// Audio system result codes
enum
{
  kOkAsRC = cmOkRC,
  kThreadErrAsRC,
  kMutexErrAsRC,
  kTsQueueErrAsRC,
  kMsgEnqueueFailAsRC,
  kAudioDevSetupErrAsRC,
  kAudioBufSetupErrAsRC,
  kAudioDevStartFailAsRC,
  kAudioDevStopFailAsRC,
  kBufTooSmallAsRC,
  kNoMsgWaitingAsRC,
  kMidiSysFailAsRC,
  kSerialPortFailAsRC,
  kMsgSerializeFailAsRC,
  kStateBufFailAsRC,
  kInvalidArgAsRC,
  kNotInitAsRC
};

enum
{
  kAsDfltMsgQueueByteCnt   = 0xffff,
  kAsDfltDevFramesPerCycle = 512,
  kAsDfltDspFramesPerCycle = 64,
  kAsDfltBufCnt            = 3,
  kAsDfltSrate             = 44100,
  kAsDfltSyncToInputFl     = 1,
  kAsDfltMinMeterMs        = 10,
  kAsDfltMeterMs           = 50,
  kAsDfltMaxMeterMs        = 1000
};

typedef cmHandle_t cmAudioSysH_t;   // Audio system handle type
typedef unsigned   cmAsRC_t;        // Audio system result code

struct cmAudioSysCtx_str;

//
// DSP system callback function.
//
// This is the sole point of entry into the DSP system while the audio system is running.
//
// ctxPtr is pointer to a cmAudioSysCtx_t record.
//
// This function is called under two circumstances:
//
// 1) To notify the DSP system that the audio input/output buffers need to be serviced.
// This is a perioidic request which the DSP system uses as its execution trigger.
// cmAudioSysCtx_t.audioRateFl is set to true to indicate this type of callback.
//
// 2) To pass messages from the host application to the DSP system.
// The DSP system is asyncronous with the host because it executes in the 
// audio system thread rather than the host thread.  The cmAudioSysDeliverMsg() 
// function synchronizes incoming messages with the internal audio system 
// thread to prevent thread collisions.
//
// Notes:
// This callback is always made with the internal audio system mutex locked.
//
// The signal time covered by the callback is from 
// ctx-&gtbegSmpIdx to ctx-&gtbegSmpIdx+cfg-&gtdspFramesPerCycle.
//
// The return value is currently not used.
typedef cmRC_t (*cmAsCallback_t)(void* ctxPtr, unsigned msgByteCnt, const void* msgDataPtr );


// Audio device sub-sytem configuration record 
typedef struct cmAudioSysArgs_str
{
  cmRpt_t*        rpt;                // system console object
  const cmChar_t* inDevLabel;         // input audio device text label
  const cmChar_t* outDevLabel;        // output audio device text label
  unsigned        inDevIdx;           // input audio device index
  unsigned        outDevIdx;          // output audio device index 
  bool            syncInputFl;        // true/false sync the DSP update callbacks with audio input/output
  unsigned        msgQueueByteCnt;    // Size of the internal msg queue used to buffer msgs arriving via cmAudioSysDeliverMsg().
  unsigned        devFramesPerCycle;  // (512) Audio device samples per channel per device update buffer.
  unsigned        dspFramesPerCycle;  // (64) Audio samples per channel per DSP cycle.
  unsigned        audioBufCnt;        // (3) Audio device buffers.
  double          srate;              // Audio sample rate.
  int             srateMult;          // Sample rate multiplication factor (negative for divide)
} cmAudioSysArgs_t;

// Audio sub-system configuration record.
// This record is provided by the host to configure the audio system
// via cmAudioSystemAllocate() or cmAudioSystemInitialize().
typedef struct cmAudioSysSubSys_str
{
  cmAudioSysArgs_t args;               // Audio device configuration
  cmAsCallback_t   cbFunc;             // DSP system entry point function.
  void*            cbDataPtr;          // Host provided data for the DSP system callback. 
} cmAudioSysSubSys_t;


