import asyncio
from unittest.mock import AsyncMock, MagicMock

import pytest

from ingestor.connection.certs import CertificateNotConfiguredError, CertProvider, LazyMinio


def certificate(certificate_id=1, name='sientia-platform', ext='pem', bucket='opc-certificates'):
    """A client certificate as the slot v2 carries it."""
    return {
        'certificate_id': certificate_id,
        'application_uri': 'urn:sientia:opc-ingestor',
        'cert': {'bucket': bucket, 'object_name': f'client/{name}/cert.{ext}'},
        'private_key': {'bucket': bucket, 'object_name': f'client/{name}/key.{ext}'},
    }


def _provider(tmp_path, data=b'pem'):
    minio = MagicMock()
    minio.download_file = AsyncMock(return_value=data)
    return CertProvider(minio=minio, cache_dir=str(tmp_path)), minio


@pytest.mark.asyncio
async def test_fetch_downloads_the_objects_the_certificate_names(tmp_path):
    minio = AsyncMock()
    minio.download_file.side_effect = [b'cert-bytes', b'key-bytes']
    provider = CertProvider(minio, cache_dir=str(tmp_path))

    cert, key = await provider.fetch(certificate(7))

    assert (cert, key) == (str(tmp_path / '7' / 'cert.pem'), str(tmp_path / '7' / 'key.pem'))
    assert [c.args for c in minio.download_file.await_args_list] == [
        ('client/sientia-platform/cert.pem', 'opc-certificates', {}),
        ('client/sientia-platform/key.pem', 'opc-certificates', {}),
    ]
    assert (tmp_path / '7' / 'cert.pem').read_bytes() == b'cert-bytes'
    assert (tmp_path / '7' / 'key.pem').read_bytes() == b'key-bytes'


@pytest.mark.asyncio
async def test_local_files_keep_the_object_extension(tmp_path):
    """asyncua picks the format (.pem / .der) by the extension"""
    provider, _minio = _provider(tmp_path)

    cert, key = await provider.fetch(certificate(ext='der'))

    assert cert.endswith('cert.der') and key.endswith('key.der')


@pytest.mark.asyncio
@pytest.mark.parametrize(
    'broken',
    [
        pytest.param({'cert': None}, id='no-cert'),
        pytest.param({'private_key': {'bucket': 'b'}}, id='key-without-object'),
        pytest.param({'certificate_id': None}, id='no-id'),
        pytest.param({'certificate_id': '../etc'}, id='id-not-an-integer'),
    ],
)
async def test_fetch_of_an_incomplete_certificate_raises_clear_error(tmp_path, broken):
    provider, minio = _provider(tmp_path)

    with pytest.raises(CertificateNotConfiguredError, match='opc_certificates|certificate_id'):
        await provider.fetch({**certificate(), **broken})
    minio.download_file.assert_not_awaited()


@pytest.mark.asyncio
async def test_fetch_is_cached_per_certificate_until_invalidated(tmp_path):
    provider, minio = _provider(tmp_path)

    first = await provider.fetch(certificate(1))
    assert await provider.fetch(certificate(1)) == first
    assert minio.download_file.await_count == 2  # cert + key, once

    other = await provider.fetch(certificate(2, name='other'))
    assert other != first
    assert minio.download_file.await_count == 4

    provider.invalidate(1)
    await provider.fetch(certificate(1))
    await provider.fetch(certificate(2, name='other'))  # still cached
    assert minio.download_file.await_count == 6


@pytest.mark.asyncio
async def test_a_replaced_certificate_is_downloaded_again(tmp_path):
    """Same certificate_id, other objects in the slot: the cache does not serve the old files"""
    provider, minio = _provider(tmp_path)

    await provider.fetch(certificate(1, name='old'))
    await provider.fetch(certificate(1, name='new'))

    assert minio.download_file.await_count == 4
    assert minio.download_file.await_args_list[-1].args[0] == 'client/new/key.pem'


@pytest.mark.asyncio
async def test_concurrent_fetches_download_once(tmp_path):
    provider, minio = _provider(tmp_path)

    results = await asyncio.gather(*(provider.fetch(certificate()) for _ in range(5)))

    assert len(set(results)) == 1
    assert minio.download_file.await_count == 2


@pytest.mark.asyncio
async def test_download_replaces_file_atomically(tmp_path):
    provider, _minio = _provider(tmp_path, data=b'new')
    (tmp_path / '1').mkdir()
    (tmp_path / '1' / 'cert.pem').write_bytes(b'old')

    cert_path, _ = await provider.fetch(certificate(1))

    assert (tmp_path / '1' / 'cert.pem').read_bytes() == b'new'
    assert cert_path == str(tmp_path / '1' / 'cert.pem')
    assert not list(tmp_path.glob('**/*.tmp'))


@pytest.mark.asyncio
async def test_lazy_minio_builds_one_client_per_bucket_on_first_download():
    clients = {'a': AsyncMock(), 'b': AsyncMock()}
    for client in clients.values():
        client.download_file.return_value = b'bytes'
    factory = MagicMock(side_effect=lambda bucket: clients[bucket])
    minio = LazyMinio(factory)

    factory.assert_not_called()  # no network at construction
    assert await minio.download_file('x.pem', 'a', {}) == b'bytes'
    await minio.download_file('y.pem', 'a', {})
    await minio.download_file('z.pem', 'b', {})

    assert [c.args for c in factory.call_args_list] == [('a',), ('b',)]
    assert clients['a'].download_file.await_count == 2
    clients['b'].download_file.assert_awaited_once_with('z.pem', 'b', {})


def test_build_cert_provider_is_lazy_and_uses_config(monkeypatch):
    from ingestor.config import GatewayConfig
    from ingestor.connection import certs

    minio_cls = MagicMock()
    monkeypatch.setattr(certs, 'MinioRepository', minio_cls)

    provider = certs.build_cert_provider(
        config=GatewayConfig(cert_cache_dir='certs-cache'),
        logger=MagicMock(),
        notification_handler=MagicMock(),
        metrics_controller=MagicMock(),
    )

    assert provider.cache_dir == 'certs-cache'
    assert isinstance(provider.minio, certs.LazyMinio)
    minio_cls.assert_not_called()  # MinIO is only reached when a cert is needed
    provider.minio._factory('opc-certificates')
    assert minio_cls.call_args.kwargs['bucket'] == 'opc-certificates'