"""Tests for CommitRecord schema v2.

Changes:
- ``format_version`` field removed entirely.
- ``branch`` renamed to ``created_on_branch``.

These tests are written RED-first. They fail against the current implementation
and pass once the schema changes are applied to ``muse/core/store.py``.
"""

from __future__ import annotations

import datetime

import pytest

from muse.core.store import CommitRecord, CommitDict
from muse.core._types import MsgpackDict


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

_NOW = datetime.datetime(2025, 1, 1, 0, 0, 0, tzinfo=datetime.timezone.utc)
_TS = _NOW.isoformat()
_CID = "sha256:" + "a" * 64
_SID = "sha256:" + "b" * 64


def _minimal_msgpack(branch_key: str = "created_on_branch") -> MsgpackDict:
    """Minimal raw dict for CommitRecord.from_msgpack."""
    return {
        "commit_id": _CID,
        "repo_id": "test-repo",
        branch_key: "main",
        "snapshot_id": _SID,
        "message": "test commit",
        "committed_at": _TS,
    }


# ---------------------------------------------------------------------------
# CommitRecord field existence
# ---------------------------------------------------------------------------


class TestCommitRecordFields:
    def test_has_created_on_branch(self) -> None:
        rec = CommitRecord(
            commit_id=_CID,
            repo_id="r",
            created_on_branch="main",
            snapshot_id=_SID,
            message="m",
            committed_at=_NOW,
        )
        assert rec.created_on_branch == "main"

    def test_has_no_branch_field(self) -> None:
        rec = CommitRecord(
            commit_id=_CID,
            repo_id="r",
            created_on_branch="main",
            snapshot_id=_SID,
            message="m",
            committed_at=_NOW,
        )
        assert not hasattr(rec, "branch"), (
            "CommitRecord must not have a 'branch' field after v2 schema change"
        )

    def test_has_no_format_version_field(self) -> None:
        rec = CommitRecord(
            commit_id=_CID,
            repo_id="r",
            created_on_branch="main",
            snapshot_id=_SID,
            message="m",
            committed_at=_NOW,
        )
        assert not hasattr(rec, "format_version"), (
            "CommitRecord must not have a 'format_version' field after v2 schema change"
        )


# ---------------------------------------------------------------------------
# to_dict serialisation
# ---------------------------------------------------------------------------


class TestCommitRecordToDict:
    def _make(self) -> CommitRecord:
        return CommitRecord(
            commit_id=_CID,
            repo_id="r",
            created_on_branch="dev",
            snapshot_id=_SID,
            message="m",
            committed_at=_NOW,
        )

    def test_to_dict_has_created_on_branch(self) -> None:
        d = self._make().to_dict()
        assert d["created_on_branch"] == "dev"

    def test_to_dict_has_no_branch_key(self) -> None:
        d = self._make().to_dict()
        assert "branch" not in d, (
            "to_dict() must not emit 'branch' key in v2 schema"
        )

    def test_to_dict_has_no_format_version_key(self) -> None:
        d = self._make().to_dict()
        assert "format_version" not in d, (
            "to_dict() must not emit 'format_version' key in v2 schema"
        )


# ---------------------------------------------------------------------------
# from_msgpack deserialisation
# ---------------------------------------------------------------------------


class TestCommitRecordFromMsgpack:
    def test_reads_created_on_branch(self) -> None:
        raw = _minimal_msgpack("created_on_branch")
        rec = CommitRecord.from_msgpack(raw)
        assert rec.created_on_branch == "main"

    def test_falls_back_to_branch_key_for_old_records(self) -> None:
        """Old records serialised with 'branch' key must still deserialise.

        This shim supports the migration window: old commit files on disk
        carry 'branch', new files carry 'created_on_branch'.  Once all repos
        are migrated via 'muse code migrate', this path is dead but harmless.
        """
        raw = _minimal_msgpack("branch")
        rec = CommitRecord.from_msgpack(raw)
        assert rec.created_on_branch == "main"

    def test_raises_when_neither_key_present(self) -> None:
        raw = _minimal_msgpack("created_on_branch")
        del raw["created_on_branch"]
        with pytest.raises(TypeError, match="created_on_branch"):
            CommitRecord.from_msgpack(raw)

    def test_from_msgpack_ignores_format_version_key(self) -> None:
        """Old records with format_version in the dict must still deserialise
        without storing the field on the returned record."""
        raw = _minimal_msgpack("created_on_branch")
        raw["format_version"] = 8
        rec = CommitRecord.from_msgpack(raw)
        assert not hasattr(rec, "format_version")


# ---------------------------------------------------------------------------
# CommitDict TypedDict
# ---------------------------------------------------------------------------


class TestCommitDict:
    def test_commit_dict_has_created_on_branch_key(self) -> None:
        """CommitDict must declare 'created_on_branch', not 'branch'."""
        annotations = CommitDict.__annotations__
        assert "created_on_branch" in annotations, (
            "CommitDict must have 'created_on_branch' key"
        )
        assert "branch" not in annotations, (
            "CommitDict must not have 'branch' key"
        )

    def test_commit_dict_has_no_format_version_key(self) -> None:
        annotations = CommitDict.__annotations__
        assert "format_version" not in annotations, (
            "CommitDict must not have 'format_version' key"
        )