[IMP] account_statement_import_sheet_file_bg: Filter empty rows by date column

Stop processing Excel rows when timestamp column is empty

Previously, the import would process all rows in the Excel file until
the end, including thousands of empty rows. This caused performance
issues and unnecessary data processing.

Now the system:
- Identifies the date/timestamp column from sheet_mapping_id configuration
- Only processes rows where the timestamp column has a value
- Stops processing at the first empty timestamp row

This prevents importing empty rows and improves performance when
handling Excel files with many empty rows at the end.

closes #356

X-original-commit: ded1456
Signed-off-by: Filoquin adhoc <maq@adhoc.com.ar>
Signed-off-by: rov-adhoc <rov@adhoc.com.ar>

Author: rov-adhoc

account_statement_import_sheet_file_bg/models/account_statement_import.py

@@ -126,7 +126,8 @@ def import_file_button(self, wizard_data=None):
 
     def split_base64_excel(self, header_rows_count, rows_per_file_limit):
         """Split Excel file into multiple parts to avoid overloading the system.
-        Returns empty list if file is not a valid Excel or if split is not needed."""
+        Returns empty list if file is not a valid Excel or if split is not needed.
+        Only processes rows where the date column is not empty."""
         if not self.statement_file:
             return []
 
@@ -145,6 +146,16 @@ def split_base64_excel(self, header_rows_count, rows_per_file_limit):
 
         header_rows = all_rows[:header_rows_count]
         data_rows = all_rows[header_rows_count:]
+
+        # Get the date column index from the sheet mapping using the parser's method
+        parser = self.env["account.statement.import.sheet.parser"]
+        header = parser.parse_header((input_workbook, input_worksheet), self.sheet_mapping_id)
+        date_column_indexes = parser._get_column_indexes(header, "timestamp_column", self.sheet_mapping_id)
+        date_column_index = date_column_indexes[0] if date_column_indexes else None
+
+        # Filter out rows where the date column is empty
+        data_rows = self._filter_rows_with_date(data_rows, date_column_index)
+
         start_row_index = 0
         total_data_rows = len(data_rows)
 
@@ -171,3 +182,20 @@ def split_base64_excel(self, header_rows_count, rows_per_file_limit):
 
             start_row_index = end_row_index
         return output_base64_list
+
+    def _filter_rows_with_date(self, data_rows, date_column_index):
+        """Filter data rows to only include rows where the date column is not empty.
+        If date_column_index is None, return all rows."""
+        if date_column_index is None:
+            return data_rows
+
+        filtered_rows = []
+        for row in data_rows:
+            # Check if the row has enough columns and the date column is not empty
+            if len(row) > date_column_index and row[date_column_index].value:
+                filtered_rows.append(row)
+            elif len(row) > date_column_index and not row[date_column_index].value:
+                # Stop processing when we find the first empty date
+                break
+
+        return filtered_rows