from fastapi import FastAPI, File, UploadFile, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from pathlib import Path
import os
import tempfile
import logging
from contextlib import asynccontextmanager

from ocr_api.ocr_service import OCRService
from ocr_api.mock_ocr_service import MockOCRService

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

ocr_service = None
use_gpu = False

@asynccontextmanager
async def lifespan(app: FastAPI):
    global ocr_service
    try:
        ocr_service = OCRService(use_gpu=use_gpu, lang="en")
        logger.info("OCR Service initialized")
    except Exception as e:
        logger.warning(f"PaddleOCR failed, using mock: {e}")
        ocr_service = MockOCRService(use_gpu=False, lang="en")
    yield

app = FastAPI(
    title="OCR API",
    version="1.0.0",
    lifespan=lifespan
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

@app.get("/")
def root():
    return {
        "message": "OCR API running",
        "endpoints": {
            "health": "/health",
            "ocr": "/api/ocr"
        }
    }

@app.get("/health")
def health():
    return {"status": "ok"}

@app.post("/api/ocr")
async def ocr(file: UploadFile = File(...)):
    if not ocr_service:
        raise HTTPException(503, "OCR not ready")

    ext = Path(file.filename).suffix.lower()
    if ext not in {".jpg", ".jpeg", ".png"}:
        raise HTTPException(400, "Unsupported file type")

    with tempfile.NamedTemporaryFile(delete=False, suffix=ext) as tmp:
        tmp.write(await file.read())
        tmp_path = tmp.name

    try:
        result = ocr_service.process_image(tmp_path)
        return JSONResponse(result)
    finally:
        os.unlink(tmp_path)