import json
import pytest
from app.mobile.protocol import Handshake, ProtocolError, fragments
from app.mobile.session import SessionManager


def connection(clock=lambda: 0, *, manager=None, on_session_open=None):
    calls = []
    if manager is None:
        manager = SessionManager(lambda method, params: calls.append(method) or {}, lambda: {"device_id": "test"},
                                 clock=clock, on_session_open=on_session_open)
    assert manager.connect('a')
    assert not manager.connect('b')
    client = Handshake()
    result = None
    for part in fragments(1, 0, client.hello, 247):
        result = manager.accept('a', part)
    cipher = client.finish(result[1], server=False)
    return manager, cipher, calls


def request(manager, cipher, mid, rid, method, params=None):
    raw = json.dumps(dict(id=rid, method=method, params=params or {})).encode()
    for part in fragments(3, mid, cipher.encrypt(raw), 247):
        result = manager.accept('a', part)
    return json.loads(cipher.decrypt(result[1]))


def test_no_control_before_open():
    manager, cipher, calls = connection()
    with pytest.raises(ProtocolError):
        request(manager, cipher, 1, '1', 'settings.patch')
    assert calls == []


def test_single_owner_duplicate_and_disconnect():
    manager, cipher, calls = connection()
    assert request(manager, cipher, 1, '1', 'session.open', {'client_name': '手机'})['ok']
    assert manager.status()['client_name'] == '手机'
    assert request(manager, cipher, 2, '2', 'content.play')['ok']
    assert not request(manager, cipher, 3, '2', 'content.play')['ok']
    assert calls == ['content.play']
    manager.disconnect('b')
    assert manager.status()['connected']
    manager.disconnect('a')
    assert not manager.status()['connected']
    assert manager.connect('b')


def test_handshake_and_idle_deadlines():
    now = [0]
    manager, cipher, _ = connection(lambda: now[0])
    now[0] = 10
    assert manager.expired()
    manager, cipher, _ = connection(lambda: now[0])
    request(manager, cipher, 1, '1', 'session.open', {'client_name': '手机'})
    now[0] = 29
    assert not manager.expired()
    now[0] = 30
    assert manager.expired()


def test_negotiated_receive_mtu_resets_on_disconnect():
    manager, cipher, _ = connection()
    assert manager.peer_mtu == 23
    assert request(manager, cipher, 1, '1', 'session.open', {'client_name': '手机', 'receive_mtu': 247})['ok']
    assert manager.peer_mtu == 247
    manager.disconnect('a')
    assert manager.peer_mtu == 23


@pytest.mark.parametrize('mtu', [0, 22, 518, True, '247'])
def test_invalid_receive_mtu_never_opens_session(mtu):
    opened = []
    manager, cipher, _ = connection(on_session_open=lambda: opened.append(True))
    assert not request(manager, cipher, 1, '1', 'session.open', {'client_name': '手机', 'receive_mtu': mtu})['ok']
    assert not manager.opened
    assert opened == []


def test_open_notification_only_after_valid_encrypted_session():
    opened = []
    manager, cipher, _ = connection(on_session_open=lambda: opened.append(manager.status()['connected']))
    assert opened == []  # Neither the link nor the handshake is a session.
    assert not request(manager, cipher, 1, '1', 'session.open', {'client_name': ''})['ok']
    assert opened == []
    assert request(manager, cipher, 2, '2', 'session.open', {'client_name': '手机'})['ok']
    assert opened == [True]
    assert not request(manager, cipher, 3, '3', 'session.open', {'client_name': '手机'})['ok']
    request(manager, cipher, 4, '4', 'session.ping')
    manager.disconnect('a')
    assert opened == [True]


def test_failed_handshake_never_notifies():
    opened = []
    manager = SessionManager(lambda *args: {}, lambda: {}, on_session_open=lambda: opened.append(True))
    assert manager.connect('a')
    with pytest.raises(ProtocolError):
        for part in fragments(1, 0, b'invalid-handshake', 247):
            manager.accept('a', part)
    assert not manager.opened
    assert opened == []


def test_notification_failure_does_not_break_open_session(caplog):
    def failed_notification():
        raise OSError('test notification failure')
    manager, cipher, _ = connection(on_session_open=failed_notification)
    assert request(manager, cipher, 1, '1', 'session.open', {'client_name': '手机'})['ok']
    assert request(manager, cipher, 2, '2', 'session.ping')['ok']
    assert 'session-open notification failed' in caplog.text