#include "voxel_block.h"
#include "../util/zprofiling.h"
#include <scene/3d/spatial.h>
#include <scene/resources/concave_polygon_shape.h>

// Faster version of Mesh::create_trimesh_shape()
// See https://github.com/Zylann/godot_voxel/issues/54
//
static Ref<ConcavePolygonShape> create_concave_polygon_shape(Array surface_arrays) {

	PoolVector<Vector3> positions = surface_arrays[Mesh::ARRAY_VERTEX];
	PoolVector<int> indices = surface_arrays[Mesh::ARRAY_INDEX];

	ERR_FAIL_COND_V(positions.size() < 3, Ref<ConcavePolygonShape>());
	ERR_FAIL_COND_V(indices.size() < 3, Ref<ConcavePolygonShape>());
	ERR_FAIL_COND_V(indices.size() % 3 != 0, Ref<ConcavePolygonShape>());

	int face_points_count = indices.size();
	int face_count = face_points_count / 3;

	PoolVector<Vector3> face_points;
	face_points.resize(face_points_count);

	{
		PoolVector<Vector3>::Write w = face_points.write();
		PoolVector<int>::Read index_r = indices.read();
		PoolVector<Vector3>::Read position_r = positions.read();

		for (int i = 0; i < face_points_count; ++i) {
			w[i] = position_r[index_r[i]];
		}
	}

	Ref<ConcavePolygonShape> shape = memnew(ConcavePolygonShape);
	shape->set_faces(face_points);
	return shape;
}

// Helper
VoxelBlock *VoxelBlock::create(Vector3i bpos, Ref<VoxelBuffer> buffer, unsigned int size, unsigned int p_lod_index) {
	const int bs = size;
	ERR_FAIL_COND_V(buffer.is_null(), NULL);
	ERR_FAIL_COND_V(buffer->get_size() != Vector3i(bs, bs, bs), NULL);

	VoxelBlock *block = memnew(VoxelBlock);
	block->position = bpos;
	block->lod_index = p_lod_index;
	block->_position_in_voxels = bpos * (size << p_lod_index);
	block->voxels = buffer;

	return block;
}

VoxelBlock::VoxelBlock() {
}

VoxelBlock::~VoxelBlock() {
}

void VoxelBlock::set_mesh(Ref<Mesh> mesh, Spatial *node, bool generate_collision, Array surface_arrays, bool debug_collision) {
	// TODO Don't add mesh instance to the world if it's not visible.
	// I suspect Godot is trying to include invisible mesh instances into the culling process,
	// which is killing performance when LOD is used (i.e many meshes are in pool but hidden)
	// This needs investigation.

	if (mesh.is_valid()) {

		ERR_FAIL_COND(node == nullptr);
		Ref<World> world = node->get_world();
		ERR_FAIL_COND(world.is_null());

		if (!_mesh_instance.is_valid()) {
			// Create instance if it doesn't exist
			_mesh_instance.create();
			_mesh_instance.set_world(*world);
			_mesh_instance.set_visible(_visible);
		}

		Transform transform(Basis(), _position_in_voxels.to_vec3());

		_mesh_instance.set_mesh(mesh);
		_mesh_instance.set_transform(transform);
		// TODO The day VoxelTerrain becomes a Spatial, this transform will need to be updatable separately

		if (generate_collision) {
			Ref<Shape> shape = create_concave_polygon_shape(surface_arrays);

			if (!_static_body.is_valid()) {
				_static_body.create();
				_static_body.set_world(*world);
				_static_body.set_attached_object(node);
				_static_body.set_transform(transform);
			} else {
				_static_body.remove_shape(0);
			}
			_static_body.add_shape(shape);
			_static_body.set_debug(debug_collision, *world);
			_static_body.set_shape_enabled(0, _visible);
		}

	} else {

		if (_mesh_instance.is_valid()) {
			// Delete instance if it exists
			_mesh_instance.destroy();
		}

		if (_static_body.is_valid()) {
			_static_body.destroy();
		}
	}

	++_mesh_update_count;

	//	if(_mesh_update_count > 1) {
	//		print_line(String("Block {0} was updated {1} times").format(varray(pos.to_vec3(), _mesh_update_count)));
	//	}
}

bool VoxelBlock::has_mesh() const {
	return _mesh_instance.get_mesh().is_valid();
}

void VoxelBlock::set_mesh_state(MeshState ms) {
	_mesh_state = ms;
}

VoxelBlock::MeshState VoxelBlock::get_mesh_state() const {
	return _mesh_state;
}

void VoxelBlock::set_world(World *world) {
	if (_mesh_instance.is_valid()) {
		_mesh_instance.set_world(world);
	}
	if (_static_body.is_valid()) {
		_static_body.set_world(world);
	}
}

void VoxelBlock::set_visible(bool visible) {
	if (_visible && visible) {
		return;
	}
	_visible = visible;
	_set_visible(_visible && _parent_visible);
}

bool VoxelBlock::is_visible() const {
	return _visible;
}

void VoxelBlock::_set_visible(bool visible) {
	if (_mesh_instance.is_valid()) {
		_mesh_instance.set_visible(visible);
	}
	if (_static_body.is_valid()) {
		_static_body.set_shape_enabled(0, visible);
	}
}

void VoxelBlock::set_parent_visible(bool parent_visible) {
	if (_parent_visible && parent_visible) {
		return;
	}
	_parent_visible = parent_visible;
	_set_visible(_visible && _parent_visible);
}

void VoxelBlock::set_needs_lodding(bool need_lodding) {
	_needs_lodding = need_lodding;
}

bool VoxelBlock::is_modified() const {
	return _modified;
}

void VoxelBlock::set_modified(bool modified) {
	//	if (_modified != modified) {
	//		print_line(String("Marking block {0}[lod{1}] as modified").format(varray(bpos.to_vec3(), lod_index)));
	//	}
	_modified = modified;
}