/*
Copyright (c) 2019-2022 Péter Magyar

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#include "texture_layer_merger.h"

int TextureLayerMerger::get_width() const {
	return _width;
}

void TextureLayerMerger::set_width(const int p_value) {
	_width = p_value;
}

int TextureLayerMerger::get_height() const {
	return _height;
}

void TextureLayerMerger::set_height(const int p_value) {
	_height = p_value;
}

uint32_t TextureLayerMerger::get_texture_flags() const {
	return _texture_flags;
}
void TextureLayerMerger::set_texture_flags(uint32_t p_flags) {
	_texture_flags = p_flags;
}

Color TextureLayerMerger::get_base_color() const {
	return _base_color;
}
void TextureLayerMerger::set_base_color(const Color &p_color) {
	_base_color = p_color;
}

Ref<Image> TextureLayerMerger::get_data() const {
	return _image;
}

void TextureLayerMerger::set_data(const Ref<Image> &p_image) {
	ERR_FAIL_COND(p_image.is_null());

	_image = p_image;
}

Ref<ImageTexture> TextureLayerMerger::get_result_as_texture() const {
	ERR_FAIL_COND_V(!_image.is_valid(), Ref<ImageTexture>());

	Ref<ImageTexture> tex;
	tex.instance();
	tex->create_from_image(_image);

	return tex;
}

void TextureLayerMerger::add_texture(const Ref<Texture> &p_texture, const Color &p_color, const Vector2 &p_position, Rect2 p_rect) {
	ERR_FAIL_COND(!p_texture.is_valid());

	LayerMergerEntry entry;

	entry.texture = p_texture;
	entry.color = p_color;
	entry.position = p_position;

	if (p_rect.size.x <= 0)
		p_rect.size.x = p_texture->get_width();

	if (p_rect.size.y <= 0)
		p_rect.size.y = p_texture->get_height();

	entry.rect = p_rect;

	if (_width == 0 || _height == 0) {
		Ref<AtlasTexture> at = p_texture;

		int w = 0;
		int h = 0;

		if (at.is_valid()) {
			w = at->get_region().size.x;
			h = at->get_region().size.y;
		} else {
			w = p_texture->get_width();
			h = p_texture->get_height();
		}

		if (_width == 0)
			_width = w;

		if (_height == 0)
			_height = h;
	}

	_entries.push_back(entry);
}

Ref<Texture> TextureLayerMerger::get_texture(const int p_index) {
	ERR_FAIL_INDEX_V(p_index, _entries.size(), Ref<Texture>());

	return _entries.get(p_index).texture;
}
void TextureLayerMerger::set_texture(const int p_index, const Ref<Texture> &p_texture) {
	ERR_FAIL_INDEX(p_index, _entries.size());

	_entries.get(p_index).texture = p_texture;
}

Color TextureLayerMerger::get_color(const int p_index) {
	ERR_FAIL_INDEX_V(p_index, _entries.size(), Color());

	return _entries.get(p_index).color;
}
void TextureLayerMerger::set_color(const int p_index, const Color &p_color) {
	ERR_FAIL_INDEX(p_index, _entries.size());

	_entries.get(p_index).color = p_color;
}

Vector2 TextureLayerMerger::get_position(const int p_index) {
	ERR_FAIL_INDEX_V(p_index, _entries.size(), Vector2());

	return _entries.get(p_index).position;
}
void TextureLayerMerger::set_position(const int p_index, const Vector2 &p_position) {
	ERR_FAIL_INDEX(p_index, _entries.size());

	_entries.get(p_index).position = p_position;
}

Rect2 TextureLayerMerger::get_rect(const int p_index) {
	ERR_FAIL_INDEX_V(p_index, _entries.size(), Rect2());

	return _entries.get(p_index).rect;
}
void TextureLayerMerger::set_rect(const int p_index, const Rect2 &p_rect) {
	ERR_FAIL_INDEX(p_index, _entries.size());

