"""S2.5 MAF version-guard — a TEST-TIME tripwire + a two-sided install pin.

The offline simulation depends on MAF's PRIVATE API (the ``_inner_get_response`` keyword-only
signature + ``_build_response_stream`` construction — see ``conftest`` / ``simulation``'s scripted
client). A major ``agent-framework-core`` bump could change those without notice. This is NOT a
runtime guard (an un-wired ``src`` helper would be green-but-dead); it is a test-time tripwire
against the installed distribution PLUS a two-sided pin in ``pyproject.toml`` (install-time).

Critical: the guard reads the DISTRIBUTION version via
``importlib.metadata.version("agent-framework-core")`` (verified ``1.9.0``), NOT
``agent_framework.__version__`` (verified ``0.0.0`` placeholder — reading that would make the guard
permanently RED / meaningless). Modelled on ``test_smoke``'s version-assert + ``test_portfolio``'s
grep-pin.
"""

from __future__ import annotations

import importlib.metadata
from pathlib import Path

import pytest

_DIST = "agent-framework-core"


def assert_supported_maf_version(version_str: str) -> None:
    """Raise ``ValueError`` when ``version_str`` is outside the supported ``>=1.9.0,<2`` range, naming
    the private-API premises to re-verify before a bump. Pure string parse — no import side effects,
    so a fake version can be passed directly (the RED-proof) without touching the real install."""
    parts = version_str.split(".")
    major = int(parts[0])
    minor = int(parts[1]) if len(parts) > 1 else 0
    if not (major == 1 and minor >= 9):
        raise ValueError(
            f"{_DIST} {version_str} is outside the supported range >=1.9.0,<2. Before bumping, "
            "re-verify the private-API premises the offline sim relies on: the _inner_get_response "
            "keyword-only signature (messages/options/stream) and the _build_response_stream "
            "construction. Update the pin in pyproject.toml once confirmed."
        )


def test_installed_maf_version_is_supported() -> None:
    """T-2.5d: the real installed distribution (verified 1.9.0) passes the guard — read from
    ``importlib.metadata.version``, NOT ``agent_framework.__version__`` (a 0.0.0 placeholder)."""
    assert_supported_maf_version(importlib.metadata.version(_DIST))


def test_guard_rejects_future_major() -> None:
    """T-2.5d: a future major (``2.0.0``) trips the guard with the actionable upgrade message —
    RED-proof without touching the real install."""
    with pytest.raises(ValueError, match="private-API premises"):
        assert_supported_maf_version("2.0.0")


def test_guard_rejects_too_old_minor() -> None:
    """T-2.5d: a pre-1.9 minor (``1.8.0``) also trips the guard (the pin is two-sided)."""
    with pytest.raises(ValueError, match="private-API premises"):
        assert_supported_maf_version("1.8.0")


def test_pyproject_pins_agent_framework_core_below_2() -> None:
    """T-2.5d: ``pyproject.toml`` pins ``agent-framework-core>=1.9.0,<2`` — the install-time half of
    the guard (the test above is the test-time half)."""
    pyproject = (Path(__file__).resolve().parents[1] / "pyproject.toml").read_text(encoding="utf-8")
    assert "agent-framework-core>=1.9.0,<2" in pyproject