[Improvement] Use SQLite for chat memory (#910)

Co-authored-by: Deven Patel <deven298@yahoo.com>

embedchain/memory/message.py

@@ -0,0 +1,72 @@
+import logging
+from typing import Any, Dict, Optional
+
+from embedchain.helper.json_serializable import JSONSerializable
+
+
+class BaseMessage(JSONSerializable):
+    """
+    The base abstract message class.
+
+    Messages are the inputs and outputs of Models.
+    """
+
+    # The string content of the message.
+    content: str
+
+    # The creator of the message. AI, Human, Bot etc.
+    by: str
+
+    # Any additional info.
+    metadata: Dict[str, Any]
+
+    def __init__(self, content: str, creator: str, metadata: Optional[Dict[str, Any]] = None) -> None:
+        super().__init__()
+        self.content = content
+        self.creator = creator
+        self.metadata = metadata
+
+    @property
+    def type(self) -> str:
+        """Type of the Message, used for serialization."""
+
+    @classmethod
+    def is_lc_serializable(cls) -> bool:
+        """Return whether this class is serializable."""
+        return True
+
+    def __str__(self) -> str:
+        return f"{self.creator}: {self.content}"
+
+
+class ChatMessage(JSONSerializable):
+    """
+    The base abstract chat message class.
+
+    Chat messages are the pair of (question, answer) conversation
+    between human and model.
+    """
+
+    human_message: Optional[BaseMessage] = None
+    ai_message: Optional[BaseMessage] = None
+
+    def add_user_message(self, message: str, metadata: Optional[dict] = None):
+        if self.human_message:
+            logging.info(
+                "Human message already exists in the chat message,\
+                overwritting it with new message."
+            )
+
+        self.human_message = BaseMessage(content=message, creator="human", metadata=metadata)
+
+    def add_ai_message(self, message: str, metadata: Optional[dict] = None):
+        if self.ai_message:
+            logging.info(
+                "AI message already exists in the chat message,\
+                overwritting it with new message."
+            )
+
+        self.ai_message = BaseMessage(content=message, creator="ai", metadata=metadata)
+
+    def __str__(self) -> str:
+        return f"{self.human_message} | {self.ai_message}"