#include iostream>
 #include fstream>
 #include stdint.h>
 #include cstdlib>
 #include ctime>
 #include math.h>

using namespace std;

struct RIFFHeader
{
    char    chunkId[4]; // 4 byte character array
    uint32_t chunkSize; // 4 bytes
    char    format[4]; // 4 byte array
};

struct FormatSubChunk
{
    char chunkId[4];
    uint32_t chunkSize;
    uint16_t audioFormat;
    uint16_t channels;
    uint32_t frequency; //
    uint32_t byteRate;  //
    uint16_t blockAlign;
    uint16_t bitsPerSample;
};

    struct DataSubChunkHeader
    {
    char chunkId[4];
    uint32_t chunkSize; //
};

struct Sample
{
    uint16_t leftchannel;
    uint16_t rightchannel;
};

double coeff_11025[17]={0.0011468,0.0051113,0.014364,0.030915,
0.054955,0.083795,0.11194,0.13262,0.14024,0.13262,0.11194,0.083795,
0.054955,0.030915,0.014364,0.0051113,0.0011468};

double coeff_22050[25] = {0.00093276,0.0033739,0.0062125,0.011378,0.018027,
0.026654,0.036717,0.047821,0.059142,0.069811,0.078867,0.085459,0.08893,
0.085459,0.078867,0.069811,0.059142,0.047821,0.036717,0.026654,0.018027,
0.011378,0.0062125,0.0033739,0.00093276};

void shiftArray22050(int16_t array[])
{
    for(int i = 0; i < 24; i++)
    {
        array[i] = array[i+1];
    }
}

void shiftArray11025(int16_t array[])
{
    for(int i = 0; i < 16; i++)
    {
        array[i] = array[i+1];
    }
}


int main()
{

clock_t start;
double duration;
start = clock();

string infile = "Frederick_N_mod.wav";
string outfile = "Frederick_N_lp.wav";
ifstream in(infile.c_str(), ios::in | ios::binary);
ofstream output(outfile.c_str());

RIFFHeader RIFF;
in.read((char*)&RIFF,sizeof(RIFF));


FormatSubChunk Format;
in.read((char*)&Format,sizeof(Format));


DataSubChunkHeader Data;
in.read((char*)&Data,sizeof(Data));


cout << "Chunk ID: " << RIFF.chunkId[0] << RIFF.chunkId[1] << RIFF.chunkId[2] << RIFF.chunkId[3] << endl;
cout << "Chunk Size: " << RIFF.chunkSize << endl;
cout << "Format: " << RIFF.format[0] << RIFF.format[1] << RIFF.format[2] << RIFF.format[3] <<endl;
cout << "Sub-chunk1 ID: " << Format.chunkId[0] << Format.chunkId[1] << Format.chunkId[2] << Format.chunkId[3] <<endl;
cout << "Sub-chunk1 Size: " << Format.chunkSize << endl;
cout << "Audio Format: " << Format.audioFormat << endl;
cout << "Number of Channels: " << Format.channels << endl;
cout << "Sample Rate: " << Format.frequency << endl;
cout << "Byte Rate: " << Format.byteRate << endl;
cout << "Block Align: " << Format.blockAlign << endl;
cout << "Bits Per Sample: " << Format.bitsPerSample << endl;
cout << "Sub-chunk2 ID: " << Data.chunkId[0] << Data.chunkId[1] << Data.chunkId[2] << Data.chunkId[3] << endl;
cout << "Sub-chunk2 Size: " << Data.chunkSize << endl << endl;


//uint16_t clear = 0;

output.write((char*)&RIFF, sizeof(RIFF));
output.write((char*)&Format, sizeof(Format));
output.write((char*)&Data, sizeof(Data));

int16_t leftSample;
int16_t rightSample;

double leftDouble = 0;
double rightDouble = 0;

int16_t leftFilter;
int16_t rightFilter;

int32_t count = 0;

if(Format.frequency == 22050)
{
  int16_t pastSamplesLeft[25] = {0};
  int16_t pastSamplesRight[25] = {0};


  while(!in.eof())
  {
      shiftArray22050(pastSamplesLeft);
      shiftArray22050(pastSamplesRight);

