"""Unit tests for Podman runtime backend, socket candidate generation,
host-gateway resolution, and multi-layer socket fallthrough.
"""

from __future__ import annotations

import json
from pathlib import Path
from types import SimpleNamespace
from typing import Any
from unittest.mock import MagicMock, patch

import pytest

from strix.interface.environment import check_docker_installed
from strix.interface.utils import check_docker_connection
from strix.runtime.backends import (
    _BACKENDS,
    _BIND_MOUNT_BACKENDS,
    auto_detect_podman_socket,
    backend_supports_bind_mounts,
    get_backend,
    get_docker_client,
    get_host_gateway,
    get_podman_socket_candidates,
    normalize_socket_url,
    parse_podman_machine_inspect,
    register_backend,
    resolve_runtime_socket,
    supported_backends,
)


# ============================================================================
# 1. Host Gateway Resolution (3 tests)
# ============================================================================


def test_get_host_gateway_docker() -> None:
    """Docker backend maps to host.docker.internal."""
    assert get_host_gateway("docker") == "host.docker.internal"


def test_get_host_gateway_podman() -> None:
    """Podman backend maps to host.containers.internal (case-insensitive)."""
    assert get_host_gateway("podman") == "host.containers.internal"
    assert get_host_gateway("Podman") == "host.containers.internal"
    assert get_host_gateway("PODMAN") == "host.containers.internal"


def test_get_host_gateway_default_and_fallback(monkeypatch: pytest.MonkeyPatch) -> None:
    """Default or unknown backend falls back to host.docker.internal."""
    monkeypatch.delenv("STRIX_RUNTIME_BACKEND", raising=False)
    monkeypatch.setattr(
        "strix.config.load_settings",
        lambda: SimpleNamespace(runtime=SimpleNamespace(backend="docker")),
    )
    assert get_host_gateway(None) == "host.docker.internal"
    assert get_host_gateway("unknown_backend") == "host.docker.internal"


# ============================================================================
# 2. Backend Registry (4 tests)
# ============================================================================


def test_backend_registry_get_docker() -> None:
    """Docker backend is registered and callable."""
    backend = get_backend("docker")
    assert callable(backend)
    assert "docker" in supported_backends()
    assert backend_supports_bind_mounts("docker") is True


def test_backend_registry_get_podman() -> None:
    """Podman backend is registered, callable, and supports bind mounts."""
    backend = get_backend("podman")
    assert callable(backend)
    assert "podman" in supported_backends()
    assert backend_supports_bind_mounts("podman") is True


def test_backend_registry_unknown_raises() -> None:
    """Querying an unknown backend raises ValueError listing supported options."""
    with pytest.raises(ValueError, match="Unknown STRIX_RUNTIME_BACKEND: 'unknown_rt'"):
        get_backend("unknown_rt")


def test_backend_registry_custom_registration() -> None:
    """Custom backend can be registered and looked up with bind-mount support."""

    async def _dummy_backend(**_kwargs: Any) -> tuple[Any, Any]:
        return MagicMock(), MagicMock()

    try:
        register_backend("test_custom", _dummy_backend, supports_bind_mounts=True)
        assert get_backend("test_custom") is _dummy_backend
        assert backend_supports_bind_mounts("test_custom") is True
        assert "test_custom" in supported_backends()
    finally:
        _BACKENDS.pop("test_custom", None)
        _BIND_MOUNT_BACKENDS.discard("test_custom")


# ============================================================================
# 3. podman machine inspect JSON Parsing (6 tests)
# ============================================================================


def test_parse_machine_inspect_single_machine() -> None:
    """Extract socket path from a single machine inspect dictionary or list."""
    sock_path = "/Users/user/.local/share/containers/podman/machine/applehv/podman.sock"
    payload = json.dumps(
        [
            {
                "Name": "podman-machine-default",
                "Running": True,
                "ConnectionInfo": {
                    "PodmanSocket": {
                        "Path": sock_path,
                    }
                },
            }
        ]
    )
    result = parse_podman_machine_inspect(payload)
    assert result == [sock_path]


def test_parse_machine_inspect_multi_machine_running_priority() -> None:
    """When multiple machines exist, running machines take priority."""
    payload = json.dumps(
        [
            {
                "Name": "machine-stopped",
                "Running": False,
                "State": "stopped",
                "ConnectionInfo": {"PodmanSocket": {"Path": "/path/to/stopped.sock"}},
            },
            {
                "Name": "machine-active",
                "Running": True,
                "State": "running",
                "ConnectionInfo": {"PodmanSocket": {"Path": "/path/to/active.sock"}},
            },
        ]
    )
    result = parse_podman_machine_inspect(payload)
    assert result == ["/path/to/active.sock", "/path/to/stopped.sock"]


