/*
  deadbeef.d -- plugin API of the DeaDBeeF audio player
  http://deadbeef.sourceforge.net

  Copyright (C) 2009-2013 Alexey Yakovenko

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
module deadbeef.deadbeef;

import core.stdc.time: time_t;
import core.stdc.stdint: uintptr_t, intptr_t;
import core.stdc.stdio: FILE;
import core.sys.posix.dirent: dirent;

extern (C):
@trusted:
@nogc:
nothrow:


// every plugin must define the following entry-point:
// extern "C" DB_plugin_t* $MODULENAME_load (DB_functions_t *api);
// where $MODULENAME is a name of module
// e.g. if your plugin is called "myplugin.so", $MODULENAME is "myplugin"
// this function should return pointer to DB_plugin_t structure
// that is enough for both static and dynamic modules

// backwards compatibility is supported since API version 1.0
// that means that the plugins which use the API 1.0 will work without recompiling until API 2.0.
//
// increments in the major version number mean that there are API breaks, and
// plugins must be recompiled to be compatible.
//
// add DDB_REQUIRE_API_VERSION(x,y) macro when you define the plugin structure
// like this:
// static DB_decoder_t plugin = {
//   DDB_REQUIRE_API_VERSION(1,0)
//  ............
// }
// this is required for versioning
// if you don't do it -- no version checking will be done (useful for debugging/development)
//
// please DON'T release plugins without version requirement
//
// to ensure compatibility, use the following before including deadbeef.h:
// #define DDB_API_LEVEL x
// where x is the minor API version number.
// that way, you'll get errors or warnings when using incompatible stuff.
//
// if you also want to get the deprecation warnings, use the following:
// #define DDB_WARN_DEPRECATED 1
//
// NOTE: deprecation doesn't mean the API is going to be removed, it just means
// that there's a better replacement in the newer deadbeef versions.

// api version history:
// 1.9 -- deadbeef-0.7.2
// 1.8 -- deadbeef-0.7.0
// 1.7 -- deadbeef-0.6.2
// 1.6 -- deadbeef-0.6.1
// 1.5 -- deadbeef-0.6
// 1.4 -- deadbeef-0.5.5
// 1.3 -- deadbeef-0.5.3
// 1.2 -- deadbeef-0.5.2
// 1.1 -- deadbeef-0.5.1
//   adds pass_through method to dsp plugins for optimization purposes
// 1.0 -- deadbeef-0.5.0
// 0.10 -- deadbeef-0.4.4-portable-r1 (note: 0.4.4 uses api v0.9)
// 0.9 -- deadbeef-0.4.3-portable-build3
// 0.8 -- deadbeef-0.4.2
// 0.7 -- deabdeef-0.4.0
// 0.6 -- deadbeef-0.3.3
// 0.5 -- deadbeef-0.3.2
// 0.4 -- deadbeef-0.3.0
// 0.3 -- deadbeef-0.2.3.2
// 0.2 -- deadbeef-0.2.3
// 0.1 -- deadbeef-0.2.0

enum DB_API_VERSION_MAJOR = 1;
enum DB_API_VERSION_MINOR = 9;

enum DDB_API_LEVEL = DB_API_VERSION_MINOR;
/+ … +/

////////////////////////////
// default values for some common config variables should go here

// network.ctmapping : content-type to plugin mapping
enum DDB_DEFAULT_CTMAPPING = "audio/mpeg {stdmpg ffmpeg} audio/x-mpeg {stdmpg ffmpeg} application/ogg {stdogg ffmpeg} audio/ogg {stdogg ffmpeg} audio/aac {aac ffmpeg} audio/aacp {aac ffmpeg} audio/x-m4a {aac ffmpeg} audio/wma {wma ffmpeg}";

enum {
	DDB_IS_SUBTRACK = (1<<0), // file is not single-track, might have metainfo in external file
	DDB_IS_READONLY = (1<<1), // check this flag to block tag writing (e.g. in iso.wv)
	DDB_HAS_EMBEDDED_CUESHEET = (1<<2),

	DDB_TAG_ID3V1 = (1<<8),
	DDB_TAG_ID3V22 = (1<<9),
	DDB_TAG_ID3V23 = (1<<10),
	DDB_TAG_ID3V24 = (1<<11),
	DDB_TAG_APEV2 = (1<<12),
	DDB_TAG_VORBISCOMMENTS = (1<<13),
	DDB_TAG_CUESHEET = (1<<14),
	DDB_TAG_ICY = (1<<15),
	DDB_TAG_ITUNES = (1<<16),

	DDB_TAG_MASK = 0x000fff00
}

// playlist item
// these are "public" fields, available to plugins
struct DB_playItem_s {
	int startsample; // start sample of track, or -1 for auto
	int endsample; // end sample of track, or -1 for auto
	int shufflerating; // sort order for shuffle mode
}
alias ddb_playItem_t = DB_playItem_s;
alias DB_playItem_t = ddb_playItem_t;

struct ddb_playlist_t {
}

struct DB_metaInfo_s {
	DB_metaInfo_s *next;
	immutable char *key;
	immutable char *value;
}
alias DB_metaInfo_t = DB_metaInfo_s;

// FIXME: that needs to be in separate plugin

enum JUNK_STRIP_ID3V2 = 1;
enum JUNK_STRIP_APEV2 = 2;
enum JUNK_STRIP_ID3V1 = 4;
enum JUNK_WRITE_ID3V2 = 8;
enum JUNK_WRITE_APEV2 = 16;
enum JUNK_WRITE_ID3V1 = 32;

struct DB_id3v2_frame_s {
	DB_id3v2_frame_s *next;
	char[5] id;
	uint size;
	ubyte[2] flags;
	ubyte[0] data;
}
alias DB_id3v2_frame_t = DB_id3v2_frame_s;

struct DB_id3v2_tag_s {
	ubyte[2] ver;
	ubyte flags;
	DB_id3v2_frame_t *frames;
}
alias DB_id3v2_tag_t = DB_id3v2_tag_s;

struct DB_apev2_frame_s {
	DB_apev2_frame_s *next;
	uint flags;
	char[256] key;
	uint size; // size of data
	ubyte *data; /+uint8_t data[0]; — don't know how to implement it in D+/
}
alias DB_apev2_frame_t = DB_apev2_frame_s;

struct DB_apev2_tag_s {
	uint ver;
	uint flags;
	DB_apev2_frame_t *frames;
}
alias DB_apev2_tag_t = DB_apev2_tag_s;

// plugin types
enum {
	DB_PLUGIN_DECODER = 1,
	DB_PLUGIN_OUTPUT  = 2,
	DB_PLUGIN_DSP     = 3,
	DB_PLUGIN_MISC    = 4,
	DB_PLUGIN_VFS     = 5,
	DB_PLUGIN_PLAYLIST = 6,
	DB_PLUGIN_GUI = 7,
}

// output plugin states
enum output_state_t {
	OUTPUT_STATE_STOPPED = 0,
	OUTPUT_STATE_PLAYING = 1,
	OUTPUT_STATE_PAUSED = 2,
}

// playback order
enum playback_order_t {
	PLAYBACK_ORDER_LINEAR = 0,
	PLAYBACK_ORDER_SHUFFLE_TRACKS = 1,
	PLAYBACK_ORDER_RANDOM = 2,
	PLAYBACK_ORDER_SHUFFLE_ALBUMS = 3,
}

// playback modes
enum playback_mode_t {
	PLAYBACK_MODE_LOOP_ALL = 0, // loop playlist
	PLAYBACK_MODE_NOLOOP = 1, // don't loop
	PLAYBACK_MODE_LOOP_SINGLE = 2, // loop single track
}

static if (DDB_API_LEVEL >= 8) {
	// playlist change info, used in the DB_EV_PLAYLISTCHANGED p1 argument
	enum ddb_playlist_change_t {
		DDB_PLAYLIST_CHANGE_CONTENT, // this is the most generic one, will work for the cases when p1 was omitted (0)
		DDB_PLAYLIST_CHANGE_CREATED,
		DDB_PLAYLIST_CHANGE_DELETED,
		DDB_PLAYLIST_CHANGE_POSITION,
		DDB_PLAYLIST_CHANGE_TITLE,
		DDB_PLAYLIST_CHANGE_SELECTION,
		DDB_PLAYLIST_CHANGE_SEARCHRESULT,
		DDB_PLAYLIST_CHANGE_PLAYQUEUE,
	}
}

struct ddb_event_t {
	int event;
	int size;
}

struct ddb_event_track_t {
	ddb_event_t ev;
	DB_playItem_t *track;
	float playtime; // for SONGFINISHED event -- for how many seconds track was playing
	time_t started_timestamp; // time when "track" started playing
}

struct ddb_event_trackchange_t {
	ddb_event_t ev;
	DB_playItem_t *from;
	DB_playItem_t *to;
	float playtime; // for SONGCHANGED event -- for how many seconds prev track was playing
	time_t started_timestamp; // time when "from" started playing
}

struct ddb_event_state_t {
	ddb_event_t ev;
	int state;
}

struct ddb_event_playpos_t {
	ddb_event_t ev;
	DB_playItem_t *track;
	float playpos;
}

struct DB_conf_item_s {
	char *key;
	char *value;
	DB_conf_item_s *next;
}
alias DB_conf_item_t = DB_conf_item_s;

