clc;
close all;
clear;

% === Global figure styling (light mode defaults) ===
set(0, 'DefaultFigureColor', 'w');        % white figure background
set(0, 'DefaultAxesColor', 'w');          % white plotting area
set(0, 'DefaultAxesXColor', 'k');         % black x-axis lines and text
set(0, 'DefaultAxesYColor', 'k');         % black y-axis lines and text
set(0, 'DefaultTextColor', 'k');          % black text for titles, labels
set(0, 'DefaultLineColor', 'b');          % blue lines by default
clear saveFigure

% === Automatic figure export counter ===
fig_counter = 1;
save_fig = @saveFigure;

function saveFigure(name)
    persistent counter
    if isempty(counter)
        counter = 1;
    end

    % Force painters renderer and white backgrounds
    set(gcf, 'Renderer', 'painters');
    set(gcf, 'Color', [1 1 1]);
    axesHandles = findall(gcf, 'Type', 'axes');
    for ax = axesHandles'
        set(ax, 'Color', [1 1 1]);
    end

    % Export clean EPS with no transparency problems
    print(gcf, '-depsc2', '-r300', '-painters', sprintf('%d_%s.eps', counter, name));

    counter = counter + 1;
end

[y1, Fs1] = audioread('flac.wav');
[y2, Fs2] = audioread('flac2.wav');
[y_sem2, Fs_sem2] = audioread('sem2.wav');

% Časové priebehy
t1 = (0:length(y1)-1)/Fs1;
t2 = (0:length(y2)-1)/Fs2;
t_sem2 = (0:length(y_sem2)-1)/Fs_sem2;

figPos = get(0, 'DefaultFigurePosition');
figPos(4) = figPos(4) / 2;   % polovičná výška (4 = height element)
figure('Position', figPos);  % style defaults 
plot(t_sem2, y_sem2);
xlabel('Čas [s]');
ylabel('Amplitúda');
title('sem2.wav – pôvodný (RAW) signál');
grid on;
save_fig('orig_sem2'); fig_counter = fig_counter + 1;

figure;
subplot(2,1,1);
plot(t1, y1);
xlabel('Čas [s]');
ylabel('Amplitúda');
title('flac.wav');
grid on;

subplot(2,1,2);
plot(t2, y2, 'r');
xlabel('Čas [s]');
ylabel('Amplitúda');
title('flac2.wav');
grid on;
save_fig('time'); fig_counter = fig_counter + 1;

% Fourierova transformácia
N1 = length(y1);
N2 = length(y2);
X1 = fft(y1);
X2 = fft(y2);

freq_shift1 = (-N1/2 : N1/2 - 1) * (Fs1 / N1);
freq_shift2 = (-N2/2 : N2/2 - 1) * (Fs2 / N2);

% Real a imag časť spektra
figure;
subplot(2,1,1);
plot(freq_shift2, real(fftshift(X2)));
xlabel('Frekvencia [Hz]');
ylabel('Amplitúda');
title('flac2.wav – Reálna časť spektra');
xlim([-550 550]);
grid on;

subplot(2,1,2);
plot(freq_shift2, imag(fftshift(X2)), 'r');
xlabel('Frekvencia [Hz]');
ylabel('Amplitúda');
title('flac2.wav – Imaginárna časť spektra');
xlim([-550 550]);
grid on;
save_fig('spectrum'); fig_counter = fig_counter + 1;

% Real a imag časť spektra
figure;
subplot(2,1,1);
plot(freq_shift1, real(fftshift(X1)));
xlabel('Frekvencia [Hz]');
ylabel('Amplitúda');
title('flac.wav – Reálna časť spektra');
xlim([-3500 3500]);
grid on;

subplot(2,1,2);
plot(freq_shift1, imag(fftshift(X1)), 'r');
xlabel('Frekvencia [Hz]');
ylabel('Amplitúda');
title('flac.wav – Imaginárna časť spektra');
xlim([-3500 3500]);
grid on;
save_fig('spectrum2'); fig_counter = fig_counter + 1;

% Detekcia dominantných frekvencií
halfN2 = floor(N2 / 2);
freq = (0:halfN2-1) * (Fs2 / N2);
magX = abs(X2(1:halfN2));

[pks, locs] = findpeaks(magX, 'NPeaks', 3, 'SortStr', 'descend');
f_tonal = sort(freq(locs));

fprintf('\nDetekovane frekvencie z (flac2.wav):\n');
fprintf('  %.1f Hz\n', f_tonal);

