from datetime import date

import pandas as pd

from pdf_export import SECTION_AGP, SECTION_EVENTS, SECTION_SUMMARY, build_report_pdf


def _sample_glucose():
    timestamps = pd.date_range("2026-01-01", periods=48, freq="30min")
    return pd.DataFrame({"timestamp": timestamps, "mmol": [6.0 + (i % 5) for i in range(48)]})


def test_build_report_pdf_produces_valid_pdf_bytes():
    glucose = _sample_glucose()
    events_summary = {
        "Hypo Level 1": {"count": 2, "avg_duration_minutes": 20.0, "events_per_week": 1.0},
    }
    pdf_bytes = build_report_pdf(
        [SECTION_SUMMARY, SECTION_AGP, SECTION_EVENTS],
        glucose,
        events_summary,
        date(2026, 1, 1),
        date(2026, 1, 2),
    )
    assert isinstance(pdf_bytes, bytes)
    assert pdf_bytes.startswith(b"%PDF")
    assert len(pdf_bytes) > 500


def test_build_report_pdf_handles_empty_glucose():
    empty = pd.DataFrame(columns=["timestamp", "mmol"])
    pdf_bytes = build_report_pdf(
        [SECTION_SUMMARY, SECTION_AGP], empty, {}, date(2026, 1, 1), date(2026, 1, 2)
    )
    assert pdf_bytes.startswith(b"%PDF")


def test_build_report_pdf_handles_no_sections_selected():
    glucose = _sample_glucose()
    pdf_bytes = build_report_pdf([], glucose, {}, date(2026, 1, 1), date(2026, 1, 2))
    assert pdf_bytes.startswith(b"%PDF")