# server_utils.py -- Git server compatibility utilities
# Copyright (C) 2010 Google, Inc.
#
# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
# Dulwich is dual-licensed under the Apache License, Version 2.0 and the GNU
# General Public License as published by the Free Software Foundation; version 2.0
# or (at your option) any later version. You can redistribute it and/or
# modify it under the terms of either of these two licenses.
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# You should have received a copy of the licenses; if not, see
# <http://www.gnu.org/licenses/> for a copy of the GNU General Public License
# and <http://www.apache.org/licenses/LICENSE-2.0> for a copy of the Apache
# License, Version 2.0.
#

"""Utilities for testing git server compatibility."""

import errno
import os
import shutil
import socket
import tempfile

from dulwich.objects import hex_to_sha
from dulwich.protocol import CAPABILITY_SIDE_BAND_64K
from dulwich.repo import Repo
from dulwich.server import ReceivePackHandler
from dulwich.tests.utils import tear_down_repo

from .utils import require_git_version, run_git_or_fail


class _StubRepo:
    """A stub repo that just contains a path to tear down."""

    def __init__(self, name) -> None:
        temp_dir = tempfile.mkdtemp()
        self.path = os.path.join(temp_dir, name)
        os.mkdir(self.path)

    def close(self) -> None:
        pass


def _get_shallow(repo):
    shallow_file = repo.get_named_file("shallow")
    if not shallow_file:
        return []
    shallows = []
    with shallow_file:
        for line in shallow_file:
            sha = line.strip()
            if not sha:
                continue
            hex_to_sha(sha)
            shallows.append(sha)
    return shallows


class ServerTests:
    """Base tests for testing servers.

    Does not inherit from TestCase so tests are not automatically run.
    """

    min_single_branch_version = (
        1,
        7,
        10,
    )

    def import_repos(self) -> None:
        self._old_repo = self.import_repo("server_old.export")
        self._new_repo = self.import_repo("server_new.export")

    def url(self, port) -> str:
        return f"{self.protocol}://localhost:{port}/"

    def branch_args(self, branches=None):
        if branches is None:
            branches = ["master", "branch"]
        return [f"{b}:{b}" for b in branches]

    def test_push_to_dulwich(self) -> None:
        self.import_repos()
        self.assertReposNotEqual(self._old_repo, self._new_repo)
        port = self._start_server(self._old_repo)

        run_git_or_fail(
            ["push", self.url(port), *self.branch_args()],
            cwd=self._new_repo.path,
        )
        self.assertReposEqual(self._old_repo, self._new_repo)

    def test_push_to_dulwich_no_op(self) -> None:
        self._old_repo = self.import_repo("server_old.export")
        self._new_repo = self.import_repo("server_old.export")
        self.assertReposEqual(self._old_repo, self._new_repo)
        port = self._start_server(self._old_repo)

        run_git_or_fail(
            ["push", self.url(port), *self.branch_args()],
            cwd=self._new_repo.path,
        )
        self.assertReposEqual(self._old_repo, self._new_repo)

    def test_push_to_dulwich_remove_branch(self) -> None:
        self._old_repo = self.import_repo("server_old.export")
        self._new_repo = self.import_repo("server_old.export")
        self.assertReposEqual(self._old_repo, self._new_repo)
        port = self._start_server(self._old_repo)

        run_git_or_fail(["push", self.url(port), ":master"], cwd=self._new_repo.path)

        self.assertEqual(list(self._old_repo.get_refs().keys()), [b"refs/heads/branch"])

    def test_fetch_from_dulwich(self) -> None:
        self.import_repos()
        self.assertReposNotEqual(self._old_repo, self._new_repo)
        port = self._start_server(self._new_repo)

        run_git_or_fail(
            ["fetch", self.url(port), *self.branch_args()],
            cwd=self._old_repo.path,
        )
        # flush the pack cache so any new packs are picked up
        self._old_repo.object_store._pack_cache_time = 0
        self.assertReposEqual(self._old_repo, self._new_repo)

    def test_fetch_from_dulwich_no_op(self) -> None:
        self._old_repo = self.import_repo("server_old.export")
        self._new_repo = self.import_repo("server_old.export")
        self.assertReposEqual(self._old_repo, self._new_repo)
        port = self._start_server(self._new_repo)

