def passage_lines_df_from_answer(line_df, answer_json):
    a = json.loads(answer_json)
    sp, sl = a["start_page_num"], a["start_line_num"]
    ep, el = a["end_page_num"], a["end_line_num"]
    if sp is None: return line_df.iloc[0:0]
    mask = (
        line_df["page_num"].between(sp, ep)
        & ((line_df["page_num"] != sp) | (line_df["line_num"] >= sl))
        & ((line_df["page_num"] != ep) | (line_df["line_num"] <= el))
    )
    return line_df.loc[mask].copy()

def passage_bbox_by_page(passage_df):
    return passage_df.groupby("page_num", as_index=False).agg(
        x0=("x0", "min"), y0=("y0", "min"),
        x1=("x1", "max"), y1=("y1", "max"))

def draw_passage_rectangles(pdf_path, bboxes_df, out_path):
    doc = fitz.open(pdf_path)
    for _, r in bboxes_df.iterrows():
        page = doc[int(r["page_num"]) - 1]
        page.add_rect_annot(fitz.Rect(r["x0"], r["y0"], r["x1"], r["y1"]))
    doc.save(out_path)