/*
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 "terrain_prop_job.h"

#include "../../defines.h"

#include "../../library/terrain_library.h"
#include "../../library/terrain_material_cache.h"
#include "../../library/terrain_surface.h"

#include "../../meshers/default/terrain_mesher_default.h"
#include "../../meshers/terrain_mesher.h"
#include "../default/terrain_chunk_default.h"
#include "scene/resources/world.h"
#include "servers/physics_server.h"

#ifdef MESH_DATA_RESOURCE_PRESENT
#include "../../../mesh_data_resource/mesh_data_resource.h"
#endif

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

#ifdef MESH_UTILS_PRESENT
#include "../../../mesh_utils/fast_quadratic_mesh_simplifier.h"
#endif

Ref<TerrainMesher> TerrainPropJob::get_prop_mesher() const {
	return _prop_mesher;
}
void TerrainPropJob::set_prop_mesher(const Ref<TerrainMesher> &mesher) {
	_prop_mesher = mesher;
}

Ref<TerrainMesherJobStep> TerrainPropJob::get_jobs_step(int index) const {
	ERR_FAIL_INDEX_V(index, _job_steps.size(), Ref<TerrainMesherJobStep>());

	return _job_steps.get(index);
}
void TerrainPropJob::set_jobs_step(int index, const Ref<TerrainMesherJobStep> &step) {
	ERR_FAIL_INDEX(index, _job_steps.size());

	_job_steps.set(index, step);
}
void TerrainPropJob::remove_jobs_step(const int index) {
	ERR_FAIL_INDEX(index, _job_steps.size());

	_job_steps.remove(index);
}
void TerrainPropJob::add_jobs_step(const Ref<TerrainMesherJobStep> &step) {
	_job_steps.push_back(step);
}
int TerrainPropJob::get_jobs_step_count() const {
	return _job_steps.size();
}

void TerrainPropJob::phase_physics_process() {
	ERR_FAIL_COND(!_chunk.is_valid());

	Ref<TerrainChunkDefault> chunk = _chunk;

	//TODO this should only update the differences
	for (int i = 0; i < chunk->collider_get_count(); ++i) {
		PhysicsServer::get_singleton()->free(chunk->collider_get_body(i));
	}

	chunk->colliders_clear();

#ifdef MESH_DATA_RESOURCE_PRESENT
	for (int i = 0; i < chunk->mesh_data_resource_get_count(); ++i) {
		Ref<MeshDataResource> mdr = chunk->mesh_data_resource_get(i);

		for (int j = 0; j < mdr->get_collision_shape_count(); ++j) {
			Ref<Shape> shape = mdr->get_collision_shape(j);
			Transform offset = mdr->get_collision_shape_offset(j);

			if (!shape.is_valid()) {
				continue;
			}

			RID body = PhysicsServer::get_singleton()->body_create(PhysicsServer::BODY_MODE_STATIC);

			Transform transform = chunk->mesh_data_resource_get_transform(i);
			transform *= offset;

			PhysicsServer::get_singleton()->body_add_shape(body, shape->get_rid());

			//TODO store the layer mask somewhere
			PhysicsServer::get_singleton()->body_set_collision_layer(body, 1);
			PhysicsServer::get_singleton()->body_set_collision_mask(body, 1);

			if (chunk->get_voxel_world()->is_inside_tree() && chunk->get_voxel_world()->is_inside_world()) {
				Ref<World> world = chunk->get_voxel_world()->get_world();

				if (world.is_valid() && world->get_space() != RID()) {
					PhysicsServer::get_singleton()->body_set_space(body, world->get_space());
				}
			}

