module patest_sine_hello;

/** @file patest_sine.c
    @ingroup test_src
    @brief Play a sine wave for several seconds.
    @author Ross Bencina <rossb@audiomulch.com>
    @author Phil Burk <philburk@softsynth.com>
    @author D conversion: Jonas Kivi <satelliittipupu@y????.co.uk>
    @author D2 conversion: Andrej Mitrovic <andrej.mitrovich@gmail.com>
 */

import portaudio;

import std.math : sin;
import std.stdio;
import core.memory;
import core.thread;

const NUM_SECONDS       = 1;
const SAMPLE_RATE       = 44100;
// buffer size
const FRAMES_PER_BUFFER = 64; // 64;
const TABLE_SIZE = 200;

struct paTestData
{
    float[TABLE_SIZE] sine;
    int left_phase;
    int right_phase;
    char[20] message;
}

/* This routine will be called by the PortAudio engine when audio is needed.
** It may be called at interrupt level on some machines so don't do anything
** that could mess up the system like calling malloc() or free().
*/

extern (C) static int patestCallback(void* inputBuffer, void* outputBuffer,
                          uint framesPerBuffer,
                          PaStreamCallbackTimeInfo* timeInfo,
                          PaStreamCallbackFlags statusFlags,
                          void* userData)
{
    paTestData* data = cast(paTestData*) userData;
    float* toOut     = cast(float*) outputBuffer;
    uint i;

    for (i = 0; i < framesPerBuffer; i++)
    {
        *toOut++         = data.sine[data.left_phase];  /* left */
        *toOut++         = data.sine[data.right_phase]; /* right */
        data.left_phase += 1;

        if (data.left_phase >= TABLE_SIZE)
        {
            data.left_phase -= TABLE_SIZE;
        }

        data.right_phase += 3; /* higher pitch so we can distinguish left and right. */

        if (data.right_phase >= TABLE_SIZE)
        {
            data.right_phase -= TABLE_SIZE;
        }
    }

    return PaStreamCallbackResult.paContinue;
}

/*
 * This routine is called by portaudio when playback is done.
 */
extern (C) static void StreamFinished(void* userData)
{
    paTestData* data = cast(paTestData*) userData;

    writeln("Stream Completed: ", data.message);
}

int main()
{
    writeln("PortAudio test.");

    PaStreamParameters outputParameters;
    PaStream* stream;
    PaError err;
    paTestData data;
    int i;

    writeln("PortAudio Test: output sine wave. Sample rate: ", SAMPLE_RATE, " Buffer size: ", FRAMES_PER_BUFFER);

    /* initialise sinusoidal wavetable */
    for (i=0; i < TABLE_SIZE; i++)
    {
        data.sine[i] = cast(float) sin((cast(double) i / cast(double) TABLE_SIZE) * PI * 2.0);
    }
    data.left_phase = data.right_phase = 0;

    err = Pa_Initialize();

    if (err != PaErrorCode.paNoError)
    {
        goto error;
    }

    outputParameters.device           = Pa_GetDefaultOutputDevice(); /* default output device */
    outputParameters.channelCount     = 2;   /* stereo output */
    outputParameters.sampleFormat     = paFloat32; /* 32 bit floating point output */
    outputParameters.suggestedLatency = Pa_GetDeviceInfo(outputParameters.device).defaultLowOutputLatency;
    outputParameters.hostApiSpecificStreamInfo = null;

    err = Pa_OpenStream(
        &stream,
        null,       /* no input */
        &outputParameters,
        SAMPLE_RATE,
        FRAMES_PER_BUFFER,
        /* we won't output out of range samples so don't bother clipping them */
        paClipOff,
        &patestCallback,
        &data);

    if (err != PaErrorCode.paNoError)
    {
        goto error;
    }

    writeln(data.message, "No Message");
    err = Pa_SetStreamFinishedCallback(stream, &StreamFinished);

    if(err != PaErrorCode.paNoError) goto error;

    // Used as a precaution
    GC.disable();

    err = Pa_StartStream(stream);
    if( err != PaErrorCode.paNoError ) goto error;

    writeln("Play for seconds: ", NUM_SECONDS);
    Thread.sleep( NUM_SECONDS * 10_000_000 );

    GC.enable();

    ///~ // You can exit the infinite_loop if you're in a command line with CTRL-C.
    ///~ int infinite_loop = 1;
    ///~ while (infinite_loop == 1)
    ///~ {
    ///~ }

    err = Pa_StopStream(stream);

    if( err != PaErrorCode.paNoError ) goto error;

    err = Pa_CloseStream(stream);

    if( err != PaErrorCode.paNoError ) goto error;

    Pa_Terminate();
    writeln("Test finished.\n");

    return err;
error:
    Pa_Terminate();

    writeln("An error occured while using the portaudio stream");
    writeln("Error number: ", err);
    writeln("Error message: ", Pa_GetErrorText(err));
    return err;
}