import asyncio
from typing import NamedTuple

import pytest

from libp2p.exceptions import ValidationError
from libp2p.peer.id import ID
from libp2p.pubsub.pb import rpc_pb2
from libp2p.tools.pubsub.utils import make_pubsub_msg
from libp2p.tools.utils import connect
from libp2p.utils import encode_varint_prefixed

TESTING_TOPIC = "TEST_SUBSCRIBE"
TESTING_DATA = b"data"


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_subscribe_and_unsubscribe(pubsubs_fsub):
    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    assert TESTING_TOPIC in pubsubs_fsub[0].my_topics

    await pubsubs_fsub[0].unsubscribe(TESTING_TOPIC)
    assert TESTING_TOPIC not in pubsubs_fsub[0].my_topics


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_re_subscribe(pubsubs_fsub):
    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    assert TESTING_TOPIC in pubsubs_fsub[0].my_topics

    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    assert TESTING_TOPIC in pubsubs_fsub[0].my_topics


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_re_unsubscribe(pubsubs_fsub):
    # Unsubscribe from topic we didn't even subscribe to
    assert "NOT_MY_TOPIC" not in pubsubs_fsub[0].my_topics
    await pubsubs_fsub[0].unsubscribe("NOT_MY_TOPIC")
    assert "NOT_MY_TOPIC" not in pubsubs_fsub[0].my_topics

    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    assert TESTING_TOPIC in pubsubs_fsub[0].my_topics

    await pubsubs_fsub[0].unsubscribe(TESTING_TOPIC)
    assert TESTING_TOPIC not in pubsubs_fsub[0].my_topics

    await pubsubs_fsub[0].unsubscribe(TESTING_TOPIC)
    assert TESTING_TOPIC not in pubsubs_fsub[0].my_topics


@pytest.mark.asyncio
async def test_peers_subscribe(pubsubs_fsub):
    await connect(pubsubs_fsub[0].host, pubsubs_fsub[1].host)
    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    # Yield to let 0 notify 1
    await asyncio.sleep(0.1)
    assert pubsubs_fsub[0].my_id in pubsubs_fsub[1].peer_topics[TESTING_TOPIC]
    await pubsubs_fsub[0].unsubscribe(TESTING_TOPIC)
    # Yield to let 0 notify 1
    await asyncio.sleep(0.1)
    assert pubsubs_fsub[0].my_id not in pubsubs_fsub[1].peer_topics[TESTING_TOPIC]


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_get_hello_packet(pubsubs_fsub):
    def _get_hello_packet_topic_ids():
        packet = pubsubs_fsub[0].get_hello_packet()
        return tuple(sub.topicid for sub in packet.subscriptions)

    # Test: No subscription, so there should not be any topic ids in the hello packet.
    assert len(_get_hello_packet_topic_ids()) == 0

    # Test: After subscriptions, topic ids should be in the hello packet.
    topic_ids = ["t", "o", "p", "i", "c"]
    await asyncio.gather(*[pubsubs_fsub[0].subscribe(topic) for topic in topic_ids])
    topic_ids_in_hello = _get_hello_packet_topic_ids()
    for topic in topic_ids:
        assert topic in topic_ids_in_hello


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_set_and_remove_topic_validator(pubsubs_fsub):

    is_sync_validator_called = False

    def sync_validator(peer_id, msg):
        nonlocal is_sync_validator_called
        is_sync_validator_called = True

    is_async_validator_called = False

    async def async_validator(peer_id, msg):
        nonlocal is_async_validator_called
        is_async_validator_called = True

    topic = "TEST_VALIDATOR"

    assert topic not in pubsubs_fsub[0].topic_validators

    # Register sync validator
    pubsubs_fsub[0].set_topic_validator(topic, sync_validator, False)

    assert topic in pubsubs_fsub[0].topic_validators
    topic_validator = pubsubs_fsub[0].topic_validators[topic]
    assert not topic_validator.is_async

    # Validate with sync validator
    topic_validator.validator(peer_id=ID(b"peer"), msg="msg")

    assert is_sync_validator_called
    assert not is_async_validator_called

    # Register with async validator
    pubsubs_fsub[0].set_topic_validator(topic, async_validator, True)

    is_sync_validator_called = False
    assert topic in pubsubs_fsub[0].topic_validators
    topic_validator = pubsubs_fsub[0].topic_validators[topic]
    assert topic_validator.is_async

    # Validate with async validator
    await topic_validator.validator(peer_id=ID(b"peer"), msg="msg")

    assert is_async_validator_called
    assert not is_sync_validator_called

    # Remove validator
    pubsubs_fsub[0].remove_topic_validator(topic)
    assert topic not in pubsubs_fsub[0].topic_validators