// event callback type
alias DB_callback_t = int function(ddb_event_t *, uintptr_t data);

// events
enum {
	DB_EV_NEXT = 1, // switch to next track
	DB_EV_PREV = 2, // switch to prev track
	DB_EV_PLAY_CURRENT = 3, // play current track (will start/unpause if stopped or paused)
	DB_EV_PLAY_NUM = 4, // play track nr. p1
	DB_EV_STOP = 5, // stop current track
	DB_EV_PAUSE = 6, // pause playback
	DB_EV_PLAY_RANDOM = 7, // play random track
	DB_EV_TERMINATE = 8, // must be sent to player thread to terminate
	DB_EV_PLAYLIST_REFRESH = 9, // [DEPRECATED IN API LEVEL 8, use DB_EV_PLAYLISTCHANGED instead] save and redraw current playlist
	DB_EV_REINIT_SOUND = 10, // reinitialize sound output with current output_plugin config value
	DB_EV_CONFIGCHANGED = 11, // one or more config options were changed
	DB_EV_TOGGLE_PAUSE = 12,
	DB_EV_ACTIVATED = 13, // will be fired every time player is activated
	DB_EV_PAUSED = 14, // player was paused or unpaused

	DB_EV_PLAYLISTCHANGED = 15, // playlist contents were changed (e.g. metadata in any track)
	// DB_EV_PLAYLISTCHANGED NOTE: it's usually sent on LARGE changes,
	// when multiple tracks are affected, while for single tracks
	// the DB_EV_TRACKINFOCHANGED is preferred
	// added in API level 8:
	// p1 is one of ddb_playlist_change_t enum values, detailing what exactly has been changed.

	DB_EV_VOLUMECHANGED = 16, // volume was changed
	DB_EV_OUTPUTCHANGED = 17, // sound output plugin changed
	DB_EV_PLAYLISTSWITCHED = 18, // playlist switch occured
	DB_EV_SEEK = 19, // seek current track to position p1 (ms)
	DB_EV_ACTIONSCHANGED = 20, // plugin actions were changed, e.g. for reinitializing gui
	DB_EV_DSPCHAINCHANGED = 21, // emitted when any parameter of the main dsp chain has been changed
}

	// since 1.5
static if (DDB_API_LEVEL >= 5) {
	enum {
		DB_EV_SELCHANGED = 22, // selection changed in playlist p1 iter p2, ctx should be a pointer to playlist viewer instance, which caused the change, or NULL
		DB_EV_PLUGINSLOADED = 23, // after all plugins have been loaded and connected
	}
}

static if (DDB_API_LEVEL >= 8) {
	enum {
		DB_EV_FOCUS_SELECTION = 24, // tell playlist viewer to focus on selection
	}
}

enum {
	// -----------------
	// structured events

	DB_EV_FIRST = 1000,
	DB_EV_SONGCHANGED = 1000, // current song changed from one to another, ctx=ddb_event_trackchange_t
	DB_EV_SONGSTARTED = 1001, // song started playing, ctx=ddb_event_track_t
	DB_EV_SONGFINISHED = 1002, // song finished playing, ctx=ddb_event_track_t

	DB_EV_TRACKINFOCHANGED = 1004, // trackinfo was changed (included medatata, playback status, playqueue state, etc), ctx=ddb_event_track_t
	// DB_EV_TRACKINFOCHANGED NOTE: when multiple tracks change, DB_EV_PLAYLISTCHANGED may be sent instead,
	// for speed reasons, so always handle both events.

	DB_EV_SEEKED = 1005, // seek happened, ctx=ddb_event_playpos_t
}

// since 1.5
static if (DDB_API_LEVEL >= 5) {
	enum {
		// NOTE: this is not a structured event, but too late to fix, needs to stay here for backwards compat
		DB_EV_TRACKFOCUSCURRENT = 1006, // user wants to highlight/find the current playing track
	}
}

enum {
	DB_EV_MAX = 1007
}

// preset columns, working using IDs
// DON'T add new ids in range 2-7, they are reserved for backwards compatibility
enum pl_column_t {
	DB_COLUMN_FILENUMBER = 0,
	DB_COLUMN_PLAYING = 1,
	DB_COLUMN_ALBUM_ART = 8,
};

// replaygain constants
enum {
	DDB_REPLAYGAIN_ALBUMGAIN,
	DDB_REPLAYGAIN_ALBUMPEAK,
	DDB_REPLAYGAIN_TRACKGAIN,
	DDB_REPLAYGAIN_TRACKPEAK,
}

// sort order constants
enum {
	DDB_SORT_DESCENDING = 0,
	DDB_SORT_ASCENDING = 1,
}

// since 1.3
static if (DDB_API_LEVEL >= 3) {
	enum DDB_SORT_RANDOM = 2;
}

enum ddb_sys_directory_t {
	DDB_SYS_DIR_CONFIG = 1,
	DDB_SYS_DIR_PREFIX = 2,
	DDB_SYS_DIR_DOC = 3,
	DDB_SYS_DIR_PLUGIN = 4,
	DDB_SYS_DIR_PIXMAP = 5,
	DDB_SYS_DIR_CACHE = 6,
}

/+ do we really need it in D?
// typecasting macros
#define DB_PLUGIN(x) ((DB_plugin_t *)(x))
#define DB_CALLBACK(x) ((DB_callback_t)(x))
#define DB_EVENT(x) ((ddb_event_t *)(x))
#define DB_PLAYITEM(x) ((DB_playItem_t *)(x))
+/

// FILE object wrapper for vfs access
struct DB_FILE {
	DB_vfs_s *vfs;
};

// md5 calc control structure (see md5/md5.h)
struct DB_md5_s {
	char[88] data;
}
alias DB_md5_t = DB_md5_s;

struct ddb_waveformat_t {
	int bps;
	int channels;
	int samplerate;
	uint channelmask;
	int is_float; // bps must be 32 if this is true
	int is_bigendian;
}

// since 1.5
static if (DDB_API_LEVEL >= 5) {
	enum DDB_FREQ_BANDS = 256;
	enum DDB_FREQ_MAX_CHANNELS = 9;
	struct ddb_audio_data_s {
		immutable ddb_waveformat_t *fmt;
		immutable float *data;
		int nframes;
	}
	alias ddb_audio_data_t = ddb_audio_data_s;

	struct ddb_fileadd_data_s {
		int visibility;
		ddb_playlist_t *plt;
		ddb_playItem_t *track;
	}
	alias ddb_fileadd_data_t = ddb_fileadd_data_s;
}

// since 1.8
static if (DDB_API_LEVEL >= 8) {
	enum {
		DDB_TF_CONTEXT_HAS_INDEX = 1,
		DDB_TF_CONTEXT_HAS_ID = 2,
		DDB_TF_CONTEXT_NO_DYNAMIC = 4, // skip dynamic fields (%playback_time%)
	}
	static if (DDB_API_LEVEL >= 9) {
		// Don't convert linebreaks to semicolons
		enum DDB_TF_CONTEXT_MULTILINE = 8;
	}

	// context for title formatting interpreter
	struct ddb_tf_context_t {
		int _size; // must be set to sizeof(tf_context_t)
		uint flags; // DDB_TF_CONTEXT_ flags
		ddb_playItem_t *it; // track to get information from, or NULL
		ddb_playlist_t *plt; // playlist in which the track resides, or NULL

		// NOTE: when plt is NULL, it means that the track is not in any playlist,
		// that is -- playlist will never be automatically guessed, for performance
		// reasons.

