"""Regression checks for research-phase session logging."""

import ast
from pathlib import Path


def test_fresh_research_binds_slog_before_use():
    """Catch the UI-only NameError where _slog was referenced before assignment."""
    source = Path("chat_interface.py").read_text()
    module = ast.parse(source)
    target = next(
        node
        for node in module.body
        if isinstance(node, ast.ClassDef) and node.name == "ChatDemoInterface"
    )
    method = next(
        node
        for node in target.body
        if isinstance(node, ast.FunctionDef) and node.name == "_run_fresh_research"
    )

    saw_assignment = False
    for node in ast.walk(method):
        if isinstance(node, ast.Name) and node.id == "_slog" and isinstance(node.ctx, ast.Load):
            assert saw_assignment, "_slog is read before it is assigned in _run_fresh_research"
            return
        if isinstance(node, ast.Assign):
            saw_assignment = any(
                isinstance(target, ast.Name) and target.id == "_slog"
                for target in node.targets
            ) or saw_assignment

    raise AssertionError("_run_fresh_research does not read _slog; regression test needs updating")