from fastapi import FastAPI, File, UploadFile
from pydantic import BaseModel
from pathlib import Path
from fastapi import Form
from fastapi.responses import JSONResponse
from langchain.text_splitter import RecursiveCharacterTextSplitter
from PyPDF2 import PdfReader
from fastapi import Depends

def generate_random_string(length):
    letters = string.ascii_lowercase
    return ''.join(random.choice(letters) for i in range(length))  

app = FastAPI()

class FileToProcess(BaseModel):
    uploaded_file: UploadFile = File(...)

@app.get("/")
async def home():
    return "API Working!"

@app.post("/file/upload")
async def upload_file(username: str, file_to_process: FileToProcess = Depends()):
    uploaded_file = file_to_process.uploaded_file
    
    random_string=generate_random_string(20)
    file_path = random_string
    #path_to_save_file = Path.home() / username / "saved_files"
    #path_to_save_file.mkdir(parents=True, exist_ok=True)
    file_saved_in_api = f"{file_path}/{uploaded_file.filename}"
    with open(file_saved_in_api, "wb+") as file_object:
        file_object.write(uploaded_file.file.read())

    # 下面是你要处理的代码
    text_splitter = RecursiveCharacterTextSplitter(        
        #separator = "\n",
        chunk_size = 500,
        chunk_overlap  = 100, #striding over the text
        length_function = len,
    )        

    doc_reader = PdfReader(file_saved_in_api)
    raw_text = ''
    for i, page in enumerate(doc_reader.pages):
        text = page.extract_text()
        if text:
            raw_text += text
    temp_texts = text_splitter.split_text(raw_text)
    print(temp_texts)

    return {"INFO": f"File '{uploaded_file.filename}' saved to your profile."}