      in.read((char*)&leftSample, 2);
      pastSamplesLeft[24] = leftSample;
    if(in.eof())
        break;

      in.read((char*)&rightSample, 2);
      pastSamplesRight[24] = rightSample;
    if(in.eof())
        break;

      for(int i = 0; i < 25; i++)
      {
          leftDouble +=((double)pastSamplesLeft[i] * coeff_22050[i]);
          rightDouble += ((double)pastSamplesRight[i] * coeff_22050[i]);
      }

      leftFilter = (int16_t)leftDouble;
      rightFilter = (int16_t)rightDouble;




      output.write((char*)&leftFilter, sizeof(leftFilter));
      output.write((char*)&rightFilter, sizeof(rightFilter));
      leftDouble = 0;
      rightDouble = 0;
      leftFilter = 0;
      rightFilter = 0;
      count++;
  }
}
else if(Format.frequency == 11025)
{
  int16_t pastSamplesLeft[17] = {0};
  int16_t pastSamplesRight[17] = {0};


  while(!in.eof())
  {
      shiftArray11025(pastSamplesLeft);
      shiftArray11025(pastSamplesRight);

      in.read((char*)&leftSample, 2);
      pastSamplesLeft[16] = leftSample;
    if(in.eof())
        break;

      in.read((char*)&rightSample, 2);
      pastSamplesRight[16] = rightSample;
    if(in.eof())
        break;

      for(int i = 0; i < 17; i++)
      {
          leftDouble = leftDouble + ((double)pastSamplesLeft[i] * coeff_11025[i]);
          rightDouble = rightDouble + ((double)pastSamplesRight[i] * coeff_11025[i]);
      }

      leftFilter = (int16_t)leftDouble;
      rightFilter = (int16_t)rightDouble;

      leftDouble = 0;
      rightDouble = 0;


      output.write((char*)&leftFilter, sizeof(leftFilter));
      output.write((char*)&rightFilter, sizeof(rightFilter));
      count++;
  }
}
else
{
    cout << "Frequency not supported, please use a wav file with frequency 11025 or 22050" << endl;
    return 0;
}

in.close();

output.close();

    string infile1 = "Frederick_N_lp.wav";
ifstream in1(infile1.c_str(), ios::in | ios::binary);

RIFFHeader riff1;
in1.read((char*)&riff1,sizeof(riff1));


FormatSubChunk format1;
in1.read((char*)&format1,sizeof(format1));

DataSubChunkHeader data1;
in1.read((char*)&data1,sizeof(data1));
in.close();

cout << "Chunk ID: " << riff1.chunkId[0] << riff1.chunkId[1] << riff1.chunkId[2] << riff1.chunkId[3] << endl;
cout << "Chunk Size: " << riff1.chunkSize << endl;
cout << "Format: " << riff1.format[0] << riff1.format[1] << riff1.format[2] << riff1.format[3] <<endl;
cout << "Sub-chunk1 ID: " << format1.chunkId[0] << format1.chunkId[1] << format1.chunkId[2] << format1.chunkId[3] <<endl;
cout << "Sub-chunk1 Size: " << format1.chunkSize << endl;
cout << "Audio Format: " << format1.audioFormat << endl;
cout << "Number of Channels: " << format1.channels << endl;
cout << "Sample Rate: " << format1.frequency << endl;
cout << "Byte Rate: " << format1.byteRate << endl;
cout << "Block Align: " << format1.blockAlign << endl;
cout << "Bits Per Sample: " << format1.bitsPerSample << endl;
cout << "Sub-chunk2 ID: " << data1.chunkId[0] << data1.chunkId[1] << data1.chunkId[2] << data1.chunkId[3] << endl;
cout << "Sub-chunk2 Size: " << data1.chunkSize << endl << endl;
//---------------------------------------------------------------------------------------------------------------------------------

duration = ( std::clock() - start ) / (double) CLOCKS_PER_SEC;

string sumoutfile = "summary_filter.txt";
ofstream sumoutput(sumoutfile.c_str());
sumoutput << "sampling frequency = " << Format.frequency << 'n';
long recordTime = count/Format.frequency;
sumoutput << "record time = " << recordTime << " seconds" << 'n';
sumoutput << "execution time = " << duration << " seconds" << 'n';


sumoutput.close();

return 0;
}