#ifndef VOXEL_TERRAIN_H
#define VOXEL_TERRAIN_H

#include "vector3i.h"
#include "zprofiling.h"
#include "voxel_provider.h"
#include "voxel_provider_thread.h"
#include "voxel_mesh_updater.h"
#include "rect3i.h"

#include <scene/3d/spatial.h>

class VoxelMap;
class VoxelLibrary;

// Infinite static terrain made of voxels.
// It is loaded around VoxelTerrainStreamers.
class VoxelTerrain : public Spatial /*, public IVoxelMapObserver*/ {
	GDCLASS(VoxelTerrain, Spatial)
public:

	enum BlockDirtyState {
		BLOCK_NONE,
		BLOCK_LOAD,
		BLOCK_UPDATE_NOT_SENT,
		BLOCK_UPDATE_SENT,
		BLOCK_IDLE
	};

	VoxelTerrain();
	~VoxelTerrain();

	void set_provider(Ref<VoxelProvider> provider);
	Ref<VoxelProvider> get_provider() const;

	void set_voxel_library(Ref<VoxelLibrary> library);
	Ref<VoxelLibrary> get_voxel_library() const;

	void make_block_dirty(Vector3i bpos);
	//void make_blocks_dirty(Vector3i min, Vector3i size);
	void make_voxel_dirty(Vector3i pos);
	bool is_block_dirty(Vector3i bpos) const;

	void set_generate_collisions(bool enabled);
	bool get_generate_collisions() const { return _generate_collisions; }

	int get_view_distance() const;
	void set_view_distance(int distance_in_voxels);

	void set_viewer_path(NodePath path);
	NodePath get_viewer_path() const;

	void set_material(int id, Ref<Material> material);
	Ref<Material> get_material(int id) const;

	Ref<VoxelMap> get_map() { return _map; }

	struct Stats {
		VoxelMeshUpdater::Stats updater;
		VoxelProviderThread::Stats provider;
		uint32_t mesh_alloc_time;
		int updated_blocks;
		int dropped_provider_blocks;
		int dropped_updater_blocks;
		int remaining_main_thread_blocks;

		Stats():
			mesh_alloc_time(0),
			updated_blocks(0),
			dropped_provider_blocks(0),
			dropped_updater_blocks(0),
			remaining_main_thread_blocks(0)
		{ }
	};

protected:
	void _notification(int p_what);

private:
	bool _set(const StringName &p_name, const Variant &p_value);
	bool _get(const StringName &p_name, Variant &r_ret) const;
	void _get_property_list(List<PropertyInfo> *p_list) const;

	void _process();

	void make_all_view_dirty_deferred();

	Spatial *get_viewer(NodePath path) const;

	void immerge_block(Vector3i bpos);

	Dictionary get_statistics() const;

	static void _bind_methods();

	// Convenience
	Vector3 _voxel_to_block_binding(Vector3 pos);
	Vector3 _block_to_voxel_binding(Vector3 pos);
	//void _force_load_blocks_binding(Vector3 center, Vector3 extents) { force_load_blocks(center, extents); }
	//void _make_block_dirty_binding(Vector3 bpos) { make_block_dirty(bpos); }
	//void _make_blocks_dirty_binding(Vector3 min, Vector3 size) { make_blocks_dirty(min, size); }
	void _make_voxel_dirty_binding(Vector3 pos) { make_voxel_dirty(pos); }

	Variant _raycast_binding(Vector3 origin, Vector3 direction, real_t max_distance);

	void set_voxel(Vector3 pos, int value, int c);
	int get_voxel(Vector3 pos, int c);
	BlockDirtyState get_block_state(Vector3 p_bpos) const;

	static void remove_positions_outside_box(Vector<Vector3i> &positions, Rect3i box, HashMap<Vector3i, BlockDirtyState, Vector3iHasher> &state_map);

private:
	// Voxel storage
	Ref<VoxelMap> _map;

	// How many blocks to load around the viewer
	int _view_distance_blocks;

	// TODO Terrains only need to handle the visible portion of voxels, which reduces the bounds blocks to handle.
	// Therefore, could a simple grid be better to use than a hashmap?

	Vector<Vector3i> _blocks_pending_load;
	Vector<Vector3i> _blocks_pending_update;
	HashMap<Vector3i, BlockDirtyState, Vector3iHasher> _dirty_blocks; // TODO Rename _block_states
	Vector<VoxelMeshUpdater::OutputBlock> _blocks_pending_main_thread_update;

	Ref<VoxelProvider> _provider;
	VoxelProviderThread *_provider_thread;

	Ref<VoxelLibrary> _library;
	VoxelMeshUpdater *_block_updater;

	NodePath _viewer_path;
	Vector3i _last_viewer_block_pos;
	int _last_view_distance_blocks;

	bool _generate_collisions;

	Ref<Material> _materials[VoxelMesher::MAX_MATERIALS];

	Stats _stats;
};

VARIANT_ENUM_CAST(VoxelTerrain::BlockDirtyState)

#endif // VOXEL_TERRAIN_H