Refactor mail and retriever modules to use the new database model; add FAISS dependency for vector storage

app/controllers/mail.py

@@ -15,7 +15,7 @@ from langchain_community.document_loaders import (
     UnstructuredImageLoader,
 )
 
-from models.chroma import vectorstore
+from models.db import vectorstore
 from models.mails import build_gmail_service
 
 SCOPES = ["https://www.googleapis.com/auth/gmail.readonly"]

app/models/db/__init__.py

@@ -0,0 +1,18 @@
+"""This module is responsible for initializing the database connection and creating the necessary tables."""
+import faiss
+from langchain_community.vectorstores import FAISS
+from langchain_community.docstore.in_memory import InMemoryDocstore
+# from langchain_chroma import Chroma
+from models.llm import EmbeddingsModel
+
+embeddings = EmbeddingsModel("all-MiniLM-L6-v2")
+
+index = faiss.IndexFlatL2(len(embeddings.embed_query("hello world")))
+print(index)
+
+vectorstore = FAISS(
+    embedding_function=embeddings,
+    index=index,
+    docstore=InMemoryDocstore(),
+    index_to_docstore_id={}
+)

app/requirements.txt

@@ -30,6 +30,7 @@ dnspython==2.7.0
 durationpy==0.9
 emoji==2.14.1
 eval_type_backport==0.2.2
+faiss-cpu==1.10.0
 fastapi==0.115.11
 filelock==3.17.0
 filetype==1.2.0

app/retriever/__init__.py

@@ -2,7 +2,7 @@
 from venv import logger
 from langchain_core.retrievers import BaseRetriever
 from langchain_core.vectorstores import VectorStoreRetriever
-from models.chroma import vectorstore
+from models.db import vectorstore
 
 class DocRetriever(BaseRetriever):
     """