"""TDD — ``_coerce_commit_dict`` must preserve ``structured_delta`` from the wire.

Root cause (found while debugging a real staging clone / `muse verify` failure
report): every field in ``_coerce_commit_dict`` reads from the incoming wire
dict via ``raw.get(...)`` *except* ``structured_delta``, which was hardcoded
to ``None`` -- discarding whatever the server actually sent. The function's
own docstring claims "structured_delta is preserved as-is", which was false.

Effect: every ``muse fetch`` / ``muse clone`` / ``muse pull`` permanently
loses structured_delta for every commit, even though the server sends it
correctly (confirmed separately via a live push+fetch round trip against
staging.musehub.ai). This is unrelated to a separate, historical-only
signature-corruption issue found in the same investigation (~1179 pre-existing
commits with invalid signatures) -- that one does not reproduce on a fresh
push+fetch cycle and needs its own data-repair investigation, not a code fix.
"""
from __future__ import annotations

from muse.core.transport import _coerce_commit_dict


def _raw_wire_commit(**overrides: object) -> dict[str, object]:
    base: dict[str, object] = {
        "commit_id": "sha256:" + "a" * 64,
        "repo_id": "sha256:" + "b" * 64,
        "branch": "main",
        "snapshot_id": "sha256:" + "c" * 64,
        "message": "a commit",
        "committed_at": "2026-05-20T14:43:25.290457+00:00",
        "parent_commit_id": None,
        "parent2_commit_id": None,
        "author": "gabriel",
        "metadata": {},
        "structured_delta": {
            "domain": "code",
            "ops": [{"op": "patch", "address": "src/foo.py"}],
            "summary": "1 modified file",
        },
        "sem_ver_bump": "patch",
        "breaking_changes": [],
        "agent_id": "claude-code",
        "model_id": "claude-sonnet-5",
        "toolchain_id": "",
        "prompt_hash": "",
        "signature": "ed25519:" + "d" * 86,
        "signer_public_key": "ed25519:" + "e" * 43,
        "signer_key_id": "sha256:" + "f" * 64,
        "reviewed_by": [],
        "test_runs": 0,
    }
    base.update(overrides)
    return base


class TestCoerceCommitDictStructuredDelta:
    def test_real_structured_delta_is_preserved(self) -> None:
        raw = _raw_wire_commit()
        result = _coerce_commit_dict(raw)
        assert result["structured_delta"] == raw["structured_delta"]

    def test_missing_structured_delta_stays_none(self) -> None:
        raw = _raw_wire_commit()
        del raw["structured_delta"]
        result = _coerce_commit_dict(raw)
        assert result["structured_delta"] is None

    def test_non_dict_structured_delta_is_rejected_not_passed_through(self) -> None:
        """A malformed wire value (e.g. a string or list) must not be trusted
        as structured_delta -- coerce to None rather than propagate garbage."""
        raw = _raw_wire_commit(structured_delta="not-a-dict")
        result = _coerce_commit_dict(raw)
        assert result["structured_delta"] is None

    def test_other_fields_unaffected(self) -> None:
        """Regression guard: every other field this function handles must
        keep working exactly as before -- this bug only ever affected
        structured_delta."""
        raw = _raw_wire_commit()
        result = _coerce_commit_dict(raw)
        assert result["commit_id"] == raw["commit_id"]
        assert result["signature"] == raw["signature"]
        assert result["signer_public_key"] == raw["signer_public_key"]
        assert result["agent_id"] == raw["agent_id"]
        assert result["sem_ver_bump"] == "patch"