		// index of the track in playlist the track belongs to
		// if present, DDB_TF_CONTEXT_HAS_INDEX flag must be set
		int idx;

		// predefined column id, one of the DB_COLUMN_
		// if present, DDB_TF_CONTEXT_HAS_ID flag must be set
		int id;

		int iter; // playlist iteration (PL_MAIN, PL_SEARCH)

		// update is a returned value
		// meaning:
		// 0: no automatic updates
		// <0: updates on every call
		// >0: number of milliseconds between updates / until next update
		int update;
	}
}

// player api definition
struct DB_functions_t {
	// versioning
	int vmajor;
	int vminor;

	// md5sum calc
	void function(ubyte[16] sig, in char *input, int len) nothrow @nogc md5;
	void function(char *str, in ubyte[16] sig) nothrow @nogc md5_to_str;
	void function(DB_md5_t *s) nothrow @nogc md5_init;
	void function(DB_md5_t *s, in ubyte *data, int nbytes) nothrow @nogc md5_append;
	void function(DB_md5_t *s, ubyte[16] digest) nothrow @nogc md5_finish;

	// playback control
	DB_output_s* function() nothrow @nogc get_output;
	float function() nothrow @nogc playback_get_pos; // [0..100]
	void function(float pos) nothrow @nogc playback_set_pos; // [0..100]

	// streamer access
	DB_playItem_t *function() nothrow @nogc streamer_get_playing_track;
	DB_playItem_t *function() nothrow @nogc streamer_get_streaming_track;
	float function() nothrow @nogc streamer_get_playpos;
	int function(int len) nothrow @nogc streamer_ok_to_read;
	void function(int full) nothrow @nogc streamer_reset;
	int function(char *bytes, int size) nothrow @nogc streamer_read;
	void function(int bitrate) nothrow @nogc streamer_set_bitrate;
	int function() nothrow @nogc streamer_get_apx_bitrate;
	DB_fileinfo_s *function() nothrow @nogc streamer_get_current_fileinfo;
	int function() nothrow @nogc streamer_get_current_playlist;
	ddb_dsp_context_s * function() nothrow @nogc streamer_get_dsp_chain;
	void function(ddb_dsp_context_s *chain) nothrow @nogc streamer_set_dsp_chain;
	void function() nothrow @nogc streamer_dsp_refresh; // call after changing parameters

	// system folders
	// normally functions will return standard folders derived from --prefix
	// portable version will return pathes specified in comments below
	/+static if (DDB_API_LEVEL < 8) {+/
		immutable char* function() nothrow @nogc get_config_dir; // installdir/config | $XDG_CONFIG_HOME/.config/deadbeef
		immutable char* function() nothrow @nogc get_prefix; // installdir | PREFIX
		immutable char* function() nothrow @nogc get_doc_dir; // installdir/doc | DOCDIR
		immutable char* function() nothrow @nogc get_plugin_dir; // installdir/plugins | LIBDIR/deadbeef
		immutable char* function() nothrow @nogc get_pixmap_dir; // installdir/pixmaps | PREFIX "/share/deadbeef/pixmaps"
	/+}+/

	// process control
	void function() quit;

	// threading
	intptr_t function(void function(void *ctx) fn, void *ctx) nothrow @nogc thread_start;
	intptr_t function(void function(void *ctx) fn, void *ctx) nothrow @nogc thread_start_low_priority;
	int function(intptr_t tid) nothrow @nogc thread_join;
	int function(intptr_t tid) nothrow @nogc thread_detach;
	void function(void *retval) nothrow @nogc thread_exit;
	uintptr_t function() nothrow @nogc mutex_create;
	uintptr_t function() nothrow @nogc mutex_create_nonrecursive;
	void function(uintptr_t mtx) nothrow @nogc mutex_free;
	int function(uintptr_t mtx) nothrow @nogc mutex_lock;
	int function(uintptr_t mtx) nothrow @nogc mutex_unlock;
	uintptr_t function() nothrow @nogc cond_create;
	void function(uintptr_t cond) nothrow @nogc cond_free;
	int function(uintptr_t cond, uintptr_t mutex) nothrow @nogc cond_wait;
	int function(uintptr_t cond) nothrow @nogc cond_signal;
	int function(uintptr_t cond) nothrow @nogc cond_broadcast;

	/////// playlist management //////
	void function(ddb_playlist_t *plt) nothrow @nogc plt_ref;
	void function(ddb_playlist_t *plt) nothrow @nogc plt_unref;

	// total number of playlists
	int function() nothrow @nogc plt_get_count;


	// 1st item in playlist nr. 'plt'
	DB_playItem_t * function(int plt) nothrow @nogc plt_get_head;

	// nr. of selected items in playlist nr. 'plt'
	int function(int plt) nothrow @nogc plt_get_sel_count;

	// add new playlist into position before nr. 'before', with title='title'
	// returns index of new playlist
	int function(int before, in char *title) nothrow @nogc plt_add;

	// remove playlist nr. plt
	void function(int plt) nothrow @nogc plt_remove;

	// clear playlist
	void function(ddb_playlist_t *plt) nothrow @nogc plt_clear;
	void function() nothrow @nogc pl_clear;

	// set current playlist
	void function(ddb_playlist_t *plt) nothrow @nogc plt_set_curr;
	void function(int plt) nothrow @nogc plt_set_curr_idx;

	// get current playlist
	// note: caller is responsible to call plt_unref after using pointer
	// returned by plt_get_curr
	ddb_playlist_t* function() nothrow @nogc plt_get_curr;
	int function() nothrow @nogc plt_get_curr_idx;

	// move playlist nr. 'from' into position before nr. 'before', where
	// before=-1 means last position
	void function(int from, int before) nothrow @nogc plt_move;

	// playlist saving and loading
	/+static if (DDB_API_LEVEL < 5) {+/
		DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, in char *fname, int *pabort, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_load;
	/+}+/
	int function(ddb_playlist_t *plt, DB_playItem_t *first, DB_playItem_t *last, in char *fname, int *pabort, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_save;

	ddb_playlist_t* function(int idx) nothrow @nogc plt_get_for_idx;
	int function(ddb_playlist_t *plt, char *buffer, int bufsize) nothrow @nogc plt_get_title;
	int function(ddb_playlist_t *plt, in char *title) nothrow @nogc plt_set_title;

	// increments modification index
	void function(ddb_playlist_t *handle) nothrow @nogc plt_modified;

	// returns modication index
	// the index is incremented by 1 every time playlist changes
	int function(ddb_playlist_t *handle) nothrow @nogc plt_get_modification_idx;

	// return index of an item in specified playlist, or -1 if not found
	int function(ddb_playlist_t *plt, DB_playItem_t *it, int iter) nothrow @nogc plt_get_item_idx;

	// playlist metadata
	// this kind of metadata is stored in playlist (dbpl) files
	// that is, this is the properties of playlist itself,
	// not of the tracks in the playlist.
	// for example, playlist tab color can be stored there, etc

	// add meta if it doesn't exist yet
	void function(ddb_playlist_t *handle, in char *key, in char *value) nothrow @nogc plt_add_meta;

	// replace (or add) existing meta
	void function(ddb_playlist_t *handle, in char *key, in char *value) nothrow @nogc plt_replace_meta;

	// append meta to existing one, or add if doesn't exist
	void function(ddb_playlist_t *handle, in char *key, in char *value) nothrow @nogc plt_append_meta;

	// set integer meta (works same as replace)
	void function(ddb_playlist_t *handle, in char *key, int value) nothrow @nogc plt_set_meta_int;

	// set float meta (works same as replace)
	void function(ddb_playlist_t *handle, in char *key, float value) nothrow @nogc plt_set_meta_float;

	// plt_find_meta must always be used in the pl_lock/unlock block
	immutable char* function(ddb_playlist_t *handle, in char *key) nothrow @nogc plt_find_meta;

	// returns head of metadata linked list, for direct access
	// remember pl_lock/unlock
	DB_metaInfo_t* function(ddb_playlist_t *handle) nothrow @nogc plt_get_metadata_head;

	// delete meta item from list
	void function(ddb_playlist_t *handle, DB_metaInfo_t *meta) nothrow @nogc plt_delete_metadata;

	// returns integer value of requested meta, def is the default value if not found
	int function(ddb_playlist_t *handle, in char *key, int def) nothrow @nogc plt_find_meta_int;

	// returns float value of requested meta, def is the default value if not found
	float function(ddb_playlist_t *handle, in char *key, float def) nothrow @nogc plt_find_meta_float;

	// delete all metadata
	void function(ddb_playlist_t *handle) nothrow @nogc plt_delete_all_meta;

