add last chat in list chat head response

chat/blueprint.py

@@ -7,6 +7,7 @@
 from auth.function import get_user
 from flask import Blueprint, request
 from pagination.pagination import create_pagination_options_from_request
+from user.service import UserService
 
 from chat.service import ChatService
 
@@ -20,6 +21,13 @@ def list_chat():
     user = get_user()
     pagination_options = create_pagination_options_from_request(request)
     result = ChatService.list_chat_head(user, pagination_options)
+
     for chat_head in result:
-        response.append(chat_head.json_populated())
+        new_json = chat_head.json_populated()
+        from_user = UserService.find_by_id(chat_head.user_id)
+        to_user = UserService.find_by_id(chat_head.target_user_id)
+        last_chat = ChatService.get_last_chat_message(from_user, to_user)
+        new_json["last_chat"] = last_chat.json()
+        response.append(new_json)
+
     return response

chat/service.py

@@ -7,7 +7,9 @@
 
 from database.database import db_session
 from marshmallow import fields, validate
-from pagination.pagination import Pagination, PaginationOptions, PaginationSortOptions
+from pagination.pagination import (Pagination, PaginationOptions,
+                                   PaginationSortOptions)
+from sqlalchemy import desc
 from sqlalchemy.orm.query import Query
 from sqlalchemy.sql import and_, or_
 from user.model import User
@@ -98,6 +100,28 @@ def update_chat_head(user: User, from_user: User):
             db_session.rollback()
             raise InternalServerError("Failed to update chat head!")
 
+    @staticmethod
+    def get_last_chat_message(from_user: User, to_user: User) -> Chat:
+        query: Query = db_session.query(Chat)
+        query = query.where(
+            or_(
+                (
+                    and_(
+                        Chat.from_user_id == from_user.id,
+                        Chat.to_user_id == to_user.id,
+                    )
+                ),
+                (
+                    and_(
+                        Chat.from_user_id == to_user.id,
+                        Chat.to_user_id == from_user.id,
+                    )
+                ),
+            )
+        )
+        query = query.order_by(desc(Chat.id)).limit(1)
+        return query.one()
+
     @staticmethod
     def list_chat_head(
         user: User, pagination_options: PaginationOptions

example/chat.py

@@ -36,3 +36,12 @@
 
 for chat in chats:
     print(chat)
+
+print("=" * 10)
+
+# get last chat message
+from_user = UserService.find_by_id(2)
+to_user = UserService.find_by_id(3)
+
+last_chat_message = ChatService.get_last_chat_message(from_user, to_user)
+print(last_chat_message)

mock/seed_chat.py

@@ -15,13 +15,16 @@ def seed_chat():
     charlie = UserService.find_by_email("[email protected]")
 
     # mock dummy chat
-    ChatService.send_chat(annie, bobbie, "Hello Bobbie!")
-    ChatService.send_chat(bobbie, annie, "Hi Annie!")
-    ChatService.send_chat(annie, bobbie, "How are you?")
-    ChatService.send_chat(bobbie, annie, "I'm good!")
+    ChatService.send_chat(annie, bobbie, "1 start Hello Bobbie!")
+    ChatService.send_chat(bobbie, annie, "2 Hi Annie!")
+    ChatService.send_chat(annie, bobbie, "3 How are you?")
+    ChatService.send_chat(bobbie, annie, "4 end I'm good!")
 
-    ChatService.send_chat(bobbie, charlie, "Hello Charlie!")
-    ChatService.send_chat(charlie, bobbie, "Hi Bobbie!")
+    ChatService.send_chat(bobbie, charlie, "1 start Hello Charlie!")
+    ChatService.send_chat(charlie, bobbie, "2 end Hi Bobbie!")
+
+    ChatService.send_chat(annie, charlie, "1 start Hello Charlie!")
+    ChatService.send_chat(charlie, annie, "2 end Hi Annie!")
 
 
 if __name__ == "__main__":