from __future__ import annotations

import importlib.util

import pytest

from graph.models import ExecutionGraphDefinition, ExecutionGraphVersion, ExecutionGraphVersionStatus, GraphRun, GraphRunStatus
from graph.langgraph_runtime import LangGraphRuntime
from graph.registry import NodeHandlerRegistry, NodeResult
from graph.spec import ExecutionGraphSpec, GraphEdgeSpec, GraphNodeSpec


def test_langgraph_runtime_reports_missing_dependency() -> None:
    if importlib.util.find_spec("langgraph") is not None:
        pytest.skip("langgraph is installed; adapter execution is covered by integration parity tests")

    runtime = LangGraphRuntime()

    with pytest.raises(RuntimeError, match="langgraph package|NodeHandlerRegistry"):
        runtime.run_until_terminal_or_paused(None)  # type: ignore[arg-type]


class LangGraphFixtureNode:
    node_type = "langgraph_fixture"
    idempotent = True
    replay_safe = True
    destructive = False

    def run(self, context: object) -> NodeResult:
        return NodeResult("COMPLETE", "success", {"executed": True}, {"model_requests": 0})


def test_langgraph_runtime_executes_artifex_graph_when_installed() -> None:
    if importlib.util.find_spec("langgraph") is None:
        pytest.skip("langgraph is not installed")
    spec = ExecutionGraphSpec(
        name="langgraph_fixture",
        version=1,
        graph_type="FIXTURE",
        entry="step",
        nodes={"step": GraphNodeSpec("step", "langgraph_fixture"), "done": GraphNodeSpec("done", "terminal")},
        edges=[GraphEdgeSpec("step", "done", "success")],
        terminal_nodes=["done"],
    )
    definition = ExecutionGraphDefinition.objects.create(name=spec.name, graph_type=spec.graph_type)
    version = ExecutionGraphVersion.objects.create(graph=definition, version=1, status=ExecutionGraphVersionStatus.CHAMPION, graph_spec=spec.to_dict())
    graph_run = GraphRun.objects.create(execution_graph_version=version, current_node=spec.entry)
    registry = NodeHandlerRegistry()
    registry.register(LangGraphFixtureNode())

    result = LangGraphRuntime(registry).run_until_terminal_or_paused(graph_run)

    assert result.status == GraphRunStatus.COMPLETE
    assert result.current_node == "done"
    assert result.node_runs.get(node_id="step").output_metadata["executed"] is True