add: flutter scaffolding, outlines for WebRTC conn

ui/lib/call.dart

@@ -0,0 +1,74 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_webrtc/flutter_webrtc.dart';
+import 'package:logger/logger.dart';
+
+class Call extends StatefulWidget {
+  final String host;
+  const Call({required this.host, super.key});
+
+  @override
+  _CallState createState() => _CallState();
+}
+
+class _CallState extends State<Call> {
+  Logger logger = Logger();
+  RTCVideoRenderer _remoteRenderer = RTCVideoRenderer();
+
+  void _connect(BuildContext context) async {}
+
+  Future<Session> _createSesson() async {
+    RTCPeerConnection peerConnection = await createPeerConnection({
+      // Ice servers; just use the Google one for now
+      'iceServers': [
+        {'url': 'stun:stun.l.google.com:19302'}
+      ],
+    }, {
+      /* Empty config */
+    });
+
+    peerConnection.onAddStream = (stream) {
+      // Stream has been added; connect it to our renderer
+      _remoteRenderer.srcObject = stream;
+    };
+
+    peerConnection.onIceCandidate = (candidate) {
+      if (candidate.candidate == null) {
+        logger.i("Out of candidates");
+        return;
+      }
+
+      // Send the candidate on to the signaling server
+    };
+
+    peerConnection.onIceConnectionState = (state) {};
+
+    peerConnection.onRemoveStream = (stream) {};
+
+    peerConnection.onDataChannel = (channel) {};
+
+    // Get list of candidates from signaling server
+    for (final remoteCandidate in []) {
+      peerConnection.addCandidate(remoteCandidate);
+    }
+    // This will find the intersection of my candidates and the remote,
+    // then propose one to use
+    var offer = peerConnection.createOffer();
+    // Send offer through signaling server
+    logger.i("Offer is $offer");
+
+    var session = Session(peerConnection);
+    return session;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return RTCVideoView(_remoteRenderer);
+  }
+}
+
+class Session {
+  RTCPeerConnection peerConnection;
+
+  Session(this.peerConnection);
+  List<RTCIceCandidate> remoteCandidates = [];
+}