from __future__ import annotations

import importlib.util
import sys
from pathlib import Path
from types import ModuleType
from typing import Any, cast

import pytest


def _load_langchain_example_module() -> ModuleType:
    path = Path("examples/langchain_vm_run.py")
    spec = importlib.util.spec_from_file_location("langchain_vm_run", path)
    if spec is None or spec.loader is None:
        raise AssertionError("failed to load LangChain example module")
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


def test_langchain_example_delegates_to_pyro(monkeypatch: pytest.MonkeyPatch) -> None:
    module = _load_langchain_example_module()
    monkeypatch.setattr(
        module,
        "Pyro",
        lambda: type(
            "StubPyro",
            (),
            {
                "run_in_vm": staticmethod(
                    lambda **kwargs: {"exit_code": 0, "stdout": kwargs["command"], "network": False}
                )
            },
        )(),
    )
    result = module.run_vm_run_tool(
        profile="debian-git",
        command="git --version",
        vcpu_count=1,
        mem_mib=1024,
    )
    assert "git --version" in result


def test_langchain_example_builds_vm_run_tool(monkeypatch: pytest.MonkeyPatch) -> None:
    module = _load_langchain_example_module()
    fake_langchain_tools = ModuleType("langchain_core.tools")

    def fake_tool(name: str) -> Any:
        def decorator(fn: Any) -> Any:
            fn.name = name
            return fn

        return decorator

    cast(Any, fake_langchain_tools).tool = fake_tool
    fake_langchain_core = ModuleType("langchain_core")
    monkeypatch.setitem(sys.modules, "langchain_core", fake_langchain_core)
    monkeypatch.setitem(sys.modules, "langchain_core.tools", fake_langchain_tools)

    tool = module.build_langchain_vm_run_tool()

    assert tool.name == "vm_run"