# test_paramiko_vendor.py
#
# 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.
#

"""Tests for paramiko_vendor."""

import os
import socket
import tempfile
import threading
import time
from io import StringIO
from unittest import skipIf
from unittest.mock import patch

from tests import TestCase

try:
    import paramiko
except ImportError:
    has_paramiko = False
else:
    has_paramiko = True
    import paramiko.transport

    from contrib.paramiko_vendor import ParamikoSSHVendor

    class Server(paramiko.ServerInterface):
        """http://docs.paramiko.org/en/2.4/api/server.html."""

        def __init__(self, commands, *args, **kwargs) -> None:
            super().__init__(*args, **kwargs)
            self.commands = commands

        def check_channel_exec_request(self, channel, command) -> bool:
            self.commands.append(command)
            return True

        def check_auth_password(self, username, password):
            if username == USER and password == PASSWORD:
                return paramiko.AUTH_SUCCESSFUL
            return paramiko.AUTH_FAILED

        def check_auth_publickey(self, username, key):
            pubkey = paramiko.RSAKey.from_private_key(StringIO(CLIENT_KEY))
            if username == USER and key == pubkey:
                return paramiko.AUTH_SUCCESSFUL
            return paramiko.AUTH_FAILED

        def check_channel_request(self, kind, chanid):
            if kind == "session":
                return paramiko.OPEN_SUCCEEDED
            return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED

        def get_allowed_auths(self, username) -> str:
            return "password,publickey"

    class SSHServer:
        """A real SSH server using Paramiko that listens on a TCP port."""

        def __init__(self):
            self.commands = []
            self.server_socket = None
            self.server_thread = None
            self.host_key = paramiko.RSAKey.from_private_key(StringIO(SERVER_KEY))
            self.running = False
            self.connection_threads = []

        def start(self):
            """Start the SSH server on a random port."""
            self.server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
            self.server_socket.bind(("127.0.0.1", 0))
            self.port = self.server_socket.getsockname()[1]
            self.server_socket.listen(5)

            self.running = True
            self.server_thread = threading.Thread(target=self._run_server)
            self.server_thread.daemon = True
            self.server_thread.start()

            # Give the server a moment to start up
            time.sleep(0.1)

        def stop(self):
            """Stop the SSH server."""
            self.running = False
            if self.server_socket:
                try:
                    self.server_socket.close()
                except OSError:
                    pass

            # Clean up connection threads
            for thread in self.connection_threads:
                if thread.is_alive():
                    thread.join(timeout=1)

            if self.server_thread and self.server_thread.is_alive():
                self.server_thread.join(timeout=5)

        def _run_server(self):
            """Main server loop."""
            self.server_socket.settimeout(
                1.0
            )  # Allow checking self.running periodically

            while self.running:
                try:
                    client_socket, _addr = self.server_socket.accept()

                    # Handle each connection in a separate thread
                    conn_thread = threading.Thread(
                        target=self._handle_connection, args=(client_socket,)
                    )
                    conn_thread.daemon = True
                    conn_thread.start()
                    self.connection_threads.append(conn_thread)

                except TimeoutError:
                    # Normal timeout, continue to check if we should keep running
                    continue
                except OSError as e:
                    # Socket was closed, exit gracefully
                    if not self.running:
                        break
                    # Otherwise re-raise the error
                    raise e

        def _handle_connection(self, client_socket):
            """Handle a single SSH connection."""
            transport = None
            try:
                transport = paramiko.Transport(client_socket)
                transport.add_server_key(self.host_key)

                server = Server(self.commands)
                transport.start_server(server=server)

                # Wait for channel requests and handle them
                while self.running and transport.is_active():
                    channel = transport.accept(1)
                    if channel is None:
                        continue

                    # Handle channel in a separate thread to allow multiple channels
                    channel_thread = threading.Thread(
                        target=self._handle_channel, args=(channel,)
                    )
                    channel_thread.daemon = True
                    channel_thread.start()

            except paramiko.SSHException as e:
                print(f"SSH error in connection handler: {e}")
            except OSError as e:
                print(f"Socket error in connection handler: {e}")
            finally:
                if transport:
                    transport.close()
                if client_socket:
                    client_socket.close()

        def _handle_channel(self, channel):
            """Handle a single SSH channel - echo server."""
            try:
                # Set channel to blocking mode
                channel.setblocking(True)
                channel.settimeout(10.0)

