Update app.py

app.py

@@ -264,7 +264,7 @@ def _add_sheet(sheets: dict, order: list, name: str, df: pd.DataFrame, ndigits:
     order.append(name)
 
 def _available_sections() -> list[str]:
-    """Compute which sections exist, to pre-check them in the export UI."""
+    """Compute which sections exist (offered in the export dropdown)."""
     res = st.session_state.get("results", {})
     sections = []
     if "Train" in res:        sections += ["Training","Training_Metrics","Training_Summary"]
@@ -352,56 +352,49 @@ def build_export_workbook(selected: list[str], ndigits: int = 3, do_autofit: boo
     fname = f"YM_Export_{datetime.now().strftime('%Y%m%d_%H%M%S')}.xlsx"
     return bio.getvalue(), fname, order
 
-def render_export_button(phase_key: str, default_sections: list[str]) -> None:
-    """Export UI — dropdown checklists for sheets & options; fixed rounding=3."""
+# --------- SIMPLE export UI (dropdown checklist, starts empty) ----------
+def render_export_button(phase_key: str) -> None:
+    """
+    Export UI — one multiselect dropdown that starts EMPTY.
+    The download button is disabled until at least one sheet is selected.
+    """
+    res = st.session_state.get("results", {})
+    if not res:
+        return
+
     st.divider()
     st.markdown("### Export to Excel")
 
-    # ---- Dropdown checklist: sheets ----
-    all_sections = [
-        "Training","Training_Metrics","Training_Summary",
-        "Testing","Testing_Metrics","Testing_Summary",
-        "Validation","Validation_Metrics","Validation_Summary","Validation_OOR",
-        "Prediction","Prediction_Summary",
-        "Training_Ranges","Info"
-    ]
+    options = _available_sections()  # only what exists right now
     selected_sheets = st.multiselect(
         "Sheets to include",
-        options=all_sections,
-        default=default_sections,
-        help="Pick the sheets to include in the Excel export.",
+        options=options,
+        default=[],
+        placeholder="Choose an option",
+        help="Pick the sheets you want to include in the Excel export.",
         key=f"sheets_{phase_key}",
     )
 
-    # ---- Dropdown checklist: export options ----
-    export_options = st.multiselect(
-        "Export options",
-        options=[
-            "Auto-fit columns & freeze header",
-            "Append timestamp to filename",
-        ],
-        default=["Auto-fit columns & freeze header", "Append timestamp to filename"],
-        help="Choose extra export behaviors.",
-        key=f"opts_{phase_key}",
-    )
-    do_autofit  = "Auto-fit columns & freeze header" in export_options
-    add_stamp   = "Append timestamp to filename" in export_options
-
-    base_name = st.text_input("Base filename", value="YM_Export", key=f"basename_{phase_key}")
-
-    # Build workbook (fixed rounding=3)
-    data, _, names = build_export_workbook(selected=selected_sheets, ndigits=3, do_autofit=do_autofit)
+    if not selected_sheets:
+        st.caption("Select one or more sheets above to enable the export.")
+        st.download_button(
+            label="⬇️ Export Excel",
+            data=b"",
+            file_name="YM_Export.xlsx",
+            mime="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
+            disabled=True,
+            key=f"download_{phase_key}",
+        )
+        return
 
+    data, fname, names = build_export_workbook(selected=selected_sheets, ndigits=3, do_autofit=True)
     if names:
         st.caption("Will include: " + ", ".join(names))
 
-    suffix = "_" + datetime.now().strftime("%Y%m%d_%H%M%S") if add_stamp else ""
-    file_name = (base_name or "YM_Export") + suffix + ".xlsx"
-
     st.download_button(
         "⬇️ Export Excel",
         data=(data or b""),
-        file_name=file_name if data else "YM_Export.xlsx",
+        file_name=(fname or "YM_Export.xlsx"),
         mime="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
         disabled=(data is None),
         key=f"download_{phase_key}",
@@ -747,14 +740,14 @@ if st.session_state.app_step == "dev":
 
         st.session_state.results["Train"]=tr; st.session_state.results["Test"]=te
         st.session_state.results["m_train"]={
-            "R": pearson_r(tr[TARGET], tr[PRED_COL]),
+            "R":   pearson_r(tr[TARGET], tr[PRED_COL]),
             "RMSE": rmse(tr[TARGET], tr[PRED_COL]),
-            "MAE": mean_absolute_error(tr[TARGET], tr[PRED_COL])
+            "MAE":  mean_absolute_error(tr[TARGET], tr[PRED_COL])
         }
         st.session_state.results["m_test"]={
-            "R": pearson_r(te[TARGET], te[PRED_COL]),
+            "R":   pearson_r(te[TARGET], te[PRED_COL]),
             "RMSE": rmse(te[TARGET], te[PRED_COL]),
-            "MAE": mean_absolute_error(te[TARGET], te[PRED_COL])
+            "MAE":  mean_absolute_error(te[TARGET], te[PRED_COL])
         }
 
         tr_min = tr[FEATURES].min().to_dict(); tr_max = tr[FEATURES].max().to_dict()
@@ -794,9 +787,8 @@ if st.session_state.app_step == "dev":
             with tab2:
                 _dev_block(st.session_state.results["Test"], st.session_state.results["m_test"])
 
-        # Export UI for this phase
-        default_sections = _available_sections()
-        render_export_button(phase_key="dev", default_sections=default_sections)
+        # Export UI for this phase (dropdown checklist starts empty)
+        render_export_button(phase_key="dev")
 
 # =========================
 # VALIDATION (with actual Ym)
@@ -872,9 +864,8 @@ if st.session_state.app_step == "validate":
                 use_container_width=False
             )
 
-        # Export UI for this phase
-        default_sections = _available_sections()
-        render_export_button(phase_key="validate", default_sections=default_sections)
+        # Export UI for this phase (dropdown checklist starts empty)
+        render_export_button(phase_key="validate")
 
         sv = st.session_state.results["sv_val"]
         if sv["oor"] > 0: st.markdown('<div class="st-message-box st-warning">Some inputs fall outside **training min–max** ranges.</div>', unsafe_allow_html=True)
@@ -945,9 +936,8 @@ if st.session_state.app_step == "predict":
                 config={"displayModeBar": False, "scrollZoom": True}
             )
 
-        # Export UI for this phase
-        default_sections = _available_sections()
-        render_export_button(phase_key="predict", default_sections=default_sections)
+        # Export UI for this phase (dropdown checklist starts empty)
+        render_export_button(phase_key="predict")
 
 # =========================
 # Run preview modal after all other elements