"""The public Python CLI exposes exactly the approved workflow surface."""
from __future__ import annotations

import json
from pathlib import Path

from typer.main import get_command
from typer.testing import CliRunner

from tht.cli import app

_FIXTURE = Path(__file__).parent / "fixtures" / "approved_cli_surface.json"


def _leaf_paths(command, prefix: tuple[str, ...] = ()) -> set[str]:
    """Return the terminal paths offered by the real Typer/Click command tree."""
    children = getattr(command, "commands", {})
    if not children:
        return {" ".join(prefix)} if prefix else set()
    paths: set[str] = set()
    for name, child in children.items():
        paths.update(_leaf_paths(child, prefix + (name,)))
    return paths


def _approved_surface() -> dict[str, list[str]]:
    return json.loads(_FIXTURE.read_text(encoding="utf-8"))


def test_typer_tree_matches_the_approved_command_surface():
    """Catches a missing live command or an accidentally re-registered erased command."""
    approved = _approved_surface()
    expected = set(approved["maintained"]) | set(approved["enhanced"])

    assert len(approved["maintained"]) == 57
    assert len(approved["enhanced"]) == 8
    assert len(approved["erased"]) == 14
    assert not (expected & set(approved["erased"]))
    assert _leaf_paths(get_command(app)) == expected


def test_erased_commands_are_rejected_with_the_standard_typer_error():
    """Catches a regression that restores a retired command under an existing group."""
    runner = CliRunner()
    for path in _approved_surface()["erased"]:
        result = runner.invoke(app, [*path.split(), "--help"])
        assert result.exit_code != 0, path
        assert "no such command" in result.output.casefold(), path