from pathlib import Path

from app.core.config import settings

_ocr_engine = None


def get_ocr_engine():
    global _ocr_engine
    if _ocr_engine is None:
        from paddleocr import PaddleOCR

        _ocr_engine = PaddleOCR(use_angle_cls=True, lang="ch", show_log=False)
    return _ocr_engine


def run_ocr(image_path: str) -> str:
    engine = get_ocr_engine()
    result = engine.ocr(image_path, cls=True)
    if not result or not result[0]:
        return ""
    lines = []
    for line in result[0]:
        if line and len(line) >= 2:
            text = line[1][0]
            if text:
                lines.append(text)
    return "\n".join(lines)


def save_upload_file(user_id: str, question_id: str, filename: str, content: bytes) -> str:
    ext = Path(filename).suffix.lower() or ".jpg"
    if ext not in {".jpg", ".jpeg", ".png", ".webp"}:
        ext = ".jpg"
    user_dir = Path(settings.UPLOAD_DIR) / user_id
    user_dir.mkdir(parents=True, exist_ok=True)
    rel_path = f"{user_id}/{question_id}{ext}"
    full_path = Path(settings.UPLOAD_DIR) / rel_path
    full_path.write_bytes(content)
    return rel_path