#include <psemek/ui/impl/label_base.hpp>
#include <psemek/react/map.hpp>
#include <psemek/react/join.hpp>

namespace psemek::ui::impl
{

	label_base::label_base()
		: font_(react::value<fonts::font *>(nullptr))
		, glyphs_(react::value<std::vector<fonts::shaped_glyph>>(std::vector<fonts::shaped_glyph>{}))
		, size_(react::map([](std::vector<fonts::shaped_glyph> const & glyphs, fonts::font * font){
			if (!font)
				return geom::vector{0.f, 0.f};
			geom::box<float, 2> bbox;
			for (auto const & glyph : glyphs)
				bbox |= glyph.position;
			return geom::vector{bbox[0].length(), font->size()[1]};
		}, react::join(glyphs_), react::join(font_)))
		, size_constraints_(react::map([](geom::vector<float, 2> const & size){
			geom::box<float, 2> result;
			result[0].min = size[0];
			result[0].max = size_constraints::infinity;
			result[1].min = size[1];
			result[1].max = size_constraints::infinity;
			return impl::size_constraints{result};
		}, size_))
	{}

	react::value<size_constraints> label_base::size_constraints() const
	{
		return size_constraints_;
	}

	void label_base::draw(renderer & renderer)
	{
		if (!glyphs_ || !*glyphs_)
			return;

		auto const size = *size_;
		auto const shape = this->shape();

		geom::vector<float, 2> origin;
		origin[0] = std::round(geom::lerp(shape[0].min, shape[0].max - size[0], lerp_factor(*halign_)));
		origin[1] = std::round(geom::lerp(shape[1].min, shape[1].max - size[1], lerp_factor(*valign_)));
		origin[1] += std::round((size[1] + (**font_)->xheight()) / 2.f);

		for (auto const & glyph : **glyphs_)
			renderer.draw_glyph(*glyph.texture, glyph.position + origin, glyph.texcoords, *color_);
	}

	void label_base::update(label const & value)
	{
		font_.set(value.font);
		glyphs_.set(react::map([](std::string const & str, fonts::font * font) -> std::vector<fonts::shaped_glyph> {
			if (!font)
				return {};
			return font->shape(str, {});
		}, value.text, value.font));
		color_ = value.color;
		halign_ = value.halign;
		valign_ = value.valign;
	}

}