/*

     File: AUTimestampGenerator.h

 Abstract: Part of CoreAudio Utility Classes

  Version: 1.1

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*/

#ifndef __AUTimestampGenerator_h__

#define __AUTimestampGenerator_h__

#include <math.h>

#include "CAHostTimeBase.h"

#include <stdio.h>

#define TSGFMT "0x%10qx"

//#define TSGFMT "%10qd"

// This class generates a continuously increasing series of timestamps based

// on a series of potentially discontinuous timestamps (as can be delivered from

// CoreAudio in the event of an overload or major engine change).

// N.B.: "output" = downstream (source) timestamp

//       "input"  = upstream (derived) timestamp

class AUTimestampGenerator {

public:

    AUTimestampGenerator(bool hostTimeDiscontinuityCorrection = false)

    {

        mState.mStartInputAtZero = true;

        mState.mBypassed = false;

        mState.mHostTimeDiscontinuityCorrection = hostTimeDiscontinuityCorrection;

#if DEBUG

        mVerbosity = 0;

        snprintf(mDebugName, sizeof(mDebugName), "tsg @ %p", this);

#endif

        // CAHostTimeBase should be used instead of the calls in <CoreAudio/HostTime.h>

        // we make this call here to ensure that this is initialized, otherwise the first time

        // you do actually call CAHostTimeBase to do work, can be on the render thread, and lead to unwanted VM faults

        CAHostTimeBase::GetFrequency();

        Reset();

    }

    void    SetStartInputAtZero(bool b) { mState.mStartInputAtZero = b; }

    bool    GetStartInputAtZero() const { return mState.mStartInputAtZero; }

    // bypassing is intended for a narrow special case. the upstream sample time will always be the same as the downstream time.

    void    SetBypassed(bool b) { mState.mBypassed = b; }

    bool    GetBypassed() const { return mState.mBypassed; }

    // Call this to reset the timeline.

    void    Reset()

    {

        mState.mCurrentInputTime.mSampleTime = 0.;

        mState.mNextInputSampleTime = 0.;

        mState.mCurrentOutputTime.mSampleTime = 0.;

        mState.mNextOutputSampleTime = 0.;

        mState.mLastOutputTime.mFlags = 0;

        mState.mRateScalarAdj = 1.;

        mFirstTime = true;

#if DEBUG

        if (mVerbosity)

            printf("%-20.20s: Reset\n", mDebugName);

#endif

    }

    // Call this once per render cycle with the downstream timestamp.

    // expectedDeltaFrames is the expected difference between the current and NEXT 

    //  downstream timestamps.

    // sampleRate is the OUTPUT sample rate.

    void    AddOutputTime(const AudioTimeStamp &inTimeStamp, Float64 expectedDeltaFrames, double outputSampleRate, double rateScalarAdj=1.0);

    // Call this once per render cycle to obtain the upstream timestamp.

    // framesToAdvance is the number of frames the input timeline is to be

    //  advanced during this render cycle.

    // sampleRate is the INPUT sample rate.

    const AudioTimeStamp &  GenerateInputTime(Float64 framesToAdvance, double inputSampleRate, bool advanceHostTime = false);

    // this can be called to override the setting of the next input sample time in GenerateInputTime

    void                    Advance(Float64 framesToAdvance)

    {

#if DEBUG

        if (mVerbosity > 1)

            printf("%-20.20s:   ADVANCE         in = " TSGFMT "                    advance = " TSGFMT "\n", mDebugName, (SInt64)mState.mCurrentInputTime.mSampleTime, (SInt64)framesToAdvance);

#endif

        mState.mNextInputSampleTime = mState.mCurrentInputTime.mSampleTime + framesToAdvance;

    }

    struct State {

        AudioTimeStamp      mCurrentInputTime;

        Float64             mNextInputSampleTime;

        Float64             mNextOutputSampleTime;

        Float64             mInputSampleTimeForOutputPull;

        AudioTimeStamp      mLastOutputTime;

        AudioTimeStamp      mCurrentOutputTime;

        bool                mStartInputAtZero;  // if true, input timeline starts at 0, else it starts

                                                // synced with the output timeline

        bool                mDiscontinuous;

        bool                mBypassed;

        Float64             mDiscontinuityDeltaSamples;

        double              mRateScalarAdj;

        bool                mHostTimeDiscontinuityCorrection; // If true, propagate timestamp discontinuities using host time.

    };

    void GetState(State& outState) const { outState = mState; }

    void SetState(State const& inState) { mState = inState; mFirstTime = false; }

private:

    struct State        mState;

    bool                mFirstTime; 

#if DEBUG

public:

    int                 mVerbosity;

    char                mDebugName[64];

#endif

};

#endif // __AUTimestampGenerator_h__