			PhysicsServer::get_singleton()->body_set_state(body, PhysicsServer::BODY_STATE_TRANSFORM, chunk->get_transform() * transform);

			chunk->collider_add(transform, shape, shape->get_rid(), body);
		}
	}
#endif

#if TOOLS_ENABLED
	if (SceneTree::get_singleton()->is_debugging_collisions_hint() && chunk->collider_get_count() > 0) {
		chunk->draw_debug_mdr_colliders();
	}
#endif

	set_build_phase_type(BUILD_PHASE_TYPE_NORMAL);
	next_phase();
}

void TerrainPropJob::phase_prop() {
#ifdef MESH_DATA_RESOURCE_PRESENT
	Ref<TerrainChunkDefault> chunk = _chunk;

	if (!get_prop_mesher().is_valid()) {
		set_complete(true); //So threadpool knows it's done
		next_job();
		return;
	}

	if (should_do()) {
		if (chunk->mesh_data_resource_get_count() == 0) {
			reset_stages();
			set_complete(true); //So threadpool knows it's done
			next_job();
			return;
		}

		for (int i = 0; i < chunk->mesh_data_resource_get_count(); ++i) {
			if (chunk->mesh_data_resource_get_is_inside(i)) {
				get_prop_mesher()->add_mesh_data_resource_transform(chunk->mesh_data_resource_get(i), chunk->mesh_data_resource_get_transform(i), chunk->mesh_data_resource_get_uv_rect(i));
			}
		}

		if (should_return()) {
			return;
		}
	}

	if (should_do()) {
		if ((chunk->get_build_flags() & TerrainChunkDefault::BUILD_FLAG_USE_LIGHTING) != 0) {
			get_prop_mesher()->bake_colors(_chunk);
		}

		if (should_return()) {
			return;
		}
	}

	if (should_do()) {
		if ((chunk->get_build_flags() & TerrainChunkDefault::BUILD_FLAG_USE_LIGHTING) != 0) {
			TerrainWorldDefault *world = Object::cast_to<TerrainWorldDefault>(chunk->get_voxel_world());

			if (world) {
				for (int i = 0; i < chunk->mesh_data_resource_get_count(); ++i) {
					if (!chunk->mesh_data_resource_get_is_inside(i)) {
						Ref<MeshDataResource> mdr = chunk->mesh_data_resource_get(i);

						ERR_CONTINUE(!mdr.is_valid());

						Transform trf = chunk->mesh_data_resource_get_transform(i);

						Array arr = mdr->get_array();

						if (arr.size() <= Mesh::ARRAY_VERTEX) {
							continue;
						}

						PoolVector3Array varr = arr[Mesh::ARRAY_VERTEX];

						if (varr.size() == 0) {
							continue;
						}

						PoolColorArray carr = world->get_vertex_colors(trf, varr);

						get_prop_mesher()->add_mesh_data_resource_transform_colored(mdr, trf, carr, chunk->mesh_data_resource_get_uv_rect(i));
					}
				}
			}
		}
	}

	if (get_prop_mesher()->get_vertex_count() == 0) {
		reset_stages();

		set_complete(true); //So threadpool knows it's done
		next_job();
		return;
	}

#endif

	reset_stages();
	next_phase();
}

void TerrainPropJob::_physics_process(float delta) {
	if (_phase == 0)
		phase_physics_process();
}

void TerrainPropJob::_execute_phase() {
	ERR_FAIL_COND(!_chunk.is_valid());

	Ref<TerrainLibrary> library = _chunk->get_library();

	ERR_FAIL_COND(!library.is_valid());

	Ref<TerrainChunkDefault> chunk = _chunk;

	if (!chunk.is_valid()
#ifdef MESH_DATA_RESOURCE_PRESENT
			|| chunk->mesh_data_resource_get_count() == 0
#endif
	) {
		set_complete(true);
		next_job();
		return;
	}

	if (_phase == 1) {
		phase_setup();
	} else if (_phase == 2) {
		phase_prop();
	} else if (_phase == 3) {
		phase_steps();
	} else if (_phase > 3) {
		set_complete(true); //So threadpool knows it's done
		next_job();
		ERR_FAIL_MSG("TerrainPropJob: _phase is too high!");
	}
}

void TerrainPropJob::_reset() {
	TerrainJob::_reset();

	_build_done = false;
	_phase = 0;

