//
//  audio.c


#include "audio.h"
#include <CoreAudio/AudioHardware.h>

unsigned long    deviceBufferSize;
AudioDeviceID    device;
Boolean        initialized;    // successful init?
Boolean        soundPlaying;    // playing now?
AudioStreamBasicDescription    deviceFormat;    // info about the default device
float amp;
float pan;
PSG *myPSG;

int sTestCount=0;


// コールバック関数です　外部から直接この関数を呼び出すことはありません

OSStatus appIOProc (AudioDeviceID  inDevice, const AudioTimeStamp*  inNow, const AudioBufferList*   inInputData,
                    const AudioTimeStamp*  inInputTime, AudioBufferList*  outOutputData, const AudioTimeStamp* inOutputTime,
                    void* defptr)
{
    int i;
    
    // load instance vars into registers
    
    
    int numSamples = deviceBufferSize / deviceFormat.mBytesPerFrame;
    
    // assume floats for now....
    float *out = (float*)outOutputData->mBuffers[0].mData;
    float wave;
    float pzl=1.0*amp;//左ボリューム
    float pzr=1.0*amp;//右ボリューム
    
    for (i=0; i<numSamples; ++i) {
        
    //サウンド生成のコア部分　約440Hzの矩形波を生成

        wave+=(sTestCount<55)?5000:0;
        sTestCount++;
        if (sTestCount>109){sTestCount=0;}
        wave = wave/32768.0;
        
        // write output
        *out++ = wave * pzl;        // left channel
        *out++ = wave * pzr;        // right channel
    }
    
    return kAudioHardwareNoError;
}

// 初期設定です。ViewのviewDidLoad()などから呼び出すものです
//　大昔のネットのサンプルからのコピペです

void audioSetup(void)
{
    OSStatus                err = kAudioHardwareNoError;
    UInt32                count;
    device = kAudioDeviceUnknown;
    
    initialized = false;
    
    // get the default output device for the HAL
    count = sizeof(device);        // it is required to pass the size of the data to be returned
    err = AudioHardwareGetProperty(kAudioHardwarePropertyDefaultOutputDevice,  &count, (void *) &device);
    if (err != kAudioHardwareNoError) {
        fprintf(stderr, "get kAudioHardwarePropertyDefaultOutputDevice error %d\n", err);
        return;
    }
    
    // get the buffersize that the default device uses for IO
    count = sizeof(deviceBufferSize);    // it is required to pass the size of the data to be returned
    err = AudioDeviceGetProperty(device, 0, false, kAudioDevicePropertyBufferSize, &count, &deviceBufferSize);
    if (err != kAudioHardwareNoError) {
        fprintf(stderr, "get kAudioDevicePropertyBufferSize error %d\n", err);
        return;
    }
    fprintf(stderr, "deviceBufferSize = %ld\n", deviceBufferSize);
    
    // get a description of the data format used by the default device
    count = sizeof(deviceFormat);    // it is required to pass the size of the data to be returned
    err = AudioDeviceGetProperty(device, 0, false, kAudioDevicePropertyStreamFormat, &count, &deviceFormat);
    if (err != kAudioHardwareNoError) {
        fprintf(stderr, "get kAudioDevicePropertyStreamFormat error %d\n", err);
        return;
    }
    if (deviceFormat.mFormatID != kAudioFormatLinearPCM) {
        fprintf(stderr, "mFormatID !=  kAudioFormatLinearPCM\n");
        return;
    }
    if (!(deviceFormat.mFormatFlags & kLinearPCMFormatFlagIsFloat)) {
        fprintf(stderr, "Sorry, currently only works with float format....\n");
        return;
    }
    
    initialized = true;
    amp=1.0;
    pan=1.0;

    err = AudioDeviceAddIOProc(device, appIOProc, nil);    // setup our device with an IO proc
     if (err != kAudioHardwareNoError) {
         fprintf(stderr, "get AudioDeviceAddIOProc error %d\n", err);
         return;
     }

     err = AudioDeviceStart(device, appIOProc);                // start playing sound through the device
     if (err != kAudioHardwareNoError) {
         fprintf(stderr, "get AudioDeviceStart error %d\n", err);
         return;
     }

    
     soundPlaying = true;                        // set the playing status global to true

}