/*
Copyright (c) 2019-2020 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 "voxel_mesher_blocky.h"

#include "../../world/default/voxel_chunk_default.h"

bool VoxelMesherBlocky::get_always_add_colors() const {
	return _always_add_colors;
}
void VoxelMesherBlocky::set_always_add_colors(const bool value) {
	_always_add_colors = value;
}

void VoxelMesherBlocky::_add_chunk(Ref<VoxelChunk> p_chunk) {
	Ref<VoxelChunkDefault> chunk = p_chunk;

	ERR_FAIL_COND(!chunk.is_valid());

	//if ((get_build_flags() & VoxelChunkDefault::BUILD_FLAG_GENERATE_AO) != 0)
	//	if (!chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_AO))
	//		chunk->generate_ao();

	int x_size = chunk->get_size_x();
	int y_size = chunk->get_size_y();
	int z_size = chunk->get_size_z();

	float voxel_scale = get_voxel_scale();

	uint8_t *channel_type = chunk->get_channel(_channel_index_type);

	if (!channel_type)
		return;

	uint8_t *channel_color_r = NULL;
	uint8_t *channel_color_g = NULL;
	uint8_t *channel_color_b = NULL;
	uint8_t *channel_ao = NULL;
	uint8_t *channel_rao = NULL;

	Color base_light(_base_light_value, _base_light_value, _base_light_value);
	Color light(1, 1, 1);
	bool use_lighting = (get_build_flags() & VoxelChunkDefault::BUILD_FLAG_USE_LIGHTING) != 0;
	bool use_ao = (get_build_flags() & VoxelChunkDefault::BUILD_FLAG_USE_AO) != 0;
	bool use_rao = (get_build_flags() & VoxelChunkDefault::BUILD_FLAG_USE_RAO) != 0;

	if (use_lighting) {
		channel_color_r = chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_LIGHT_COLOR_R);
		channel_color_g = chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_LIGHT_COLOR_G);
		channel_color_b = chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_LIGHT_COLOR_B);

		if (use_ao)
			channel_ao = chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_AO);

		if (use_rao)
			channel_rao = chunk->get_channel(VoxelChunkDefault::DEFAULT_CHANNEL_RANDOM_AO);
	}

	Vector<uint8_t> liquids;
	for (int i = 0; i < _library->get_num_surfaces(); ++i) {
		Ref<VoxelSurface> surface = _library->get_voxel_surface(i);

		if (!surface.is_valid())
			continue;

		if (surface->get_liquid())
			liquids.push_back(static_cast<uint8_t>(i + 1));
	}

	for (int y = chunk->get_margin_start(); y < y_size + chunk->get_margin_start(); ++y) {
		for (int z = chunk->get_margin_start(); z < z_size + chunk->get_margin_start(); ++z) {
			for (int x = chunk->get_margin_start(); x < x_size + chunk->get_margin_start(); ++x) {

				int index = chunk->get_data_index(x, y, z);
				int indexxp = chunk->get_data_index(x + 1, y, z);
				int indexxn = chunk->get_data_index(x - 1, y, z);
				int indexyp = chunk->get_data_index(x, y + 1, z);
				int indexyn = chunk->get_data_index(x, y - 1, z);
				int indexzp = chunk->get_data_index(x, y, z + 1);
				int indexzn = chunk->get_data_index(x, y, z - 1);

				uint8_t type = channel_type[index];

				if (type == 0)
					continue;

				if (liquids.find(type) != -1)
					continue;

				Ref<VoxelSurface> surface = _library->get_voxel_surface(type - 1);

				if (!surface.is_valid())
					continue;

				uint8_t neighbours[] = {
					channel_type[indexxp],
					channel_type[indexxn],
					channel_type[indexyp],
					channel_type[indexyn],
					channel_type[indexzp],
					channel_type[indexzn],
				};

				for (int i = 0; i < 6; ++i) {
					if (liquids.find(neighbours[i]) != -1) {
						neighbours[i] = 0;
					}
				}

				//x + 1
				if (neighbours[0] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexxp] / 255.0,
								channel_color_g[indexxp] / 255.0,
								channel_color_b[indexxp] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexxp] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexxp] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;

						light.r = CLAMP(light.r, 0, 1.0);
						light.g = CLAMP(light.g, 0, 1.0);
						light.b = CLAMP(light.b, 0, 1.0);
					}

					int vc = get_vertex_count();
					add_indices(vc + 2);
					add_indices(vc + 1);
					add_indices(vc + 0);
					add_indices(vc + 3);
					add_indices(vc + 2);
					add_indices(vc + 0);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(1, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(1, 0, 0));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}

