# utils.py -- Git 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 interacting with cgit."""

import errno
import functools
import os
import shutil
import socket
import stat
import subprocess
import sys
import tempfile
import time

from dulwich.protocol import TCP_GIT_PORT
from dulwich.repo import Repo

from .. import SkipTest, TestCase

_DEFAULT_GIT = "git"
_VERSION_LEN = 4
_REPOS_DATA_DIR = os.path.abspath(
    os.path.join(os.path.dirname(__file__), os.pardir, os.pardir, "testdata", "repos")
)


def git_version(git_path=_DEFAULT_GIT):
    """Attempt to determine the version of git currently installed.

    Args:
      git_path: Path to the git executable; defaults to the version in
        the system path.
    Returns: A tuple of ints of the form (major, minor, point, sub-point), or
        None if no git installation was found.
    """
    try:
        output = run_git_or_fail(["--version"], git_path=git_path)
    except OSError:
        return None
    version_prefix = b"git version "
    if not output.startswith(version_prefix):
        return None

    parts = output[len(version_prefix) :].split(b".")
    nums = []
    for part in parts:
        try:
            nums.append(int(part))
        except ValueError:
            break

    while len(nums) < _VERSION_LEN:
        nums.append(0)
    return tuple(nums[:_VERSION_LEN])


def require_git_version(required_version, git_path=_DEFAULT_GIT) -> None:
    """Require git version >= version, or skip the calling test.

    Args:
      required_version: A tuple of ints of the form (major, minor, point,
        sub-point); omitted components default to 0.
      git_path: Path to the git executable; defaults to the version in
        the system path.

    Raises:
      ValueError: if the required version tuple has too many parts.
      SkipTest: if no suitable git version was found at the given path.
    """
    found_version = git_version(git_path=git_path)
    if found_version is None:
        raise SkipTest(f"Test requires git >= {required_version}, but c git not found")

    if len(required_version) > _VERSION_LEN:
        raise ValueError(
            f"Invalid version tuple {required_version}, expected {_VERSION_LEN} parts"
        )

    required_version = list(required_version)
    while len(found_version) < len(required_version):
        required_version.append(0)
    required_version = tuple(required_version)

    if found_version < required_version:
        required_version = ".".join(map(str, required_version))
        found_version = ".".join(map(str, found_version))
        raise SkipTest(
            f"Test requires git >= {required_version}, found {found_version}"
        )


def run_git(
    args,
    git_path=_DEFAULT_GIT,
    input=None,
    capture_stdout=False,
    capture_stderr=False,
    **popen_kwargs,
):
    """Run a git command.

    Input is piped from the input parameter and output is sent to the standard
    streams, unless capture_stdout is set.

    Args:
      args: A list of args to the git command.
      git_path: Path to to the git executable.
      input: Input data to be sent to stdin.
      capture_stdout: Whether to capture and return stdout.
      popen_kwargs: Additional kwargs for subprocess.Popen;
        stdin/stdout args are ignored.
    Returns: A tuple of (returncode, stdout contents, stderr contents).
        If capture_stdout is False, None will be returned as stdout contents.
        If capture_stderr is False, None will be returned as stderr contents.

    Raises:
      OSError: if the git executable was not found.
    """
    env = popen_kwargs.pop("env", {})
    env["LC_ALL"] = env["LANG"] = "C"
    env["PATH"] = os.getenv("PATH")

    # Preserve Git identity environment variables if they exist, otherwise set dummy values
    git_env_defaults = {
        "GIT_AUTHOR_NAME": "Test User",
        "GIT_AUTHOR_EMAIL": "test@example.com",
        "GIT_COMMITTER_NAME": "Test User",
        "GIT_COMMITTER_EMAIL": "test@example.com",
    }

    for git_env_var, default_value in git_env_defaults.items():
        if git_env_var not in env:
            # If the environment variable is not set, use the default value
            env[git_env_var] = default_value

    args = [git_path, *args]
    popen_kwargs["stdin"] = subprocess.PIPE
    if capture_stdout:
        popen_kwargs["stdout"] = subprocess.PIPE
    else:
        popen_kwargs.pop("stdout", None)
    if capture_stderr:
        popen_kwargs["stderr"] = subprocess.PIPE
    else:
        popen_kwargs.pop("stderr", None)
    p = subprocess.Popen(args, env=env, **popen_kwargs)
    stdout, stderr = p.communicate(input=input)
    return (p.returncode, stdout, stderr)


