// Copyright (C) 2002-2008 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#ifndef __I_MESH_CACHE_H_INCLUDED__
#define __I_MESH_CACHE_H_INCLUDED__

#include "IReferenceCounted.h"
#include "irrString.h"

namespace irr
{

namespace scene
{
	class IMesh;
	class IAnimatedMesh;
	class IAnimatedMeshSceneNode;
	class IMeshLoader;

	//! The mesh cache stores already loaded meshes and provides an interface to them.
	/** You can access it using ISceneManager::getMeshCache(). All existing
	scene managers will return a pointer to the same mesh cache, because it
	is shared between them. With this interface, it is possible to manually
	add new loaded meshes (if ISceneManager::getMesh() is not sufficient),
	to remove them and to iterate through already loaded meshes. */
	class IMeshCache : public virtual IReferenceCounted
	{
	public:

		//! Destructor
		virtual ~IMeshCache() {}

		//! Adds a mesh to the internal list of loaded meshes.
		/** Usually, ISceneManager::getMesh() is called to load a mesh
		from a file. That method searches the list of loaded meshes if
		a mesh has already been loaded and returns a pointer to if it
		is in that list and already in memory. Otherwise it loads the
		mesh. With IMeshCache::addMesh(), it is possible to pretend
		that a mesh already has been loaded. This method can be used
		for example by mesh loaders who need to load more than one mesh
		with one call. They can add additional meshes with this method
		to the scene manager. The COLLADA loader for example uses this
		method.
		\param filename Filename of the mesh. When calling
		ISceneManager::getMesh() with this name it will return the mesh
		set by this method.
		\param mesh Pointer to a mesh which will now be referenced by
		this name. */
		virtual void addMesh(const c8* filename, IAnimatedMesh* mesh) = 0;

		//! Removes a mesh from the cache.
		/** After loading a mesh with getMesh(), the mesh can be
		removed from the cache using this method, freeing a lot of
		memory.
		\param mesh Pointer to the mesh which shall be removed. */
		virtual void removeMesh(const IAnimatedMesh* const mesh) = 0;

		//! Removes a mesh from the cache.
		/** After loading a mesh with getMesh(), the mesh can be
		removed from the cache using this method, freeing a lot of
		memory.
		\param mesh Pointer to the mesh which shall be removed. */
		virtual void removeMesh(const IMesh* const mesh) = 0;

		//! Returns amount of loaded meshes in the cache.
		/** You can load new meshes into the cache using getMesh() and
		addMesh(). If you ever need to access the internal mesh cache,
		you can do this using removeMesh(), getMeshNumber(),
		getMeshByIndex() and getMeshFilename().
		\return Number of meshes in cache. */
		virtual u32 getMeshCount() const = 0;

		//! Returns current index number of the mesh, and -1 if it is not in the cache.
		/** \param mesh Pointer to the mesh to search for.
		\return Index of the mesh in the cache, or -1 if not found. */
		virtual s32 getMeshIndex(const IAnimatedMesh* const mesh) const = 0;

		//! Returns current index number of the mesh, and -1 if it is not in the cache.
		/** \param mesh Pointer to the mesh to search for.
		\return Index of the mesh in the cache, or -1 if not found. */
		virtual s32 getMeshIndex(const IMesh* const mesh) const = 0;

		//! Returns a mesh based on its index number.
		/** \param index: Index of the mesh, number between 0 and
		getMeshCount()-1.
		Note that this number is only valid until a new mesh is loaded
		or removed.
		\return Pointer to the mesh or 0 if there is none with this
		number. */
		virtual IAnimatedMesh* getMeshByIndex(u32 index) = 0;

		//! Returns a mesh based on its filename.
		/** \param filename Name of the mesh.
		\return Pointer to the mesh or 0 if there is none with this number. */
		virtual IAnimatedMesh* getMeshByFilename(const c8* filename) = 0;

		//! Get the filename of a loaded mesh, based on its index.
		/** \param index: Index of the mesh, number between 0 and getMeshCount()-1.
		\return String with name if mesh was found and has a name, else
		0. */
		virtual const c8* getMeshFilename(u32 index) const = 0;

		//! Get the filename of a loaded mesh, if there is any.
		/** \param mesh Pointer to mesh to query.
		\return String with name if mesh was found and has a name, else
		0. */
		virtual const c8* getMeshFilename(const IAnimatedMesh* const mesh) const = 0;

		//! Get the filename of a loaded mesh, if there is any.
		/** \param mesh Pointer to mesh to query.
		\return String with name if mesh was found and has a name, else
		0. */
		virtual const c8* getMeshFilename(const IMesh* const mesh) const = 0;

		//! Renames a loaded mesh.
		/** Note that renaming meshes might change the ordering of the
		meshes, and so the index of the meshes as returned by
		getMeshIndex() or taken by some methods will change.
		\param index The index of the mesh in the cache.
		\param filename New name for the mesh.
		\return True if mesh was renamed. */
		virtual bool setMeshFilename(u32 index, const c8* filename) = 0;

		//! Renames a loaded mesh.
		/** Note that renaming meshes might change the ordering of the
		meshes, and so the index of the meshes as returned by
		getMeshIndex() or taken by some methods will change.
		\param mesh Mesh to be renamed.
		\param filename New name for the mesh.
		\return True if mesh was renamed. */
		virtual bool setMeshFilename(const IAnimatedMesh* const mesh, const c8* filename) = 0;

		//! Renames a loaded mesh.
		/** Note that renaming meshes might change the ordering of the
		meshes, and so the index of the meshes as returned by
		getMeshIndex() or taken by some methods will change.
		\param mesh Mesh to be renamed.
		\param filename New name for the mesh.
		\return True if mesh was renamed. */
		virtual bool setMeshFilename(const IMesh* const mesh, const c8* filename) = 0;

		//! Check if a mesh was already loaded.
		/** \param filename Name of the mesh.
		\return True if the mesh has been loaded, else false. */
		virtual bool isMeshLoaded(const c8* filename) = 0;

		//! Clears the whole mesh cache, removing all meshes.
		/** All meshes will be reloaded completely when using ISceneManager::getMesh()
		after calling this method.
		Warning: If you have pointers to meshes that were loaded with ISceneManager::getMesh()
		and you did not grab them, then they may become invalid. */
		virtual void clear() = 0;

		//! Clears all meshes that are held in the mesh cache but not used anywhere else.
		/** Warning: If you have pointers to meshes that were loaded with ISceneManager::getMesh()
		and you did not grab them, then they may become invalid. */
		virtual void clearUnusedMeshes() = 0;
	};


} // end namespace scene
} // end namespace irr

#endif

