/* Copyright 2015, Michele Santullo
 * This file is part of DoorKeeper.
 *
 * DoorKeeper is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * DoorKeeper is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with DoorKeeper.  If not, see <http://www.gnu.org/licenses/>.
 */

namespace dk {
	template <uint32_t D>
	Viewport<D>::Viewport (Tyler<D>& parTyler) :
		m_tyler(parTyler),
		m_pixel_offset(0)
	{
	}

	template <uint32_t D>
	Viewport<D>::Viewport (Tyler<D>& parTyler, const coords& parSize, const coords& parPos) :
		m_view(parPos, parSize - 1),
		m_tyler(parTyler),
		m_pixel_offset(0)
	{
		DK_ASSERT(parPos < parPos + parSize); //parSize > 0
		DK_ASSERT(parSize + parPos <= parTyler.map_size());
		m_tyler.preload(m_view.position(), m_view.position() + this->size());
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::iterator Viewport<D>::begin (Layer<T, D>& parLayer) const {
		typedef typename Layer<T, D>::iterator IterType;
		return IterType(&parLayer.m_tiles, parLayer.m_tilemap->pixel_conv(), m_view.position(), m_view.upper());
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::iterator Viewport<D>::end (Layer<T, D>& parLayer) const {
		typedef typename Layer<T, D>::iterator IterType;
		return IterType(&parLayer.m_tiles, parLayer.m_tilemap->pixel_conv(), make_past_end_coords<D>(m_view.upper()), make_past_end_coords<D>(m_view.upper()));
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::const_iterator Viewport<D>::begin (const Layer<T, D>& parLayer) const {
		return this->cbegin(parLayer);
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::const_iterator Viewport<D>::end (const Layer<T, D>& parLayer) const {
		return this->cend(parLayer);
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::const_iterator Viewport<D>::cbegin (const Layer<T, D>& parLayer) const {
		typedef typename Layer<T, D>::const_iterator IterType;
		return IterType(&parLayer.m_tiles, parLayer.m_tilemap->pixel_conv(), m_view.position(), m_view.upper());
	}

	template <uint32_t D>
	template <typename T>
	typename Layer<T, D>::const_iterator Viewport<D>::cend (const Layer<T, D>& parLayer) const {
		typedef typename Layer<T, D>::const_iterator IterType;
		return IterType(&parLayer.m_tiles, parLayer.m_tilemap->pixel_conv(), make_past_end_coords<D>(m_view.upper()), make_past_end_coords<D>(m_view.upper()));
	}

	template <uint32_t D>
	void Viewport<D>::setFrom (const coords& parFrom) {
		DK_ASSERT(this->size() + parFrom <= m_tyler.map_size());
		m_view.set_position(parFrom);
		m_tyler.preload(m_view.position(), m_view.position() + this->size());
	}

	template <uint32_t D>
	typename Viewport<D>::coords Viewport<D>::size() const {
		return (m_view.upper() + 1);
	}

	template <uint32_t D>
	Viewport<D>& Viewport<D>::operator+= (const coords_f& parValue) {
		m_pixel_offset += parValue;
		clip_pixel_offset();
		return *this;
	}

	template <uint32_t D>
	Viewport<D>& Viewport<D>::operator-= (const coords_f& parValue) {
		m_pixel_offset -= parValue;
		clip_pixel_offset();
		return *this;
	}

	template <uint32_t D>
	void Viewport<D>::clip_pixel_offset() {
		const auto& tile_size = m_tyler.tile_size();
		for (uint32_t z = 0; z < D; ++z) {
			auto offs = static_cast<CoordinateScalarType>(m_pixel_offset[z]);
			if (std::abs(offs) >= tile_size[z]) {
				auto curr_tile_size_f = static_cast<CoordinateAccumType>(tile_size[z]);
				if (offs < 0) {
					do {
						offs += tile_size[z];
						m_pixel_offset[z] += curr_tile_size_f;
						--m_view;
					} while(offs >= tile_size[z]);
				}
				else {
					DK_ASSERT(offs > 0);
					do {
						offs -= tile_size[z];
						m_pixel_offset[z] -= curr_tile_size_f;
						++m_view;
					} while(offs >= tile_size[z]);
				}
			}
		}
	}

	template <uint32_t D>
	auto Viewport<D>::pixel_offset() const -> coords {
		return static_cast<coords>(m_pixel_offset);
	}
} //namespace dk