import asyncio

import pytest

from libp2p.stream_muxer.mplex.exceptions import (
    MplexStreamClosed,
    MplexStreamEOF,
    MplexStreamReset,
)
from libp2p.tools.constants import MAX_READ_LEN

DATA = b"data_123"


@pytest.mark.asyncio
async def test_mplex_stream_read_write(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.write(DATA)
    assert (await stream_1.read(MAX_READ_LEN)) == DATA


@pytest.mark.asyncio
async def test_mplex_stream_pair_read_until_eof(mplex_stream_pair):
    read_bytes = bytearray()
    stream_0, stream_1 = mplex_stream_pair

    async def read_until_eof():
        read_bytes.extend(await stream_1.read())

    task = asyncio.ensure_future(read_until_eof())

    expected_data = bytearray()

    # Test: `read` doesn't return before `close` is called.
    await stream_0.write(DATA)
    expected_data.extend(DATA)
    await asyncio.sleep(0.01)
    assert len(read_bytes) == 0
    # Test: `read` doesn't return before `close` is called.
    await stream_0.write(DATA)
    expected_data.extend(DATA)
    await asyncio.sleep(0.01)
    assert len(read_bytes) == 0

    # Test: Close the stream, `read` returns, and receive previous sent data.
    await stream_0.close()
    await asyncio.sleep(0.01)
    assert read_bytes == expected_data

    task.cancel()


@pytest.mark.asyncio
async def test_mplex_stream_read_after_remote_closed(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    assert not stream_1.event_remote_closed.is_set()
    await stream_0.write(DATA)
    await stream_0.close()
    await asyncio.sleep(0.01)
    assert stream_1.event_remote_closed.is_set()
    assert (await stream_1.read(MAX_READ_LEN)) == DATA
    with pytest.raises(MplexStreamEOF):
        await stream_1.read(MAX_READ_LEN)


@pytest.mark.asyncio
async def test_mplex_stream_read_after_local_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.reset()
    with pytest.raises(MplexStreamReset):
        await stream_0.read(MAX_READ_LEN)


@pytest.mark.asyncio
async def test_mplex_stream_read_after_remote_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.write(DATA)
    await stream_0.reset()
    # Sleep to let `stream_1` receive the message.
    await asyncio.sleep(0.01)
    with pytest.raises(MplexStreamReset):
        await stream_1.read(MAX_READ_LEN)


@pytest.mark.asyncio
async def test_mplex_stream_read_after_remote_closed_and_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.write(DATA)
    await stream_0.close()
    await stream_0.reset()
    # Sleep to let `stream_1` receive the message.
    await asyncio.sleep(0.01)
    assert (await stream_1.read(MAX_READ_LEN)) == DATA


@pytest.mark.asyncio
async def test_mplex_stream_write_after_local_closed(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.write(DATA)
    await stream_0.close()
    with pytest.raises(MplexStreamClosed):
        await stream_0.write(DATA)


@pytest.mark.asyncio
async def test_mplex_stream_write_after_local_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.reset()
    with pytest.raises(MplexStreamClosed):
        await stream_0.write(DATA)


@pytest.mark.asyncio
async def test_mplex_stream_write_after_remote_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_1.reset()
    await asyncio.sleep(0.01)
    with pytest.raises(MplexStreamClosed):
        await stream_0.write(DATA)


@pytest.mark.asyncio
async def test_mplex_stream_both_close(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    # Flags are not set initially.
    assert not stream_0.event_local_closed.is_set()
    assert not stream_1.event_local_closed.is_set()
    assert not stream_0.event_remote_closed.is_set()
    assert not stream_1.event_remote_closed.is_set()
    # Streams are present in their `mplex_conn`.
    assert stream_0 in stream_0.muxed_conn.streams.values()
    assert stream_1 in stream_1.muxed_conn.streams.values()

    # Test: Close one side.
    await stream_0.close()
    await asyncio.sleep(0.01)

    assert stream_0.event_local_closed.is_set()
    assert not stream_1.event_local_closed.is_set()
    assert not stream_0.event_remote_closed.is_set()
    assert stream_1.event_remote_closed.is_set()
    # Streams are still present in their `mplex_conn`.
    assert stream_0 in stream_0.muxed_conn.streams.values()
    assert stream_1 in stream_1.muxed_conn.streams.values()

    # Test: Close the other side.
    await stream_1.close()
    await asyncio.sleep(0.01)
    # Both sides are closed.
    assert stream_0.event_local_closed.is_set()
    assert stream_1.event_local_closed.is_set()
    assert stream_0.event_remote_closed.is_set()
    assert stream_1.event_remote_closed.is_set()
    # Streams are removed from their `mplex_conn`.
    assert stream_0 not in stream_0.muxed_conn.streams.values()
    assert stream_1 not in stream_1.muxed_conn.streams.values()

    # Test: Reset after both close.
    await stream_0.reset()


@pytest.mark.asyncio
async def test_mplex_stream_reset(mplex_stream_pair):
    stream_0, stream_1 = mplex_stream_pair
    await stream_0.reset()
    await asyncio.sleep(0.01)

    # Both sides are closed.
    assert stream_0.event_local_closed.is_set()
    assert stream_1.event_local_closed.is_set()
    assert stream_0.event_remote_closed.is_set()
    assert stream_1.event_remote_closed.is_set()
    # Streams are removed from their `mplex_conn`.
    assert stream_0 not in stream_0.muxed_conn.streams.values()
    assert stream_1 not in stream_1.muxed_conn.streams.values()

    # `close` should do nothing.
    await stream_0.close()
    await stream_1.close()
    # `reset` should do nothing as well.
    await stream_0.reset()
    await stream_1.reset()