Get older messages

lib/helpers/conversations_helper.dart

@@ -29,21 +29,16 @@ class ConversationsHelper {
   ///
   /// Return the ID of the newly created conversation or -1 in case of failure
   Future<int> createConversation(ConversationSettings settings) async {
+    final response =
+        await APIRequest(uri: "conversations/create", needLogin: true, args: {
+      "name": settings.hasName ? settings.name : "false",
+      "follow": settings.following ? "true" : "false",
+      "users": settings.members.join(",")
+    }).exec();
 
-    final response = await APIRequest(
-      uri: "conversations/create",
-      needLogin: true,
-      args: {
-        "name" : settings.hasName ? settings.name : "false",
-        "follow" : settings.following ? "true" : "false",
-        "users": settings.members.join(",")
-      }
-    ).exec();
-
-    if(response.code != 200) return -1;
+    if (response.code != 200) return -1;
 
     return response.getObject()["conversationID"];
-
   }
 
   /// Download the list of conversations from the server
@@ -156,6 +151,28 @@ class ConversationsHelper {
     );
   }
 
+  /// Parse a list of messages given by the server
+  Future<ConversationMessagesList> _parseConversationMessageFromServer(
+      int conversationID, APIResponse response) async {
+    if (response.code != 200) return null;
+
+    // Parse the response of the server
+    ConversationMessagesList list = ConversationMessagesList();
+    response.getArray().forEach((f) {
+      list.add(
+        _apiToConversationMessage(
+          conversationID: conversationID,
+          map: f,
+        ),
+      );
+    });
+
+    // Save messages in the cache
+    _conversationMessagesDatabaseHelper.insertOrUpdateAll(list);
+
+    return list;
+  }
+
   /// Refresh the list of messages of a conversation
   ///
   /// Set [lastMessageID] to 0 to specify that we do not have any message of the
@@ -172,24 +189,26 @@ class ConversationsHelper {
           "last_message_id": lastMessageID.toString()
         }).exec();
 
-    if (response.code != 200) return null;
+    return await _parseConversationMessageFromServer(conversationID, response);
+  }
 
-    // Parse the response of the server
-    ConversationMessagesList list = ConversationMessagesList();
-    response.getArray().forEach((f) {
-      list.add(ConversationMessage(
-          id: f["ID"],
-          conversationID: conversationID,
-          userID: f["ID_user"],
-          timeInsert: f["time_insert"],
-          message: f["message"],
-          imageURL: f["image_path"]));
-    });
+  /// Get older messages for a given conversation from an online source
+  Future<ConversationMessagesList> getOlderMessages({
+    @required int conversationID,
+    @required int oldestMessagesID,
+    int limit = 15,
+  }) async {
+    // Perform the request online
+    final response = await APIRequest(
+        uri: "conversations/get_older_messages",
+        needLogin: true,
+        args: {
+          "conversationID": conversationID.toString(),
+          "oldest_message_id": oldestMessagesID.toString(),
+          "limit": limit.toString()
+        }).exec();
 
-    // Save messages in the cache
-    _conversationMessagesDatabaseHelper.insertOrUpdateAll(list);
-
-    return list;
+    return await _parseConversationMessageFromServer(conversationID, response);
   }
 
   /// Get new messages for a given conversation
@@ -237,4 +256,19 @@ class ConversationsHelper {
 
     return SendMessageResult.SUCCESS;
   }
+
+  /// Turn an API response into a ConversationMessage object
+  ConversationMessage _apiToConversationMessage({
+    @required int conversationID,
+    @required Map<String, dynamic> map,
+  }) {
+    return ConversationMessage(
+      id: map["ID"],
+      conversationID: conversationID,
+      userID: map["ID_user"],
+      timeInsert: map["time_insert"],
+      message: map["message"],
+      imageURL: map["image_path"],
+    );
+  }
 }