	// operating on playlist items
	DB_playItem_t* function(ddb_playlist_t *playlist, DB_playItem_t *after, DB_playItem_t *it) nothrow @nogc plt_insert_item;
	/+static if (DDB_API_LEVEL < 5) {+/
		DB_playItem_t* function(ddb_playlist_t *playlist, DB_playItem_t *after, in char *fname, int *pabort, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_insert_file;
		DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, in char *dirname, int *pabort, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_insert_dir;
	/+}+/
	void function(ddb_playlist_t *plt, DB_playItem_t *it, float duration) nothrow @nogc plt_set_item_duration;
	int function(ddb_playlist_t *playlist, DB_playItem_t *it) nothrow @nogc plt_remove_item;
	int function(ddb_playlist_t *playlist) nothrow @nogc plt_getselcount;
	float function(ddb_playlist_t *plt) nothrow @nogc plt_get_totaltime;
	int function(ddb_playlist_t *plt, int iter) nothrow @nogc plt_get_item_count;
	int function(ddb_playlist_t *plt) nothrow @nogc plt_delete_selected;
	void function(ddb_playlist_t *plt, int iter, int cursor) nothrow @nogc plt_set_cursor;
	int function(ddb_playlist_t *plt, int iter) nothrow @nogc plt_get_cursor;
	void function(ddb_playlist_t *plt) nothrow @nogc plt_select_all;
	void function(ddb_playlist_t *plt) nothrow @nogc plt_crop_selected;
	DB_playItem_t* function(ddb_playlist_t *plt, int iter) nothrow @nogc plt_get_first;
	DB_playItem_t* function(ddb_playlist_t *plt, int iter) nothrow @nogc plt_get_last;
	DB_playItem_t* function(ddb_playlist_t *playlist, int idx, int iter) nothrow @nogc plt_get_item_for_idx;
	void function(ddb_playlist_t *to, int iter, ddb_playlist_t *from, DB_playItem_t *drop_before, uint *indexes, int count) nothrow @nogc plt_move_items;
	void function(ddb_playlist_t *to, int iter, ddb_playlist_t * from, DB_playItem_t *before, uint *indices, int cnt) nothrow @nogc plt_copy_items;
	void function(ddb_playlist_t *plt) nothrow @nogc plt_search_reset;
	void function(ddb_playlist_t *plt, in char *text) nothrow @nogc plt_search_process;

	// sort using the title formatting v1 (deprecated)
	/+static if (DDB_API_LEVEL < 8) {+/
		void function(ddb_playlist_t *plt, int iter, int id, in char *format, int order) nothrow @nogc plt_sort;
	/+}+/

	/+static if (DDB_API_LEVEL < 5) {+/
		// add files and folders to current playlist
		int function(ddb_playlist_t *plt, in char *fname, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_add_file;
		int function(ddb_playlist_t *plt, in char *dirname, int function(DB_playItem_t *it, void *data) cb, void *user_data) nothrow @nogc plt_add_dir;
	/+}+/

	// cuesheet support
	DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, DB_playItem_t *origin, in ubyte *buffer, int buffersize, int numsamples, int samplerate) nothrow @nogc plt_insert_cue_from_buffer;
	DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, DB_playItem_t *origin, int numsamples, int samplerate) nothrow @nogc plt_insert_cue;

	// playlist locking
	void function() nothrow @nogc pl_lock;
	void function() nothrow @nogc pl_unlock;

	// playlist tracks access
	DB_playItem_t* function() nothrow @nogc pl_item_alloc;
	DB_playItem_t* function(in char *fname, in char *decoder_id) nothrow @nogc pl_item_alloc_init;
	void function(DB_playItem_t *it) nothrow @nogc pl_item_ref;
	void function(DB_playItem_t *it) nothrow @nogc pl_item_unref;
	void function(DB_playItem_t *output, DB_playItem_t *input) nothrow @nogc pl_item_copy;

	// request lock for adding files to playlist
	// this function may return -1 if it is not possible to add files right now.
	// caller must cancel operation in this case,
	// or wait until previous operation finishes
	/+static if (DDB_API_LEVEL < 5) {+/
		int function(ddb_playlist_t *plt) nothrow @nogc pl_add_files_begin;

		// release the lock for adding files to playlist
		// end must be called when add files operation is finished
		void function() nothrow @nogc pl_add_files_end;
	/+}+/

	// most of this functions are self explanatory
	// if you don't get what they do -- look in the code

	// --- the following functions work with current playlist ---

	// get index of the track in MAIN
	int function(DB_playItem_t *it) nothrow @nogc pl_get_idx_of;

	// get index of the track in MAIN or SEARCH
	int function(DB_playItem_t *it, int iter) nothrow @nogc pl_get_idx_of_iter;

	// get track for index in MAIN
	DB_playItem_t* function(int idx) nothrow @nogc pl_get_for_idx;

	// get track for index in MAIN or SEARCH
	DB_playItem_t* function(int idx, int iter) nothrow @nogc pl_get_for_idx_and_iter;

	// get total play time of all tracks in MAIN
	float function() nothrow @nogc pl_get_totaltime;

	// get number of tracks in MAIN or SEARCH
	int function(int iter) nothrow @nogc pl_getcount;

	// delete selected tracks
	int function() nothrow @nogc pl_delete_selected;

	// set cursor position in MAIN or SEARCH
	void function(int iter, int cursor) nothrow @nogc pl_set_cursor;

	// get cursor position in MAIN
	int function(int iter) nothrow @nogc pl_get_cursor;

	// remove all except selected tracks
	void function() nothrow @nogc pl_crop_selected;

	// get number of selected tracks
	int function() nothrow @nogc pl_getselcount;

	// get first track in MAIN or SEARCH
	DB_playItem_t* function(int iter) nothrow @nogc pl_get_first;

	// get last track in MAIN or SEARCH
	DB_playItem_t* function(int iter) nothrow @nogc pl_get_last;

	// --- misc functions ---

	// mark the track as selected or unselected (1 or 0 respectively)
	void function(DB_playItem_t *it, int sel) nothrow @nogc pl_set_selected;

	// test whether the track is selected
	int function(DB_playItem_t *it) nothrow @nogc pl_is_selected;

	// save current playlist
	int function() nothrow @nogc pl_save_current;

	// save all playlists
	int function() nothrow @nogc pl_save_all;

	// select all tracks in current playlist
	void function() nothrow @nogc pl_select_all;

	// get next track
	DB_playItem_t* function(DB_playItem_t *it, int iter) nothrow @nogc pl_get_next;

    // get previous track
	DB_playItem_t* function(DB_playItem_t *it, int iter) nothrow @nogc pl_get_prev;

	/*
		pl_format_title formats the line for display in playlist
		@it pointer to playlist item
		@idx number of that item in playlist (or -1)
		@s output buffer
		@size size of output buffer
		@id one of IDs defined in pl_column_id_t enum, can be -1
		@fmt format string, used if id is -1
		format is printf-alike. specification:
		%a artist
		%t title
		%b album
		%B band / album artist
		%n track
		%l length (duration)
		%y year
		%g genre
		%c comment
		%r copyright
		%T tags
		%f filename without path
		%F full pathname/uri
		%d directory without path (e.g. /home/user/file.mp3 -> user)
		%D directory name with full path (e.g. /home/user/file.mp3 -> /home/user)
		more to come
	*/
	/+static if (DDB_API_LEVEL < 8) {+/
		int function(DB_playItem_t *it, int idx, char *s, int size, int id, in char *fmt) nothrow @nogc pl_format_title;

		// _escaped version wraps all conversions with '' and replaces every ' in conversions with \'
		int function(DB_playItem_t *it, int idx, char *s, int size, int id, in char *fmt) nothrow @nogc pl_format_title_escaped;
	/+}+/
	// format duration 't' (fractional seconds) into string, for display in playlist
	void function(float t, char *dur, int size) nothrow @nogc pl_format_time;

	// find which playlist the specified item belongs to, returns NULL if none
	ddb_playlist_t* function(DB_playItem_t *it) nothrow @nogc pl_get_playlist;

	// direct access to metadata structures
	// not thread-safe, make sure to wrap with pl_lock/pl_unlock
	DB_metaInfo_t* function(DB_playItem_t *it) nothrow @nogc pl_get_metadata_head; // returns head of metadata linked list
	void function(DB_playItem_t *it, DB_metaInfo_t *meta) nothrow @nogc pl_delete_metadata;

	// high-level access to metadata
	void function(DB_playItem_t *it, in char *key, in char *value) nothrow @nogc pl_add_meta;
	void function(DB_playItem_t *it, in char *key, in char *value) nothrow @nogc pl_append_meta;
	void function(DB_playItem_t *it, in char *key, int value) nothrow @nogc pl_set_meta_int;
	void function(DB_playItem_t *it, in char *key, float value) nothrow @nogc pl_set_meta_float;
	void function(DB_playItem_t *it, in char *key) nothrow @nogc pl_delete_meta;

	// this function is not thread-safe
	// make sure to wrap it with pl_lock/pl_unlock block
	immutable char* function(DB_playItem_t *it, in char *key) nothrow @nogc pl_find_meta;

