// Hook: AfterCalculation
// Halt the job if the Summary total cell is blank or zero after calculation.
//
// Empty totals usually indicate a datasource connection problem. Catching the
// problem here prevents an empty report from reaching an executive inbox.

var sheet = Workbook.Worksheets["Summary"];
if (sheet == null)
{
    AddWarning("Sheet 'Summary' not found - skipping total validation.");
    return;
}

var totalCell = sheet.Cells["B2"];
if (totalCell.Type == CellValueType.IsNull ||
    (totalCell.Type == CellValueType.IsNumeric && totalCell.DoubleValue == 0))
{
    AddError("Summary!B2 is zero or blank after calculation. This usually indicates a datasource connection problem. Job halted.");
}

Logger.LogInformation($"Total validation passed - B2 = {totalCell.Value}");