"""The shape ledger's schema contract (#2787, milestone 294, note 2786).

Step 1 pins the model: identity, the classification vocabulary, and the
token-free serialisation. The sync pass (step 2) and the classification
surface (step 3) grow their tests here; DB-backed behavior lands in the
integration lane once there is behavior to exercise.
"""
from scribe.models import Base
from scribe.models.code_shape import SHAPE_CLASSIFIERS, SHAPE_STATUSES, CodeShape


def test_identity_is_project_repo_path_symbol_kind():
    """Kind is part of identity on purpose: one file can define `.foo` (css)
    and `foo` (sym) as distinct shapes — the extractor emits both."""
    table = Base.metadata.tables["code_shapes"]
    unique = next(
        c for c in table.constraints
        if getattr(c, "name", "") == "uq_code_shapes_identity"
    )
    assert [c.name for c in unique.columns] == [
        "project_id", "repo_key", "path", "symbol", "kind",
    ]


def test_the_todo_state_is_the_default():
    """A shape nobody has judged yet must read `unclassified` — the ledger's
    todo list — never silently look classified."""
    assert CodeShape.__table__.c.status.default.arg == "unclassified"
    assert "unclassified" in SHAPE_STATUSES
    assert set(SHAPE_STATUSES) == {
        "canonical", "instance", "variant", "exempt", "unclassified",
    }
    assert set(SHAPE_CLASSIFIERS) == {
        "agent", "audit", "hook", "mechanical", "import",
    }


def test_snippet_reference_survives_snippet_deletion_as_null():
    """SET NULL, not CASCADE: a deleted snippet must not silently erase the
    accounting rows that pointed at it — the sync pass re-files them as
    unclassified so they rejoin the todo."""
    fk = next(iter(CodeShape.__table__.c.snippet_id.foreign_keys))
    assert fk.ondelete == "SET NULL"
    assert fk.column.table.name == "notes"


def test_status_queries_have_an_index():
    """list_shapes(status=unclassified) is THE todo query (step 3) — it must
    not degrade into a project-wide scan as ledgers reach thousands of rows."""
    names = {ix.name for ix in CodeShape.__table__.indexes}
    assert "ix_code_shapes_project_status" in names
    assert "ix_code_shapes_snippet" in names