// Signature of a callback function provided by the audio system to receive messages 
// from the DSP system for later dispatch to the host application.
// This declaration is used by the DSP system implementation and the audio system.
// Note that this function is intended to convey one message broken into multiple parts.
// See cmTsQueueEnqueueSegMsg() for the equivalent interface.
typedef cmAsRC_t (*cmAsDspToHostFunc_t)(struct cmAudioSysCtx_str* p, const void* msgDataPtrArray[], unsigned msgByteCntArray[], unsigned msgSegCnt);

// Record passed with each call to the DSP callback function cmAsCallback_t
typedef struct cmAudioSysCtx_str
{
  void*               reserved;       // used internally by the audio system
  
  bool                audioRateFl;    // true if this is an audio update callback
  
  unsigned            srcNetNodeId;   // Source net node if this is a msg callback originating from a remote network node. 
  unsigned            asSubIdx;       // index of the sub-system this DSP process is serving
  
  cmAudioSysSubSys_t* ss;             // ptr to a copy of the cfg recd used to initialize the audio system
  unsigned            begSmpIdx;      // gives signal time as a sample count
  
  cmAsDspToHostFunc_t dspToHostFunc;  // Callback used by the DSP process to send messages to the host via the audio system. Returns a cmAsRC_t result code.
  
  // output (playback) buffers
  cmSample_t**        oChArray;       // each ele is a ptr to buffer with cfg.dspFramesPerCycle samples
  unsigned            oChCnt;         // count of output channels (ele's in oChArray[])
  cmTimeSpec_t        oTimeStamp;
  
  // input (recording) buffers
  cmSample_t**        iChArray;       // each ele is a ptr to buffer with cfg.dspFramesPerCycle samples
  unsigned            iChCnt;         // count of input channels (ele's in iChArray[])
  cmTimeSpec_t        iTimeStamp;
  
} cmAudioSysCtx_t;


// Audio system configuration record used by cmAudioSysAllocate().
typedef struct cmAudioSysCfg_str
{
  cmAudioSysSubSys_t*   ssArray;       // sub-system cfg record array
  unsigned              ssCnt;         // count of sub-systems 
  unsigned              meterMs;       // Meter sample period in milliseconds
  void*                 clientCbData;  // User arg. for clientCbFunc().
  cmTsQueueCb_t         clientCbFunc;  // Called by cmAudioSysReceiveMsg() to deliver internally generated msg's to the host. Set to NULL if msg's will be directly returned by buffers passed to
                                       // cmAudioSysReceiveMsg().  
  cmUdpNetH_t           netH;
  cmSeH_t               serialPortH;
} cmAudioSysCfg_t;

extern cmAudioSysH_t cmAudioSysNullHandle;

// Allocate and initialize an audio system as a collection of 'cfgCnt' sub-systems.
// Prior to call this function the audio audio ports system must be initalized 
// (via cmApInitialize()) and the MIDI port system must be initialized 
// (via cmMpInitialize()).  Note also that cmApFinalize() and cmMpFinalize() 
// cannot be called prior to cmAudioSysFree().
// See cmAudioSystemTest() for a complete example.
cmAsRC_t  cmAudioSysAllocate( cmAudioSysH_t* hp, cmRpt_t* rpt, const cmAudioSysCfg_t* cfg  );

// Finalize and release any resources held by the audio system.
cmAsRC_t  cmAudioSysFree( cmAudioSysH_t* hp );

// Returns true if 'h' is a handle which was successfully allocated by 
// cmAudioSysAllocate().
bool      cmAudioSysHandleIsValid( cmAudioSysH_t h );

// Reinitialize a previously allocated audio system.  This function
// begins with a call to cmAudioSysFinalize().   
// Use cmAudioSysEnable(h,true) to begin processing audio following this call.
cmAsRC_t  cmAudioSysInitialize( cmAudioSysH_t h, const cmAudioSysCfg_t* cfg );

// Complements cmAudioSysInitialize(). In general there is no need to call this function
// since calls to cmAudioSysInitialize() and cmAudioSysFree() automaticatically call it.
cmAsRC_t  cmAudioSysFinalize( cmAudioSysH_t h );