	// following functions are thread-safe
	int function(DB_playItem_t *it, in char *key, int def) nothrow @nogc pl_find_meta_int;
	float function(DB_playItem_t *it, in char *key, float def) nothrow @nogc pl_find_meta_float;
	void function(DB_playItem_t *it, in char *key, in char *value) nothrow @nogc pl_replace_meta;
	void function(DB_playItem_t *it) nothrow @nogc pl_delete_all_meta;
	float function(DB_playItem_t *it) nothrow @nogc pl_get_item_duration;
	uint function(DB_playItem_t *it) nothrow @nogc pl_get_item_flags;
	void function(DB_playItem_t *it, uint flags) nothrow @nogc pl_set_item_flags;
	void function(DB_playItem_t *from, DB_playItem_t *first, DB_playItem_t *last) nothrow @nogc pl_items_copy_junk;
	// idx is one of DDB_REPLAYGAIN_* constants
	void function(DB_playItem_t *it, int idx, float value) nothrow @nogc pl_set_item_replaygain;
	float function(DB_playItem_t *it, int idx) nothrow @nogc pl_get_item_replaygain;

	// playqueue support (obsolete since API 1.8)
	/+static if (DDB_API_LEVEL < 8) {+/
		int function(DB_playItem_t *it) nothrow @nogc pl_playqueue_push;
		void function() nothrow @nogc pl_playqueue_clear;
		void function() nothrow @nogc pl_playqueue_pop;
		void function(DB_playItem_t *it) nothrow @nogc pl_playqueue_remove;
		int function(DB_playItem_t *it) nothrow @nogc pl_playqueue_test;
	/+}+/

	// volume control
	void function(float dB) nothrow @nogc volume_set_db;
	float function() nothrow @nogc volume_get_db;
	void function(float amp) nothrow @nogc volume_set_amp;
	float function() nothrow @nogc volume_get_amp;
	float function() nothrow @nogc volume_get_min_db;

	// junk reading/writing
	int function(DB_playItem_t *it, DB_FILE *fp) nothrow @nogc junk_id3v1_read;
	int function(DB_FILE *fp) nothrow @nogc junk_id3v1_find;
	int function(FILE *fp, DB_playItem_t *it, in char *enc) nothrow @nogc junk_id3v1_write;
	int function(DB_FILE *fp, int *psize) nothrow @nogc junk_id3v2_find;
	int function(DB_playItem_t *it, DB_FILE *fp) nothrow @nogc junk_id3v2_read;
	int function(DB_playItem_t *it, DB_id3v2_tag_t *tag, DB_FILE *fp) nothrow @nogc junk_id3v2_read_full;
	int function(DB_id3v2_tag_t *tag24, DB_id3v2_tag_t *tag23) nothrow @nogc junk_id3v2_convert_24_to_23;
	int function(DB_id3v2_tag_t *tag23, DB_id3v2_tag_t *tag24) nothrow @nogc junk_id3v2_convert_23_to_24;
	int function(DB_id3v2_tag_t *tag22, DB_id3v2_tag_t *tag24) nothrow @nogc junk_id3v2_convert_22_to_24;
	void function(DB_id3v2_tag_t *tag) nothrow @nogc junk_id3v2_free;
	int function(FILE *file, DB_id3v2_tag_t *tag) nothrow @nogc junk_id3v2_write;
	DB_id3v2_frame_t* function(DB_id3v2_tag_t *tag, in char *frame_id, in char *value) nothrow @nogc junk_id3v2_add_text_frame;
	int function(DB_id3v2_tag_t *tag, in char *frame_id) nothrow @nogc junk_id3v2_remove_frames;
	int function(DB_playItem_t *it, DB_FILE *fp) nothrow @nogc junk_apev2_read;
	int function(DB_playItem_t *it, char *mem, int size) nothrow @nogc junk_apev2_read_mem;
	int function(DB_playItem_t *it, DB_apev2_tag_t *tag_store, DB_FILE *fp) nothrow @nogc junk_apev2_read_full;
	int function(DB_playItem_t *it, DB_apev2_tag_t *tag_store, char *mem, int memsize) nothrow @nogc junk_apev2_read_full_mem;
	int function(DB_FILE *fp, int *psize, uint *pflags, uint *pnumitems) nothrow @nogc junk_apev2_find;
	int function(DB_apev2_tag_t *tag, in char *frame_id) nothrow @nogc junk_apev2_remove_frames;
	DB_apev2_frame_t* function(DB_apev2_tag_t *tag, in char *frame_id, in char *value) nothrow @nogc junk_apev2_add_text_frame;
	void function(DB_apev2_tag_t *tag) nothrow @nogc junk_apev2_free;
	int function(FILE *fp, DB_apev2_tag_t *tag, int write_header, int write_footer) nothrow @nogc junk_apev2_write;
	int function(DB_FILE *fp) nothrow @nogc junk_get_leading_size;
	int function(FILE *fp) nothrow @nogc junk_get_leading_size_stdio;
	void function(DB_playItem_t *from, DB_playItem_t *first, DB_playItem_t *last) nothrow @nogc junk_copy;
	immutable char * function(in char *s) nothrow @nogc junk_detect_charset;
	int function(in char *input, int inlen, char *output, int outlen, in char *cs) nothrow @nogc junk_recode;
	int function(in char *input, int inlen, char *output, int outlen, in char *cs_in, in char *cs_out) nothrow @nogc junk_iconv;
	int function(DB_playItem_t *it, uint flags, int id3v2_version, in char *id3v1_encoding) nothrow @nogc junk_rewrite_tags;

	// vfs
	DB_FILE* function(in char *fname) nothrow @nogc fopen;
	void function(DB_FILE *f) nothrow @nogc fclose;
	size_t function(void *ptr, size_t size, size_t nmemb, DB_FILE *stream) nothrow @nogc fread;
	int function(DB_FILE *stream, long offset, int whence) nothrow @nogc fseek;
	long function(DB_FILE *stream) nothrow @nogc ftell;
	void function(DB_FILE *stream) nothrow @nogc rewind;
	long function(DB_FILE *stream) nothrow @nogc fgetlength;
	immutable char * function(DB_FILE *stream) nothrow @nogc fget_content_type;
	void function(DB_FILE *stream, DB_playItem_t *it) nothrow @nogc fset_track;
	void function(DB_FILE *stream) nothrow @nogc fabort;

	// message passing
	int function(uint id, uintptr_t ctx, uint p1, uint p2) nothrow @nogc sendmessage;

	// convenience functions to send events, uses sendmessage internally
	ddb_event_t * function(uint id) nothrow @nogc event_alloc;
	void function(ddb_event_t *ev) nothrow @nogc event_free;
	int function(ddb_event_t *ev, uint p1, uint p2) nothrow @nogc event_send;

	// configuration access
	//
	// conf_get_str_fast is not thread-safe, and
	// must only be used from within conf_lock/conf_unlock block
	// it should be preferred for fast non-blocking lookups
	//
	// all the other config access functions are thread safe
	void function() nothrow @nogc conf_lock;
	void function() nothrow @nogc conf_unlock;
	immutable char * function(in char *key, in char *def) nothrow @nogc conf_get_str_fast;
	void function(in char *key, in char *def, char *buffer, int buffer_size) nothrow @nogc conf_get_str;
	float function(in char *key, float def) nothrow @nogc conf_get_float;
	int function(in char *key, int def) nothrow @nogc conf_get_int;
	long function(in char *key, long def) nothrow @nogc conf_get_int64;
	void function(in char *key, in char *val) nothrow @nogc conf_set_str;
	void function(in char *key, int val) nothrow @nogc conf_set_int;
	void function(in char *key, long val) nothrow @nogc conf_set_int64;
	void function(in char *key, float val) nothrow @nogc conf_set_float;
	DB_conf_item_t* function(in char *group, DB_conf_item_t *prev) nothrow @nogc conf_find;
	void function(in char *key) nothrow @nogc conf_remove_items;
	int function() nothrow @nogc conf_save;

	// plugin communication
	DB_decoder_s** function() nothrow @nogc plug_get_decoder_list;
	DB_vfs_s** function() nothrow @nogc plug_get_vfs_list;
	DB_output_s** function() nothrow @nogc plug_get_output_list;
	DB_dsp_s** function() nothrow @nogc plug_get_dsp_list;
	DB_playlist_s** function() nothrow @nogc plug_get_playlist_list;
	DB_plugin_s** function() nothrow @nogc plug_get_list;
	immutable char** function() nothrow @nogc plug_get_gui_names;
	immutable char * function(in char *id) nothrow @nogc plug_get_decoder_id;
	void function(in char *id) nothrow @nogc plug_remove_decoder_id;
	DB_plugin_s* function(in char *id) nothrow @nogc plug_get_for_id;

	// misc utilities
	// returns 1 if the track is represented as a local file
	// returns 0 if it's a remote file, e.g. a network stream
	// since API 1.5 it also returns 1 for vfs tracks, e.g. from ZIP files
	int function(in char *fname) nothrow @nogc is_local_file;

	// pcm utilities
	int function(in ddb_waveformat_t * inputfmt, in char *input, in ddb_waveformat_t *outputfmt, char *output, int inputsize) nothrow @nogc pcm_convert;