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_get_msg_validators(pubsubs_fsub):

    times_sync_validator_called = 0

    def sync_validator(peer_id, msg):
        nonlocal times_sync_validator_called
        times_sync_validator_called += 1

    times_async_validator_called = 0

    async def async_validator(peer_id, msg):
        nonlocal times_async_validator_called
        times_async_validator_called += 1

    topic_1 = "TEST_VALIDATOR_1"
    topic_2 = "TEST_VALIDATOR_2"
    topic_3 = "TEST_VALIDATOR_3"

    # Register sync validator for topic 1 and 2
    pubsubs_fsub[0].set_topic_validator(topic_1, sync_validator, False)
    pubsubs_fsub[0].set_topic_validator(topic_2, sync_validator, False)

    # Register async validator for topic 3
    pubsubs_fsub[0].set_topic_validator(topic_3, async_validator, True)

    msg = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[topic_1, topic_2, topic_3],
        data=b"1234",
        seqno=b"\x00" * 8,
    )

    topic_validators = pubsubs_fsub[0].get_msg_validators(msg)
    for topic_validator in topic_validators:
        if topic_validator.is_async:
            await topic_validator.validator(peer_id=ID(b"peer"), msg="msg")
        else:
            topic_validator.validator(peer_id=ID(b"peer"), msg="msg")

    assert times_sync_validator_called == 2
    assert times_async_validator_called == 1


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.parametrize(
    "is_topic_1_val_passed, is_topic_2_val_passed",
    ((False, True), (True, False), (True, True)),
)
@pytest.mark.asyncio
async def test_validate_msg(pubsubs_fsub, is_topic_1_val_passed, is_topic_2_val_passed):
    def passed_sync_validator(peer_id, msg):
        return True

    def failed_sync_validator(peer_id, msg):
        return False

    async def passed_async_validator(peer_id, msg):
        return True

    async def failed_async_validator(peer_id, msg):
        return False

    topic_1 = "TEST_SYNC_VALIDATOR"
    topic_2 = "TEST_ASYNC_VALIDATOR"

    if is_topic_1_val_passed:
        pubsubs_fsub[0].set_topic_validator(topic_1, passed_sync_validator, False)
    else:
        pubsubs_fsub[0].set_topic_validator(topic_1, failed_sync_validator, False)

    if is_topic_2_val_passed:
        pubsubs_fsub[0].set_topic_validator(topic_2, passed_async_validator, True)
    else:
        pubsubs_fsub[0].set_topic_validator(topic_2, failed_async_validator, True)

    msg = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[topic_1, topic_2],
        data=b"1234",
        seqno=b"\x00" * 8,
    )

    if is_topic_1_val_passed and is_topic_2_val_passed:
        await pubsubs_fsub[0].validate_msg(pubsubs_fsub[0].my_id, msg)
    else:
        with pytest.raises(ValidationError):
            await pubsubs_fsub[0].validate_msg(pubsubs_fsub[0].my_id, msg)


class FakeNetStream:
    _queue: asyncio.Queue

    class FakeMplexConn(NamedTuple):
        peer_id: ID = ID(b"\x12\x20" + b"\x00" * 32)

    muxed_conn = FakeMplexConn()

    def __init__(self) -> None:
        self._queue = asyncio.Queue()

    async def read(self, n: int = -1) -> bytes:
        buf = bytearray()
        # Force to blocking wait if no data available now.
        if self._queue.empty():
            first_byte = await self._queue.get()
            buf.extend(first_byte)
        # If `n == -1`, read until no data is in the buffer(_queue).
        # Else, read until no data is in the buffer(_queue) or we have read `n` bytes.
        while (n == -1) or (len(buf) < n):
            if self._queue.empty():
                break
            buf.extend(await self._queue.get())
        return bytes(buf)

    async def write(self, data: bytes) -> int:
        for i in data:
            await self._queue.put(i.to_bytes(1, "big"))
        return len(data)


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_continuously_read_stream(pubsubs_fsub, monkeypatch):
    stream = FakeNetStream()

    await pubsubs_fsub[0].subscribe(TESTING_TOPIC)

    event_push_msg = asyncio.Event()
    event_handle_subscription = asyncio.Event()
    event_handle_rpc = asyncio.Event()

    async def mock_push_msg(msg_forwarder, msg):
        event_push_msg.set()

    def mock_handle_subscription(origin_id, sub_message):
        event_handle_subscription.set()

    async def mock_handle_rpc(rpc, sender_peer_id):
        event_handle_rpc.set()

    monkeypatch.setattr(pubsubs_fsub[0], "push_msg", mock_push_msg)
    monkeypatch.setattr(
        pubsubs_fsub[0], "handle_subscription", mock_handle_subscription
    )
    monkeypatch.setattr(pubsubs_fsub[0].router, "handle_rpc", mock_handle_rpc)

    async def wait_for_event_occurring(event):
        try:
            await asyncio.wait_for(event.wait(), timeout=1)
        except asyncio.TimeoutError as error:
            event.clear()
            raise asyncio.TimeoutError(
                f"Event {event} is not set before the timeout. "
                "This indicates the mocked functions are not called properly."
            ) from error
        else:
            event.clear()

