"""Shared persistent approval-mode command logic.

Approval mode is profile-scoped configuration, not conversation state. Changing it affects
subsequent terminal guard checks immediately because approval.py loads config on each check; it must
not rebuild a live agent or mutate its system prompt/tool schema, preserving the prompt-cache
prefix.
"""

from __future__ import annotations

from contextlib import redirect_stderr, redirect_stdout
from dataclasses import dataclass
from io import StringIO
from typing import Optional

VALID_APPROVAL_MODES = ("manual", "smart", "off")


@dataclass(frozen=True)
class ApprovalModeResult:
    ok: bool
    mode: str
    changed: bool
    message: str


def _effective_mode() -> str:
    """Return the exact mode enforced by the terminal approval guard."""
    from tools.approval_context import _get_approval_mode
    return _get_approval_mode()


def run_approval_mode_command(requested_mode: Optional[str]) -> ApprovalModeResult:
    """Inspect or persist ``approvals.mode`` through canonical config APIs."""
    current = _effective_mode()
    requested = (requested_mode or "").strip().lower()

    if not requested:
        return ApprovalModeResult(True, current, False, f"Approval mode: {current} (persistent profile setting).")
    if requested not in VALID_APPROVAL_MODES:
        return ApprovalModeResult(False, current, False, "Usage: /approvals [manual|smart|off]")

    # set_config_value is the canonical managed-scope/write-safety chokepoint. It reports managed
    # policy through stderr + SystemExit, and the fail-closed write guard raises RuntimeError on an
    # unparseable config.yaml; capture both for slash-command output instead of terminating the
    # interactive worker.
    from hermes_cli.config import set_config_value
    output = StringIO()
    try:
        with redirect_stdout(output), redirect_stderr(output):
            set_config_value("approvals.mode", requested)
    except SystemExit:
        detail = output.getvalue().strip() or "Approval mode is managed and cannot be changed."
        return ApprovalModeResult(False, current, False, detail)
    except Exception as exc:
        return ApprovalModeResult(False, current, False, f"Failed to save approval mode: {exc}")

    effective = _effective_mode()
    if effective != requested:
        return ApprovalModeResult(
            False, effective, False,
            f"Approval mode remains {effective}; the requested value did not become effective.",
        )
    return ApprovalModeResult(
        True, effective, effective != current, f"Approval mode: {effective} (persistent profile setting).",
    )