import time
from sqlalchemy.orm import Session
from app.models.document import Document


def generate_document_id(db: Session) -> str:
    ts = int(time.time())
    ts_hex = format(ts, "x")

    n = 0
    while True:
        n_hex = format(n, "x")
        candidate = f"doc_{ts_hex}-{n_hex}"

        exists = (
            db.query(Document)
            .filter(Document.document_id == candidate)
            .first()
        )
        if not exists:
            return candidate

        n += 1