    # Kick off the task `continuously_read_stream`
    task = asyncio.ensure_future(pubsubs_fsub[0].continuously_read_stream(stream))

    # Test: `push_msg` is called when publishing to a subscribed topic.
    publish_subscribed_topic = rpc_pb2.RPC(
        publish=[rpc_pb2.Message(topicIDs=[TESTING_TOPIC])]
    )
    await stream.write(
        encode_varint_prefixed(publish_subscribed_topic.SerializeToString())
    )
    await wait_for_event_occurring(event_push_msg)
    # Make sure the other events are not emitted.
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_handle_subscription)
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_handle_rpc)

    # Test: `push_msg` is not called when publishing to a topic-not-subscribed.
    publish_not_subscribed_topic = rpc_pb2.RPC(
        publish=[rpc_pb2.Message(topicIDs=["NOT_SUBSCRIBED"])]
    )
    await stream.write(
        encode_varint_prefixed(publish_not_subscribed_topic.SerializeToString())
    )
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_push_msg)

    # Test: `handle_subscription` is called when a subscription message is received.
    subscription_msg = rpc_pb2.RPC(subscriptions=[rpc_pb2.RPC.SubOpts()])
    await stream.write(encode_varint_prefixed(subscription_msg.SerializeToString()))
    await wait_for_event_occurring(event_handle_subscription)
    # Make sure the other events are not emitted.
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_push_msg)
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_handle_rpc)

    # Test: `handle_rpc` is called when a control message is received.
    control_msg = rpc_pb2.RPC(control=rpc_pb2.ControlMessage())
    await stream.write(encode_varint_prefixed(control_msg.SerializeToString()))
    await wait_for_event_occurring(event_handle_rpc)
    # Make sure the other events are not emitted.
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_push_msg)
    with pytest.raises(asyncio.TimeoutError):
        await wait_for_event_occurring(event_handle_subscription)

    task.cancel()


# TODO: Add the following tests after they are aligned with Go.
#   (Issue #191: https://github.com/libp2p/py-libp2p/issues/191)
#         - `test_stream_handler`
#         - `test_handle_peer_queue`


@pytest.mark.parametrize("num_hosts", (1,))
def test_handle_subscription(pubsubs_fsub):
    assert len(pubsubs_fsub[0].peer_topics) == 0
    sub_msg_0 = rpc_pb2.RPC.SubOpts(subscribe=True, topicid=TESTING_TOPIC)
    peer_ids = [ID(b"\x12\x20" + i.to_bytes(32, "big")) for i in range(2)]
    # Test: One peer is subscribed
    pubsubs_fsub[0].handle_subscription(peer_ids[0], sub_msg_0)
    assert (
        len(pubsubs_fsub[0].peer_topics) == 1
        and TESTING_TOPIC in pubsubs_fsub[0].peer_topics
    )
    assert len(pubsubs_fsub[0].peer_topics[TESTING_TOPIC]) == 1
    assert peer_ids[0] in pubsubs_fsub[0].peer_topics[TESTING_TOPIC]
    # Test: Another peer is subscribed
    pubsubs_fsub[0].handle_subscription(peer_ids[1], sub_msg_0)
    assert len(pubsubs_fsub[0].peer_topics) == 1
    assert len(pubsubs_fsub[0].peer_topics[TESTING_TOPIC]) == 2
    assert peer_ids[1] in pubsubs_fsub[0].peer_topics[TESTING_TOPIC]
    # Test: Subscribe to another topic
    another_topic = "ANOTHER_TOPIC"
    sub_msg_1 = rpc_pb2.RPC.SubOpts(subscribe=True, topicid=another_topic)
    pubsubs_fsub[0].handle_subscription(peer_ids[0], sub_msg_1)
    assert len(pubsubs_fsub[0].peer_topics) == 2
    assert another_topic in pubsubs_fsub[0].peer_topics
    assert peer_ids[0] in pubsubs_fsub[0].peer_topics[another_topic]
    # Test: unsubscribe
    unsub_msg = rpc_pb2.RPC.SubOpts(subscribe=False, topicid=TESTING_TOPIC)
    pubsubs_fsub[0].handle_subscription(peer_ids[0], unsub_msg)
    assert peer_ids[0] not in pubsubs_fsub[0].peer_topics[TESTING_TOPIC]