	_current_job_step = 0;
	_current_mesh = 0;

	if (get_prop_mesher().is_valid()) {
		get_prop_mesher()->reset();
		get_prop_mesher()->set_library(_chunk->get_library());
	}

	set_build_phase_type(BUILD_PHASE_TYPE_PHYSICS_PROCESS);
}

void TerrainPropJob::phase_setup() {
	Ref<TerrainLibrary> library = _chunk->get_library();

	if (!library->supports_caching()) {
		next_phase();
		return;
	}

	if (library->supports_caching()) {
		if (!_chunk->prop_material_cache_key_has()) {
			library->prop_material_cache_get_key(_chunk);

			if (!_chunk->prop_material_cache_key_has()) {
				//chunk does not need a key
				next_phase();
				return;
			}
		}

		Ref<TerrainMaterialCache> cache = library->prop_material_cache_get(_chunk->prop_material_cache_key_get());

		//Note: without threadpool and threading none of this can happen, as cache will get initialized the first time a thread requests it!
		while (!cache->get_initialized()) {
			//Means it's currently merging the atlases on a different thread.
			//Let's just wait
			OS::get_singleton()->delay_usec(100);
		}

#if MESH_DATA_RESOURCE_PRESENT
		for (int i = 0; i < _chunk->mesh_data_resource_get_count(); ++i) {
			Ref<Texture> tex = _chunk->mesh_data_resource_get_texture(i);

			if (!tex.is_valid())
				continue;

			Rect2 r = cache->additional_texture_get_uv_rect(tex);

			_chunk->mesh_data_resource_set_uv_rect(i, r);
		}
#endif
	}

	next_phase();

	if (should_return()) {
		return;
	}
}

void TerrainPropJob::phase_steps() {
	Ref<TerrainChunkDefault> chunk = _chunk;

	ERR_FAIL_COND(!_prop_mesher.is_valid());

	if (should_return()) {
		return;
	}

	if (_prop_mesher->get_vertex_count() == 0) {
		reset_stages();
		//next_phase();
		set_complete(true); //So threadpool knows it's done
		next_job();

		return;
	}

	//set up the meshes
	if (should_do()) {
		RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, 0);

		if (mesh_rid == RID()) {
			//need to allocate the meshes

			//first count how many we need
			int count = 0;
			for (int i = 0; i < _job_steps.size(); ++i) {
				Ref<TerrainMesherJobStep> step = _job_steps[i];

				ERR_FAIL_COND(!step.is_valid());

				switch (step->get_job_type()) {
					case TerrainMesherJobStep::TYPE_NORMAL:
						++count;
						break;
					case TerrainMesherJobStep::TYPE_NORMAL_LOD:
						++count;
						break;
					case TerrainMesherJobStep::TYPE_DROP_UV2:
						++count;
						break;
					case TerrainMesherJobStep::TYPE_MERGE_VERTS:
						++count;
						break;
					case TerrainMesherJobStep::TYPE_BAKE_TEXTURE:
						++count;
						break;
					case TerrainMesherJobStep::TYPE_SIMPLIFY_MESH:
#ifdef MESH_UTILS_PRESENT
						count += step->get_simplification_steps();
#endif
						break;
					default:
						break;
				}
			}

			//allocate
			if (count > 0)
				chunk->meshes_create(TerrainChunkDefault::MESH_INDEX_PROP, count);

		} else {
			//we have the meshes, just clear
			int count = chunk->mesh_rid_get_count(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH);

			for (int i = 0; i < count; ++i) {
				mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, i);

				if (VS::get_singleton()->mesh_get_surface_count(mesh_rid) > 0)
					VS::get_singleton()->mesh_remove_surface(mesh_rid, 0);
			}
		}
	}

	for (; _current_job_step < _job_steps.size();) {
		Ref<TerrainMesherJobStep> step = _job_steps[_current_job_step];

		ERR_FAIL_COND(!step.is_valid());

		switch (step->get_job_type()) {
			case TerrainMesherJobStep::TYPE_NORMAL:
				step_type_normal();
				break;
			case TerrainMesherJobStep::TYPE_NORMAL_LOD:
				step_type_normal_lod();
				break;
			case TerrainMesherJobStep::TYPE_DROP_UV2:
				step_type_drop_uv2();
				break;
			case TerrainMesherJobStep::TYPE_MERGE_VERTS:
				step_type_merge_verts();
				break;
			case TerrainMesherJobStep::TYPE_BAKE_TEXTURE:
				step_type_bake_texture();
				break;
			case TerrainMesherJobStep::TYPE_SIMPLIFY_MESH:
				step_type_simplify_mesh();
				break;
			case TerrainMesherJobStep::TYPE_OTHER:
				//do nothing
				break;
		}

