import streamlit as st
import io



def render_batch_errorlog(errorlog, ui):
    """Optionales Fehlerprotokoll mit Download im UI anzeigen, sofern Fehler vorhanden."""
    if errorlog:
        with st.expander(ui["batch"]["errorlog_show"], expanded=False):
            st.markdown(ui["batch"]["errorlog_message"].format(count=len(errorlog)))
            for line in errorlog:
                st.write(line)
            # Download als Textdatei
            buf = io.StringIO()
            for l in errorlog:
                buf.write(f"{l}\n")
            st.download_button(
                label=ui["batch"]["errorlog_download"],
                data=buf.getvalue().encode("utf-8"),
                file_name="batch_errorlog.txt",
                mime="text/plain"
            )