"""D15 (§4.8): effective_decisions must stale-filter name-subject decisions too.

The reference bug (CRITICA #1): effective_decisions only filtered decisions whose
subject was "phase:N". cte_approved uses the CTE *name* as subject, so a cte_approved
from F6 stayed "effective" after a rollback to F4 -- a stale decision that still counted
(the exact invariant §4.8 forbids). The fix records the emitting phase on each
DecisionRecord (high-water-mark) and effective_decisions falls back to it when the
subject is not "phase:N".
"""
from pathlib import Path

from tht.decisions import append_decision
from tht.phase import approved_ctes, current_phase, effective_decisions


def _walk_to_phase(session: Path, target: int) -> None:
    """Approva in ordine fino a raggiungere `target` (il fold avanza solo su n==cur)."""
    while current_phase(session) < target:
        append_decision(session, type="phase_approved", subject=f"phase:{current_phase(session)}")


def test_cte_approved_name_subject_is_stale_after_reopen(tmp_path):
    s = tmp_path / "sess"
    s.mkdir()
    _walk_to_phase(s, 6)  # ora in F6
    # piano CTE + approvazione di un CTE (subject = NOME del CTE, non "phase:6")
    (s / "cte_plan.json").write_text('["pazienti_base"]')
    append_decision(s, type="cte_approved", subject="pazienti_base")
    assert "pazienti_base" in approved_ctes(s)
    assert current_phase(s) == 6

    # rollback a F4: la cte_approved di F6 deve diventare stale (esclusa dalla vista)
    append_decision(s, type="phase_reopened", subject="phase:4")
    assert current_phase(s) == 4
    assert "pazienti_base" not in approved_ctes(s), (
        "cte_approved (subject a nome) di F6 NON deve contare dopo un reopen a F4"
    )
    types = [d.type for d in effective_decisions(s)]
    assert "cte_approved" not in types


def test_phase_field_recorded_on_append(tmp_path):
    s = tmp_path / "sess"
    s.mkdir()
    _walk_to_phase(s, 4)
    rec = append_decision(s, type="value_grounded", subject="ablazione")
    assert rec.phase == 4  # emitting phase recorded for the high-water-mark filter