from __future__ import annotations

from copy import deepcopy

from fin_hub.fabric_cutover import evaluate_fabric_cutover, fabric_content_hash


def _authority() -> dict:
    return {
        "apiVersion": "railiance.fabric/v1alpha2",
        "kind": "FabricGraphExport",
        "schema_version": "financial-fabric-v1",
        "generated_at": "2026-08-31T12:00:00Z",
        "source": {
            "producer": "railiance-fabric",
            "commit": "snapshot-set:sha256:abc",
            "path": "registry://accepted-snapshots",
        },
        "actors": [{"id": "actor.king"}],
        "fabrics": [{"id": "fabric.main"}],
        "nodes": [{"id": "service.one"}],
        "edges": [],
        "unresolved": [],
    }


def _projection(authority: dict) -> dict:
    return {
        "schema_version": authority["schema_version"],
        "node_count": 1,
        "edge_count": 0,
        "actor_count": 1,
        "fabric_count": 1,
        "unresolved_count": 0,
        "latest_import": {
            "api_version": authority["apiVersion"],
            "schema_version": authority["schema_version"],
            "export_kind": authority["kind"],
            "content_hash": fabric_content_hash(authority),
            "source_commit": authority["source"]["commit"],
            "source_path": authority["source"]["path"],
            "exported_at": authority["generated_at"],
        },
    }


def test_cutover_gate_accepts_exact_counts_hash_and_provenance() -> None:
    authority = _authority()
    report = evaluate_fabric_cutover(authority, _projection(authority))
    assert report["ready"] is True
    assert report["failures"] == []


def test_cutover_gate_rejects_count_or_hash_drift() -> None:
    authority = _authority()
    projection = _projection(authority)
    projection["node_count"] = 2
    projection["latest_import"]["content_hash"] = "stale"
    report = evaluate_fabric_cutover(authority, projection)
    assert report["ready"] is False
    assert {"node_count", "content_hash"}.issubset(report["failures"])


def test_cutover_gate_rejects_unversioned_authority_provenance() -> None:
    authority = deepcopy(_authority())
    authority["source"]["commit"] = "working-tree"
    report = evaluate_fabric_cutover(authority, _projection(authority))
    assert report["ready"] is False
    assert "authority:source.commit must identify an immutable authority revision" in report["failures"]