	_entries.get(p_index).rect = p_rect;
}

void TextureLayerMerger::remove_texture(const int p_index) {
	ERR_FAIL_INDEX(p_index, _entries.size());

	return _entries.remove(p_index);
}

int TextureLayerMerger::get_texture_count() {
	return _entries.size();
}

void TextureLayerMerger::clear() {
	_entries.clear();
}

void TextureLayerMerger::merge() {
	ERR_FAIL_COND(_width <= 0 || _height <= 0);

	if (!_image.is_valid()) {
		_image.instance();
	}

	PoolVector<uint8_t> data;
	data.resize(_width * _height * 4);

	write_base_color_to_array(data);

	for (int i = 0; i < _entries.size(); ++i) {
		const LayerMergerEntry &e = _entries[i];

		ERR_CONTINUE(!e.texture.is_valid());

		int rx = e.rect.position.x + 0.1;
		int ry = e.rect.position.y + 0.1;
		int rw = e.rect.size.x + 0.1;
		int rh = e.rect.size.y + 0.1;

		int posx = e.position.x + 0.1;
		int posy = e.position.y + 0.1;

		int atlas_x = 0;
		int atlas_y = 0;

		if (posx > _width || posy > _height)
			continue;

		Ref<AtlasTexture> altas_texture = e.texture;
		Ref<Image> input_image;

		if (altas_texture.is_valid()) {
			Ref<Texture> atlas = altas_texture->get_atlas();

			ERR_CONTINUE(!atlas.is_valid());

			input_image = atlas->get_data();

			Rect2 region = altas_texture->get_region();

			atlas_x = region.position.x + 0.1;
			atlas_y = region.position.y + 0.1;

			int atlas_w = region.size.x + 0.1;
			int atlas_h = region.size.y + 0.1;

			if (rw > atlas_w)
				rw = atlas_w;

			if (rh > atlas_h)
				rh = atlas_h;
		} else {
			input_image = e.texture->get_data();
		}

		ERR_CONTINUE(!input_image.is_valid());

		int iiw = input_image->get_width();
		int iih = input_image->get_height();
		PoolVector<uint8_t> input_image_data = input_image->get_data();

		const Color &blendcolor = e.color;

		float blend_arr[] = {
			blendcolor.r,
			blendcolor.g,
			blendcolor.b,
			blendcolor.a
		};

		ERR_CONTINUE(iiw == 0 || iih == 0);
		ERR_CONTINUE(rx > iiw || ry > iih);

		//clamp width, and height if bigger (for ease of use)
		if (atlas_x + rx + rw >= iiw)
			rw -= (atlas_x + rx + rw) - iiw;

		if (atlas_y + ry + rh >= iih)
			rh -= (atlas_y + ry + rh) - iih;

		//Let's take position into account
		if (rx + rw + posx >= _width)
			rw -= (rx + rw + posx) - _width;

		if (ry + rh + posy >= _height)
			rh -= (ry + rh + posy) - _height;

		if (rw <= 0 || rh <= 0)
			continue;

		int elen = 0;

		if (input_image->get_format() == Image::FORMAT_RGBA8) {
			elen = 4;
		} else if (input_image->get_format() == Image::FORMAT_RGB8) {
			elen = 3;
		}

		ERR_CONTINUE_MSG(elen == 0, "Unsupported image format! Format: " + String::num(input_image->get_format()));

		for (int y = 0; y < rh; ++y) {
			int img_gen_index = (posx + ((y + posy) * _width)) * 4;
			int img_input_index = (rx + atlas_x + ((y + atlas_y + ry) * iiw)) * elen;

			for (int x = 0; x < rw; ++x) {
				float blend_alpha = blendcolor.a;

				if (elen == 4) {
					float orig_alpha = input_image_data.get(img_input_index + 3) / 255.0;

					blend_alpha -= 1.0 - orig_alpha;

					if (blend_alpha < 0)
						blend_alpha = 0;

					blend_alpha = orig_alpha;
				}

				for (int sp = 0; sp < elen; ++sp) {
					int main_index = img_gen_index + sp;

					int main_val = data.get(main_index);
					int input_val = input_image_data.get(img_input_index + sp);

					main_val = (input_val * blend_arr[sp]) * blend_alpha + (main_val * (1 - blend_alpha));

					if (main_val > 255)
						main_val = 255;

					data.set(main_index, main_val);
				}

				img_gen_index += 4;
				img_input_index += elen;
			}
		}
	}

	_image->create(_width, _height, (_texture_flags & Texture::FLAG_MIPMAPS) != 0, Image::FORMAT_RGBA8, data);
}