        run_git_or_fail(
            ["fetch", self.url(port), *self.branch_args()],
            cwd=self._old_repo.path,
        )
        # flush the pack cache so any new packs are picked up
        self._old_repo.object_store._pack_cache_time = 0
        self.assertReposEqual(self._old_repo, self._new_repo)

    def test_clone_from_dulwich_empty(self) -> None:
        old_repo_dir = tempfile.mkdtemp()
        self.addCleanup(shutil.rmtree, old_repo_dir)
        self._old_repo = Repo.init_bare(old_repo_dir)
        port = self._start_server(self._old_repo)

        new_repo_base_dir = tempfile.mkdtemp()
        self.addCleanup(shutil.rmtree, new_repo_base_dir)
        new_repo_dir = os.path.join(new_repo_base_dir, "empty_new")
        run_git_or_fail(["clone", self.url(port), new_repo_dir], cwd=new_repo_base_dir)
        new_repo = Repo(new_repo_dir)
        self.addCleanup(new_repo.close)
        self.assertReposEqual(self._old_repo, new_repo)

    def test_lsremote_from_dulwich(self) -> None:
        self._repo = self.import_repo("server_old.export")
        port = self._start_server(self._repo)
        o = run_git_or_fail(["ls-remote", self.url(port)])
        self.assertEqual(len(o.split(b"\n")), 4)

    def test_new_shallow_clone_from_dulwich(self) -> None:
        require_git_version(self.min_single_branch_version)
        self._source_repo = self.import_repo("server_new.export")
        self._stub_repo = _StubRepo("shallow")
        self.addCleanup(tear_down_repo, self._stub_repo)
        port = self._start_server(self._source_repo)

        # Fetch at depth 1
        run_git_or_fail(
            [
                "clone",
                "--mirror",
                "--depth=1",
                "--no-single-branch",
                self.url(port),
                self._stub_repo.path,
            ]
        )
        self._stub_repo.close()
        clone = self._stub_repo = Repo(self._stub_repo.path)
        self.addCleanup(clone.close)
        expected_shallow = [
            b"35e0b59e187dd72a0af294aedffc213eaa4d03ff",
            b"514dc6d3fbfe77361bcaef320c4d21b72bc10be9",
        ]
        self.assertEqual(expected_shallow, _get_shallow(clone))
        self.assertReposNotEqual(clone, self._source_repo)

    def test_shallow_clone_from_git_is_identical(self) -> None:
        require_git_version(self.min_single_branch_version)
        self._source_repo = self.import_repo("server_new.export")
        self._stub_repo_git = _StubRepo("shallow-git")
        self.addCleanup(tear_down_repo, self._stub_repo_git)
        self._stub_repo_dw = _StubRepo("shallow-dw")
        self.addCleanup(tear_down_repo, self._stub_repo_dw)

        # shallow clone using stock git, then using dulwich
        run_git_or_fail(
            [
                "clone",
                "--mirror",
                "--depth=1",
                "--no-single-branch",
                "file://" + self._source_repo.path,
                self._stub_repo_git.path,
            ]
        )

        port = self._start_server(self._source_repo)
        run_git_or_fail(
            [
                "clone",
                "--mirror",
                "--depth=1",
                "--no-single-branch",
                self.url(port),
                self._stub_repo_dw.path,
            ]
        )

        # compare the two clones; they should be equal
        repo_git = Repo(self._stub_repo_git.path)
        self.addCleanup(repo_git.close)
        repo_dw = Repo(self._stub_repo_dw.path)
        self.addCleanup(repo_dw.close)
        self.assertReposEqual(repo_git, repo_dw)

    def test_fetch_same_depth_into_shallow_clone_from_dulwich(self) -> None:
        require_git_version(self.min_single_branch_version)
        self._source_repo = self.import_repo("server_new.export")
        self._stub_repo = _StubRepo("shallow")
        self.addCleanup(tear_down_repo, self._stub_repo)
        port = self._start_server(self._source_repo)

        # Fetch at depth 2
        run_git_or_fail(
            [
                "clone",
                "--mirror",
                "--depth=2",
                "--no-single-branch",
                self.url(port),
                self._stub_repo.path,
            ]
        )
        self._stub_repo.close()
        clone = self._stub_repo = Repo(self._stub_repo.path)
        self.addCleanup(clone.close)

