p2p transaction logic

loc_chain_app/lib/util/bluetooth.dart

@@ -7,18 +7,32 @@ import 'package:nearby_connections/nearby_connections.dart';
 
 import 'package:shared_preferences/shared_preferences.dart';
 
+import 'package:loc_chain_app/util/keyfile_manager.dart';
+import 'package:loc_chain_app/util/transaction_manager.dart';
+
 class Connect {
   final serviceId = "com.yourdomain.appname";
   final Strategy strategy = Strategy.P2P_STAR;
   late final _userName;
+  final BuildContext? context;
 
   Map<String, ConnectionInfo> endpointMap = Map();
+  Map<String, Transaction> transactionMap = Map();
 
-  Connect() {
+  Connect({this.context}) {
     SharedPreferences.getInstance()
         .then((s) => _userName = s.getString('userName') ?? '0');
   }
 
+  void showSnackbar(dynamic a) {
+    if (context == null) {
+      return;
+    }
+    ScaffoldMessenger.of(context!).showSnackBar(SnackBar(
+      content: Text(a.toString()),
+    ));
+  }
+
   void startConnect() async {
     // final prefs = await SharedPreferences.getInstance();
     // final userName = prefs.getString('userName') ?? " ";
@@ -27,19 +41,21 @@ class Connect {
       bool advertise = await Nearby().startAdvertising(
         _userName,
         strategy,
-        onConnectionInitiated: (String id, ConnectionInfo info) {
-          // Called whenever a discoverer requests connection
-          //
-          // onConnectionInit
-        },
+        onConnectionInitiated: onConnectionInit,
         onConnectionResult: (String id, Status status) {
           // Called when connection is accepted/rejected
           // if connection is accepted send the transaction
-          //
-          //
+          endpointMap.forEach((key, value) async {
+            String str = await Transaction.generateHash(key);
+            Nearby().sendBytesPayload(key, Uint8List.fromList(str.codeUnits));
+          });
         },
         onDisconnected: (String id) {
           // Callled whenever a discoverer disconnects from advertiser
+          // delete connection info
+          endpointMap.remove(id);
+          // delete transaction info
+          transactionMap.remove(id);
         },
         serviceId: serviceId, // uniquely identifies your app
       );
@@ -49,6 +65,19 @@ class Connect {
         strategy,
         onEndpointFound: (String id, String userName, String serviceId) {
           // called when an advertiser is found
+          Nearby().requestConnection(
+            userName,
+            id,
+            onConnectionInitiated: onConnectionInit,
+            onConnectionResult: (id, status) {
+              showSnackbar(status);
+            },
+            onDisconnected: (id) {
+              endpointMap.remove(id);
+              showSnackbar(
+                  "Disconnected from: ${endpointMap[id]!.endpointName}, id $id");
+            },
+          );
         },
         onEndpointLost: (String? id) {
           //called when an advertiser is lost (only if we weren't connected to it )
@@ -59,9 +88,49 @@ class Connect {
       // platform exceptions like unable to start bluetooth or insufficient permissions
     }
   }
-}
-
 
+  void onConnectionInit(String otherId, ConnectionInfo info) {
+    // Called whenever a discoverer requests connection
+    //
+    // onConnectionInit
+    if (endpointMap.containsKey(otherId)) {
+      Nearby().rejectConnection(otherId);
+    }
+    endpointMap[otherId] = info;
+    Nearby().acceptConnection(
+      otherId,
+      onPayLoadRecieved: (_otherId, payload) async {
+        if (payload.type != PayloadType.BYTES) return;
+        // completed payload from other connection
+        String str = String.fromCharCodes(payload.bytes!);
+        var parts = str.split(':');
+        if (parts.length != 2) {
+          showSnackbar("$_otherId invalid payload: $str");
+          return;
+        }
+        // Store transaction
+        var combinedHash = parts[0];
+        var publicKey = parts[1];
+        transactionMap[_otherId] =
+            Transaction(hash: combinedHash, pubKey: publicKey);
+        // sign combined hash with our private key
+        // upload hash+otherKey to firebase
+        transactionMap.remove(_otherId);
+      },
+      onPayloadTransferUpdate: (endid, payloadTransferUpdate) {
+        if (payloadTransferUpdate.status == PayloadStatus.IN_PROGRESS) {
+          print(payloadTransferUpdate.bytesTransferred);
+        } else if (payloadTransferUpdate.status == PayloadStatus.FAILURE) {
+          print("failed");
+          showSnackbar(endid + ": FAILED to transfer file");
+        } else if (payloadTransferUpdate.status == PayloadStatus.SUCCESS) {
+          showSnackbar(
+              "$endid success, total bytes = ${payloadTransferUpdate.totalBytes}");
+        }
+      },
+    );
+  }
+}
 
 
 //  ElevatedButton(
@@ -77,10 +146,6 @@ class Connect {
 //               },
 //             ),
 
-
-
-
- 
 // void onConnectionInit(String id, ConnectionInfo info) {
 //     showModalBottomSheet(
 //       context: context,

loc_chain_app/lib/util/transaction_manager.dart

@@ -9,12 +9,10 @@ import 'package:loc_chain_app/util/keyfile_manager.dart';
 import 'dart:io';
 
 class Transaction {
-  Transaction({required this.hash}) {
-    SharedPreferences.getInstance()
-        .then((s) => _id = s.getString('userName') ?? '0');
-  }
-  late final String _id;
+  Transaction({required this.hash, required this.pubKey});
   final String hash;
+  final String pubKey;
+
   static Future<String> generateHash(String otherUserId) async {
     String id = await SharedPreferences.getInstance()
         .then((s) => s.getString('userName') ?? '');
@@ -24,6 +22,9 @@ class Transaction {
     return DBCrypt()
         .hashpw("$lesser-$greater", KeyFileManager.keyPair.privateKey);
   }
+
+  Future<String> generateP2PPayload(String otherUserId) async =>
+      "${await generateHash(otherUserId)}:${KeyFileManager.keyPair.publicKey}";
 }
 
 class TransactionsDBManager {