Add MIDI device persistence functionality

- Add configuration file system to remember MIDI device selection
- Load saved MIDI device preference on application startup
- Automatically save MIDI device selection when changed
- Handle device disconnection gracefully with fallback
- Smart initialization with validation and error handling
- Create config.json for storing device preferences
- Improve user experience by eliminating need to re-select device

src/main.py

@@ -2,6 +2,7 @@ import asyncio
 import tkinter as tk
 from tkinter import ttk, messagebox  # Import messagebox for confirmations
 import json
+import os
 from async_tkinter_loop import async_handler, async_mainloop
 from networking import WebSocketClient
 import color_utils
@@ -10,6 +11,9 @@ import mido  # Import mido for MIDI port detection
 import time
 from midi import MidiHandler  # Import MidiHandler
 
+# Configuration file path
+CONFIG_FILE = "config.json"
+
 # Dark theme colors (unchanged)
 bg_color = "#2e2e2e"
 fg_color = "white"
@@ -36,11 +40,11 @@ class App:
 
         # --- MIDI Configuration ---
         self.available_midi_ports = self.get_midi_ports()
-        self.current_midi_port_index = 0  # Default to first port
+        self.current_midi_port_index = self.load_midi_device_preference()  # Load saved preference
         self.midi_handler: MidiHandler | None = None
         self.midi_task: asyncio.Task | None = None
         
-        # Initialize MIDI handler with first available port (will be done after GUI is created)
+        # Initialize MIDI handler with saved port (will be done after GUI is created)
         self.pending_midi_init = True if self.available_midi_ports else False
 
         # Configure ttk style (unchanged)
@@ -61,7 +65,12 @@ class App:
         # MIDI port dropdown
         self.midi_port_var = tk.StringVar()
         if self.available_midi_ports:
-            self.midi_port_var.set(self.available_midi_ports[0])
+            # Set to saved preference if available, otherwise first port
+            if 0 <= self.current_midi_port_index < len(self.available_midi_ports):
+                self.midi_port_var.set(self.available_midi_ports[self.current_midi_port_index])
+            else:
+                self.midi_port_var.set(self.available_midi_ports[0])
+                self.current_midi_port_index = 0
         
         midi_dropdown = ttk.Combobox(
             midi_frame, 
@@ -230,6 +239,32 @@ class App:
 
         async_mainloop(self.root)
 
+    def load_midi_device_preference(self):
+        """Load saved MIDI device preference from config file"""
+        try:
+            if os.path.exists(CONFIG_FILE):
+                with open(CONFIG_FILE, 'r') as f:
+                    config = json.load(f)
+                    saved_index = config.get('midi_device_index', 0)
+                    print(f"Loaded MIDI device preference: index {saved_index}")
+                    return saved_index
+        except Exception as e:
+            print(f"Error loading MIDI device preference: {e}")
+        return 0  # Default to first port
+
+    def save_midi_device_preference(self):
+        """Save current MIDI device preference to config file"""
+        try:
+            config = {
+                'midi_device_index': self.current_midi_port_index,
+                'midi_device_name': self.available_midi_ports[self.current_midi_port_index] if self.available_midi_ports else None
+            }
+            with open(CONFIG_FILE, 'w') as f:
+                json.dump(config, f, indent=2)
+            print(f"Saved MIDI device preference: {config['midi_device_name']} (index {config['midi_device_index']})")
+        except Exception as e:
+            print(f"Error saving MIDI device preference: {e}")
+
     def get_midi_ports(self):
         """Get list of available MIDI input ports"""
         try:
@@ -286,6 +321,7 @@ class App:
                 # Current selection is no longer available, select first available
                 self.midi_port_var.set(self.available_midi_ports[0])
                 self.current_midi_port_index = 0
+                self.save_midi_device_preference()  # Save the new preference
                 self.restart_midi_handler()
             elif not self.available_midi_ports:
                 # No ports available
@@ -305,6 +341,7 @@ class App:
         if selected_port in self.available_midi_ports:
             self.current_midi_port_index = self.available_midi_ports.index(selected_port)
             print(f"MIDI port changed to: {selected_port} (index: {self.current_midi_port_index})")
+            self.save_midi_device_preference()  # Save the new preference
             self.restart_midi_handler()
 
     @async_handler