	// dsp preset management
	int function(in char *fname, ddb_dsp_context_s **head) nothrow @nogc dsp_preset_load;
	int function(in char *fname, ddb_dsp_context_s *head) nothrow @nogc dsp_preset_save;
	void function(ddb_dsp_context_s *head) nothrow @nogc dsp_preset_free;

	// since 1.2
	static if (DDB_API_LEVEL >= 2) {
		ddb_playlist_t* function(in char *title) nothrow @nogc plt_alloc;
		void function(ddb_playlist_t *plt) nothrow @nogc plt_free;

		void function(ddb_playlist_t *plt, int fast) nothrow @nogc plt_set_fast_mode;
		int function(ddb_playlist_t *plt) nothrow @nogc plt_is_fast_mode;

		immutable char * function(in char *str) nothrow @nogc metacache_add_string;
		void function(in char *str) nothrow @nogc metacache_remove_string;
		void function(in char *str) nothrow @nogc metacache_ref;
		void function(in char *str) nothrow @nogc metacache_unref;

		// this function must return original un-overriden value (ignoring the keys prefixed with '!')
		// it's not thread-safe, and must be used under the same conditions as the
		// pl_find_meta
		immutable char * function(DB_playItem_t *it, in char *key) nothrow @nogc pl_find_meta_raw;
	}

	// since 1.3
	static if (DDB_API_LEVEL >= 3) {
		int function() nothrow @nogc streamer_dsp_chain_save;
	}

	// since 1.4
	static if (DDB_API_LEVEL >= 4) {
		int function(DB_playItem_t *it, in char *key, char *val, int size) nothrow @nogc pl_get_meta;
		int function(DB_playItem_t *it, in char *key, char *val, int size) nothrow @nogc pl_get_meta_raw;
		int function(ddb_playlist_t *handle, in char *key, char *val, int size) nothrow @nogc plt_get_meta;

		// fast way to test if a field exists in playitem
		int function(DB_playItem_t *it, in char *key) nothrow @nogc pl_meta_exists;
	}

	// since 1.5
	static if (DDB_API_LEVEL >= 5) {
		// register/unregister for getting continuous wave data
		// mainly for visualization
		// ctx must be unique
		// the waveform data can be arbitrary size
		// the samples are interleaved
		void function(void *ctx, void function(void *ctx, ddb_audio_data_t *data) callback) nothrow @nogc vis_waveform_listen;
		void function(void *ctx) nothrow @nogc vis_waveform_unlisten;

		// register/unregister for getting continuous spectrum (frequency domain) data
		// mainly for visualization
		// ctx must be unique
		// the data always contains DDB_FREQ_BANDS frames
		// max number of channels is DDB_FREQ_MAX_CHANNELS
		// the samples are non-interleaved
		void function(void *ctx, void function(void *ctx, ddb_audio_data_t *data) callback) nothrow @nogc vis_spectrum_listen;
		void function(void *ctx) nothrow @nogc vis_spectrum_unlisten;

		// this is useful to mute/unmute audio, and query the muted status, from
		// plugins, without touching the volume control
		void function(int mute) nothrow @nogc audio_set_mute;
		int function() nothrow @nogc audio_is_mute;

		// this is useful for prompting a user when he attempts to quit the player
		// while something is working in background, e.g. the Converter,
		// and let him finish or cancel the background jobs.
		void function() nothrow @nogc background_job_increment;
		void function() nothrow @nogc background_job_decrement;
		int function() nothrow @nogc have_background_jobs;

		// utility function to get plt idx from handle
		int function(ddb_playlist_t *plt) nothrow @nogc plt_get_idx;

		// save referenced playlist in config
		// same as pl_save_current, but for index
		int function(int n) nothrow @nogc plt_save_n;

		// same as pl_save_current, but for playlist pointer
		int function(ddb_playlist_t *plt) nothrow @nogc plt_save_config;

		// register file added callback
		// the callback will be called for each file
		// the visibility is taken from plt_add_* arguments
		// the callback must return 0 to continue, or -1 to abort the operation.
		// returns ID
		int function(int function(ddb_fileadd_data_t *data, void *user_data) callback, void *user_data) nothrow @nogc listen_file_added;
		void function(int id) nothrow @nogc unlisten_file_added;

		int function(void function(ddb_fileadd_data_t *data, void *user_data) callback_begin, void function(ddb_fileadd_data_t *data, void *user_data) callback_end, void *user_data) nothrow @nogc listen_file_add_beginend;
		void function(int id) nothrow @nogc unlisten_file_add_beginend;

		// visibility is a number, which tells listeners about the caller.
		// the value DDB_FILEADD_VISIBILITY_GUI (or 0) is reserved for callers which
		// want the GUI to intercept the calls and show visual updates.
		//
		// this is the default value passed from plt_load, plt_add_dir, plt_add_file.
		//
		// the values up to 10 are registered for deadbeef itself, so please avoid
		// using them in your plugins, unless you really know what you're doing.
		// any values above 10 are free for any use.
		//
		// the "callback", if not NULL, will be called with the passed "user_data",
		// for each track.
		//
		// the registered listeners will be called too, the ddb_fileadd_data_t
		// has the visibility
		DB_playItem_t* function(int visibility, ddb_playlist_t *plt, ddb_playItem_t *after, in char *fname, int *pabort, int function(DB_playItem_t *it, void *user_data) callback, void *user_data) nothrow @nogc plt_load2;
		int function(int visibility, ddb_playlist_t *plt, in char *fname, int function(DB_playItem_t *it, void *user_data) callback, void *user_data) nothrow @nogc plt_add_file2;
		int function(int visibility, ddb_playlist_t *plt, in char *dirname, int function(DB_playItem_t *it, void *user_data) callback, void *user_data) nothrow @nogc plt_add_dir2;
		ddb_playItem_t* function(int visibility, ddb_playlist_t *playlist, ddb_playItem_t *after, in char *fname, int *pabort, int function(DB_playItem_t *it, void *user_data) callback, void *user_data) nothrow @nogc plt_insert_file2;
		ddb_playItem_t* function(int visibility, ddb_playlist_t *plt, ddb_playItem_t *after, in char *dirname, int *pabort, int function(DB_playItem_t *it, void *user_data) callback, void *user_data) nothrow @nogc plt_insert_dir2;

		// request lock for adding files to playlist
		// returns 0 on success
		// this function may return -1 if it is not possible to add files right now.
		// caller must cancel operation in this case,
		// or wait until previous operation finishes
		// NOTE: it's not guaranteed that all deadbeef versions support
		// adding the files to different playlists in parallel.
		int function(ddb_playlist_t *plt, int visibility) nothrow @nogc plt_add_files_begin;

		// release the lock for adding files to playlist
		// end must be called when add files operation is finished
		void function(ddb_playlist_t *plt, int visibility) nothrow @nogc plt_add_files_end;

		// deselect all tracks in playlist
		void function(ddb_playlist_t *plt) nothrow @nogc plt_deselect_all;
	}
	// since 1.6
	static if (DDB_API_LEVEL >= 6) {
		void function(ddb_playlist_t *plt, int scroll) nothrow @nogc plt_set_scroll;
		int function(ddb_playlist_t *plt) nothrow @nogc plt_get_scroll;
	}

	// since 1.8
	static if (DDB_API_LEVEL >= 8) {
		// **** title formatting v2 ****

		// compile the input title formatting string into bytecode
		// script: freeform string with title formatting special characters in it
		// returns the pointer to compiled bytecode, which must be tf_free'd by the caller.
		char * function(in char *script) nothrow @nogc tf_compile;

		// free the code returned by tf_compile
		void function(char *code) nothrow @nogc tf_free;

		// evaluate the titleformatting script in a given context
		// ctx: a pointer to ddb_tf_context_t structure initialized by the caller
		// code: the bytecode data created by tf_compile
		// out: buffer allocated by the caller, must be big enough to fit the output string
		// outlen: the size of out buffer
		// returns -1 on fail, output size on success
		int function(ddb_tf_context_t *ctx, in char *code, char *output, int outlen) nothrow @nogc tf_eval;

		// sort using title formatting v2
		void function(ddb_playlist_t *plt, int iter, int id, in char *format, int order) nothrow @nogc plt_sort_v2;

		// playqueue APIs
		int function(DB_playItem_t *it) nothrow @nogc playqueue_push;
		void function() nothrow @nogc playqueue_pop;
		void function(DB_playItem_t *it) nothrow @nogc playqueue_remove;
		void function() nothrow @nogc playqueue_clear;
		int function(DB_playItem_t *it) nothrow @nogc playqueue_test;
		int function() nothrow @nogc playqueue_get_count;
		DB_playItem_t* function(int n) nothrow @nogc playqueue_get_item;
		int function(int n) nothrow @nogc playqueue_remove_nth;
		void function(int n, DB_playItem_t *it) nothrow @nogc playqueue_insert_at;

