text: #pragma once
  
  #include <functional>
  
  //! Common class for handling picture data. \n
  //! Type of contained picture data is unknown and to be determined according to memory block contents by code parsing/rendering the picture. Commonly encountered types are: BMP, PNG, JPEG and GIF. \n
  //! Implementation: use album_art_data_impl.
  class NOVTABLE album_art_data : public service_base {
  public:
  	//! Retrieves a pointer to a memory block containing the picture.
  	virtual const void * get_ptr() const = 0;
  	//! Retrieves size of the memory block containing the picture.
  	virtual t_size get_size() const = 0;
  
  	//! Determine whether two album_art_data objects store the same picture data.
  	static bool equals(album_art_data const & v1, album_art_data const & v2) {
  		const t_size s = v1.get_size();
  		if (s != v2.get_size()) return false;
  		return memcmp(v1.get_ptr(), v2.get_ptr(),s) == 0;
  	}
  	bool operator==(const album_art_data & other) const {return equals(*this,other);}
  	bool operator!=(const album_art_data & other) const {return !equals(*this,other);}
  
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_data,service_base);
  };
  
  typedef service_ptr_t<album_art_data> album_art_data_ptr;
  
  //! Namespace containing identifiers of album art types.
  namespace album_art_ids {
  	//! Front cover.
  	static const GUID cover_front = { 0xf1e66f4e, 0xfe09, 0x4b94, { 0x91, 0xa3, 0x67, 0xc2, 0x3e, 0xd1, 0x44, 0x5e } };
  	//! Back cover.
  	static const GUID cover_back = { 0xcb552d19, 0x86d5, 0x434c, { 0xac, 0x77, 0xbb, 0x24, 0xed, 0x56, 0x7e, 0xe4 } };
  	//! Picture of a disc or other storage media.
  	static const GUID disc = { 0x3dba9f36, 0xf928, 0x4fa4, { 0x87, 0x9c, 0xd3, 0x40, 0x47, 0x59, 0x58, 0x7e } };
  	//! Album-specific icon (NOT a file type icon).
  	static const GUID icon = { 0x74cdf5b4, 0x7053, 0x4b3d, { 0x9a, 0x3c, 0x54, 0x69, 0xf5, 0x82, 0x6e, 0xec } };
  	//! Artist picture.
  	static const GUID artist = { 0x9a654042, 0xacd1, 0x43f7, { 0xbf, 0xcf, 0xd3, 0xec, 0xf, 0xfe, 0x40, 0xfa } };
  
  	size_t num_types();
  	GUID query_type( size_t );
  	// returns lowercase name
  	const char * query_name( size_t );
  	const char * name_of( const GUID & );
  	// returns Capitalized name
  	const char * query_capitalized_name( size_t );
  	const char * capitalized_name_of( const GUID & );
  };
  
  PFC_DECLARE_EXCEPTION(exception_album_art_not_found,exception_io_not_found,"Attached picture not found");
  PFC_DECLARE_EXCEPTION(exception_album_art_unsupported_entry,exception_io_data,"Unsupported attached picture entry");
  
  PFC_DECLARE_EXCEPTION(exception_album_art_unsupported_format,exception_io_data,"Attached picture operations not supported for this file format");
  
  //! Class encapsulating access to album art stored in a media file. Use album_art_extractor class obtain album_art_extractor_instance referring to specified media file.
  class NOVTABLE album_art_extractor_instance : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_extractor_instance,service_base);
  public:
  	//! Throws exception_album_art_not_found when the requested album art entry could not be found in the referenced media file.
  	virtual album_art_data_ptr query(const GUID & p_what,abort_callback & p_abort) = 0;
  
  	bool have_entry( const GUID & what, abort_callback & abort );
  	bool query(const GUID & what, album_art_data::ptr & out, abort_callback & abort);
  };
  
  //! Class encapsulating access to album art stored in a media file. Use album_art_editor class to obtain album_art_editor_instance referring to specified media file.
  class NOVTABLE album_art_editor_instance : public album_art_extractor_instance {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_editor_instance,album_art_extractor_instance);
  public:
  	//! Throws exception_album_art_unsupported_entry when the file format we're dealing with does not support specific entry.
  	virtual void set(const GUID & p_what,album_art_data_ptr p_data,abort_callback & p_abort) = 0;
  
  	//! Removes the requested entry. Fails silently when the entry doesn't exist.
  	virtual void remove(const GUID & p_what) = 0;
  
  	//! Finalizes file tag update operation.
  	virtual void commit(abort_callback & p_abort) = 0;
  
