import importlib.util
from pathlib import Path

SCRIPT = Path(__file__).parents[1] / "scripts" / "run_firebird_discovery.py"


def load_script():
    spec = importlib.util.spec_from_file_location("run_firebird_discovery_dependency", SCRIPT)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


def valid_fdb():
    return type(
        "Fdb",
        (),
        {
            "__version__": "2.0.4",
            "ISOLATION_LEVEL_READ_COMMITED_RO": b"\x03\x08\x06\x0f\x11",
        },
    )()


def patch_valid_environment(monkeypatch, module, tmp_path):
    client = tmp_path / "fbclient.dll"
    client.write_bytes(b"client")
    monkeypatch.setattr(module, "CLIENT_LIBRARY", client)
    monkeypatch.setattr(module, "validate_fdb_provenance", lambda: {
        "status": "VALID",
        "distribution_name": "fdb",
        "distribution_version": "2.0.4",
    })
    monkeypatch.setattr(module.importlib.metadata, "version", lambda name: "2.0.4")
    monkeypatch.setattr(module, "_client_metadata", lambda path: {
        "path": str(path),
        "exists": True,
        "version": "2.5.9.27139",
        "architecture": "x64",
    })
    return client


def test_validate_firebird_runtime_returns_complete_compatibility_evidence(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)

    evidence = module.validate_firebird_runtime(fdb_module=valid_fdb())

    assert evidence["status"] == "VALID"
    assert evidence["python_runtime"]["architecture"] == "x64"
    assert evidence["fdb"]["version"] == "2.0.4"
    assert evidence["client"]["version"] == "2.5.9.27139"
    assert evidence["client"]["architecture"] == "x64"
    assert evidence["compatibility"] == {
        "status": "VALID",
        "python_client_architecture_match": True,
        "fdb_client_version_match": True,
        "read_only_api": True,
    }


def test_validate_firebird_runtime_without_module_is_unknown(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)

    evidence = module.validate_firebird_runtime()

    assert evidence["status"] == "UNKNOWN"
    assert evidence["compatibility"]["read_only_api"] is False
    assert evidence["blocker"] == "compatibility_unproven"


def test_preimport_gate_requires_client_architecture(monkeypatch, tmp_path):
    module = load_script()
    client = tmp_path / "fbclient.dll"
    client.write_bytes(b"client")
    monkeypatch.setattr(module, "CLIENT_LIBRARY", client)
    monkeypatch.setattr(module, "validate_fdb_provenance", lambda: {"status": "VALID"})
    monkeypatch.setattr(module, "_client_metadata", lambda path: {
        "path": str(path), "exists": True, "version": "2.5.9.27139"
    })
    monkeypatch.setattr(module, "_read_client_architecture", lambda path: "UNKNOWN")
    monkeypatch.setattr(module.importlib.metadata, "version", lambda name: "2.0.4")

    try:
        module._validate_preimport_compatibility()
    except RuntimeError as error:
        assert "compatibility" in str(error)
    else:
        raise AssertionError("unknown client architecture must block before import")


def test_preimport_gate_requires_exact_read_only_api(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)
    monkeypatch.setattr(module, "_preimport_read_only_api_proven", lambda: False)

    try:
        module._validate_preimport_compatibility()
    except RuntimeError as error:
        assert "compatibility" in str(error)
    else:
        raise AssertionError("unproven read-only API must block before import")


def test_unknown_client_architecture_blocks(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)
    monkeypatch.setattr(module, "_client_metadata", lambda path: {
        "path": str(path), "exists": True, "version": "2.5.9.27139", "architecture": "UNKNOWN"
    })

    evidence = module.validate_firebird_runtime(fdb_module=valid_fdb())

    assert evidence["status"] == "UNKNOWN"
    assert evidence["blocker"] == "compatibility_unproven"


def test_unknown_client_version_blocks(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)
    monkeypatch.setattr(module, "_client_metadata", lambda path: {
        "path": str(path), "exists": True, "version": None, "architecture": "x64"
    })

    evidence = module.validate_firebird_runtime(fdb_module=valid_fdb())

    assert evidence["status"] == "UNKNOWN"
    assert evidence["blocker"] == "compatibility_unproven"


def test_unsupported_read_only_api_is_unknown(monkeypatch, tmp_path):
    module = load_script()
    patch_valid_environment(monkeypatch, module, tmp_path)
    fdb = type("Fdb", (), {"__version__": "2.0.4"})()

    evidence = module.validate_firebird_runtime(fdb_module=fdb)

    assert evidence["status"] == "UNKNOWN"
    assert evidence["blocker"] == "compatibility_unproven"