Implement last heard and info

lib/models/last_heard_item.dart

@@ -0,0 +1,127 @@
+class LastHeardItem {
+  final String linkName;
+  final String sessionID;
+  final int linkType;
+  final int contextID;
+  final int sessionType;
+  final int slot;
+  final int sourceID;
+  final int destinationID;
+  final String route;
+  final String linkCall;
+  final String sourceCall;
+  final String? sourceName;
+  final String destinationCall;
+  final String? destinationName;
+  final int start;
+  final int stop;
+  final int? rssi;
+  final int? ber;
+  final int reflectorID;
+  final String linkTypeName;
+  final List<String> callTypes;
+  final int lossCount;
+  final int totalCount;
+  final String master;
+  final String? talkerAlias;
+  final int flagSet;
+  final String event;
+
+  LastHeardItem({
+    required this.linkName,
+    required this.sessionID,
+    required this.linkType,
+    required this.contextID,
+    required this.sessionType,
+    required this.slot,
+    required this.sourceID,
+    required this.destinationID,
+    required this.route,
+    required this.linkCall,
+    required this.sourceCall,
+    this.sourceName,
+    required this.destinationCall,
+    this.destinationName,
+    required this.start,
+    required this.stop,
+    this.rssi,
+    this.ber,
+    required this.reflectorID,
+    required this.linkTypeName,
+    required this.callTypes,
+    required this.lossCount,
+    required this.totalCount,
+    required this.master,
+    this.talkerAlias,
+    required this.flagSet,
+    required this.event,
+  });
+
+  factory LastHeardItem.fromJson(Map<String, dynamic> json) {
+    return LastHeardItem(
+      linkName: json['LinkName'] as String? ?? '',
+      sessionID: json['SessionID'] as String? ?? '',
+      linkType: json['LinkType'] as int? ?? 0,
+      contextID: json['ContextID'] as int? ?? 0,
+      sessionType: json['SessionType'] as int? ?? 0,
+      slot: json['Slot'] as int? ?? 0,
+      sourceID: json['SourceID'] as int? ?? 0,
+      destinationID: json['DestinationID'] as int? ?? 0,
+      route: json['Route'] as String? ?? '',
+      linkCall: json['LinkCall'] as String? ?? '',
+      sourceCall: json['SourceCall'] as String? ?? '',
+      sourceName: json['SourceName'] as String?,
+      destinationCall: json['DestinationCall'] as String? ?? '',
+      destinationName: json['DestinationName'] as String?,
+      start: json['Start'] as int? ?? 0,
+      stop: json['Stop'] as int? ?? 0,
+      rssi: json['RSSI'] as int?,
+      ber: json['BER'] as int?,
+      reflectorID: json['ReflectorID'] as int? ?? 0,
+      linkTypeName: json['LinkTypeName'] as String? ?? '',
+      callTypes: (json['CallTypes'] as List<dynamic>?)
+              ?.map((e) => e as String)
+              .toList() ??
+          [],
+      lossCount: json['LossCount'] as int? ?? 0,
+      totalCount: json['TotalCount'] as int? ?? 0,
+      master: json['Master'] as String? ?? '',
+      talkerAlias: json['TalkerAlias'] as String?,
+      flagSet: json['FlagSet'] as int? ?? 0,
+      event: json['Event'] as String? ?? '',
+    );
+  }
+
+  String get displayName {
+    if (sourceName != null && sourceName!.isNotEmpty) {
+      return '$sourceCall ($sourceName)';
+    }
+    return sourceCall;
+  }
+
+  String get destinationDisplayName {
+    if (destinationName != null && destinationName!.isNotEmpty) {
+      return '$destinationCall ($destinationName)';
+    }
+    return destinationCall;
+  }
+
+  DateTime get timestamp {
+    return DateTime.fromMillisecondsSinceEpoch(start * 1000);
+  }
+
+  String get timeAgo {
+    final now = DateTime.now();
+    final difference = now.difference(timestamp);
+
+    if (difference.inSeconds < 60) {
+      return '${difference.inSeconds}s ago';
+    } else if (difference.inMinutes < 60) {
+      return '${difference.inMinutes}m ago';
+    } else if (difference.inHours < 24) {
+      return '${difference.inHours}h ago';
+    } else {
+      return '${difference.inDays}d ago';
+    }
+  }
+}