clean up

lib/pages/chat/model/message_model.dart

@@ -0,0 +1,92 @@
+import 'dart:async';
+
+import 'package:cloud_firestore/cloud_firestore.dart';
+import 'package:fcs/data/services/services.dart';
+import 'package:fcs/domain/constants.dart';
+import 'package:fcs/domain/vo/message.dart';
+import 'package:fcs/pages/main/model/base_model.dart';
+import 'package:logging/logging.dart';
+
+class MessageModel extends BaseModel {
+  final log = Logger('MessageModel');
+
+  List<Message> messages;
+
+  @override
+  logout() async {
+    if (listener != null) await listener.cancel();
+    messages = [];
+  }
+
+  Query query;
+  DocumentSnapshot prevSnap;
+  bool isEnded;
+  bool isLoading;
+  String userID;
+  StreamSubscription<QuerySnapshot> listener;
+
+  static const int rowPerLoad = 20;
+  void initQuery(String userID) {
+    this.messages = [];
+    this.userID = userID;
+    this.prevSnap = null;
+    query = Firestore.instance
+        .collection("$user_collection/$userID/$messages_collection")
+        .orderBy('date', descending: true);
+    load();
+  }
+
+  Future<void> load() async {
+    Query _query =
+        prevSnap != null ? query.startAfterDocument(prevSnap) : query;
+    QuerySnapshot snapshot =
+        await _query.limit(rowPerLoad).getDocuments(source: Source.server);
+
+    int count = snapshot.documents.length;
+    isEnded = count < rowPerLoad;
+    prevSnap = count > 0 ? snapshot.documents[count - 1] : prevSnap;
+
+    snapshot.documents.forEach((e) {
+      messages.add(Message.fromMap(e.data, e.documentID));
+      if (messages.length == 1) {
+        _initListener(e);
+      }
+    });
+    notifyListeners();
+  }
+
+  void _initListener(DocumentSnapshot snap) {
+    if (listener != null) listener.cancel();
+
+    listener = Firestore.instance
+        .collection("$user_collection/$userID/$messages_collection")
+        .endBeforeDocument(snap)
+        .orderBy('date', descending: true)
+        .snapshots(includeMetadataChanges: true)
+        .listen((qs) {
+      qs.documentChanges.forEach((c) {
+        switch (c.type) {
+          case DocumentChangeType.added:
+            log.info("added!! $c");
+            messages.insert(
+                0, Message.fromMap(c.document.data, c.document.documentID));
+            notifyListeners();
+            break;
+          case DocumentChangeType.modified:
+            log.info("modified!! $c");
+            break;
+          default:
+        }
+      });
+    });
+  }
+
+  Future<void> sendMessage(String msg, String receiverID) {
+    Message message = Message(message: msg, receiverID: receiverID);
+    return Services.instance.commonService.sendMessage(message);
+  }
+
+  Future<void> seenMessages(String ownerID, bool seenByOwner) {
+    return Services.instance.commonService.seenMessage(ownerID, seenByOwner);
+  }
+}