#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <unistd.h>
#include <cmath>
#include <algorithm>
#include <string>
#include <AL/al.h>
#include <AL/alc.h>

using namespace std;

#ifndef M_PI
#define M_PI (3.14159265)
#endif
#define null nullptr
#define FREQ (44100)
#define MULV (32768)

ALCdevice*  dev;
ALCcontext* ctx;
ALfloat listenerPos[] = {0.0,0.0,0.0};
const ALfloat listenerVel[] = {5.0,0.0,0.0};
const ALfloat listenerOri[] = {0.0,0.0,1.0, 0.0,1.0,0.0};
const ALfloat srcPos[] = {0.0,0.0,1.0};
ALuint srcId,bufId;
float volume=0.75f;

double smoothstep(double a)
{
	return 3*a*a - 2*a*a*a;
}

int main(int argc, char** argv)
{
	if(argc!=6){puts("Usage: playsine <Seconds> <Hz> <TFadeoff> <Exp> <Amp>");return -1;}
	
	string sT(argv[1]),sF(argv[2]),sExp(argv[4]),sTFO(argv[3]),sAmp(argv[5]);
	int freq = stoi(sF);
	int time = stoi(sT);
	double Vexp = double(stof(sExp));
	double Tfo = double(stof(sTFO));
	double Amp = double(stof(sAmp));
	int FLEN = time * FREQ;
	
	dev = alcOpenDevice(null);
	if(!dev){return -2;}
	ctx = alcCreateContext(dev,null);
	alcMakeContextCurrent(ctx);
	if(!ctx){return -2;}

	alListenerfv(AL_POSITION, listenerPos);
	alListenerfv(AL_VELOCITY, listenerVel);
	alListenerfv(AL_ORIENTATION, listenerOri);
	if(alGetError()!=AL_NO_ERROR){return -2;}
	
	alGenSources(1,&srcId);
	if(alGetError()!=AL_NO_ERROR){return -3;}
	alSourcefv(srcId, AL_POSITION, srcPos);
	alGenBuffers(1,&bufId);
	if(alGetError()!=AL_NO_ERROR){return -3;}
	
	vector<short> arr;
	arr.resize(FLEN);
	double Seclim = Tfo;
	int ilim = FLEN-int(FREQ*Tfo);
	for(int i=0;i<FLEN;i++)
	{
		double t = double(i)/double(FREQ);
		double tfe=double(FLEN-i)/double(FREQ);
		double tf = tfe/Seclim;
		double OT = (2.f*float(M_PI)*freq)/double(FREQ);
		double Val = sin( OT * i )*MULV*Amp;
		if(i>ilim)
		{
			Val *= pow(tf,Vexp);
		}
		Val *= volume;
		arr[ i ] = short(Val);
	}
	
	alBufferData(bufId,AL_FORMAT_MONO16,arr.data(),FLEN*2,FREQ);
	alSourcei(srcId, AL_BUFFER, bufId);
	alSourcePlay(srcId);
	ALint state;
	//sleep(time);
	do
	{
		alGetSourcei(srcId,AL_SOURCE_STATE,&state);
		//listenerPos[0]+=1.0;
		//alListenerfv(AL_POSITION, listenerPos);
		usleep(1000);
	}while(state == AL_PLAYING);
	
	
	alDeleteSources(1,&srcId);
	alDeleteBuffers(1,&bufId);
	alcDestroyContext(ctx);
	alcCloseDevice(dev);
	return 0;
}