  	//! Helper; se ealbum_art_editor_instance_v2::remove_all();
  	void remove_all_();
  };
  
  class NOVTABLE album_art_editor_instance_v2 : public album_art_editor_instance {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_editor_instance_v2, album_art_editor_instance);
  public:
  	//! Tells the editor to remove all entries, including unsupported picture types that do not translate to fb2k ids.
  	virtual void remove_all() = 0;
  };
  
  typedef service_ptr_t<album_art_extractor_instance> album_art_extractor_instance_ptr;
  typedef service_ptr_t<album_art_editor_instance> album_art_editor_instance_ptr;
  
  //! Entrypoint class for accessing album art extraction functionality. Register your own implementation to allow album art extraction from your media file format. \n
  //! If you want to extract album art from a media file, it's recommended that you use album_art_manager API instead of calling album_art_extractor directly.
  class NOVTABLE album_art_extractor : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT(album_art_extractor);
  public:
  	//! Returns whether the specified file is one of formats supported by our album_art_extractor implementation.
  	//! @param p_path Path to file being queried.
  	//! @param p_extension Extension of file being queried (also present in p_path parameter) - provided as a separate parameter for performance reasons.
  	virtual bool is_our_path(const char * p_path,const char * p_extension) = 0;
  	
  	//! Instantiates album_art_extractor_instance providing access to album art stored in a specified media file. \n
  	//! Throws one of I/O exceptions on failure; exception_album_art_not_found when the file has no album art record at all.
  	//! @param p_filehint Optional; specifies a file interface to use for accessing the specified file; can be null - in that case, the implementation will open and close the file internally.
  	virtual album_art_extractor_instance_ptr open(file_ptr p_filehint,const char * p_path,abort_callback & p_abort) = 0;
  
  	static bool g_get_interface(service_ptr_t<album_art_extractor> & out,const char * path);
  	static bool g_is_supported_path(const char * path);
  	static album_art_extractor_instance_ptr g_open(file_ptr p_filehint,const char * p_path,abort_callback & p_abort);
  	static album_art_extractor_instance_ptr g_open_allowempty(file_ptr p_filehint,const char * p_path,abort_callback & p_abort);
  
  	//! Returns GUID of the corresponding input class. Null GUID if none.
  	GUID get_guid(); 
  };
  
  //! \since 1.5
  class NOVTABLE album_art_extractor_v2 : public album_art_extractor {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_extractor_v2 , album_art_extractor);
  public:
  	//! Returns GUID of the corresponding input class. Null GUID if none.
  	virtual GUID get_guid() = 0;
  };
  
  //! Entrypoint class for accessing album art editing functionality. Register your own implementation to allow album art editing on your media file format.
  class NOVTABLE album_art_editor : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT(album_art_editor);
  public:
  	//! Returns whether the specified file is one of formats supported by our album_art_editor implementation.
  	//! @param p_path Path to file being queried.
  	//! @param p_extension Extension of file being queried (also present in p_path parameter) - provided as a separate parameter for performance reasons.
  	virtual bool is_our_path(const char * p_path,const char * p_extension) = 0;
  
  	//! Instantiates album_art_editor_instance providing access to album art stored in a specified media file. \n
  	//! @param p_filehint Optional; specifies a file interface to use for accessing the specified file; can be null - in that case, the implementation will open and close the file internally.
  	virtual album_art_editor_instance_ptr open(file_ptr p_filehint,const char * p_path,abort_callback & p_abort) = 0;
  
  	//! Helper; attempts to retrieve an album_art_editor service pointer that supports the specified file.
  	//! @returns True on success, false on failure (no registered album_art_editor supports this file type).
  	static bool g_get_interface(service_ptr_t<album_art_editor> & out,const char * path);
  	//! Helper; returns whether one of registered album_art_editor implementations is capable of opening the specified file.
  	static bool g_is_supported_path(const char * path);
  
  	static album_art_editor_instance_ptr g_open(file_ptr p_filehint,const char * p_path,abort_callback & p_abort);
  
  	//! Returns GUID of the corresponding input class. Null GUID if none.
  	GUID get_guid();
  };
  
  //! \since 1.5
  class NOVTABLE album_art_editor_v2 : public album_art_editor {
  	FB2K_MAKE_SERVICE_INTERFACE( album_art_editor_v2, album_art_editor )
  public:
  	//! Returns GUID of the corresponding input class. Null GUID if none.
  	virtual GUID get_guid() = 0;
  };
  
  //! \since 0.9.5
  //! Helper API for extracting album art from APEv2 tags.
  class NOVTABLE tag_processor_album_art_utils : public service_base {
  	FB2K_MAKE_SERVICE_COREAPI(tag_processor_album_art_utils)
  public:
  
  	//! Throws one of I/O exceptions on failure; exception_album_art_not_found when the file has no album art record at all.
  	virtual album_art_extractor_instance_ptr open(file_ptr p_file,abort_callback & p_abort) = 0;
  