% SOS IIR filter
r = 0.99;
Fs = Fs1;
sos = zeros(length(f_tonal), 6);

for k = 1:length(f_tonal)
    theta = 2 * pi * (f_tonal(k) / Fs);
    b = [1, -2*cos(theta), 1];
    a = [1, -2*r*cos(theta), r^2];
    sos(k, :) = [b, a];
end

% Nuly a póly
figure;
[z, p, k_gain] = sos2zp(sos);
zplane(z, p);
title('Nuly a póly notch filtrov');
xlabel('Reálna časť');
ylabel('Imaginárna časť');
save_fig('pz_notch'); fig_counter = fig_counter + 1;

% Frekvenčná charakteristika
figure;
[h, w] = freqz(sos, 4096, Fs);
freqz(sos, 4096, Fs);
title('Frekvenčná charakteristika notch filtra');
subplot(2,1,1); xlim([0 0.5]);
subplot(2,1,2); xlim([0 0.5]);
save_fig('freqz_notch'); fig_counter = fig_counter + 1;

% Filtrovanie flac.wav a flac2.wav
y1_filtered = sosfilt(sos, double(y1));
y2_filtered = sosfilt(sos, double(y2));

figure;
subplot(2,1,1);
plot(y2);
title('Pôvodný signál flac2.wav');
xlabel('Vzorky');
ylabel('Amplitúda');
ax1 = gca;
grid on;

subplot(2,1,2);
plot(y2_filtered, 'r');
title('Filtrovaný signál flac2.wav');
xlabel('Vzorky');
ylabel('Amplitúda');
ax2 = gca;
grid on;

% spolocna y os pre oba grafy
ylim_common = [min([ax1.YLim, ax2.YLim]), max([ax1.YLim, ax2.YLim])];
ax1.YLim = ylim_common;
ax2.YLim = ylim_common;
save_fig('orig_vs_filtered_flac2'); fig_counter = fig_counter + 1;

% Aplikácia filtrov na sem2.wav
y_sem2_filtered = sosfilt(sos, double(y_sem2));

figure;
subplot(2,1,1);
plot(t_sem2, y_sem2);
xlabel('Čas [s]');
ylabel('Amplitúda');
title('sem2.wav – pôvodný signál');
grid on;

subplot(2,1,2);
plot(t_sem2, y_sem2_filtered, 'r');
xlabel('Čas [s]');
ylabel('Amplitúda');
title('sem2.wav – filtrovaný signál');
grid on;

ylim_common = [min([min(y_sem2), min(y_sem2_filtered)]), ...
               max([max(y_sem2), max(y_sem2_filtered)])];
subplot(2,1,1); ylim(ylim_common);
subplot(2,1,2); ylim(ylim_common);
save_fig('orig_vs_filtered_sem2'); fig_counter = fig_counter + 1;

audiowrite('filtered_sem2.wav', y_sem2_filtered, Fs_sem2);

% Butterworth filter pre rozsah ľudskej reči
[z_bp, p_bp, k_bp] = butter(4, [100 8000]/(Fs_sem2/2), 'bandpass');
[sos_bp, g_bp] = zp2sos(z_bp, p_bp, k_bp);
y_sem2_final = filtfilt(sos_bp, g_bp, y_sem2_filtered);

audiowrite('filtered_sem2_voiceband.wav', ...
    y_sem2_final / max(abs(y_sem2_final)), Fs_sem2);

t_sem2 = (0:length(y_sem2_filtered)-1) / Fs_sem2;

figure;
subplot(2,1,1);
plot(t_sem2, y_sem2_filtered);
xlabel('Čas [s]');
ylabel('Amplitúda');
title('sem2.wav – notch filtrácia');
grid on;

subplot(2,1,2);
plot(t_sem2, y_sem2_final, 'r');
xlabel('Čas [s]');
ylabel('Amplitúda');
title('sem2.wav – notch + band-pass filtrácia');
grid on;

ylim_common = [min([min(y_sem2_filtered), min(y_sem2_final)]), ...
               max([max(y_sem2_filtered), max(y_sem2_final)])];
subplot(2,1,1); ylim(ylim_common);
subplot(2,1,2); ylim(ylim_common);
save_fig('notch_vs_bandpass_sem2'); fig_counter = fig_counter + 1;

% Percentuálny rozdiel band-pass filtrácie
diff_signal = y_sem2_final - y_sem2_filtered;
power_original = sum(y_sem2_filtered.^2);
power_diff = sum(diff_signal.^2);
percent_difference = (power_diff / power_original) * 100;
fprintf('\nRozdiel medzi notch a notch+band‑pass signálom: %.2f %%\n', percent_difference);