        # Fetching at the same depth is a no-op.
        run_git_or_fail(
            ["fetch", "--depth=2", self.url(port), *self.branch_args()],
            cwd=self._stub_repo.path,
        )
        expected_shallow = [
            b"94de09a530df27ac3bb613aaecdd539e0a0655e1",
            b"da5cd81e1883c62a25bb37c4d1f8ad965b29bf8d",
        ]
        self.assertEqual(expected_shallow, _get_shallow(clone))
        self.assertReposNotEqual(clone, self._source_repo)

    def test_fetch_full_depth_into_shallow_clone_from_dulwich(self) -> None:
        require_git_version(self.min_single_branch_version)
        self._source_repo = self.import_repo("server_new.export")
        self._stub_repo = _StubRepo("shallow")
        self.addCleanup(tear_down_repo, self._stub_repo)
        port = self._start_server(self._source_repo)

        # Fetch at depth 2
        run_git_or_fail(
            [
                "clone",
                "--mirror",
                "--depth=2",
                "--no-single-branch",
                self.url(port),
                self._stub_repo.path,
            ]
        )
        self._stub_repo.close()
        clone = self._stub_repo = Repo(self._stub_repo.path)
        self.addCleanup(clone.close)

        # Fetching at the same depth is a no-op.
        run_git_or_fail(
            ["fetch", "--depth=2", self.url(port), *self.branch_args()],
            cwd=self._stub_repo.path,
        )

        # The whole repo only has depth 4, so it should equal server_new.
        run_git_or_fail(
            ["fetch", "--depth=4", self.url(port), *self.branch_args()],
            cwd=self._stub_repo.path,
        )
        self.assertEqual([], _get_shallow(clone))
        self.assertReposEqual(clone, self._source_repo)

    def test_fetch_from_dulwich_issue_88_standard(self) -> None:
        # Basically an integration test to see that the ACK/NAK
        # generation works on repos with common head.
        self._source_repo = self.import_repo("issue88_expect_ack_nak_server.export")
        self._client_repo = self.import_repo("issue88_expect_ack_nak_client.export")
        port = self._start_server(self._source_repo)

        run_git_or_fail(["fetch", self.url(port), "master"], cwd=self._client_repo.path)
        self.assertObjectStoreEqual(
            self._source_repo.object_store, self._client_repo.object_store
        )

    def test_fetch_from_dulwich_issue_88_alternative(self) -> None:
        # likewise, but the case where the two repos have no common parent
        self._source_repo = self.import_repo("issue88_expect_ack_nak_other.export")
        self._client_repo = self.import_repo("issue88_expect_ack_nak_client.export")
        port = self._start_server(self._source_repo)

        self.assertRaises(
            KeyError,
            self._client_repo.get_object,
            b"02a14da1fc1fc13389bbf32f0af7d8899f2b2323",
        )
        run_git_or_fail(["fetch", self.url(port), "master"], cwd=self._client_repo.path)
        self.assertEqual(
            b"commit",
            self._client_repo.get_object(
                b"02a14da1fc1fc13389bbf32f0af7d8899f2b2323"
            ).type_name,
        )

    def test_push_to_dulwich_issue_88_standard(self) -> None:
        # Same thing, but we reverse the role of the server/client
        # and do a push instead.
        self._source_repo = self.import_repo("issue88_expect_ack_nak_client.export")
        self._client_repo = self.import_repo("issue88_expect_ack_nak_server.export")
        port = self._start_server(self._source_repo)

        run_git_or_fail(["push", self.url(port), "master"], cwd=self._client_repo.path)
        self.assertReposEqual(self._source_repo, self._client_repo)


# TODO(dborowitz): Come up with a better way of testing various permutations of
# capabilities. The only reason it is the way it is now is that side-band-64k
# was only recently introduced into git-receive-pack.
class NoSideBand64kReceivePackHandler(ReceivePackHandler):
    """ReceivePackHandler that does not support side-band-64k."""

    def capabilities(self):
        return [c for c in super().capabilities() if c != CAPABILITY_SIDE_BAND_64K]


def ignore_error(error):
    """Check whether this error is safe to ignore."""
    (e_type, e_value, _e_tb) = error
    return issubclass(e_type, socket.error) and e_value[0] in (
        errno.ECONNRESET,
        errno.EPIPE,
    )