                # Read all available data and echo it back
                while True:
                    try:
                        data = channel.recv(4096)
                        if not data:
                            break
                        # Echo the data back immediately
                        channel.send(data)
                    except TimeoutError:
                        # No more data available, break
                        break

            except paramiko.SSHException as e:
                print(f"SSH error in channel handler: {e}")
            except OSError as e:
                print(f"Socket error in channel handler: {e}")
            finally:
                try:
                    channel.close()
                except OSError:
                    pass


USER = "testuser"
PASSWORD = "test"
SERVER_KEY = """\
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----"""
CLIENT_KEY = """\
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----"""


def _set_test_home(test_case: TestCase) -> str:
    home_dir = tempfile.TemporaryDirectory()
    old_env = {
        key: os.environ.get(key)
        for key in ("HOME", "USERPROFILE", "HOMEDRIVE", "HOMEPATH")
    }
    os.environ.update(_home_env(home_dir.name))

    def cleanup() -> None:
        for key, value in old_env.items():
            if value is None:
                os.environ.pop(key, None)
            else:
                os.environ[key] = value
        home_dir.cleanup()

    test_case.addCleanup(cleanup)
    return home_dir.name


def _home_env(home_dir: str) -> dict[str, str]:
    env = {"HOME": home_dir, "USERPROFILE": home_dir}
    if os.name == "nt":
        drive, path = os.path.splitdrive(home_dir)
        env["HOMEDRIVE"] = drive
        env["HOMEPATH"] = path or "\\"
    return env


def _write_known_host(
    home_dir: str, host: str, port: int, host_key: "paramiko.PKey"
) -> str:
    ssh_dir = os.path.join(home_dir, ".ssh")
    os.makedirs(ssh_dir, exist_ok=True)
    known_hosts_path = os.path.join(ssh_dir, "known_hosts")

    host_keys = paramiko.HostKeys()
    host_keys.add(f"[{host}]:{port}", host_key.get_name(), host_key)
    host_keys.save(known_hosts_path)
    return known_hosts_path


@skipIf(not has_paramiko, "paramiko is not installed")
class ParamikoSSHVendorTests(TestCase):
    def setUp(self) -> None:
        self.commands = []
        self.host_key = paramiko.RSAKey.from_private_key(StringIO(SERVER_KEY))
        socket.setdefaulttimeout(10)
        self.addCleanup(socket.setdefaulttimeout, None)
        self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.socket.bind(("127.0.0.1", 0))
        self.socket.listen(5)
        self.addCleanup(self.socket.close)
        self.port = self.socket.getsockname()[1]
        self.home_dir = _set_test_home(self)
        self.known_hosts_path = _write_known_host(
            self.home_dir, "127.0.0.1", self.port, self.host_key
        )
        self.thread = threading.Thread(target=self._run)
        self.thread.start()

    def tearDown(self) -> None:
        self.thread.join()

    def _run(self) -> bool | None:
        try:
            conn, _addr = self.socket.accept()
        except OSError:
            return False
        self.transport = paramiko.Transport(conn)
        self.addCleanup(self.transport.close)
        self.transport.add_server_key(self.host_key)
        server = Server(self.commands)
        self.transport.start_server(server=server)

    def test_run_command_password(self) -> None:
        vendor = ParamikoSSHVendor(
            allow_agent=False,
            look_for_keys=False,
        )
        vendor.run_command(
            "127.0.0.1",
            b"test_run_command_password",
            username=USER,
            port=self.port,
            password=PASSWORD,
        )

        self.assertIn(b"test_run_command_password", self.commands)

    def test_run_command_with_privkey(self) -> None:
        key = paramiko.RSAKey.from_private_key(StringIO(CLIENT_KEY))

        vendor = ParamikoSSHVendor(
            allow_agent=False,
            look_for_keys=False,
        )
        vendor.run_command(
            "127.0.0.1",
            b"test_run_command_with_privkey",
            username=USER,
            port=self.port,
            pkey=key,
        )

        self.assertIn(b"test_run_command_with_privkey", self.commands)

    def test_run_command_data_transfer(self) -> None:
        vendor = ParamikoSSHVendor(
            allow_agent=False,
            look_for_keys=False,
        )
        con = vendor.run_command(
            "127.0.0.1",
            b"test_run_command_data_transfer",
            username=USER,
            port=self.port,
            password=PASSWORD,
        )

        self.assertIn(b"test_run_command_data_transfer", self.commands)

        channel = self.transport.accept(5)
        channel.send(b"stdout\n")
        channel.send_stderr(b"stderr\n")
        channel.close()

        # Fixme: it's return false
        # self.assertTrue(con.can_read())

        self.assertEqual(b"stdout\n", con.read(4096))

