from datetime import datetime, timezone
from types import SimpleNamespace
from unittest.mock import AsyncMock

import pytest

from modules.reminders.commands import _errorMessage, handleReminder, validateReminder
from modules.reminders.service import _nextRun, normalizeRecurrence


@pytest.mark.parametrize(
    "command",
    [
        {"action": "list"},
        {"action": "cancel", "reminder_id": "reminder-1"},
        {"action": "set_timezone", "timezone": "America/Chicago"},
        {
            "action": "create",
            "message": "call home",
            "run_at": "2999-03-08T09:00:00-05:00",
            "recurrence": {"frequency": "weekly", "interval": 2},
        },
        {"needs_clarification": "What time should I use?"},
    ],
)
def test_reminder_validator_accepts_supported_commands(command):
    assert validateReminder(command) == []


def test_reminder_validator_reports_all_invalid_create_fields():
    errors = validateReminder(
        {
            "action": "create",
            "message": "   ",
            "run_at": "2026-03-08T09:00:00",
            "recurrence": {"frequency": "hourly"},
        }
    )

    assert "create requires a reminder message" in errors
    assert "run_at must include a timezone offset" in errors
    assert "recurrence frequency must be daily or weekly" in errors


@pytest.mark.parametrize(
    ("value", "expected"),
    [
        (None, None),
        ("once", None),
        ("daily", {"frequency": "daily", "interval": 1}),
        (
            {"frequency": "WEEKLY", "interval": "3"},
            {"frequency": "weekly", "interval": 3},
        ),
    ],
)
def test_recurrence_normalization(value, expected):
    assert normalizeRecurrence(value) == expected


@pytest.mark.parametrize(
    "value",
    [
        "hourly",
        {"frequency": "daily", "interval": 0},
        {"frequency": "weekly", "interval": 366},
        {"frequency": "daily", "interval": "many"},
    ],
)
def test_recurrence_normalization_rejects_invalid_values(value):
    with pytest.raises(ValueError):
        normalizeRecurrence(value)


@pytest.mark.parametrize(
    ("scheduled_for", "expected"),
    [
        # America/Chicago enters daylight time on March 8, 2026.
        (
            datetime(2026, 3, 7, 15, 0, tzinfo=timezone.utc),
            datetime(2026, 3, 8, 14, 0, tzinfo=timezone.utc),
        ),
        # It returns to standard time on November 1, 2026.
        (
            datetime(2026, 10, 31, 14, 0, tzinfo=timezone.utc),
            datetime(2026, 11, 1, 15, 0, tzinfo=timezone.utc),
        ),
    ],
)
def test_next_run_preserves_local_wall_clock_across_dst(scheduled_for, expected):
    result = _nextRun(
        scheduled_for,
        {"frequency": "daily", "interval": 1},
        "America/Chicago",
        now=scheduled_for,
    )

    assert result == expected
    assert result.astimezone(__import__("zoneinfo").ZoneInfo("America/Chicago")).hour == 9


def test_next_run_skips_missed_intervals_after_downtime():
    scheduled_for = datetime(2026, 3, 7, 15, 0, tzinfo=timezone.utc)

    result = _nextRun(
        scheduled_for,
        {"frequency": "daily", "interval": 1},
        "America/Chicago",
        now=datetime(2026, 3, 9, 14, 1, tzinfo=timezone.utc),
    )

    assert result == datetime(2026, 3, 10, 14, 0, tzinfo=timezone.utc)


def _context(response, status):
    api = SimpleNamespace(
        request=AsyncMock(return_value=(response, status)),
        timezone="UTC",
    )
    return SimpleNamespace(api=api, timezone="UTC", reply=AsyncMock())


@pytest.mark.asyncio
async def test_create_handler_reports_success_and_api_error():
    context = _context(
        {
            "message": "call home",
            "next_run_at": "2099-01-01T12:00:00+00:00",
            "recurrence": {"frequency": "daily"},
        },
        201,
    )
    parsed = {
        "action": "create",
        "message": "call home",
        "run_at": "2099-01-01T12:00:00Z",
        "recurrence": {"frequency": "daily"},
    }
    await handleReminder(context, parsed)
    assert "recurring" in context.reply.await_args.args[0]
    context.api.request.assert_awaited_once_with(
        "post",
        "/api/reminders",
        {
            "message": "call home",
            "run_at": "2099-01-01T12:00:00Z",
            "recurrence": {"frequency": "daily"},
        },
    )

    context = _context({"error": "database unavailable"}, 503)
    await handleReminder(context, parsed)
    assert "database unavailable" in context.reply.await_args.args[0]


@pytest.mark.asyncio
async def test_list_handler_formats_results_and_empty_state():
    context = _context(
        {
            "reminders": [
                {
                    "id": "reminder-one",
                    "next_run_at": "2099-01-01T12:00:00+00:00",
                    "message": "call home",
                }
            ]
        },
        200,
    )
    await handleReminder(context, {"action": "list"})
    reply = context.reply.await_args.args[0]
    assert "Active reminders" in reply and "reminder-one" in reply

    context = _context({"reminders": []}, 200)
    await handleReminder(context, {"action": "list"})
    assert context.reply.await_args.args[0] == "You have no active reminders."

    context = _context({"error": "offline"}, 503)
    await handleReminder(context, {"action": "list"})
    assert "offline" in context.reply.await_args.args[0]


@pytest.mark.asyncio
async def test_cancel_and_timezone_handlers_update_context():
    context = _context({"message": "call home"}, 200)
    await handleReminder(
        context,
        {"action": "cancel", "reminder_id": "reminder-one"},
    )
    assert context.reply.await_args.args[0] == "Cancelled reminder: call home"
    context.api.request.assert_awaited_once_with(
        "delete", "/api/reminders/reminder-one"
    )

    context = _context({"error": "not found"}, 404)
    await handleReminder(
        context,
        {"action": "cancel", "reminder_id": "missing"},
    )
    assert "not found" in context.reply.await_args.args[0]

    context = _context({"timezone": "America/Chicago"}, 200)
    await handleReminder(
        context,
        {"action": "set_timezone", "timezone": "America/Chicago"},
    )
    assert context.timezone == "America/Chicago"
    assert context.api.timezone == "America/Chicago"

    context = _context({}, 400)
    await handleReminder(
        context,
        {"action": "set_timezone", "timezone": "bad"},
    )
    assert "couldn't update" in context.reply.await_args.args[0]


def test_error_message_handles_structured_and_unstructured_results():
    assert _errorMessage({"error": "detail"}, "fallback") == "fallback detail"
    assert _errorMessage("not an object", "fallback") == "fallback"