#include <psemek/ui/label.hpp>

namespace psemek::ui
{

	void label::set_text(std::string text)
	{
		text_ = std::move(text);
		on_state_changed();
	}

	void label::set_halign(halignment value)
	{
		halign_ = value;
		on_state_changed();
	}

	void label::set_valign(valignment value)
	{
		valign_ = value;
		on_state_changed();
	}

	void label::set_multiline(multiline_mode value)
	{
		multiline_ = value;
		on_state_changed();
	}

	void label::set_overflow(overflow_mode value)
	{
		overflow_ = value;
		on_state_changed();
	}

	void label::reshape(geom::box<float, 2> const & bbox)
	{
		shape_.box = bbox;
		cached_state_.reset();
	}

	geom::box<float, 2> label::size_constraints() const
	{
		if (!cached_state_)
			update_cached_state();

		static float const inf = std::numeric_limits<float>::infinity();
		return {{{cached_state_->size[0], inf}, {cached_state_->size[1], inf}}};
	}

	void label::draw(painter & p) const
	{
		if (!cached_state_)
			update_cached_state();

		if (!cached_state_->font) return;

		auto st = style();
		if (!st) return;

		for (auto & g : cached_state_->glyphs)
			p.draw_glyph(*(cached_state_->font), g.character, g.position, st->text_color);
	}

	void label::on_state_changed()
	{
		cached_state_.reset();
		post_reshape();
	}

	void label::update_cached_state() const
	{
		cached_state_ = cached_state{};

		if (text_.empty()) return;

		auto st = style();
		if (!st) return;
		if (!st->font) return;

		cached_state_->font = st->font.get();

		shape_options opts;
		opts.scale = st->text_scale;
		cached_state_->glyphs = st->font->shape(text_, opts);

		geom::box<float, 2> bbox;
		for (auto const & g : cached_state_->glyphs)
			bbox |= g.position;

		int lines = 1;

		geom::vector<float, 2> offset;

		switch (halign_)
		{
		case halignment::left:
			offset[0] = shape_.box[0].min;
			break;
		case halignment::center:
			offset[0] = shape_.box[0].center() - bbox[0].length() / 2.f;
			break;
		case halignment::right:
			offset[0] = shape_.box[0].max - bbox[0].length();
			break;
		}

		switch (valign_)
		{
		case valignment::top:
			offset[1] = shape_.box[1].min;
			break;
		case valignment::center:
			offset[1] = shape_.box[1].center() - lines * st->text_scale * st->font->size()[1] / 2.f;
			break;
		case valignment::bottom:
			offset[1] = shape_.box[1].max - lines * st->text_scale * st->font->size()[1];
			break;
		}

		for (auto & g : cached_state_->glyphs)
			g.position += offset;

		cached_state_->size = bbox.dimensions();
	}

}