{"light_blue", {127, 127, 255, 255}},
		{"light_cyan", {127, 255, 255, 255}},
		{"light_magenta", {255, 127, 255, 255}},
		{"light_yellow", {255, 255, 127, 255}},
	};

	static bool all_hex(std::string_view const & text)
	{
		return std::all_of(text.begin(), text.end(), [](char c){
			return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F');
		});
	}

	static std::uint8_t from_hex(char c)
	{
		if ('0' <= c && c <= '9')
			return c - '0';
		if ('a' <= c && c <= 'f')
			return 10 + (c - 'a');
		if ('A' <= c && c <= 'F')
			return 10 + (c - 'A');
		return 0;
	}

	static std::uint8_t from_hex(char c1, char c0)
	{
		return (from_hex(c1) * 16) | from_hex(c0);
	}

	std::optional<color_rgba> parse_color(std::string_view const & text)
	{
		if (auto it = named_colors.find(text); it != named_colors.end())
			return it->second;

		if (all_hex(text))
		{
			if (text.size() == 3)
			{
				return color_rgba{
					17 * from_hex(text[0]),
					17 * from_hex(text[1]),
					17 * from_hex(text[2]),
					255
				};
			}
			else if (text.size() == 4)
			{
				return color_rgba{
					17 * from_hex(text[0]),
					17 * from_hex(text[1]),
					17 * from_hex(text[2]),
					17 * from_hex(text[3]),
				};
			}
			else if (text.size() == 6)
			{
				return color_rgba{
					from_hex(text[0], text[1]),
					from_hex(text[2], text[3]),
					from_hex(text[4], text[5]),
					255
				};
			}
			else if (text.size() == 8)
			{
				return color_rgba{
					from_hex(text[0], text[1]),
					from_hex(text[2], text[3]),
					from_hex(text[4], text[5]),
					from_hex(text[6], text[7]),
				};
			}
		}

		return std::nullopt;
	}

}