"""Unit tests for SSM-backed state helpers."""
import json

import pytest
from botocore.exceptions import ClientError

import config
from src import state


@pytest.fixture()
def mock_ssm(mocker):
    return mocker.patch('src.state._ssm')


def _ssm_param(value: str):
    return {'Parameter': {'Value': value}}


def _client_error(code: str):
    return ClientError({'Error': {'Code': code, 'Message': code}}, 'GetParameter')


def test_load_returns_state_when_param_exists(mock_ssm):
    mock_ssm.get_parameter.return_value = _ssm_param('{"pending_date": "2026-06-29"}')
    assert state.load() == {'pending_date': '2026-06-29'}


def test_load_returns_empty_dict_when_param_not_found(mock_ssm):
    mock_ssm.get_parameter.side_effect = _client_error('ParameterNotFound')
    assert state.load() == {}


def test_load_returns_empty_dict_on_invalid_json(mock_ssm):
    """Corrupted SSM value (e.g. manual edit) must not crash the Lambda."""
    mock_ssm.get_parameter.return_value = _ssm_param('not valid json {{{')
    assert state.load() == {}


@pytest.mark.parametrize('raw', ['null', '[]', '"a string"', '42'])
def test_load_returns_empty_dict_on_non_dict_json(mock_ssm, raw):
    """Valid JSON that is not an object must not crash downstream .get() calls."""
    mock_ssm.get_parameter.return_value = _ssm_param(raw)
    assert state.load() == {}


def test_load_reraises_unexpected_ssm_errors(mock_ssm):
    mock_ssm.get_parameter.side_effect = _client_error('AccessDeniedException')
    with pytest.raises(ClientError):
        state.load()


def test_save_puts_json_to_ssm(mock_ssm):
    state.save({'alerted': True})
    mock_ssm.put_parameter.assert_called_once_with(
        Name=config.SSM_STATE_PARAM,
        Value=json.dumps({'alerted': True}),
        Type='String',
        Overwrite=True,
    )