void TextureLayerMerger::write_base_color_to_array(PoolVector<uint8_t> &data) {
	int cr = _base_color.r * 255;
	int cg = _base_color.g * 255;
	int cb = _base_color.b * 255;
	int ca = _base_color.a * 255;

	for (int i = 0; i < data.size(); i += 4) {
		data.set(i, cr);
		data.set(i + 1, cg);
		data.set(i + 2, cb);
		data.set(i + 3, ca);
	}
}

void TextureLayerMerger::_bind_methods() {
	ClassDB::bind_method(D_METHOD("get_width"), &TextureLayerMerger::get_width);
	ClassDB::bind_method(D_METHOD("set_width", "image"), &TextureLayerMerger::set_width);
	ADD_PROPERTY(PropertyInfo(Variant::INT, "width"), "set_width", "get_width");

	ClassDB::bind_method(D_METHOD("get_height"), &TextureLayerMerger::get_height);
	ClassDB::bind_method(D_METHOD("set_height", "image"), &TextureLayerMerger::set_height);
	ADD_PROPERTY(PropertyInfo(Variant::INT, "height"), "set_height", "get_height");

	ClassDB::bind_method(D_METHOD("get_texture_flags"), &TextureLayerMerger::get_texture_flags);
	ClassDB::bind_method(D_METHOD("set_texture_flags", "image"), &TextureLayerMerger::set_texture_flags);
	ADD_PROPERTY(PropertyInfo(Variant::INT, "texture_flags", PROPERTY_HINT_FLAGS, "Mipmaps,Repeat,Filter"), "set_texture_flags", "get_texture_flags");

	ClassDB::bind_method(D_METHOD("get_base_color"), &TextureLayerMerger::get_base_color);
	ClassDB::bind_method(D_METHOD("set_base_color", "color"), &TextureLayerMerger::set_base_color);
	ADD_PROPERTY(PropertyInfo(Variant::COLOR, "base_color"), "set_base_color", "get_base_color");

	ClassDB::bind_method(D_METHOD("get_data"), &TextureLayerMerger::get_data);
	ClassDB::bind_method(D_METHOD("set_data", "image"), &TextureLayerMerger::set_data);
	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "data", PROPERTY_HINT_RESOURCE_TYPE, "Image"), "set_data", "get_data");

	ClassDB::bind_method(D_METHOD("get_result_as_texture"), &TextureLayerMerger::get_result_as_texture);

	ClassDB::bind_method(D_METHOD("add_texture", "texture", "color", "position", "rect"), &TextureLayerMerger::add_texture, DEFVAL(Color(1, 1, 1, 1)), DEFVAL(Vector2()), DEFVAL(Rect2()));

	ClassDB::bind_method(D_METHOD("get_texture", "index"), &TextureLayerMerger::get_texture);
	ClassDB::bind_method(D_METHOD("set_texture", "index", "texture"), &TextureLayerMerger::set_texture);

	ClassDB::bind_method(D_METHOD("get_color", "index"), &TextureLayerMerger::get_color);
	ClassDB::bind_method(D_METHOD("set_color", "index", "color"), &TextureLayerMerger::set_color);

	ClassDB::bind_method(D_METHOD("get_position", "index"), &TextureLayerMerger::get_position);
	ClassDB::bind_method(D_METHOD("set_position", "index", "position"), &TextureLayerMerger::set_position);

	ClassDB::bind_method(D_METHOD("get_rect", "index"), &TextureLayerMerger::get_rect);
	ClassDB::bind_method(D_METHOD("set_rect", "index", "rect"), &TextureLayerMerger::set_rect);

	ClassDB::bind_method(D_METHOD("remove_texture", "index"), &TextureLayerMerger::remove_texture);
	ClassDB::bind_method(D_METHOD("get_texture_count"), &TextureLayerMerger::get_texture_count);
	ClassDB::bind_method(D_METHOD("clear"), &TextureLayerMerger::clear);

	ClassDB::bind_method(D_METHOD("merge"), &TextureLayerMerger::merge);
}

TextureLayerMerger::TextureLayerMerger() {
	_width = 0;
	_height = 0;

	_texture_flags = 0;
}

TextureLayerMerger::~TextureLayerMerger() {
	_image.unref();
	_entries.clear();
}