"""Unit tests for _parse_event in the CalDAV backend."""
import json
from datetime import date, time
from unittest.mock import MagicMock

import pytest
from homeassistant.core import HomeAssistant

from custom_components.room_cal_ha.backends.caldav import _parse_event
from custom_components.room_cal_ha.models import ReservationData


# ---------------------------------------------------------------------------
# iCal helpers
# ---------------------------------------------------------------------------

_X_DATA = {
  "guest_name": "Alice Smith",
  "wifi_key": "secret-key",
  "door_code": "4567",
}


def _make_event(summary: str, dtstart: str, dtend: str, x_data=None, all_day=False):
  """Build a mock caldav.Event with the given iCal fields."""
  if all_day:
    start_line = f"DTSTART;VALUE=DATE:{dtstart}"
    end_line = f"DTEND;VALUE=DATE:{dtend}"
  else:
    start_line = f"DTSTART:{dtstart}Z"
    end_line = f"DTEND:{dtend}Z"

  lines = [
    "BEGIN:VCALENDAR",
    "VERSION:2.0",
    "BEGIN:VEVENT",
    f"SUMMARY:{summary}",
    start_line,
    end_line,
  ]
  if x_data is not None:
    lines.append(f"X-ROOMCAL-DATA:{json.dumps(x_data)}")
  lines += ["END:VEVENT", "END:VCALENDAR", ""]

  event = MagicMock()
  event.data = "\r\n".join(lines)
  return event


# ---------------------------------------------------------------------------
# Valid event
# ---------------------------------------------------------------------------

def test_parse_valid_event_returns_reservation_data(hass: HomeAssistant):
  event = _make_event("Guest: Alice", "20260701T140000", "20260705T120000", _X_DATA)
  result = _parse_event(event)

  assert isinstance(result, ReservationData)
  assert result.guest_name == "Alice Smith"
  assert result.wifi_key == "secret-key"
  assert result.door_code == "4567"


def test_parse_valid_event_extracts_dates(hass: HomeAssistant):
  event = _make_event("Guest: Alice", "20260701T140000", "20260705T120000", _X_DATA)
  result = _parse_event(event)

  assert result is not None
  assert result.check_in_date == date(2026, 7, 1)
  assert result.check_out_date == date(2026, 7, 5)


def test_parse_valid_event_extracts_times(hass: HomeAssistant):
  from zoneinfo import ZoneInfo
  from homeassistant.util import dt as dt_util

  dt_util.set_default_time_zone(ZoneInfo("UTC"))
  event = _make_event("Guest: Alice", "20260701T140000", "20260705T120000", _X_DATA)
  result = _parse_event(event)

  assert result is not None
  assert result.check_in_time == time(14, 0)
  assert result.check_out_time == time(12, 0)


# ---------------------------------------------------------------------------
# Filtering — events that should return None
# ---------------------------------------------------------------------------

def test_parse_wrong_title_prefix_returns_none(hass: HomeAssistant):
  event = _make_event("Blocked", "20260701T140000", "20260705T120000", _X_DATA)
  assert _parse_event(event) is None


def test_parse_all_day_event_returns_none(hass: HomeAssistant):
  event = _make_event("Guest: Alice", "20260701", "20260705", _X_DATA, all_day=True)
  assert _parse_event(event) is None


def test_parse_missing_x_data_returns_none(hass: HomeAssistant):
  event = _make_event("Guest: Alice", "20260701T140000", "20260705T120000", x_data=None)
  assert _parse_event(event) is None


def test_parse_invalid_json_in_x_data_returns_none(hass: HomeAssistant):
  event = _make_event("Guest: Alice", "20260701T140000", "20260705T120000")
  # Manually inject bad JSON into the iCal
  event.data = event.data.replace("END:VEVENT", "X-ROOMCAL-DATA:not-valid-json\r\nEND:VEVENT")
  assert _parse_event(event) is None


def test_parse_garbage_ical_returns_none(hass: HomeAssistant):
  event = MagicMock()
  event.data = "this is not ical at all"
  # Should not raise — catches all exceptions
  result = _parse_event(event)
  assert result is None


# ---------------------------------------------------------------------------
# Partial data
# ---------------------------------------------------------------------------

def test_parse_event_missing_dtend_still_returns_result(hass: HomeAssistant):
  """DTEND is optional — event without it should still parse (checkout fields will be None)."""
  lines = [
    "BEGIN:VCALENDAR",
    "VERSION:2.0",
    "BEGIN:VEVENT",
    "SUMMARY:Guest: Alice",
    "DTSTART:20260701T140000Z",
    f"X-ROOMCAL-DATA:{json.dumps(_X_DATA)}",
    "END:VEVENT",
    "END:VCALENDAR",
    "",
  ]
  event = MagicMock()
  event.data = "\r\n".join(lines)
  result = _parse_event(event)

  assert result is not None
  assert result.check_in_date == date(2026, 7, 1)
  assert result.check_out_date is None
  assert result.check_out_time is None


def test_parse_event_x_data_missing_optional_fields(hass: HomeAssistant):
  """X-ROOMCAL-DATA may omit wifi_key / door_code — those become None."""
  sparse = {"guest_name": "Bob"}
  event = _make_event("Guest: Bob", "20260801T140000", "20260803T120000", sparse)
  result = _parse_event(event)

  assert result is not None
  assert result.guest_name == "Bob"
  assert result.wifi_key is None
  assert result.door_code is None