add rename demo sample

app.py

@@ -29,6 +29,7 @@ from state import (
     build_all_csv_zip,
     build_xml_download,
     build_all_xml_zip,
+    rename_sample_demo_speakers,
 )
 
 # ---------------------------------------------------------------------------
@@ -178,6 +179,7 @@ isDemo = False
 if st.sidebar.button("Single File Demo (Sample)"):
     load_demo_single_sample(DEMO_SAMPLE_PATH)
     isDemo = True
+    st.session_state["_sample_demo_loaded"] = True
 
 if st.sidebar.button("Single File Demo (Full)"):
     load_demo_single(DEMO_PATH)
@@ -187,6 +189,14 @@ if st.sidebar.button("Multiple Files Demo"):
     load_demo_multi(MULTI_DEMO_PATHS)
     isDemo = True
 
+# Only show the rename demo button once the Sample demo has been loaded at
+# least once in this session, and only while that file is still registered.
+_sample_demo_fname = DEMO_SAMPLE_PATH.split("/")[-1]
+if (st.session_state.get("_sample_demo_loaded", False)
+        and _sample_demo_fname in st.session_state.file_names):
+    if st.sidebar.button("Rename Sample Speakers"):
+        rename_sample_demo_speakers(_sample_demo_fname)
+
 st.sidebar.caption(
     "Single File Demo (Sample) analyzes a 10-minute sample, while "
     "Single File Demo (Full) analyzes the entire file. "