// Returns true if the audio system has been successfully initialized.
bool     cmAudioSysIsInitialized( cmAudioSysH_t );

// Returns true if the audio system is enabled.
bool      cmAudioSysIsEnabled( cmAudioSysH_t h );

// Enable/disable the audio system.  Enabling the starts audio stream
// in/out of the system.
cmAsRC_t  cmAudioSysEnable( cmAudioSysH_t h, bool enableFl );

//
// Host to DSP delivery functions
// 

// Deliver a message from the host application to the DSP process. (host -&gt DSP);
// The message is formed as a concatenation of the bytes in each of the segments
// pointed to by 'msgDataPtrArrary[segCnt][msgByteCntArray[segCnt]'.
// This is the canonical msg delivery function in so far as the other host-&gtDSP
// msg delivery function are written in terms of this function.
// The first 4 bytes in the first segment must contain the index of the audio sub-system
// which is to receive the message.
cmAsRC_t  cmAudioSysDeliverSegMsg(  cmAudioSysH_t h, const void* msgDataPtrArray[], unsigned msgByteCntArray[], unsigned msgSegCnt, unsigned srcNetNodeId );

// Deliver a single message from the host to the DSP system.
cmAsRC_t  cmAudioSysDeliverMsg(   cmAudioSysH_t h,  const void* msgPtr, unsigned msgByteCnt, unsigned srcNetNodeId );

// Deliver a single message from the host to the DSP system.
// Prior to delivery the 'id' is prepended to the message.
cmAsRC_t  cmAudioSysDeliverIdMsg(  cmAudioSysH_t h, unsigned asSubIdx, unsigned id, const void* msgPtr, unsigned msgByteCnt, unsigned srcNetNodeId );


//
// DSP to Host message functions
// 

// Is a msg from the DSP waiting to be picked up by the host?  (host &lt- DSP)
// 0  = no msgs are waiting or the msg queue is locked by the DSP process.
// &gt0 = the size of the buffer required to hold the next msg returned via 
// cmAudioSysReceiveMsg().
unsigned  cmAudioSysIsMsgWaiting(  cmAudioSysH_t h );

// Copy the next available msg sent from the DSP process to the host into the host supplied msg buffer
// pointed to by 'msgBufPtr'.  Set 'msgDataPtr' to NULL to receive msg by callback from cmAudioSysCfg_t.clientCbFunc.
// Returns kBufTooSmallAsRC if msgDataPtr[msgByteCnt] is too small to hold the msg.
// Returns kNoMsgWaitingAsRC if no messages are waiting for delivery or the msg queue is locked by the DSP process.
// Returns kOkAsRC if a msg was delivered.
// Call cmAudioSysIsMsgWaiting() prior to calling this function to get
// the size of the data buffer required to hold the next message.
cmAsRC_t  cmAudioSysReceiveMsg(    cmAudioSysH_t h,  void* msgDataPtr, unsigned msgByteCnt );


// Fill an audio system status record.
void      cmAudioSysStatus(  cmAudioSysH_t h, unsigned asSubIdx, cmAudioSysStatus_t* statusPtr );

// Enable cmAudioSysStatus_t notifications to be sent periodically to the host.
// Set asSubIdx to cmInvalidIdx to enable/disable all sub-systems.
// The notifications occur approximately every cmAudioSysCfg_t.meterMs milliseconds.
void cmAudioSysStatusNotifyEnable( cmAudioSysH_t, unsigned asSubIdx, bool enableFl );

// Return a pointer the context record associated with a sub-system
cmAudioSysCtx_t* cmAudioSysContext( cmAudioSysH_t h, unsigned asSubIdx );

// Return the count of audio sub-systems.
// This is the same as the count of cfg recds passed to cmAudioSystemInitialize().
unsigned cmAudioSysSubSystemCount( cmAudioSysH_t h );

// Audio system test and example function.
void      cmAudioSysTest( cmRpt_t* rpt, int argc, const char* argv[] );