src/main/java/com/primefactorsolutions/views/PendingRequestsListView.java

@@ -8,6 +8,8 @@ import com.primefactorsolutions.views.util.MenuBarUtils;
 import com.vaadin.flow.component.ClickEvent;
 import com.vaadin.flow.component.Component;
 import com.vaadin.flow.component.ComponentEventListener;
+import com.vaadin.flow.component.UI;
+import com.vaadin.flow.component.button.Button;
 import com.vaadin.flow.component.combobox.ComboBox;
 import com.vaadin.flow.component.contextmenu.MenuItem;
 import com.vaadin.flow.component.icon.VaadinIcon;
@@ -17,11 +19,23 @@ import com.vaadin.flow.component.orderedlayout.HorizontalLayout;
 import com.vaadin.flow.function.ValueProvider;
 import com.vaadin.flow.router.PageTitle;
 import com.vaadin.flow.router.Route;
+import com.vaadin.flow.server.StreamRegistration;
+import com.vaadin.flow.server.StreamResource;
 import com.vaadin.flow.spring.annotation.SpringComponent;
 import jakarta.annotation.security.PermitAll;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.usermodel.Workbook;
+import org.apache.poi.xssf.usermodel.XSSFWorkbook;
 import org.springframework.context.annotation.Scope;
 import org.vaadin.firitin.components.grid.PagingGrid;
 
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.time.LocalDate;
 import java.util.*;
 import java.util.stream.Collectors;
 
@@ -54,6 +68,8 @@ public class PendingRequestsListView extends BaseView {
     }
 
     private void initializeView() {
+        Button downloadButton = new Button("Descargar reporte de rechazos", event -> downloadReport());
+        getCurrentPageLayout().add(downloadButton);
         setupFilters();
         setupPendingRequestsGrid();
     }
@@ -221,4 +237,50 @@ public class PendingRequestsListView extends BaseView {
         allTeamsOption.setName("TODOS");
         return allTeamsOption;
     }
+
+    private void downloadReport() {
+        StreamResource resource = generateGeneralVacationReport();
+        getUI().ifPresent(ui -> openDocumentStream(resource, ui));
+    }
+
+    private StreamResource generateGeneralVacationReport() {
+        List<TimeOffRequest> requests = requestService.findAllTimeOffRequests().stream()
+                .filter(request -> request.getState() == TimeOffRequestStatus.RECHAZADO)
+                .collect(Collectors.toList());
+        ByteArrayInputStream excelStream = generateExcelReport(requests);
+        return new StreamResource("reporte_de_solicitudes_rechazadas_" + LocalDate.now() + ".xlsx",
+                () -> excelStream);
+    }
+
+    private void openDocumentStream(final StreamResource resource, final UI ui) {
+        StreamRegistration registration = ui.getSession().getResourceRegistry().registerResource(resource);
+        ui.getPage().open(registration.getResourceUri().toString());
+    }
+
+    private ByteArrayInputStream generateExcelReport(final List<TimeOffRequest> requests) {
+        try (Workbook workbook = new XSSFWorkbook()) {
+            Sheet sheet = workbook.createSheet("REPORTE_DE_SOLICITUDES_DE_VACACIONES_RECHAZADAS");
+            Row headerRow = sheet.createRow(0);
+
+            String[] headers = {"Empleado", "Categoria", "Observaciones"};
+            for (int i = 0; i < headers.length; i++) {
+                Cell cell = headerRow.createCell(i);
+                cell.setCellValue(headers[i]);
+            }
+
+            int rowIndex = 1;
+            for (TimeOffRequest request : requests) {
+                Row row = sheet.createRow(rowIndex++);
+                row.createCell(0).setCellValue(getEmployeeFullName(request));
+                row.createCell(1).setCellValue(getCategory(request));
+            }
+
+            try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {
+                workbook.write(out);
+                return new ByteArrayInputStream(out.toByteArray());
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException("Error al generar el archivo Excel", e);
+        }
+    }
 }