clear all;
close all;
%Reading the file
[y, fs] = audioread('gitara.wav');

%Creating the vector according to which delay is varied
a= 0.01;
b= 0.4;
low_n = round(a*fs);
high_n = round(b*fs);

%delay_step = 2 /(1/fs);
%n = low_n;
no_points = length(y(:,1));
out_wav(:,1) = zeros(1,no_points);
fwd_back = 0;
ifs = 0;
buffer_signal = 1:high_n;
k=1;

for i=1:no_points
    if(fwd_back==0)
       ifs = ifs +1;
       delay(i) = ((high_n-low_n)/(2*fs))*ifs+low_n;
    end
    
    if(ifs == 2*fs)
      fwd_back = 1;
      ifs = ifs -1;
    end
   
    if(fwd_back==1)
       ifs = ifs -1;
       delay(i) = ((high_n-low_n)/(2*fs))*ifs+low_n;
       if(ifs == 0)
           fwd_back = 0;
       end
    end
 
   if (k<=high_n) 
       buffer_signal(k) = y(i);
       if (k==high_n) max = k;
       end
       k = k+1;
   else
       k=1;
   end
   
   %n(i) = i-delay(i);
   %if uint32(n(i))>0
   if (i>low_n*2)
        %out_wav(i) = y(i)+y(uint32(n(i)));
         if (k - uint32(delay(i)) == 0) 
            prev_signal(i) = max - uint32(delay(i));
            max = max + 1;
        else
        prev_signal(i) = k - uint32(delay(i));
        end
        out_wav(i) = y(i)+ buffer_signal(prev_signal(i));
 
   else
        out_wav(i) = y(i);
   end 
   
end

p = audioplayer(out_wav,fs);
play(p);
plot(out_wav);
%hold on;
%plot(y);
pause;