import sys
import subprocess

try:
    import streamlit as st
except Exception:  # pragma: no cover
    st = None


def commit_hash() -> str:
    """Return current git commit hash or '<none>' if unavailable."""
    try:
        return subprocess.check_output(["git", "rev-parse", "HEAD"], shell=False, encoding="utf-8").strip()
    except Exception:
        return "<none>"


def versions_html() -> str:
    """Return a small HTML snippet with runtime and app environment info.

    Includes: git commit, Python version, and Streamlit version.
    """
    python_version = ".".join(str(x) for x in sys.version_info[:3])
    full_python = sys.version.replace("\n", " ")
    commit = commit_hash()
    streamlit_version = getattr(st, "__version__", "not installed")

    html = f"""
    <div style="font-size: 0.85rem; color: #b7c3d0; margin-top: 1.5rem; padding-top: 0.5rem; border-top: 1px solid rgba(255,255,255,0.15);">
      <span>commit: <code>{commit}</code></span>
      &nbsp;|&nbsp;
      <span>python: <span title="{full_python}">{python_version}</span></span>
      &nbsp;|&nbsp;
      <span>streamlit: {streamlit_version}</span>
    </div>
    """
    return html