"""Tests for kernel connection utilities"""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

import errno
import json
import os
from tempfile import TemporaryDirectory
from unittest.mock import patch

import pytest
import zmq

from traitlets.config import Config
from ipykernel import connect
from ipykernel.kernelapp import IPKernelApp

from .utils import TemporaryWorkingDirectory


sample_info = {
    'ip': '1.2.3.4',
    'transport': 'ipc',
    'shell_port': 1,
    'hb_port': 2,
    'iopub_port': 3,
    'stdin_port': 4,
    'control_port': 5,
    'key': b'abc123',
    'signature_scheme': 'hmac-md5',
}


class DummyKernelApp(IPKernelApp):
    def _default_shell_port(self):
        return 0

    def initialize(self, argv=[]):
        self.init_profile_dir()
        self.init_connection_file()


def test_get_connection_file():
    cfg = Config()
    with TemporaryWorkingDirectory() as d:
        cfg.ProfileDir.location = d
        cf = 'kernel.json'
        app = DummyKernelApp(config=cfg, connection_file=cf)
        app.initialize()

        profile_cf = os.path.join(app.connection_dir, cf)
        assert profile_cf == app.abs_connection_file
        with open(profile_cf, 'w') as f:
            f.write("{}")
        assert os.path.exists(profile_cf)
        assert connect.get_connection_file(app) == profile_cf

        app.connection_file = cf
        assert connect.get_connection_file(app) == profile_cf


def test_get_connection_info():
    with TemporaryDirectory() as d:
        cf = os.path.join(d, 'kernel.json')
        connect.write_connection_file(cf, **sample_info)
        json_info = connect.get_connection_info(cf)
        info = connect.get_connection_info(cf, unpack=True)
    assert isinstance(json_info, str)

    sub_info = {k: v for k, v in info.items() if k in sample_info}
    assert sub_info == sample_info

    info2 = json.loads(json_info)
    info2['key'] = info2['key'].encode("utf-8")
    sub_info2 = {k: v for k, v in info.items() if k in sample_info}
    assert sub_info2 == sample_info


def test_port_bind_failure_raises(request):
    cfg = Config()
    with TemporaryWorkingDirectory() as d:
        cfg.ProfileDir.location = d
        cf = 'kernel.json'
        app = DummyKernelApp(config=cfg, connection_file=cf)
        request.addfinalizer(app.close)
        app.initialize()
        with patch.object(app, '_try_bind_socket') as mock_try_bind:
            mock_try_bind.side_effect = zmq.ZMQError(-100, "fails for unknown error types")
            with pytest.raises(zmq.ZMQError):
                app.init_sockets()
            assert mock_try_bind.call_count == 1


def test_port_bind_failure_recovery(request):
    try:
        errno.WSAEADDRINUSE
    except AttributeError:
        # Fake windows address in-use code
        p = patch.object(errno, 'WSAEADDRINUSE', 12345, create=True)
        p.start()
        request.addfinalizer(p.stop)

    cfg = Config()
    with TemporaryWorkingDirectory() as d:
        cfg.ProfileDir.location = d
        cf = 'kernel.json'
        app = DummyKernelApp(config=cfg, connection_file=cf)
        request.addfinalizer(app.close)
        app.initialize()
        with patch.object(app, '_try_bind_socket') as mock_try_bind:
            mock_try_bind.side_effect = [
                zmq.ZMQError(errno.EADDRINUSE, "fails for non-bind unix"),
                zmq.ZMQError(errno.WSAEADDRINUSE, "fails for non-bind windows")
            ] + [0] * 100
            # Shouldn't raise anything as retries will kick in
            app.init_sockets()

def test_port_bind_failure_gives_up_retries(request):
    cfg = Config()
    with TemporaryWorkingDirectory() as d:
        cfg.ProfileDir.location = d
        cf = 'kernel.json'
        app = DummyKernelApp(config=cfg, connection_file=cf)
        request.addfinalizer(app.close)
        app.initialize()
        with patch.object(app, '_try_bind_socket') as mock_try_bind:
            mock_try_bind.side_effect = zmq.ZMQError(errno.EADDRINUSE, "fails for non-bind")
            with pytest.raises(zmq.ZMQError):
                app.init_sockets()
            assert mock_try_bind.call_count == 100
