//| Copyright: (C) 2019-2020 Kevin Larke <contact AT larke DOT org> 
//| License: GNU GPL version 3.0 or above. See the accompanying LICENSE file.
#ifndef cmdIf_h
#define cmdIf_h

class Fl_Output;


// This class allows the 'model' to run independently
// from the user interface. This eliminates problems with
// application unresponsiveness which would arise from
// executing compute intensive operations from UI control or
// menu callback functions.  It also allows a progress
// or status bar to be shown while the model operation
// is in progress.

// The class works by enqueueing all incoming commands
// into a thread-safe queue. An internal worker thread
// executes the commands in the order they are received
// and thereby changes the state of the model.

// The results of model changes are posted to a second
// thread-safe queue.  These responses are picked
// up by the onIdle() member and dispatched to an
// object  with a cmIfRspdr interface.  Note that because
// the onIdle() function is called from the applications
// idle handler the callbacks to the cmIfRspdr are
// always in the application thread and can therefore
// safely interact with any application data constructs.

// All calls to this object and all callbacks from it,
// therefore occur in the application thread.


class cmdIfRspdr
{
 public:
  virtual ~cmdIfRspdr(){}
  virtual void cmdIfShowStatusMsg( const char* msg ) = 0;
  virtual void cmdIfHideStatus() = 0;
  virtual void cmdIfErrorMsg( const char* msg ) = 0;
  virtual void cmdIfTimeLineMsg( const void* msg, unsigned msgByteCnt ) = 0;
  virtual void cmdIfAudioFileLoad( unsigned fileId ) = 0;
  virtual void cmdIfScoreMsg(    const void* msg, unsigned msgByteCnt ) = 0;

  virtual void cmdIfOnTimeLineMarkerSelect( unsigned markerId ) = 0;
  virtual void cmdIfOnTimeLineMidiEvtSelect(unsigned midiEvtId ) = 0;
  virtual void cmdIfOnScoreBarSelect(       unsigned scoreIndex ) = 0;


};

class cmdIf
{
 public:

  typedef enum
  {
    kOkRC,
    kCmdFailRC,
    kCmdEnqueueFailRC
  } rc_t;

  cmdIf( cmCtx_t* ctx, cmdIfRspdr* rspdr, const cmChar_t* audioPath=NULL );
  virtual ~cmdIf();

  // Open a time line.
  rc_t         open( const cmChar_t* fn );

  // Close the time line.
  rc_t         close();

  // Time line interface 
  const cmChar_t*        tlFileName() const;
  const cmTlObj_t*       tlObjIdToPtr( unsigned tlObjId ) const;
  const cmTlMidiFile_t*  tlMidiFileObjPtr(  const cmTlObj_t* op ) const;
  const cmTlAudioFile_t* tlAudioFileObjPtr( const cmTlObj_t* op ) const;
  const cmTlMidiEvt_t*   tlMidiEvtObjPtr(   const cmTlObj_t* op ) const;
  const cmTlAudioEvt_t*  tlAudioEvtObjPtr(  const cmTlObj_t* op ) const;
  const cmTlMarker_t*    tlMarkerObjPtr(    const cmTlObj_t* op ) const;

  const cmChar_t*         scoreFileName() const;
  const cmScoreEvt_t*     scoreEventIdToPtr( unsigned scEvtId ) const;
  const cmScoreSection_t* scoreSectionIdToPtr( unsigned scSectId ) const;

  // Make a time line sequence active.
  rc_t         selectSequence( unsigned id );

  // Load an audio file into the audio file mgr.
  // If an audio file path was set via setAudioFilePath() then
  // the directories referenced by 'fn' will be replaced by
  // the previously set audio file path.
  rc_t         audioFileLoad( const cmChar_t* fn, unsigned appFileId );

  // Return the audio file handle assigned to appFileId.
  cmAfmFileH_t audioFileHandle( unsigned appFileId );

  // Set the audio file location.
  void         setAudioFilePath( const cmChar_t* path ); 

  // Assign a score file
  rc_t         setScore( const cmChar_t* scoreFn );

  // Set the current score location
  void         setScoreLocation( unsigned locIdx, unsigned smpIdx, unsigned pitch, unsigned vel );