		++_current_job_step;

		if (should_return()) {
			return;
		}
	}

	reset_stages();
	//next_phase();

	set_complete(true); //So threadpool knows it's done
	next_job();
}

void TerrainPropJob::step_type_normal() {
	//TODO add a lighting generation step

	Ref<TerrainChunkDefault> chunk = _chunk;

	temp_mesh_arr = _prop_mesher->build_mesh();

	RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, _current_mesh);

	VS::get_singleton()->mesh_add_surface_from_arrays(mesh_rid, VisualServer::PRIMITIVE_TRIANGLES, temp_mesh_arr);

	Ref<Material> lmat;

	if (chunk->prop_material_cache_key_has()) {
		lmat = chunk->get_library()->prop_material_cache_get(_chunk->prop_material_cache_key_get())->material_lod_get(_current_mesh);
	} else {
		lmat = chunk->get_library()->prop_material_lod_get(_current_mesh);
	}

	if (lmat.is_valid()) {
		VisualServer::get_singleton()->mesh_surface_set_material(mesh_rid, 0, lmat->get_rid());
	}

	++_current_mesh;
}

void TerrainPropJob::step_type_normal_lod() {
	print_error("Error: step_type_normal_lod doesn't work for TerrainPropJobs!");

	++_current_mesh;
}

void TerrainPropJob::step_type_drop_uv2() {
	Ref<TerrainChunkDefault> chunk = _chunk;

	RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, _current_mesh);

	temp_mesh_arr[VisualServer::ARRAY_TEX_UV2] = Variant();

	VisualServer::get_singleton()->mesh_add_surface_from_arrays(mesh_rid, VisualServer::PRIMITIVE_TRIANGLES, temp_mesh_arr);

	Ref<Material> lmat;

	if (chunk->prop_material_cache_key_has()) {
		lmat = chunk->get_library()->prop_material_cache_get(_chunk->prop_material_cache_key_get())->material_lod_get(_current_mesh);
	} else {
		lmat = chunk->get_library()->prop_material_lod_get(_current_mesh);
	}

	if (lmat.is_valid()) {
		VisualServer::get_singleton()->mesh_surface_set_material(mesh_rid, 0, lmat->get_rid());
	}

	++_current_mesh;
}

void TerrainPropJob::step_type_merge_verts() {
	Array temp_mesh_arr2 = merge_mesh_array(temp_mesh_arr);
	temp_mesh_arr = temp_mesh_arr2;

	Ref<TerrainChunkDefault> chunk = _chunk;
	RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, _current_mesh);

	VisualServer::get_singleton()->mesh_add_surface_from_arrays(mesh_rid, VisualServer::PRIMITIVE_TRIANGLES, temp_mesh_arr);

	Ref<Material> lmat;

	if (chunk->prop_material_cache_key_has()) {
		lmat = chunk->get_library()->prop_material_cache_get(_chunk->prop_material_cache_key_get())->material_lod_get(_current_mesh);
	} else {
		lmat = chunk->get_library()->prop_material_lod_get(_current_mesh);
	}

	if (lmat.is_valid()) {
		VisualServer::get_singleton()->mesh_surface_set_material(mesh_rid, 0, lmat->get_rid());
	}

	++_current_mesh;
}

void TerrainPropJob::step_type_bake_texture() {
	Ref<TerrainChunkDefault> chunk = _chunk;

	Ref<Material> lmat;

	if (chunk->material_cache_key_has()) {
		lmat = chunk->get_library()->material_cache_get(_chunk->material_cache_key_get())->material_lod_get(_current_mesh);
	} else {
		lmat = chunk->get_library()->material_lod_get(_current_mesh);
	}