        # Fixme: it's return empty string
        # self.assertEqual(b'stderr\n', con.read_stderr(4096))

    def test_ssh_config_parsing(self) -> None:
        """Test that SSH config is properly parsed and used by ParamikoSSHVendor."""
        # Create a temporary SSH config file
        with tempfile.NamedTemporaryFile(mode="w", suffix=".config", delete=False) as f:
            f.write(
                f"""
Host testserver
    HostName 127.0.0.1
    User testuser
    Port {self.port}
    IdentityFile /path/to/key
"""
            )
            config_path = f.name

        try:
            # Mock the config path
            with patch("contrib.paramiko_vendor.os.path.expanduser") as mock_expanduser:

                def side_effect(path):
                    if path == "~/.ssh/config":
                        return config_path
                    return path

                mock_expanduser.side_effect = side_effect

                vendor = ParamikoSSHVendor(
                    allow_agent=False,
                    look_for_keys=False,
                )

                # Test that SSH config values are loaded
                host_config = vendor.ssh_config.lookup("testserver")
                self.assertEqual(host_config["hostname"], "127.0.0.1")
                self.assertEqual(host_config["user"], "testuser")
                self.assertEqual(host_config["port"], str(self.port))
                self.assertIn("/path/to/key", host_config["identityfile"])

        finally:
            os.unlink(config_path)


@skipIf(not has_paramiko, "paramiko is not installed")
class ParamikoSSHVendorRealServerTests(TestCase):
    """Tests for ParamikoSSHVendor using a real SSH server listening on TCP."""

    def setUp(self) -> None:
        self.ssh_server = SSHServer()
        self.ssh_server.start()
        self.home_dir = _set_test_home(self)
        self.known_hosts_path = _write_known_host(
            self.home_dir, "127.0.0.1", self.ssh_server.port, self.ssh_server.host_key
        )
        socket.setdefaulttimeout(10)
        self.addCleanup(socket.setdefaulttimeout, None)
        self.addCleanup(self.ssh_server.stop)

    def _run_command(self, command, **kwargs):
        """Helper to run a command with default vendor settings."""
        vendor = ParamikoSSHVendor(allow_agent=False, look_for_keys=False)
        kwargs.setdefault("port", self.ssh_server.port)
        kwargs.setdefault("username", USER)
        return vendor.run_command("127.0.0.1", command, **kwargs)

    def _test_echo(self, con, data):
        """Helper to test echo functionality."""
        con.write(data)
        response = con.read(len(data))
        self.assertEqual(data, response)

    def test_password_authentication_success(self) -> None:
        """Test successful password authentication."""
        con = self._run_command(b"test_password_auth", password=PASSWORD)
        self.assertIn(b"test_password_auth", self.ssh_server.commands)
        self._test_echo(con, b"hello\n")
        con.close()

    def test_key_authentication_success(self) -> None:
        """Test successful key authentication."""
        key = paramiko.RSAKey.from_private_key(StringIO(CLIENT_KEY))
        con = self._run_command(b"test_key_auth", pkey=key)
        self.assertIn(b"test_key_auth", self.ssh_server.commands)
        self._test_echo(con, b"key_test\n")
        con.close()

    def test_authentication_failures(self) -> None:
        """Test authentication failures."""
        # Wrong password
        with self.assertRaises(paramiko.AuthenticationException):
            self._run_command(b"should_fail", password="wrong_password")

        # Wrong key
        wrong_key = paramiko.RSAKey.generate(2048)
        with self.assertRaises(paramiko.AuthenticationException):
            self._run_command(b"should_fail", pkey=wrong_key)

    def test_connection_errors(self) -> None:
        """Test various connection errors."""
        vendor = ParamikoSSHVendor(allow_agent=False, look_for_keys=False)

        # Non-existent port
        with self.assertRaises((OSError, ConnectionRefusedError)):
            vendor.run_command(
                "127.0.0.1", b"fail", username=USER, port=65432, password=PASSWORD
            )

        # Invalid hostname
        with self.assertRaises((socket.gaierror, OSError)):
            vendor.run_command(
                "invalid.hostname.example.com",
                b"fail",
                username=USER,
                password=PASSWORD,
            )

    def test_data_transfer(self) -> None:
        """Test various data transfer scenarios."""
        con = self._run_command(b"test_data", password=PASSWORD)