  // Set the value of a score variable
  void         setScoreVarValue( unsigned locIdx, unsigned varId, double value );

  // Set the performed dynamic level of a score event.
  void         setScoreDynLevel( unsigned evtIdx, unsigned dynLvl );

  void         onTimeLineMarkerSelected( unsigned markerTlId );
  void         onTimeLineMidiEvtSelected( unsigned midiEvtTlId );
  void         onScoreBarSelected( unsigned scoreIndex );

  // Generate or delete Audio/MIDI onset markers.
  rc_t         generateOnsetMarks();
  rc_t         deleteOnsetMarks();

  // True if the worker thread is running.
  bool isBusy() const;
  
  // Called by the application to dequeue messages via callbacks to 
  // the cmdIfRspdr.
  void onIdle();
  
  void testStub();
    
 private:

  // Id's used by cmd_t 
  typedef enum
  {
    kInvalidCmdId,      // 0
    kOpenCmdId,         // 1  app->thread
    kCloseCmdId,        // 2  app->thread
    kSelectSeqCmdId,    // 3  app->thread
    kAfLoadCmdId,       // 4  app->thread and thread->app
    kScoreCmdId,        // 5  app->thread    
    kShowStatusCmdId,   // 6  thread->app
    kHideStatusCmdId,   // 7  thread->app
    kErrMsgCmdId,       // 8  thread->app
    kTimeLineMsgCmdId,  // 9  thread->app
    kScoreMsgCmdId,     //10  thread->app
    kGenOnsetMarksCmdId,
    kDelOnsetMarksCmdId

  } cmdId_t;

  // Messages are passed between the app and the worker thread
  // and v.v. using this record format.  Note that the u.msg
  // field is always dynamically allocated by _enqueue() 
  // and must be released following the dequeue operation.
  typedef struct cmd_str
  {
    cmdId_t  id;      // cmdId
    unsigned byteCnt; // length of msg
    unsigned value;   // msg value

    union 
    {
      void* msg;     // msg[byteCnt] 
      char* string;  // string[byteCnt]
    } u;
  } cmd_t;

  cmCtx_t*    _ctx;        //
  cmErr_t     _err;        // 
  cmThreadH_t _thH;        // worker thread
  cmTs1p1cH_t _cmdQueH;    // app->model
  cmTs1p1cH_t _outQueH;    // model->appl
  cmTlH_t     _tlH;        // time line handle    
  cmAfmH_t    _afmH;       // audio file manager
  cmScH_t     _scH;        // score handle
  cmChar_t*   _afPath;     // 
  cmdIfRspdr* _rspdr;      // 
  unsigned    _curSeqId;   // seqId of last selected sequence


  // Functions called from the app thread.
  rc_t _sendCmd( cmdId_t id, unsigned value=0, const char* str=NULL );
  void _releaseQue( cmTs1p1cH_t* queHPtr );

  // Functions called from the worker thread
  static bool _thFunc( void* arg );
  void        _thDoOpen(      const cmd_t* cmd );
  void        _thDoClose(     const cmd_t* cmd );
  void        _thDoSelectSeq( const cmd_t* cmd );
  void        _thDoAfLoad(    const cmd_t* cmd );
  void        _thDoScore(     const cmd_t* cmd );
  void        _thDoGenOnsetMarks( const cmd_t* cmd );
  void        _thDoDelOnsetMarks( const cmd_t* cmd );

  //void        _thErrorMsg(    const char*  fmt, va_list vl );
  void        _thErrorMsg(    const char*  fmt, ... );
  //void        _thStatusMsg(   const char*  fmt, va_list vl );
  void        _thStatusMsg(   const char*  fmt, ... );
  void        _thSendResponse( cmdId_t id, const char* str = NULL, unsigned value=0 );
  static void _thSendTimeLineMsg( void* arg, const void* msg, unsigned byteCnt );
  static void _thSendScoreMsg(    void* arg, const void* msg, unsigned byteCnt );

  // Thread independent functions 
  rc_t _enqueue( cmTs1p1cH_t qH, cmdId_t id, unsigned value, const void* msg, unsigned msgByteCnt );


  // Print context information for selected time line objects
  void _onTimeLineObjSelected( unsigned tlObjId );

};


#endif