"""D15 granularity (a): `tht decision retract` tombstones the last substantive decision.

Wires the step-granularity rollback ("re-ask current widget, discard last answer") to a
reachable CLI command. The data model (decision_retracted + retracts, honored by
effective_decisions) already existed; this pins the command that emits it.
"""
from pathlib import Path

from tht.cli.decision_cmd import retract_cmd
from tht.decisions import append_decision, list_decisions
from tht.phase import current_phase, effective_decisions


def _walk_to_phase(session: Path, target: int) -> None:
    while current_phase(session) < target:
        append_decision(session, type="phase_approved", subject=f"phase:{current_phase(session)}")


def test_retract_drops_last_substantive_decision(tmp_path, monkeypatch):
    s = tmp_path / "2026-01-01-000000-x"
    s.mkdir(parents=True)
    _walk_to_phase(s, 4)
    append_decision(s, type="table_promoted", subject="phase:4", detail="dim_pazienti")
    append_decision(s, type="table_promoted", subject="phase:4", detail="fact_ricoveri")

    # stub config + session loading (the command only needs a session dir)
    import tht.cli.decision_cmd as mod
    import tht.cli.session_cmd as session_mod
    from tht.session.models import SessionManifest, SessionSnapshot

    class _Cfg:
        class paths:
            sessions = tmp_path

    monkeypatch.setattr(mod, "_load_config_or_exit", lambda _c: _Cfg())
    monkeypatch.setattr(mod, "load_session_or_exit", lambda _cfg, _s: None)
    class _Repository:
        def get(self, session_id):
            return SessionSnapshot(
                manifest=SessionManifest(id=session_id, created_at="2026-01-01T00:00:00Z", question="q", database="d", schema="s"),
                decisions=list_decisions(tmp_path / session_id),
            )

        def append_decisions(self, session_id, decisions):
            from tht.decisions import append_decisions

            return append_decisions(tmp_path / session_id, list(decisions))

    repository = _Repository()
    monkeypatch.setattr(mod, "load_snapshot_or_exit", lambda _cfg, sid: repository.get(sid))
    monkeypatch.setattr(mod, "session_repository", lambda _cfg: repository)
    monkeypatch.setattr(session_mod, "load_snapshot_or_exit", lambda _cfg, sid: repository.get(sid))

    retract_cmd(session="2026-01-01-000000-x", config=Path("x"))

    eff = effective_decisions(s)
    promoted = [d for d in eff if d.type == "table_promoted"]
    assert len(promoted) == 1  # the last one was retracted
    assert promoted[0].detail == "dim_pazienti"
    # the audit log keeps everything (append-only): 2 promotions + the retract marker
    raw = [d.type for d in list_decisions(s)]
    assert raw.count("table_promoted") == 2
    assert "decision_retracted" in raw