	Ref<ShaderMaterial> mat = lmat;
	Ref<SpatialMaterial> spmat = lmat;
	Ref<Texture> tex;

	if (mat.is_valid()) {
		tex = mat->get_shader_param("texture_albedo");
	} else if (spmat.is_valid()) {
		tex = spmat->get_texture(SpatialMaterial::TEXTURE_ALBEDO);
	}

	if (tex.is_valid()) {
		temp_mesh_arr = bake_mesh_array_uv(temp_mesh_arr, tex);
		temp_mesh_arr[VisualServer::ARRAY_TEX_UV] = Variant();

		RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, _current_mesh);

		VisualServer::get_singleton()->mesh_add_surface_from_arrays(mesh_rid, VisualServer::PRIMITIVE_TRIANGLES, temp_mesh_arr);

		if (lmat.is_valid()) {
			VisualServer::get_singleton()->mesh_surface_set_material(mesh_rid, 0, lmat->get_rid());
		}
	}

	++_current_mesh;
}

void TerrainPropJob::step_type_simplify_mesh() {
#ifdef MESH_UTILS_PRESENT

	Ref<TerrainChunkDefault> chunk = _chunk;
	Ref<TerrainMesherJobStep> step = _job_steps[_current_job_step];
	ERR_FAIL_COND(!step.is_valid());
	Ref<FastQuadraticMeshSimplifier> fqms = step->get_fqms();
	ERR_FAIL_COND(!fqms.is_valid());

	fqms->initialize(temp_mesh_arr);

	for (int i = 0; i < step->get_simplification_steps(); ++i) {
		fqms->simplify_mesh(temp_mesh_arr.size() * step->get_simplification_step_ratio(), step->get_simplification_agressiveness());
		temp_mesh_arr = fqms->get_arrays();

		RID mesh_rid = chunk->mesh_rid_get_index(TerrainChunkDefault::MESH_INDEX_PROP, TerrainChunkDefault::MESH_TYPE_INDEX_MESH, _current_mesh);

		VisualServer::get_singleton()->mesh_add_surface_from_arrays(mesh_rid, VisualServer::PRIMITIVE_TRIANGLES, temp_mesh_arr);

		Ref<Material> lmat;

		if (chunk->prop_material_cache_key_has()) {
			lmat = chunk->get_library()->prop_material_cache_get(_chunk->prop_material_cache_key_get())->material_lod_get(_current_mesh);
		} else {
			lmat = chunk->get_library()->prop_material_lod_get(_current_mesh);
		}

		if (lmat.is_valid()) {
			VisualServer::get_singleton()->mesh_surface_set_material(mesh_rid, 0, lmat->get_rid());
		}

		++_current_mesh;
	}

#endif
}

TerrainPropJob::TerrainPropJob() {
	set_build_phase_type(BUILD_PHASE_TYPE_PHYSICS_PROCESS);

	_current_job_step = 0;
	_current_mesh = 0;
}

TerrainPropJob::~TerrainPropJob() {
}

void TerrainPropJob::_bind_methods() {
	ClassDB::bind_method(D_METHOD("get_prop_mesher"), &TerrainPropJob::get_prop_mesher);
	ClassDB::bind_method(D_METHOD("set_prop_mesher", "mesher"), &TerrainPropJob::set_prop_mesher);
	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "prop_mesher", PROPERTY_HINT_RESOURCE_TYPE, "TerrainMesher", 0), "set_prop_mesher", "get_prop_mesher");

	ClassDB::bind_method(D_METHOD("get_jobs_step", "index"), &TerrainPropJob::get_jobs_step);
	ClassDB::bind_method(D_METHOD("set_jobs_step", "index", "mesher"), &TerrainPropJob::set_jobs_step);
	ClassDB::bind_method(D_METHOD("remove_jobs_step", "index"), &TerrainPropJob::remove_jobs_step);
	ClassDB::bind_method(D_METHOD("add_jobs_step", "mesher"), &TerrainPropJob::add_jobs_step);
	ClassDB::bind_method(D_METHOD("get_jobs_step_count"), &TerrainPropJob::get_jobs_step_count);

	ClassDB::bind_method(D_METHOD("_physics_process", "delta"), &TerrainPropJob::_physics_process);
}