"""calls._parse_ts — cursor/date bounds must reach Firestore as datetimes.

A raw ISO string compared against a timestamp field sorts by type, not time,
which made the Archive's "Load more" return the first page again.
"""
from datetime import datetime, timezone

import pytest
from fastapi import HTTPException

from app.routers.calls import _next_cursor, _parse_ts


def test_empty_is_none():
    assert _parse_ts(None, "cursor") is None
    assert _parse_ts("", "cursor") is None


def test_z_suffix_parses_as_utc():
    assert _parse_ts("2026-09-20T12:00:00Z", "date_from") == datetime(2026, 9, 20, 12, tzinfo=timezone.utc)


def test_naive_is_assumed_utc():
    assert _parse_ts("2026-09-20T12:00:00", "date_to").tzinfo == timezone.utc


def test_round_trips_isoformat_cursor():
    dt = datetime(2026, 9, 20, 12, 30, 5, 123456, tzinfo=timezone.utc)
    assert _parse_ts(dt.isoformat(), "cursor") == dt


def test_garbage_is_400():
    with pytest.raises(HTTPException) as exc:
        _parse_ts("yesterday", "date_from")
    assert exc.value.status_code == 400


# ── _next_cursor ──────────────────────────────────────────────────────────


def _rows(n):
    return [{"started_at": datetime(2026, 9, 20, 12, i // 60, i % 60, tzinfo=timezone.utc)} for i in range(n)]


def test_cursor_resumes_after_last_returned_row_when_matches_overflow():
    rows = _rows(200)
    page = rows[:50]
    assert _next_cursor(rows, rows, page, 200) == page[-1]["started_at"].isoformat()


def test_cursor_resumes_after_window_when_page_holds_every_match():
    rows = _rows(200)
    matches = rows[:3]
    assert _next_cursor(rows, matches, matches, 200) == rows[-1]["started_at"].isoformat()


def test_short_window_is_the_end():
    rows = _rows(20)
    assert _next_cursor(rows, rows[:5], rows[:5], 200) is None