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_handle_talk(pubsubs_fsub):
    sub = await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    msg_0 = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[TESTING_TOPIC],
        data=b"1234",
        seqno=b"\x00" * 8,
    )
    await pubsubs_fsub[0].handle_talk(msg_0)
    msg_1 = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=["NOT_SUBSCRIBED"],
        data=b"1234",
        seqno=b"\x11" * 8,
    )
    await pubsubs_fsub[0].handle_talk(msg_1)
    assert (
        len(pubsubs_fsub[0].my_topics) == 1
        and sub == pubsubs_fsub[0].my_topics[TESTING_TOPIC]
    )
    assert sub.qsize() == 1
    assert (await sub.get()) == msg_0


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_message_all_peers(pubsubs_fsub, monkeypatch):
    peer_ids = [ID(b"\x12\x20" + i.to_bytes(32, "big")) for i in range(10)]
    mock_peers = {peer_id: FakeNetStream() for peer_id in peer_ids}
    monkeypatch.setattr(pubsubs_fsub[0], "peers", mock_peers)

    empty_rpc = rpc_pb2.RPC()
    empty_rpc_bytes = empty_rpc.SerializeToString()
    empty_rpc_bytes_len_prefixed = encode_varint_prefixed(empty_rpc_bytes)
    await pubsubs_fsub[0].message_all_peers(empty_rpc_bytes)
    for stream in mock_peers.values():
        assert (await stream.read()) == empty_rpc_bytes_len_prefixed


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_publish(pubsubs_fsub, monkeypatch):
    msg_forwarders = []
    msgs = []

    async def push_msg(msg_forwarder, msg):
        msg_forwarders.append(msg_forwarder)
        msgs.append(msg)

    monkeypatch.setattr(pubsubs_fsub[0], "push_msg", push_msg)

    await pubsubs_fsub[0].publish(TESTING_TOPIC, TESTING_DATA)
    await pubsubs_fsub[0].publish(TESTING_TOPIC, TESTING_DATA)

    assert len(msgs) == 2, "`push_msg` should be called every time `publish` is called"
    assert (msg_forwarders[0] == msg_forwarders[1]) and (
        msg_forwarders[1] == pubsubs_fsub[0].my_id
    )
    assert msgs[0].seqno != msgs[1].seqno, "`seqno` should be different every time"


@pytest.mark.parametrize("num_hosts", (1,))
@pytest.mark.asyncio
async def test_push_msg(pubsubs_fsub, monkeypatch):
    msg_0 = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[TESTING_TOPIC],
        data=TESTING_DATA,
        seqno=b"\x00" * 8,
    )

    event = asyncio.Event()

    async def router_publish(*args, **kwargs):
        event.set()

    monkeypatch.setattr(pubsubs_fsub[0].router, "publish", router_publish)

    # Test: `msg` is not seen before `push_msg`, and is seen after `push_msg`.
    assert not pubsubs_fsub[0]._is_msg_seen(msg_0)
    await pubsubs_fsub[0].push_msg(pubsubs_fsub[0].my_id, msg_0)
    assert pubsubs_fsub[0]._is_msg_seen(msg_0)
    # Test: Ensure `router.publish` is called in `push_msg`
    await asyncio.wait_for(event.wait(), timeout=0.1)

    # Test: `push_msg` the message again and it will be reject.
    #   `router_publish` is not called then.
    event.clear()
    await pubsubs_fsub[0].push_msg(pubsubs_fsub[0].my_id, msg_0)
    await asyncio.sleep(0.01)
    assert not event.is_set()

    sub = await pubsubs_fsub[0].subscribe(TESTING_TOPIC)
    # Test: `push_msg` succeeds with another unseen msg.
    msg_1 = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[TESTING_TOPIC],
        data=TESTING_DATA,
        seqno=b"\x11" * 8,
    )
    assert not pubsubs_fsub[0]._is_msg_seen(msg_1)
    await pubsubs_fsub[0].push_msg(pubsubs_fsub[0].my_id, msg_1)
    assert pubsubs_fsub[0]._is_msg_seen(msg_1)
    await asyncio.wait_for(event.wait(), timeout=0.1)
    # Test: Subscribers are notified when `push_msg` new messages.
    assert (await sub.get()) == msg_1

    # Test: add a topic validator and `push_msg` the message that
    # does not pass the validation.
    # `router_publish` is not called then.
    def failed_sync_validator(peer_id, msg):
        return False

    pubsubs_fsub[0].set_topic_validator(TESTING_TOPIC, failed_sync_validator, False)

    msg_2 = make_pubsub_msg(
        origin_id=pubsubs_fsub[0].my_id,
        topic_ids=[TESTING_TOPIC],
        data=TESTING_DATA,
        seqno=b"\x22" * 8,
    )

    event.clear()
    await pubsubs_fsub[0].push_msg(pubsubs_fsub[0].my_id, msg_2)
    await asyncio.sleep(0.01)
    assert not event.is_set()