diff --git a/inc/Application.h b/inc/Application.h
index 512956b..475dcf0 100644
--- a/inc/Application.h
+++ b/inc/Application.h
@@ -18,7 +18,7 @@ class Application {
     void InitAudio();
     void UpdateOnNoteInput();
     void PlayBufferedAudio();
-    
+
   public:
     Application(/* args */);
     ~Application();
diff --git a/src/Application.cpp b/src/Application.cpp
index b9ec571..d7e6ae2 100644
--- a/src/Application.cpp
+++ b/src/Application.cpp
@@ -1,10 +1,11 @@
 #include "Application.h"
 #include "Logger.h"
 #include "Settings.h"
-#include <string>
-#include <fstream> //read file
-#include <cmath> // log10f
+#include <cmath>    // log10f
+#include <fstream>  // read file
+#include <iostream> // log error
 #include <nlohmann/json.hpp>
+#include <string>
 using json = nlohmann::json;
 
 Application::Application(/* args */) {
@@ -98,7 +99,7 @@ void Application::UpdateOnNoteInput() {
         if (!m_synth.GetIsNoteTriggered()) {
             m_synth.Trigger((*m_current_note));
         }
-        //write_log("Note played: %s\n", m_current_note->name.c_str());
+        // write_log("Note played: %s\n", m_current_note->name.c_str());
     } else if (is_note_up() && m_synth.GetIsNoteTriggered()) {
         m_synth.Release();
     }
@@ -125,30 +126,64 @@ void Application::Run() {
 
 void Application::ParsePatch(std::string file_path) {
     std::ifstream f(file_path);
-    json data = json::parse(f);
+    if (!f.is_open()) {
+        std::cerr << "[ERR] failed to open " << file_path << '\n';
+    } else {
+        json data = json::parse(f);
 
-    auto oscillators = m_synth.GetOscillators();
-    for (int i = 0; i < oscillators.size(); i++) {
-        auto osc = oscillators[i];
-        osc->SetType(data["Oscillators"][i]["Wave"].template get<std::string>());
-        osc->SetVolume(data["Oscillators"][i]["Volume"].template get<float>());
-        osc->SetFine(data["Oscillators"][i]["Tune"].template get<float>());
+        auto oscillators = m_synth.GetOscillators();
+        for (int i = 0; i < oscillators.size(); i++) {
+            auto osc = oscillators[i];
+            auto gui_osc = m_synth_gui_state.oscillators[i];
+
+            std::string type =
+                data["Oscillators"][i]["Wave"].template get<std::string>();
+            float fine = data["Oscillators"][i]["Tune"].template get<float>();
+            float volume =
+                data["Oscillators"][i]["Volume"].template get<float>();
+
+            osc->SetType(type);
+            osc->SetFine(fine);
+            osc->SetVolume(volume);
+
+            gui_osc->waveshape = osc->GetType();
+            gui_osc->fine = fine;
+            gui_osc->volume = volume;
+        }
+
+        auto adsr = m_synth.GetADSR();
+        auto gui_adsr = m_synth_gui_state.adsr;
+
+        auto adsr_params = data["ADSR"];
+        float attack = adsr_params["Attack"].template get<float>();
+        float decay = adsr_params["Decay"].template get<float>();
+        float sustain = adsr_params["Sustain"].template get<float>();
+        float release = adsr_params["Release"].template get<float>();
+
+        adsr->SetParameters(attack, decay, sustain, release);
+        gui_adsr.attack = attack;
+        gui_adsr.decay = decay;
+        gui_adsr.sustain = sustain;
+        gui_adsr.release = release;
+
+        auto lfo = m_synth.GetLFO();
+        lfo->SetFreq(data["LFO"]["Freq"].template get<float>());
+        m_synth.SetLFOLevel(data["LFO"]["Level"].template get<float>());
+
+        auto filter_type =
+            (FilterType)data["Filter"]["Type"].template get<int>();
+        m_synth.SetFilter(filter_type);
+
+        auto filter = m_synth.GetFilter();
+        auto gui_filter = m_synth_gui_state.filter;
+
+        float filter_freq =
+            std::log10f(data["Filter"]["Cutoff"].template get<float>());
+        float filter_res = data["Filter"]["Res"].template get<float>();
+        float filter_drive = data["Filter"]["Drive"].template get<float>();
+        
+        filter->SetParameters(filter_freq, filter_res, filter_drive);
+        gui_filter.freq = filter_freq;
+        gui_filter.type = filter_type;
     }
-
-    auto adsr = m_synth.GetADSR();
-    auto adsr_params = data["ADSR"];
-    adsr->SetParameters(adsr_params["Attack"].template get<float>(),
-                        adsr_params["Decay"].template get<float>(),
-                        adsr_params["Sustain"].template get<float>(),
-                        adsr_params["Release"].template get<float>());
-
-    auto lfo = m_synth.GetLFO();
-    lfo->SetFreq(data["LFO"]["Freq"].template get<float>());
-    m_synth.SetLFOLevel(data["LFO"]["Level"].template get<float>());
-
-    m_synth.SetFilter((FilterType)data["Filter"]["Cutoff"].template get<int>());
-    auto filter = m_synth.GetFilter();
-    filter->SetParameters(std::log10f(data["Filter"]["Cutoff"].template get<float>()),
-                            data["Filter"]["Res"].template get<float>(),
-                            data["Filter"]["Drive"].template get<float>());
 }