def test_parse_machine_inspect_string_socket_path() -> None:
    """Handle ConnectionInfo where PodmanSocket is directly a string path."""
    payload = json.dumps(
        [
            {
                "Name": "default",
                "Running": True,
                "ConnectionInfo": {"PodmanSocket": "/var/run/podman-direct.sock"},
            }
        ]
    )
    result = parse_podman_machine_inspect(payload)
    assert result == ["/var/run/podman-direct.sock"]


def test_parse_machine_inspect_invalid_json() -> None:
    """Invalid JSON returns empty list without raising."""
    assert parse_podman_machine_inspect("Error: machine not found") == []
    assert parse_podman_machine_inspect("{not-valid-json") == []


def test_parse_machine_inspect_empty_or_missing_keys() -> None:
    """Empty string, empty array, or machines without socket path return empty list."""
    assert parse_podman_machine_inspect("") == []
    assert parse_podman_machine_inspect("   ") == []
    assert parse_podman_machine_inspect("[]") == []
    assert parse_podman_machine_inspect(json.dumps([{"Name": "empty"}])) == []
    assert (
        parse_podman_machine_inspect(
            json.dumps([{"Name": "null_path", "ConnectionInfo": {"PodmanSocket": None}}])
        )
        == []
    )


def test_parse_machine_inspect_non_dict_elements() -> None:
    """Lists with non-dict elements are handled gracefully."""
    payload = json.dumps([None, 123, "random-string", False])
    assert parse_podman_machine_inspect(payload) == []


# ============================================================================
# 4. Podman Socket Candidates Across Platform Variants (6 tests)
# ============================================================================


def test_socket_candidates_linux_rootless_xdg() -> None:
    """Linux rootless candidate incorporates XDG_RUNTIME_DIR."""
    candidates = get_podman_socket_candidates(
        platform="linux",
        xdg_runtime_dir="/run/user/1000",
    )
    expected = Path("/run/user/1000/podman/podman.sock")
    assert expected in candidates


def test_socket_candidates_linux_rootless_uid() -> None:
    """Linux rootless candidate incorporates UID and /tmp fallback."""
    candidates = get_podman_socket_candidates(platform="linux", uid=1001)
    assert Path("/run/user/1001/podman/podman.sock") in candidates
    assert Path("/tmp/podman-run-1001/podman/podman.sock") in candidates  # noqa: S108


def test_socket_candidates_linux_rootful() -> None:
    """Linux rootful candidates include system socket paths."""
    candidates = get_podman_socket_candidates(platform="linux")
    assert Path("/run/podman/podman.sock") in candidates
    assert Path("/var/run/podman/podman.sock") in candidates


def test_socket_candidates_darwin_applehv() -> None:
    """macOS candidate includes applehv VM socket path."""
    home = Path("/Users/developer")
    candidates = get_podman_socket_candidates(platform="darwin", home=home)
    expected = home / ".local/share/containers/podman/machine/applehv/podman.sock"
    assert expected in candidates


def test_socket_candidates_darwin_libkrun() -> None:
    """macOS candidate includes libkrun VM socket path."""
    home = Path("/Users/developer")
    candidates = get_podman_socket_candidates(platform="darwin", home=home)
    expected = home / ".local/share/containers/podman/machine/libkrun/podman.sock"
    assert expected in candidates


def test_socket_candidates_darwin_machine_inspect_integration() -> None:
    """macOS candidates prioritize sockets discovered via machine inspect."""
    home = Path("/Users/developer")
    with patch(
        "strix.runtime.backends._run_podman_machine_inspect",
        return_value=["/custom/machine/inspect.sock"],
    ):
        candidates = get_podman_socket_candidates(platform="darwin", home=home)
    assert candidates[0] == Path("/custom/machine/inspect.sock")


# ============================================================================
# 5. Socket Detection and Multi-Layer Fallthrough (5 tests)
# ============================================================================


def test_socket_fallthrough_strix_runtime_socket(monkeypatch: pytest.MonkeyPatch) -> None:
    """STRIX_RUNTIME_SOCKET takes highest precedence in socket resolution."""
    monkeypatch.setenv("STRIX_RUNTIME_SOCKET", "unix:///custom/strix.sock")
    monkeypatch.setenv("DOCKER_HOST", "unix:///custom/docker_host.sock")
    resolved = resolve_runtime_socket("podman")
    assert resolved == "unix:///custom/strix.sock"


