app.py

from fastapi import FastAPI, UploadFile, File, APIRouter
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel
import uvicorn
import tempfile
import os

print("CWD:", os.getcwd())
print("Static files:", os.listdir("static") if os.path.exists("static") else "No static directory")

from aimakerspace.text_utils import CharacterTextSplitter, TextFileLoader, PDFLoader
from aimakerspace.openai_utils.prompts import (
    UserRolePrompt,
    SystemRolePrompt,
)
from aimakerspace.vectordatabase import VectorDatabase
from aimakerspace.openai_utils.chatmodel import ChatOpenAI

app = FastAPI()
api_router = APIRouter(prefix="/api")

# Enable CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Initialize global variables
text_splitter = CharacterTextSplitter()
vector_db = None
qa_pipeline = None

system_template = """\
Use the following context to answer a users question. If you cannot find the answer in the context, say you don't know the answer."""
system_role_prompt = SystemRolePrompt(system_template)

user_prompt_template = """\
Context:
{context}

Question:
{question}
"""
user_role_prompt = UserRolePrompt(user_prompt_template)

class RetrievalAugmentedQAPipeline:
    def __init__(self, llm: ChatOpenAI(), vector_db_retriever: VectorDatabase) -> None:
        self.llm = llm
        self.vector_db_retriever = vector_db_retriever

    async def arun_pipeline(self, user_query: str):
        context_list = self.vector_db_retriever.search_by_text(user_query, k=4)

        context_prompt = ""
        for context in context_list:
            context_prompt += context[0] + "\n"

        # Format the prompts as strings
        formatted_user_prompt = user_prompt_template.format(
            question=user_query,
            context=context_prompt
        )

        messages = [
            {"role": "system", "content": system_template},
            {"role": "user", "content": formatted_user_prompt}
        ]

        # Use astream for async streaming
        response_text = ""
        async for chunk in self.llm.astream(messages):
            response_text += chunk

        return {"response": response_text, "context": context_list}

def process_file(file_path: str, file_name: str):
    # Create appropriate loader
    if file_name.lower().endswith('.pdf'):
        loader = PDFLoader(file_path)
    else:
        loader = TextFileLoader(file_path)
        
    # Load and process the documents
    documents = loader.load_documents()
    texts = text_splitter.split_texts(documents)
    return texts

class Question(BaseModel):
    query: str

@api_router.post("/upload")
async def upload_file(file: UploadFile = File(...)):
    global vector_db, qa_pipeline
    
    # Create a temporary file
    suffix = f".{file.filename.split('.')[-1]}"
    with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as temp_file:
        # Copy uploaded file content
        content = await file.read()
        temp_file.write(content)
        temp_file.flush()
        
        try:
            # Process the file
            texts = process_file(temp_file.name, file.filename)
            
            # Create vector store
            vector_db = VectorDatabase()
            vector_db = await vector_db.abuild_from_list(texts)
            
            # Initialize QA pipeline
            chat_openai = ChatOpenAI()
            qa_pipeline = RetrievalAugmentedQAPipeline(
                vector_db_retriever=vector_db,
                llm=chat_openai
            )
            
            return {"message": f"Successfully processed {file.filename}", "num_chunks": len(texts)}
        finally:
            # Clean up
            os.unlink(temp_file.name)

@api_router.post("/ask")
async def ask_question(question: Question):
    if not qa_pipeline:
        return {"error": "Please upload a document first  "}
    
    result = await qa_pipeline.arun_pipeline(question.query)
    return {
        "answer": result["response"],
        "context": [context[0] for context in result["context"]]
    }

# Include API router
app.include_router(api_router)

# Mount static files last
app.mount("/static", StaticFiles(directory="static"), name="static")
app.mount("/", StaticFiles(directory="static", html=True), name="root")

print("CWD:", os.getcwd())
print("Static files:", os.listdir("static") if os.path.exists("static") else "No static directory")

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)