import pytest
import requests
from aare.gui.auth import auth

# pytest-mock provides the 'mocker' fixture, which is a wrapper around the 
# standard unittest.mock. It simplifies mocking by automatically handling 
# cleanup (unpatching) after each test, and providing a more "pytest-native" 
# feel compared to using @patch decorators or context managers.

def test_auth_success(mocker):
    """
    Test successful authentication using pytest-mock's mocker fixture.
    
    In standard pytest/unittest, you would typically use:
    with mock.patch('requests.post') as mock_post:
        ...
    Or a decorator:
    @patch('requests.post')
    def test_auth(mock_post):
        ...
        
    pytest-mock allows you to use the 'mocker' fixture directly in the function arguments.
    This avoids deeply nested context managers and makes it easier to mock multiple things.
    """
    
    # We mock 'requests.post' to simulate a successful server response.
    # mocker.patch returns a MagicMock object.
    mock_post = mocker.patch("requests.post")
    
    # Configure the mock response
    mock_response = mocker.Mock()
    mock_response.status_code = 200
    mock_response.json.return_value = {"access_token": "fake_token_abc.123.xyz"}
    mock_post.return_value = mock_response
    
    # Call the function under test
    token = auth("http://test-server")
    
    # Verify the results
    assert token == "fake_token_abc.123.xyz"
    mock_post.assert_called_once()
    
    # Check that it was called with the expected URL
    args, kwargs = mock_post.call_args
    assert args[0] == "http://test-server/token"

def test_auth_network_failure(mocker):
    """
    Test authentication failure due to network error using mocker.
    """
    # Mock requests.post to raise an exception
    mock_post = mocker.patch("requests.post")
    mock_post.side_effect = requests.RequestException("Connection refused")
    
    with pytest.raises(RuntimeError) as excinfo:
        auth("http://test-server")
    
    assert "Cannot reach AareDAQ server" in str(excinfo.value)

def test_auth_no_url_returns_dummy_jwt(mocker):
    """
    Test that when base_url is None, it returns a dummy JWT without network calls.
    We can use mocker to verify that requests.post was NEVER called.
    """
    mock_post = mocker.patch("requests.post")
    mocker.patch("os.getlogin", return_value="testuser")
    
    token = auth(None)
    
    assert isinstance(token, str)
    assert token.count('.') == 2 # Basic JWT structure check
    mock_post.assert_not_called()