def test_socket_fallthrough_docker_host(monkeypatch: pytest.MonkeyPatch) -> None:
    """DOCKER_HOST is used when STRIX_RUNTIME_SOCKET is unset."""
    monkeypatch.delenv("STRIX_RUNTIME_SOCKET", raising=False)
    monkeypatch.setenv("DOCKER_HOST", "unix:///custom/docker_host.sock")
    resolved = resolve_runtime_socket("podman")
    assert resolved == "unix:///custom/docker_host.sock"


def test_socket_fallthrough_autodetect_podman(monkeypatch: pytest.MonkeyPatch) -> None:
    """Auto-detects first existing socket candidate when env vars are unset."""
    monkeypatch.delenv("STRIX_RUNTIME_SOCKET", raising=False)
    monkeypatch.delenv("DOCKER_HOST", raising=False)

    fake_sock = Path("/run/user/1000/podman/podman.sock")
    with (
        patch(
            "strix.runtime.backends.get_podman_socket_candidates",
            return_value=[fake_sock],
        ),
        patch.object(Path, "exists", return_value=True),
        patch.object(Path, "resolve", return_value=fake_sock),
    ):
        detected = auto_detect_podman_socket()
        assert detected == f"unix://{fake_sock}"


def test_socket_fallthrough_graceful_on_missing_or_failed_socket(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """Connection failure on detected socket gracefully falls through to docker.from_env()."""
    monkeypatch.delenv("STRIX_RUNTIME_SOCKET", raising=False)
    monkeypatch.delenv("DOCKER_HOST", raising=False)

    mock_docker = MagicMock()
    mock_bad_client = MagicMock()
    mock_bad_client.ping.side_effect = ConnectionRefusedError("Daemon unreachable")
    mock_docker.DockerClient.return_value = mock_bad_client

    mock_default_client = MagicMock()
    mock_docker.from_env.return_value = mock_default_client

    with (
        patch.dict("sys.modules", {"docker": mock_docker}),
        patch(
            "strix.runtime.backends.resolve_runtime_socket",
            return_value="unix:///unreachable.sock",
        ),
    ):
        client = get_docker_client("podman")

    assert client is mock_default_client
    mock_docker.from_env.assert_called_once()


def test_socket_fallthrough_strix_runtime_socket_raw_path_normalization() -> None:
    """Raw socket path is normalized to unix:// URI scheme."""
    assert normalize_socket_url("/run/podman/podman.sock") == "unix:///run/podman/podman.sock"
    assert normalize_socket_url("unix:///var/run/podman.sock") == "unix:///var/run/podman.sock"
    assert normalize_socket_url("tcp://127.0.0.1:2375") == "tcp://127.0.0.1:2375"


# ============================================================================
# 7. CLI Check and Connection for Podman Runtime (4 tests)
# ============================================================================


def test_check_docker_installed_podman_success(monkeypatch: pytest.MonkeyPatch) -> None:
    """When STRIX_RUNTIME_BACKEND=podman, succeeds if podman is in PATH even if docker is not."""
    monkeypatch.setenv("STRIX_RUNTIME_BACKEND", "podman")

    def fake_which(cmd: str) -> str | None:
        if cmd == "podman":
            return "/usr/bin/podman"
        return None

    monkeypatch.setattr("shutil.which", fake_which)
    # Should not raise or sys.exit
    check_docker_installed()


def test_check_docker_installed_podman_missing(monkeypatch: pytest.MonkeyPatch) -> None:
    """When STRIX_RUNTIME_BACKEND=podman and neither podman nor docker in PATH, exits with error."""
    monkeypatch.setenv("STRIX_RUNTIME_BACKEND", "podman")
    monkeypatch.setattr("shutil.which", lambda _cmd: None)

    with pytest.raises(SystemExit) as exc_info:
        check_docker_installed()
    assert exc_info.value.code == 1


def test_check_docker_installed_docker_missing(monkeypatch: pytest.MonkeyPatch) -> None:
    """When backend is docker and docker is missing from PATH, exits with error."""
    monkeypatch.setenv("STRIX_RUNTIME_BACKEND", "docker")

    def fake_which(cmd: str) -> str | None:
        if cmd == "podman":
            return "/usr/bin/podman"
        return None

    monkeypatch.setattr("shutil.which", fake_which)

    with pytest.raises(SystemExit) as exc_info:
        check_docker_installed()
    assert exc_info.value.code == 1


def test_check_docker_connection_podman_uses_podman_backend(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """check_docker_connection connects and pings backend client."""
    monkeypatch.setenv("STRIX_RUNTIME_BACKEND", "podman")

    mock_client = MagicMock()
    with patch("strix.runtime.backends.get_docker_client", return_value=mock_client) as mock_get:
        client = check_docker_connection()
        mock_get.assert_called_once_with("podman")
        mock_client.ping.assert_called_once()
        assert client is mock_client