✨ Implement port connection dialog

Implements:
- Viewing connections (routes)
- Creating and deleting connections
- Changing volume of connectons
- Muting / unmuting connections

lib/mixing_card.dart

@@ -1,13 +1,17 @@
 import 'package:flutter/material.dart';
 import 'package:gomix_flutter/mixer_state.dart' as mixer;
+import 'package:gomix_flutter/port_connection_dialog.dart';
+import 'package:gomix_flutter/utils.dart';
 
 class MixingCard extends StatefulWidget {
   final mixer.Port port;
-  final Function sendAction;
+  final mixer.MixerState mixerState;
+  final Function(Map<String, Object> data) sendAction;
   final bool isOutput;
   const MixingCard(
       {super.key,
       required this.port,
+      required this.mixerState,
       required this.sendAction,
       this.isOutput = false});
 
@@ -15,20 +19,55 @@ class MixingCard extends StatefulWidget {
   State<MixingCard> createState() => _MixingCardState();
 }
 
+class DialogDataModel extends ChangeNotifier {
+  String? portUUID;
+
+  late mixer.MixerState mixerState;
+  late mixer.Port port;
+
+  void updatePort(bool force) {
+    if (portUUID == null) {
+      return;
+    }
+    // Only update port reference if it is actually outdated
+    if (force ||
+        (!mixerState.inputs.contains(port) &&
+            !mixerState.outputs.contains(port))) {
+      mixer.Port? newPort = findPort(mixerState, portUUID!);
+      if (newPort != null) port = newPort;
+    }
+  }
+
+  void setPortUUID(String uuid) {
+    portUUID = uuid;
+    updatePort(true);
+  }
+
+  void setMixerState(mixer.MixerState state) {
+    mixerState = state;
+    updatePort(false);
+    notifyListeners();
+  }
+}
+
 class _MixingCardState extends State<MixingCard> {
   double _sliderValue = 0;
   int _debounceTimer = 0;
   bool _sliderActive = false;
 
+  DialogDataModel dataModel = DialogDataModel();
+
   @override
   void initState() {
     super.initState();
+    dataModel.setMixerState(widget.mixerState);
     _sliderValue = widget.port.state.volume;
   }
 
   @override
   void didUpdateWidget(MixingCard oldWidget) {
     if (_sliderActive) return;
+    dataModel.setMixerState(widget.mixerState);
     _sliderValue = widget.port.state.volume;
     super.didUpdateWidget(oldWidget);
   }
@@ -78,7 +117,16 @@ class _MixingCardState extends State<MixingCard> {
                     child: IconButton.outlined(
                         iconSize: 20,
                         isSelected: false,
-                        onPressed: () {},
+                        onPressed: () {
+                          dataModel.setPortUUID(widget.port.uuid);
+                          PortConnectionDialog(
+                                  sendAction: widget.sendAction,
+                                  port: widget.port,
+                                  isOutput: widget.isOutput,
+                                  dataModel: dataModel,
+                                  mixerState: widget.mixerState)
+                              .show(context);
+                        },
                         icon: const Icon(Icons.unfold_more)))
               ],
             ),