				//x - 1
				if (neighbours[1] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexxn] / 255.0,
								channel_color_g[indexxn] / 255.0,
								channel_color_b[indexxn] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexxn] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexxn] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;

						light.r = CLAMP(light.r, 0, 1.0);
						light.g = CLAMP(light.g, 0, 1.0);
						light.b = CLAMP(light.b, 0, 1.0);
					}

					int vc = get_vertex_count();
					add_indices(vc + 0);
					add_indices(vc + 1);
					add_indices(vc + 2);

					add_indices(vc + 0);
					add_indices(vc + 2);
					add_indices(vc + 3);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(0, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(-1, 0, 0));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}

				//y + 1
				if (neighbours[2] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexyp] / 255.0,
								channel_color_g[indexyp] / 255.0,
								channel_color_b[indexyp] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexyp] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexyp] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;
					}

					light.r = CLAMP(light.r, 0, 1.0);
					light.g = CLAMP(light.g, 0, 1.0);
					light.b = CLAMP(light.b, 0, 1.0);

					int vc = get_vertex_count();
					add_indices(vc + 2);
					add_indices(vc + 1);
					add_indices(vc + 0);
					add_indices(vc + 3);
					add_indices(vc + 2);
					add_indices(vc + 0);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(1, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(0, 1, 0));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}

				//y - 1
				if (neighbours[3] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexyn] / 255.0,
								channel_color_g[indexyn] / 255.0,
								channel_color_b[indexyn] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexyn] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexyn] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;
					}

					light.r = CLAMP(light.r, 0, 1.0);
					light.g = CLAMP(light.g, 0, 1.0);
					light.b = CLAMP(light.b, 0, 1.0);

					int vc = get_vertex_count();
					add_indices(vc + 0);
					add_indices(vc + 1);
					add_indices(vc + 2);

					add_indices(vc + 0);
					add_indices(vc + 2);
					add_indices(vc + 3);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(1, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(0, -1, 0));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}

				//z + 1
				if (neighbours[4] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexzp] / 255.0,
								channel_color_g[indexzp] / 255.0,
								channel_color_b[indexzp] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexzp] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexzp] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;

						light.r = CLAMP(light.r, 0, 1.0);
						light.g = CLAMP(light.g, 0, 1.0);
						light.b = CLAMP(light.b, 0, 1.0);
					}

					int vc = get_vertex_count();
					add_indices(vc + 2);
					add_indices(vc + 1);
					add_indices(vc + 0);
					add_indices(vc + 3);
					add_indices(vc + 2);
					add_indices(vc + 0);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(1, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 0, 1) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(0, 0, 1));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}

				//z - 1
				if (neighbours[5] == 0) {
					if (use_lighting) {
						light = Color(channel_color_r[indexzn] / 255.0,
								channel_color_g[indexzn] / 255.0,
								channel_color_b[indexzn] / 255.0);

						float ao = 0;

						if (use_ao)
							ao = channel_ao[indexzn] / 255.0;

						if (use_rao) {
							float rao = channel_rao[indexzn] / 255.0;
							ao += rao;
						}

						light += base_light;

						if (ao > 0)
							light -= Color(ao, ao, ao) * _ao_strength;

						light.r = CLAMP(light.r, 0, 1.0);
						light.g = CLAMP(light.g, 0, 1.0);
						light.b = CLAMP(light.b, 0, 1.0);
					}

					int vc = get_vertex_count();
					add_indices(vc + 0);
					add_indices(vc + 1);
					add_indices(vc + 2);

					add_indices(vc + 0);
					add_indices(vc + 2);
					add_indices(vc + 3);

					Vector2 uvs[] = {
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(0, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 0), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale()),
						surface->transform_uv_scaled(VoxelSurface::VOXEL_SIDE_SIDE, Vector2(1, 1), x % get_texture_scale(), z % get_texture_scale(), get_texture_scale())
					};

					Vector3 verts[] = {
						Vector3(1, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(1, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 1, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale,
						Vector3(0, 0, 0) * voxel_scale + Vector3(x - 1, y - 1, z - 1) * voxel_scale
					};

					for (int i = 0; i < 4; ++i) {
						add_normal(Vector3(0, 0, -1));

						if (use_lighting || _always_add_colors)
							add_color(light);

						add_uv(uvs[i]);
						add_vertex(verts[i]);
					}
				}
			}
		}
	}
}

VoxelMesherBlocky::VoxelMesherBlocky() {
	_always_add_colors = false;
}

VoxelMesherBlocky::~VoxelMesherBlocky() {
}

void VoxelMesherBlocky::_bind_methods() {
	ClassDB::bind_method(D_METHOD("_add_chunk", "buffer"), &VoxelMesherBlocky::_add_chunk);

	ClassDB::bind_method(D_METHOD("get_always_add_colors"), &VoxelMesherBlocky::get_always_add_colors);
	ClassDB::bind_method(D_METHOD("set_always_add_colors", "value"), &VoxelMesherBlocky::set_always_add_colors);
	ADD_PROPERTY(PropertyInfo(Variant::INT, "always_add_colors"), "set_always_add_colors", "get_always_add_colors");
}