		// system directory API, returns path by id from ddb_sys_directory_t enum
		immutable char * function(int dir_id) nothrow @nogc get_system_dir;

		// set the selected playlist for the ongoing plugin action.
		// the "set" function is expected to be called by the UI plugin,
		// while the "get" is expected to be called by the action code.
		void function(ddb_playlist_t *plt) nothrow @nogc action_set_playlist;

		// returns one of:
		// selected playlist for context menu for the DDB_ACTION_CTX_PLAYLIST,
		// or the current active playlist for any other context.
		// returned value cannot be NULL
		// returned value is refcounted, so remember to call plt_unref.
		ddb_playlist_t* function() nothrow @nogc action_get_playlist;

		// convert legacy title formatting to the new format, usable with tf_compile
		void function(in char *fmt, char *output, int outsize) nothrow @nogc tf_import_legacy;
	}
}

// NOTE: an item placement must be selected like this
// if (flags & DB_ACTION_COMMON)  -> main menu, or nowhere, or where GUI plugin wants
//    basically, to put it into main menu, prefix the item title with the menu name
//    e.g. title = "File/MyItem" --> this will add the item under File menu
//
// if (flags & PLAYLIST)  -> playlist (tab) context menu
//
// if (none of the above)  -> track context menu

enum {
	/* Action in main menu (or whereever ui prefers) */
	DB_ACTION_COMMON = 1 << 0,

	/* Can handle single track */
	DB_ACTION_SINGLE_TRACK = 1 << 1,

	/* Can handle multiple tracks */
	DB_ACTION_MULTIPLE_TRACKS = 1 << 2,

	/* DEPRECATED in API 1.5 */
	DB_ACTION_ALLOW_MULTIPLE_TRACKS = 1 << 2,

	/* DEPRECATED in API 1.5, ignored in callback2 */
	/* Action can (and prefer) traverse multiple tracks by itself */
	DB_ACTION_CAN_MULTIPLE_TRACKS = 1 << 3,

	/* Action is inactive */
	DB_ACTION_DISABLED = 1 << 4,

	/* DEPRECATED in API 1.5, ignored in callback2 */
	/* since 1.2 */
	/* Action for the playlist (tab) */
	DB_ACTION_PLAYLIST = 1 << 5,

	/* add item to menu(s), if contains slash symbol(s) */
	DB_ACTION_ADD_MENU = 1 << 6
};

// action contexts
// since 1.5
static if (DDB_API_LEVEL >= 5) {
	enum {
		DDB_ACTION_CTX_MAIN,
		DDB_ACTION_CTX_SELECTION,
		// NOTE: starting with API 1.8, plugins should be using the
		// action_get_playlist function for getting the playlist pointer.
		DDB_ACTION_CTX_PLAYLIST,
		DDB_ACTION_CTX_NOWPLAYING,
		DDB_ACTION_CTX_COUNT
	};
}

alias DB_plugin_action_callback_t = int function(DB_plugin_action_s *action, void *userdata);
static if (DDB_API_LEVEL >= 5) {
	alias DB_plugin_action_callback2_t = int function(DB_plugin_action_s *action, int ctx);
}

struct DB_plugin_action_s {
	const char *title;
	const char *name;
	uint flags;
	// the use of "callback" is deprecated,
	// only use it if the code must be compatible with API 1.4
	// otherwise switch to callback2
	DB_plugin_action_callback_t callback;
	DB_plugin_action_s *next;
	static if (DDB_API_LEVEL >= 5) {
		DB_plugin_action_callback2_t callback2;
	}
}
alias DB_plugin_action_t = DB_plugin_action_s;

// base plugin interface
struct DB_plugin_s {
	// type must be one of DB_PLUGIN_ types
	int type;
	// api version
	short api_vmajor;
	short api_vminor;
	// plugin version
	short version_major;
	short version_minor;

	uint flags; // currently unused
	uint reserved1;
	uint reserved2;
	uint reserved3;

	// any of those can be left NULL
	// though it's much better to fill them with something useful
	immutable char *id; // id used for serialization and runtime binding
	immutable char *name; // short name
	immutable char *descr; // short description (what the plugin is doing)
	immutable char *copyright; // copyright notice(s), list of developers, links to original works, etc
	immutable char *website; // plugin website

	// plugin-specific command interface; can be NULL
	int function(int cmd, ...) command;

	// start is called to start plugin; can be NULL
	int function() start;

	// stop is called to deinit plugin; can be NULL
	int function() stop;

	// connect is called to setup connections between different plugins
	// it is called after all plugin's start method was executed
	// can be NULL
	// NOTE for GUI plugin developers: don't initialize your widgets/windows in
	// the connect method. look for up-to-date information on wiki:
	// http://github.com/Alexey-Yakovenko/deadbeef/wiki/Porting-GUI-plugins-to-deadbeef-from-0.5.x-to-0.6.0
	int function() connect;

	// opposite of connect, will be called before stop, while all plugins are still
	// in "started" state
	int function() disconnect;

	// exec_cmdline may be called at any moment when user sends commandline to player
	// can be NULL if plugin doesn't support commandline processing
	// cmdline is 0-separated list of strings, guaranteed to have 0 at the end
	// cmdline_size is number of bytes pointed by cmdline
	int function(in char *cmdline, int cmdline_size) exec_cmdline;

	// @returns linked list of actions for the specified track
	// when it is NULL -- the plugin must return list of all actions
	DB_plugin_action_t* function(DB_playItem_t *it) get_actions;

	// mainloop will call this function for every plugin
	// so that plugins may handle all events;
	// can be NULL
	int function(uint id, uintptr_t ctx, uint p1, uint p2) message;

	// plugin configuration dialog is constructed from this data
	// can be NULL
	immutable char *configdialog;
}
alias DB_plugin_t = DB_plugin_s;

// file format stuff

// channel mask - combine following flags to tell streamer which channels are
// present in input/output streams
enum {
	DDB_SPEAKER_FRONT_LEFT = 0x1,
	DDB_SPEAKER_FRONT_RIGHT = 0x2,
	DDB_SPEAKER_FRONT_CENTER = 0x4,
	DDB_SPEAKER_LOW_FREQUENCY = 0x8,
	DDB_SPEAKER_BACK_LEFT = 0x10,
	DDB_SPEAKER_BACK_RIGHT = 0x20,
	DDB_SPEAKER_FRONT_LEFT_OF_CENTER = 0x40,
	DDB_SPEAKER_FRONT_RIGHT_OF_CENTER = 0x80,
	DDB_SPEAKER_BACK_CENTER = 0x100,
	DDB_SPEAKER_SIDE_LEFT = 0x200,
	DDB_SPEAKER_SIDE_RIGHT = 0x400,
	DDB_SPEAKER_TOP_CENTER = 0x800,
	DDB_SPEAKER_TOP_FRONT_LEFT = 0x1000,
	DDB_SPEAKER_TOP_FRONT_CENTER = 0x2000,
	DDB_SPEAKER_TOP_FRONT_RIGHT = 0x4000,
	DDB_SPEAKER_TOP_BACK_LEFT = 0x8000,
	DDB_SPEAKER_TOP_BACK_CENTER = 0x10000,
	DDB_SPEAKER_TOP_BACK_RIGHT = 0x20000
}

struct DB_fileinfo_s {
	DB_decoder_s *plugin;

	// these parameters should be set in decoder->open
	ddb_waveformat_t fmt;

	// readpos should be updated to current decoder time (in seconds)
	float readpos;

	// this is the (optional) file handle, that can be used by streamer to
	// request interruption of current read operation
	DB_FILE *file;
}
alias DB_fileinfo_t = DB_fileinfo_s;

// Decoders should try to output 16 bit stream when this flag is set, for
// performance reasons.
enum DDB_DECODER_HINT_16BIT = 0x1;
static if (DDB_API_LEVEL >= 8) {
	enum {
		// Decoders should only call the streamer_set_bitrate from plugin.read function,
		// and only when this flag is set.
		DDB_DECODER_HINT_NEED_BITRATE = 0x2,
		// Decoders can do their own infinite looping when this flag is set, in the
		// "Loop Single" looping mode.
		DDB_DECODER_HINT_CAN_LOOP = 0x4,
	}
}

// decoder plugin
struct DB_decoder_s {
	DB_plugin_t plugin;

	DB_fileinfo_t* function(uint hints) open;

	// init is called to prepare song to be started
	int function(DB_fileinfo_t *info, DB_playItem_t *it) init;

	// free is called after decoding is finished
	void function(DB_fileinfo_t *info) free;

	// read is called by streamer to decode specified number of bytes
	// must return number of bytes that were successfully decoded (sample aligned)
	int function(DB_fileinfo_t *info, char *buffer, int nbytes) read;

	int function(DB_fileinfo_t *info, float seconds) seek;