        # Large data (10KB)
        large_data = b"X" * 10240
        self._test_echo(con, large_data)

        # Binary data with all byte values
        binary_data = bytes(range(256))
        self._test_echo(con, binary_data)

        con.close()

    def test_multiple_connections(self) -> None:
        """Test multiple sequential connections."""
        # First connection
        con1 = self._run_command(b"test_connection_1", password=PASSWORD)
        self._test_echo(con1, b"first\n")
        con1.close()

        # Second connection
        con2 = self._run_command(b"test_connection_2", password=PASSWORD)
        self._test_echo(con2, b"second\n")
        con2.close()

        # Verify both commands were recorded
        self.assertIn(b"test_connection_1", self.ssh_server.commands)
        self.assertIn(b"test_connection_2", self.ssh_server.commands)

    def test_key_from_file(self) -> None:
        """Test authentication using key file."""
        with tempfile.NamedTemporaryFile(mode="w", suffix=".key", delete=False) as f:
            f.write(CLIENT_KEY)
            key_path = f.name

        try:
            con = self._run_command(b"test_key_from_file", key_filename=key_path)
            self.assertIn(b"test_key_from_file", self.ssh_server.commands)
            self._test_echo(con, b"file_key_test\n")
            con.close()
        finally:
            os.unlink(key_path)

    def test_protocol_versions(self) -> None:
        """Test protocol version handling."""
        # Protocol version 2 (default)
        con = self._run_command(
            b"test_protocol_v2", password=PASSWORD, protocol_version=2
        )
        self.assertIn(b"test_protocol_v2", self.ssh_server.commands)
        con.close()

        # Protocol version 1
        con = self._run_command(
            b"test_protocol_v1", password=PASSWORD, protocol_version=1
        )
        self.assertIn(b"test_protocol_v1", self.ssh_server.commands)
        con.close()

    def test_vendor_options(self) -> None:
        """Test vendor initialization options."""
        # Test with timeout
        vendor = ParamikoSSHVendor(allow_agent=False, look_for_keys=False, timeout=1)
        con = vendor.run_command(
            "127.0.0.1",
            b"test_timeout",
            username=USER,
            port=self.ssh_server.port,
            password=PASSWORD,
        )
        self.assertIn(b"test_timeout", self.ssh_server.commands)
        con.close()

    def test_can_read(self) -> None:
        """Test can_read functionality."""
        con = self._run_command(b"test_can_read", password=PASSWORD)

        # Check can_read returns bool
        self.assertIsInstance(con.can_read(), bool)

        # Send data and verify echo
        self._test_echo(con, b"test_data\n")
        con.close()

    def test_partial_reads(self) -> None:
        """Test reading data in small chunks."""
        con = self._run_command(b"test_partial", password=PASSWORD)

        test_data = b"0123456789" * 10  # 100 bytes
        con.write(test_data)

        # Read in 10-byte chunks
        received_data = b""
        while len(received_data) < len(test_data):
            chunk = con.read(10)
            if not chunk:
                break
            received_data += chunk

        self.assertEqual(test_data, received_data)
        con.close()

    def test_ssh_config_integration(self) -> None:
        """Test SSH config integration."""
        with tempfile.NamedTemporaryFile(mode="w", suffix=".config", delete=False) as f:
            f.write(f"""
Host testserver
    HostName 127.0.0.1
    User {USER}
    Port {self.ssh_server.port}
    UserKnownHostsFile {self.known_hosts_path}
""")
            config_path = f.name

        try:
            with patch("contrib.paramiko_vendor.os.path.expanduser") as mock_expanduser:
                mock_expanduser.side_effect = lambda p: (
                    config_path if p == "~/.ssh/config" else p
                )

                vendor = ParamikoSSHVendor(allow_agent=False, look_for_keys=False)
                con = vendor.run_command(
                    "testserver", b"test_ssh_config", password=PASSWORD
                )

                self.assertIn(b"test_ssh_config", self.ssh_server.commands)
                self._test_echo(con, b"config_test\n")
                con.close()
        finally:
            os.unlink(config_path)

    def test_rejects_unknown_host_key(self) -> None:
        """Unknown host keys should be rejected by default."""
        with tempfile.TemporaryDirectory() as home_dir:
            with patch.dict(os.environ, _home_env(home_dir)):
                os.mkdir(os.path.join(home_dir, ".ssh"))
                vendor = ParamikoSSHVendor(allow_agent=False, look_for_keys=False)
                with self.assertRaises(paramiko.SSHException):
                    vendor.run_command(
                        "127.0.0.1",
                        b"should_reject_unknown_host",
                        username=USER,
                        port=self.ssh_server.port,
                        password=PASSWORD,
                    )
