from datetime import date

import pandas as pd

from pdf_export import (
    DAGOVERZICHT_MAX_DAYS,
    SECTION_AGP,
    SECTION_DAGOVERZICHT,
    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 _glucose_with_hypo_and_hyper_events():
    """3 dagen data met een echte hypo- (<3.9, >=15 min) en hyperepisode (>10.0)."""
    timestamps = pd.date_range("2026-01-01", periods=3 * 24 * 12, freq="5min")
    values = [7.0] * len(timestamps)
    values[10:15] = [3.0] * 5  # 25 min hypo
    values[100:106] = [12.0] * 6  # 30 min hyper
    return pd.DataFrame({"timestamp": timestamps, "mmol": values})


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")


def test_build_report_pdf_includes_dagoverzicht_section():
    glucose = _sample_glucose()
    pdf_bytes = build_report_pdf(
        [SECTION_DAGOVERZICHT], glucose, {}, date(2026, 1, 1), date(2026, 1, 2)
    )
    assert pdf_bytes.startswith(b"%PDF")
    assert len(pdf_bytes) > 500


def test_build_report_pdf_caps_dagoverzicht_at_max_days():
    timestamps = pd.date_range("2026-01-01", periods=(DAGOVERZICHT_MAX_DAYS + 10) * 24, freq="1h")
    glucose = pd.DataFrame({"timestamp": timestamps, "mmol": [7.0] * len(timestamps)})
    pdf_bytes = build_report_pdf(
        [SECTION_DAGOVERZICHT],
        glucose,
        {},
        timestamps[0].date(),
        timestamps[-1].date(),
    )
    assert pdf_bytes.startswith(b"%PDF")


def test_build_report_pdf_draws_hypo_and_hyper_charts_when_events_present():
    glucose = _glucose_with_hypo_and_hyper_events()
    events_summary = {
        "Hypo Level 1": {"count": 1, "avg_duration_minutes": 25.0, "events_per_week": 2.3},
        "Hyper Level 1": {"count": 1, "avg_duration_minutes": 30.0, "events_per_week": 2.3},
    }
    pdf_bytes = build_report_pdf(
        [SECTION_EVENTS], glucose, events_summary, date(2026, 1, 1), date(2026, 1, 4)
    )
    assert pdf_bytes.startswith(b"%PDF")
    assert len(pdf_bytes) > 500