import os
import asyncio
from concurrent.futures import ThreadPoolExecutor
from fastapi import FastAPI, File, UploadFile
from fastapi.middleware.cors import CORSMiddleware
from fastapi.middleware.gzip import GZipMiddleware
import numpy as np
from PIL import Image
from paddleocr import PaddleOCR
from doctr.io import DocumentFile
from doctr.models import ocr_predictor
import io

app = FastAPI()
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"]
)
app.add_middleware(GZipMiddleware, minimum_size=1000)

# Initialize models once at startup
ocr_model = ocr_predictor(pretrained=True)
paddle_ocr = PaddleOCR(lang='en', use_angle_cls=True, use_gpu=True)

# Get the number of available CPUs
num_cpus = os.cpu_count()

# Initialize ThreadPoolExecutor with dynamic number of workers
executor = ThreadPoolExecutor(max_workers=num_cpus)

def ocr_with_doctr(file):
    text_output = ''
    doc = DocumentFile.from_pdf(file)
    result = ocr_model(doc)
    for page in result.pages:
        for block in page.blocks:
            for line in block.lines:
                text_output += " ".join([word.value for word in line.words]) + "\n"
    return text_output

def ocr_with_paddle(img):
    finaltext = ''
    result = paddle_ocr.ocr(img)
    for i in range(len(result[0])):
        text = result[0][i][1][0]
        finaltext += ' ' + text
    return finaltext

def generate_text_from_image(img):
    return ocr_with_paddle(img)

async def run_blocking_func(func, *args):
    loop = asyncio.get_event_loop()
    return await loop.run_in_executor(executor, func, *args)

@app.post("/ocr/")
async def perform_ocr(file: UploadFile = File(...)):
    file_bytes = await file.read()
    if file.filename.endswith('.pdf'):
        text_output = await run_blocking_func(ocr_with_doctr, io.BytesIO(file_bytes))
    else:
        img = np.array(Image.open(io.BytesIO(file_bytes)))
        text_output = await run_blocking_func(generate_text_from_image, img)
    return {"ocr_text": text_output}

@app.get("/test/")
async def test_call():
    return {"message": "Hi. I'm running"}