add export grid service

backend/src/main/java/ru/micord/ervu_dashboard/service/ExportGridV2Service.java

@@ -0,0 +1,171 @@
+package ru.micord.ervu_dashboard.service;
+
+import model.FileModel;
+import model.grid.GridColumnAggregationValues;
+import model.grid.GridDataExportFormat;
+import model.grid.GridRow;
+import model.grid.GridRows;
+import org.apache.poi.hssf.usermodel.HSSFWorkbook;
+import org.apache.poi.ss.usermodel.*;
+import org.apache.poi.xssf.streaming.SXSSFWorkbook;
+import property.grid.GridColumn;
+import service.GridV2ServiceImpl;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.time.LocalDate;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Base64;
+import java.util.Date;
+import java.util.List;
+
+public class ExportGridV2Service extends GridV2ServiceImpl {
+
+    protected FileModel getFileModelWithContent(String[] columnIdsToExport,
+                                                GridDataExportFormat exportFormat, GridRows gridRows) {
+        FileModel fileModel = new FileModel();
+        fileModel.setFileId(this.getObjectId());
+
+        switch (exportFormat) {
+            case XLS:
+                fileModel.setFileExtension(".xls");
+                fileModel.setFileContent(getXlsContent(columnIdsToExport, gridRows));
+                break;
+            case XLSX:
+                fileModel.setFileExtension(".xlsx");
+                fileModel.setFileContent(getXlsxContent(columnIdsToExport, gridRows));
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown export format = " + exportFormat);
+        }
+        fileModel.setFileName(
+                LocalDate.now().format(DateTimeFormatter.ofPattern("dd.MM.yyyy"))
+                        + fileModel.fileExtension);
+        fileModel.setIsImage(false);
+
+        return fileModel;
+    }
+
+
+    private String getXlsxContent(String[] columnIdsToExport, GridRows gridRows) {
+        return getExcelContent(columnIdsToExport, gridRows, new SXSSFWorkbook());
+    }
+
+    private String getXlsContent(String[] columnIdsToExport, GridRows gridRows) {
+        return getExcelContent(columnIdsToExport, gridRows, new HSSFWorkbook());
+    }
+
+    private String getExcelContent(String[] columnIdsToExport, GridRows gridRows,
+                                   Workbook workbook) {
+        List<GridColumn> orderedColumns = getOrderedColumns(columnIdsToExport);
+        Sheet sheet = workbook.createSheet();
+        writeHeaderLine(workbook, sheet, orderedColumns, gridRows.getAggregationValues() != null);
+        writeDataLines(workbook, sheet, orderedColumns, gridRows);
+
+        try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
+            workbook.write(bos);
+            return Base64.getEncoder().encodeToString(bos.toByteArray());
+        }
+        catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void autosizeByHeader(Sheet sheet, int columnIndex, String header, int minChars, int padding) {
+        int length = header != null ? header.length() : 0;
+
+        // Берём максимум из (минимальная ширина, длина заголовка + отступ)
+        int finalWidth = Math.max(minChars, length + padding);
+
+        sheet.setColumnWidth(columnIndex, finalWidth * 256);
+    }
+
+    private void writeHeaderLine(Workbook workbook, Sheet sheet,
+                                 List<GridColumn> orderedColumns, boolean hasAggregationValues) {
+        Row row = sheet.createRow(0);
+        CellStyle style = createBoldStyle(workbook);
+        int minWidth = 20;
+        int padding  = 5;
+
+        int colIndex = hasAggregationValues ? 1 : 0;
+        for (GridColumn column : orderedColumns) {
+            createCell(row, colIndex, column.displayName, style);
+            autosizeByHeader(sheet, colIndex, column.displayName, minWidth, padding);
+            colIndex++;
+        }
+    }
+
+    private void createCell(Row row, int columnCount, Object value, CellStyle style) {
+        Cell cell = row.createCell(columnCount);
+
+        if (value == null) {
+            cell.setBlank();
+        }
+        else if (value instanceof Number) {
+            cell.setCellValue(((Number) value).doubleValue());
+        }
+        else if (value instanceof Boolean) {
+            cell.setCellValue((Boolean) value);
+        }
+        else if (value instanceof Date) {
+            cell.setCellValue((Date) value);
+        }
+        else if (value instanceof LocalDate) {
+            cell.setCellValue((LocalDate) value);
+        }
+        else if (value instanceof LocalDateTime) {
+            cell.setCellValue((LocalDateTime) value);
+        }
+        else {
+            cell.setCellValue(value.toString());
+        }
+        cell.setCellStyle(style);
+    }
+
+    private void writeDataLines(Workbook workbook, Sheet sheet,
+                                List<GridColumn> orderedColumns, GridRows gridRows) {
+        int rowCount = 1;
+
+        CellStyle style = workbook.createCellStyle();
+        style.setWrapText(true);
+        style.setAlignment(HorizontalAlignment.CENTER);
+        style.setVerticalAlignment(VerticalAlignment.CENTER);
+        GridColumnAggregationValues aggregationValues = gridRows.getAggregationValues();
+
+        for (GridRow gridRow : gridRows.getRows()) {
+            int columnCount = aggregationValues != null ? 1 : 0;
+            Row row = sheet.createRow(rowCount++);
+            row.setHeight((short) -1);
+            for (GridColumn gridColumn : orderedColumns) {
+                createCell(row, columnCount,
+                        gridRow.get(getClientColumnId(gridColumn)), style
+                );
+                columnCount++;
+            }
+        }
+
+        if (aggregationValues != null) {
+            Row aggregationRow = sheet.createRow(rowCount);
+            CellStyle boldStyle = createBoldStyle(workbook);
+            createCell(aggregationRow, 0, aggregationHeaderForExport, boldStyle);
+
+            int columnCount = 1;
+            for (GridColumn gridColumn : orderedColumns) {
+                createCell(aggregationRow, columnCount,
+                        aggregationValues.get(getClientColumnId(gridColumn)), boldStyle
+                );
+                columnCount++;
+            }
+        }
+    }
+
+    private CellStyle createBoldStyle(Workbook workbook) {
+        CellStyle boldStyle = workbook.createCellStyle();
+        Font font = workbook.createFont();
+        font.setBold(true);
+        boldStyle.setFont(font);
+        boldStyle.setAlignment(HorizontalAlignment.CENTER);
+        return boldStyle;
+    }
+}