def run_git_or_fail(args, git_path=_DEFAULT_GIT, input=None, **popen_kwargs):
    """Run a git command, capture stdout/stderr, and fail if git fails."""
    if "stderr" not in popen_kwargs:
        popen_kwargs["stderr"] = subprocess.STDOUT
    returncode, stdout, stderr = run_git(
        args,
        git_path=git_path,
        input=input,
        capture_stdout=True,
        capture_stderr=True,
        **popen_kwargs,
    )
    if returncode != 0:
        raise AssertionError(
            f"git with args {args!r} failed with {returncode}: stdout={stdout!r} stderr={stderr!r}"
        )
    return stdout


def import_repo_to_dir(name):
    """Import a repo from a fast-export file in a temporary directory.

    These are used rather than binary repos for compat tests because they are
    more compact and human-editable, and we already depend on git.

    Args:
      name: The name of the repository export file, relative to
        dulwich/tests/data/repos.
    Returns: The path to the imported repository.
    """
    temp_dir = tempfile.mkdtemp()
    export_path = os.path.join(_REPOS_DATA_DIR, name)
    temp_repo_dir = os.path.join(temp_dir, name)
    export_file = open(export_path, "rb")
    run_git_or_fail(["init", "--quiet", "--bare", temp_repo_dir])
    run_git_or_fail(["fast-import"], input=export_file.read(), cwd=temp_repo_dir)
    export_file.close()
    return temp_repo_dir


def check_for_daemon(limit=10, delay=0.1, timeout=0.1, port=TCP_GIT_PORT) -> bool:
    """Check for a running TCP daemon.

    Defaults to checking 10 times with a delay of 0.1 sec between tries.

    Args:
      limit: Number of attempts before deciding no daemon is running.
      delay: Delay between connection attempts.
      timeout: Socket timeout for connection attempts.
      port: Port on which we expect the daemon to appear.
    Returns: A boolean, true if a daemon is running on the specified port,
        false if not.
    """
    for _ in range(limit):
        time.sleep(delay)
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.settimeout(delay)
        try:
            s.connect(("localhost", port))
            return True
        except socket.timeout:
            pass
        except OSError as e:
            if getattr(e, "errno", False) and e.errno != errno.ECONNREFUSED:
                raise
            elif e.args[0] != errno.ECONNREFUSED:
                raise
        finally:
            s.close()
    return False


class CompatTestCase(TestCase):
    """Test case that requires git for compatibility checks.

    Subclasses can change the git version required by overriding
    min_git_version.
    """

    min_git_version: tuple[int, ...] = (1, 5, 0)

    def setUp(self) -> None:
        super().setUp()
        require_git_version(self.min_git_version)

    def assertObjectStoreEqual(self, store1, store2) -> None:
        self.assertEqual(sorted(set(store1)), sorted(set(store2)))

    def assertReposEqual(self, repo1, repo2) -> None:
        self.assertEqual(repo1.get_refs(), repo2.get_refs())
        self.assertObjectStoreEqual(repo1.object_store, repo2.object_store)

    def assertReposNotEqual(self, repo1, repo2) -> None:
        refs1 = repo1.get_refs()
        objs1 = set(repo1.object_store)
        refs2 = repo2.get_refs()
        objs2 = set(repo2.object_store)
        self.assertFalse(refs1 == refs2 and objs1 == objs2)

    def import_repo(self, name):
        """Import a repo from a fast-export file in a temporary directory.

        Args:
          name: The name of the repository export file, relative to
            dulwich/tests/data/repos.
        Returns: An initialized Repo object that lives in a temporary
            directory.
        """
        path = import_repo_to_dir(name)
        repo = Repo(path)

        def cleanup() -> None:
            repo.close()
            rmtree_ro(os.path.dirname(path.rstrip(os.sep)))

        self.addCleanup(cleanup)
        return repo


def remove_ro(path: str) -> None:
    """Remove a read-only file."""
    os.chmod(path, stat.S_IWRITE)
    os.remove(path)


if sys.platform == "win32":
    rmtree_ro = functools.partial(
        shutil.rmtree, onerror=lambda action, name, exc: remove_ro(name)
    )
else:
    rmtree_ro = shutil.rmtree
