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
#在FastAPI中，Depends()函数用于声明依赖项

import random
import string
import sys
import timeit
import datetime
import io

import os
from dotenv import load_dotenv
load_dotenv()

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
    print("File received:"+uploaded_file.filename)
    #print("File received:"+file_to_process.filename)
    #`file_to_process`是`FileToProcess`类的一个实例，它具有一个名为`uploaded_file`的属性，而不是`filename`属性。
    #因此，在打印`"File received:"+file_to_process.filename`时会引发`AttributeError`。
        
    random_string = generate_random_string(20)
    file_path = Path.cwd() / random_string
    file_path.mkdir(parents=True, exist_ok=True)
    file_saved_in_api = file_path / uploaded_file.filename
    print(file_saved_in_api)
    
    with open(file_saved_in_api, "wb+") as file_object:
        file_object.write(uploaded_file.file.read())   

    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)
    print()
    
    #api_call_msg={"INFO": f"File '{uploaded_file.filename}' saved to your profile."}
    api_call_msg={"INFO": f"File '{file_saved_in_api}' saved to your profile."}    
    print(api_call_msg)

    print(api_call_msg["INFO"])
    #File 'uploaded_file' saved to your profile.
    print()

    print("API call finished...")

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