  	//! \since 1.1.6
  	//! Throws exception_not_implemented on earlier than 1.1.6.
  	virtual album_art_editor_instance_ptr edit(file_ptr p_file,abort_callback & p_abort) = 0;
  };
  
  
  //! Album art path list - see album_art_extractor_instance_v2
  class NOVTABLE album_art_path_list : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_path_list, service_base)
  public:
  	virtual const char * get_path(t_size index) const = 0;
  	virtual t_size get_count() const = 0;
  };
  
  //! album_art_extractor_instance extension; lets the frontend query referenced file paths (eg. when using external album art).
  class NOVTABLE album_art_extractor_instance_v2 : public album_art_extractor_instance {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_extractor_instance_v2, album_art_extractor_instance)
  public:
  	virtual album_art_path_list::ptr query_paths(const GUID & p_what, abort_callback & p_abort) = 0;
  };
  
  
  //! \since 1.0
  //! Provides methods for interfacing with the foobar2000 core album art loader. \n
  //! Use this when you need to load album art for a specific group of tracks.
  class NOVTABLE album_art_manager_v2 : public service_base {
  	FB2K_MAKE_SERVICE_COREAPI(album_art_manager_v2)
  public:
  	//! Instantiates an album art extractor object for the specified group of items.
  	virtual album_art_extractor_instance_v2::ptr open(metadb_handle_list_cref items, pfc::list_base_const_t<GUID> const & ids, abort_callback & abort) = 0;
  	
  	//! Instantiates an album art extractor object that retrieves stub images.
  	virtual album_art_extractor_instance_v2::ptr open_stub(abort_callback & abort) = 0;
  };
  
  
  //! \since 1.0
  //! Called when no other album art source (internal, external, other registered fallbacks) returns relevant data for the specified items. \n
  //! Can be used to implement online lookup and such.
  class NOVTABLE album_art_fallback : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE_ENTRYPOINT(album_art_fallback)
  public:
  	virtual album_art_extractor_instance_v2::ptr open(metadb_handle_list_cref items, pfc::list_base_const_t<GUID> const & ids, abort_callback & abort) = 0;
  };
  
  //! \since 1.1.7
  class NOVTABLE album_art_manager_config : public service_base {
  	FB2K_MAKE_SERVICE_INTERFACE(album_art_manager_config, service_base)
  public:
  	virtual bool get_external_pattern(pfc::string_base & out, const GUID & type) = 0;
  	virtual bool use_embedded_pictures() = 0;
  	virtual bool use_fallbacks() = 0;
  };
  
  //! \since 1.1.7
  class NOVTABLE album_art_manager_v3 : public album_art_manager_v2 {
  	FB2K_MAKE_SERVICE_COREAPI_EXTENSION(album_art_manager_v3, album_art_manager_v2)
  public:
  	//! @param config An optional album_art_manager_config object to override global settings. Pass null to use global settings.
  	virtual album_art_extractor_instance_v2::ptr open_v3(metadb_handle_list_cref items, pfc::list_base_const_t<GUID> const & ids, album_art_manager_config::ptr config, abort_callback & abort) = 0;
  };
  
  //! \since 1.4
  //! A notification about a newly loaded album art being ready to display. \n
  //! See: now_playing_album_art_notify_manager.
  class NOVTABLE now_playing_album_art_notify {
  public:
  	//! Called when album art has finished loading for the now playing track.
  	//! @param data The newly loaded album art. Never a null object - the callbacks are simply not called when there is nothing to show.
  	virtual void on_album_art( album_art_data::ptr data ) = 0;
  };
  
  //! \since 1.4
  //! Since various components require the album art of the now-playing track, a centralized loader has been provided, so the file isn't hammered independently by different components. \n
  //! Use this in conjunction with play_callback notifications to render now-playing track information.
  class NOVTABLE now_playing_album_art_notify_manager : public service_base {
  	FB2K_MAKE_SERVICE_COREAPI(now_playing_album_art_notify_manager)
  public:
  	//! Register a notification to be told when the album art has been loaded.
  	virtual void add(now_playing_album_art_notify*) = 0;
  	//! Unregister a previously registered notification.
  	virtual void remove(now_playing_album_art_notify*) = 0;
  	//! Retrieves the album art for the currently playing track.
  	//! @returns The current album art (front cover), or null if there is no art or the art is being loaded and is not yet available.
  	virtual album_art_data::ptr current() = 0;
  
  	//! Helper; register a lambda notification. Pass the returned obejct to remove() to unregister.
  	now_playing_album_art_notify* add( std::function<void (album_art_data::ptr) > );
  };
  