	// perform seeking in samples (if possible)
	// return -1 if failed, or 0 on success
	// if -1 is returned, that will mean that streamer must skip that song
	int function(DB_fileinfo_t *info, int sample) seek_sample;

	// 'insert' is called to insert new item to playlist
	// decoder is responsible to calculate duration, split it into subsongs, load cuesheet, etc
	// after==NULL means "prepend before 1st item in playlist"
	DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, in char *fname) insert;

	int function(DB_fileinfo_t *info) numvoices;
	void function(DB_fileinfo_t *info, int voice, int mute) mutevoice;

	int function(DB_playItem_t *it) read_metadata;
	int function(DB_playItem_t *it) write_metadata;

	// NULL terminated array of all supported extensions
	// examples:
	// { "aac", "wma", "tak", NULL } -- supports 3 file extensions
	// since API 1.9: { "*", NULL } -- supports any file extensions
	immutable char **exts;

	// NULL terminated array of all supported prefixes (UADE support needs that)
	// e.g. "mod.song_title"
	immutable char **prefixes;

	static if (DDB_API_LEVEL >= 7) {
		// This function's purpose is to open the file, so that the file handle is
		// immediately accessible via DB_fileinfo_t, and can be used with fabort.
		// If a plugin is using open2, it should not reopen the file from init.
		// Plugins _must_ implement open even if open2 is present,
		// because existing code may rely on it.
		DB_fileinfo_t* function(uint hints, DB_playItem_t *it) open2;
	}
}
alias DB_decoder_t = DB_decoder_s;

// output plugin
struct DB_output_s {
	DB_plugin_t plugin;
	// init is called once at plugin activation
	int function() init;
	// free is called if output plugin was changed to another, or unload is about to happen
	int function() free;
	// reconfigure output to another format
	int function(ddb_waveformat_t *fmt) setformat;
	// play, stop, pause, unpause are called by deadbeef in response to user
	// events, or as part of streaming process
	int function() play;
	int function() stop;
	int function() pause;
	int function() unpause;
	// one of output_state_t enum values
	int function() state;
	// soundcard enumeration (can be NULL)
	void function(void function(in char *name, in char *desc, void*) callback, void *userdata) enum_soundcards;

	// parameters of current output
	ddb_waveformat_t fmt;

	// set to 1 if volume control is done internally by plugin
	int has_volume;
}
alias DB_output_t = DB_output_s;

/+
// dsp plugin
// see also: examples/dsp_template.c in git
#define DDB_INIT_DSP_CONTEXT(var,type,plug) {\
    memset(var,0,sizeof(type));\
    var->ctx.plugin=plug;\
    var->ctx.enabled=1;\
}
+/

struct ddb_dsp_context_s {
	// pointer to DSP plugin which created this context
	DB_dsp_s *plugin;

	// pointer to the next DSP plugin context in the chain
	ddb_dsp_context_s *next;

	/+ wut? +/
	// read only flag; set by DB_dsp_t::enable
	//unsigned enabled : 1;
}
alias ddb_dsp_context_t = ddb_dsp_context_s;

struct DB_dsp_s {
	DB_plugin_t plugin;

	ddb_dsp_context_t* function() open;

	void function(ddb_dsp_context_t *ctx) close;

	// samples are always interleaved floating point
	// returned value is number of output frames (multichannel samples)
	// plugins are allowed to modify channels, samplerate, channelmask in the fmt structure
	// buffer size can fit up to maxframes frames
	// by default ratio=1, and plugins don't need to touch it unless they have to
	int function(ddb_dsp_context_t *ctx, float *samples, int frames, int maxframes, ddb_waveformat_t *fmt, float *ratio) process;

	void function(ddb_dsp_context_t *ctx) reset;

	// num_params can be NULL, to indicate that plugin doesn't expose any params
	//
	// if num_params is non-NULL -- get_param_name, set_param and get_param must
	// all be implemented
	//
	// param names are for display-only, and are allowed to contain spaces
	int function() num_params;
	immutable char * function(int p) get_param_name;
	void function(ddb_dsp_context_t *ctx, int p, in char *val) set_param;
	void function(ddb_dsp_context_t *ctx, int p, char *str, int len) get_param;

	// config dialog implementation uses set/get param, so they must be
	// implemented if this is nonzero
	immutable char *configdialog;

	// since 1.1
	static if (DDB_API_LEVEL >= 1) {
		// can be NULL
		// should return 1 if the DSP plugin will not touch data with the current parameters;
		// 0 otherwise
		int function(ddb_dsp_context_t *ctx, ddb_waveformat_t *fmt) can_bypass;
	}
}
alias DB_dsp_t = DB_dsp_s;

// misc plugin
// purpose is to provide extra services
// e.g. scrobbling, converting, tagging, custom gui, etc.
// misc plugins should be mostly event driven, so no special entry points in them
struct DB_misc_t {
	DB_plugin_t plugin;
} ;

// vfs plugin
// provides means for reading, seeking, etc
// api is based on stdio
struct DB_vfs_s {
	DB_plugin_t plugin;

	// capabilities
	immutable char ** function() get_schemes; // NULL-terminated list of supported schemes, e.g. {"http://", "ftp://", NULL}; can be NULL

	int function() is_streaming; // return 1 if the plugin streaming data over slow connection, e.g. http; plugins will avoid scanning entire files if this is the case

	int function(in char *fname) is_container; // should return 1 if this plugin can parse specified file

	// this allows interruption of hanging network streams
	void function(DB_FILE *stream) abort;

	// file access, follows stdio API with few extension
	DB_FILE* function(in char *fname) open;
	void function(DB_FILE *f) close;
	size_t function(void *ptr, size_t size, size_t nmemb, DB_FILE *stream) read;
	int function(DB_FILE *stream, long offset, int whence) seek;
	long function(DB_FILE *stream) tell;
	void function(DB_FILE *stream) rewind;
	long function(DB_FILE *stream) getlength;

	// should return mime-type of a stream, if known; can be NULL
	immutable char * function(DB_FILE *stream) get_content_type;

	// associates stream with a track, to allow dynamic metadata updating, like
	// in icy protocol
	void function(DB_FILE *f, DB_playItem_t *it) set_track;

	// folder access, follows dirent API, and uses dirent data structures
	int function(in char *dir, dirent ***namelist, int function(in dirent *) selector, int function(in dirent **, in dirent **) cmp) scandir;

	static if (DDB_API_LEVEL >= 6) {
		// returns URI scheme for a given file name, e.g. "zip://"
		// can be NULL
		// can return NULL
		immutable char * function(in char *fname) get_scheme_for_name;
	}
}
alias DB_vfs_t = DB_vfs_s;

// gui plugin
// only one gui plugin can be running at the same time
// should provide GUI services to other plugins

// this structure represents a gui dialog with callbacks to set/get params
// documentation should be available here:
// http://github.com/Alexey-Yakovenko/deadbeef/wiki/GUI-Script-Syntax
struct ddb_dialog_t {
	immutable char *title;
	immutable char *layout;
	void function(in char *key, in char *value) set_param;
	void function(in char *key, char *value, int len, in char *def) get_param;

	static if (DDB_API_LEVEL >= 4) {
		void *parent;
	}
}

enum {
	ddb_button_ok,
	ddb_button_cancel,
	ddb_button_close,
	ddb_button_apply,
	ddb_button_yes,
	ddb_button_no,
	ddb_button_max,
};

struct DB_gui_s {
	DB_plugin_t plugin;

	// returns response code (ddb_button_*)
	// buttons is a bitset, e.g. (1<<ddb_button_ok)|(1<<ddb_button_cancel)
	int function(ddb_dialog_t *dlg, uint buttons, int function(int button, void *ctx) callback, void *ctx) run_dialog;
}
alias DB_gui_t = DB_gui_s;

// playlist plugin
struct DB_playlist_s {
	DB_plugin_t plugin;

	DB_playItem_t* function(ddb_playlist_t *plt, DB_playItem_t *after, in char *fname, int *pabort, int function(DB_playItem_t *it, void *data) cb, void *user_data) load;

	// will save items from first to last (inclusive)
	// format is determined by extension
	// playlist is protected from changes during the call
	int function(ddb_playlist_t *plt, in char *fname, DB_playItem_t *first, DB_playItem_t *last) save;

	immutable char **extensions; // NULL-terminated list of supported file extensions, e.g. {"m3u", "pls", NULL}

	// since 1.5
	static if (DDB_API_LEVEL >= 5) {
		DB_playItem_t* function(int visibility, ddb_playlist_t *plt, DB_playItem_t *after, in char *fname, int *pabort) load2;
	}
}
alias DB_playlist_t = DB_playlist_s;