fix(export): split XLSX sheets and stream worksheet XML

apps/desktop/src/lib/export/xlsxExport.ts

@@ -11,6 +11,13 @@ export interface XlsxWorksheetData {
   numericColumnRightAlign?: boolean;
 }
 
+interface XlsxWorksheetSegment {
+  worksheet: XlsxWorksheetData;
+  sheetName?: string;
+  rowStart: number;
+  rowEnd: number;
+}
+
 type ZipEntry = {
   path: string;
   data: Uint8Array;
@@ -20,6 +27,7 @@ type ZipEntry = {
 
 const encoder = new TextEncoder();
 const CRC_TABLE = buildCrcTable();
+const XLSX_MAX_DATA_ROWS = 1_048_575;
 
 function buildCrcTable(): number[] {
   const table: number[] = [];
@@ -84,15 +92,20 @@ function normalizeSheetName(value?: string): string {
   return name.slice(0, 31);
 }
 
-function normalizeUniqueSheetNames(sheets: readonly XlsxWorksheetData[]): string[] {
+function appendSheetSuffix(base: string, suffix: number): string {
+  const suffixText = ` (${suffix})`;
+  const maxBaseLength = Math.max(0, 31 - [...suffixText].length);
+  return `${[...base].slice(0, maxBaseLength).join("")}${suffixText}`;
+}
+
+function normalizeUniqueSheetNames(sheets: readonly { sheetName?: string }[]): string[] {
   const names: string[] = [];
   sheets.forEach((sheet, index) => {
     const base = normalizeSheetName(sheet.sheetName || `Sheet${index + 1}`);
     let candidate = base;
     let suffix = 2;
     while (names.includes(candidate)) {
-      const suffixText = ` (${suffix})`;
-      candidate = `${base.slice(0, 31 - suffixText.length)}${suffixText}`;
+      candidate = appendSheetSuffix(base, suffix);
       suffix += 1;
     }
     names.push(candidate);
@@ -100,10 +113,10 @@ function normalizeUniqueSheetNames(sheets: readonly XlsxWorksheetData[]): string
   return names;
 }
 
-function estimateColumnWidths(columns: readonly string[], rows: readonly (readonly XlsxCellValue[])[], columnComments?: readonly (string | null)[]): number[] {
+function estimateColumnWidths(columns: readonly string[], rows: readonly (readonly XlsxCellValue[])[], rowStart: number, rowEnd: number, columnComments?: readonly (string | null)[]): number[] {
   return columns.map((column, colIndex) => {
     const headerText = columnComments?.[colIndex] || column;
-    const values = rows.slice(0, 100).map((row) => row[colIndex]);
+    const values = Array.from({ length: Math.min(100, rowEnd - rowStart) }, (_, index) => rows[rowStart + index]?.[colIndex]);
     const maxLen = [headerText, ...values.map((value) => (value == null ? "" : String(value)))].map((value) => Math.min(value.length, 60)).reduce((max, length) => Math.max(max, length), 8);
     return Math.max(10, Math.min(60, maxLen + 2));
   });
@@ -143,22 +156,22 @@ function cellXml(value: XlsxCellValue, rowIndex: number, colIndex: number, style
   return `<c r="${ref}" t="inlineStr"${styleAttr}><is><t>${escapeXml(String(value))}</t></is></c>`;
 }
 
-function worksheetXml(data: XlsxWorksheetData): string {
+function worksheetXml(segment: XlsxWorksheetSegment): string {
+  const data = segment.worksheet;
   const columns = data.columns;
   const rows = data.rows;
-  const totalRows = rows.length + 1;
+  const totalRows = segment.rowEnd - segment.rowStart + 1;
   const range = sheetRange(columns.length, totalRows);
-  const widths = estimateColumnWidths(columns, rows, data.columnComments);
+  const widths = estimateColumnWidths(columns, rows, segment.rowStart, segment.rowEnd, data.columnComments);
   const rightAlignEnabled = data.numericColumnRightAlign !== false;
   const colsXml = widths.map((width, index) => `<col min="${index + 1}" max="${index + 1}" width="${width}" customWidth="1"/>`).join("");
   const headerXml = `<row r="1">${columns.map((column, index) => cellXml(data.columnComments?.[index] || column, 0, index, 1)).join("")}</row>`;
-  const bodyXml = rows
-    .map((row, rowIndex) => {
-      const excelRowIndex = rowIndex + 2;
-      const cells = columns.map((_, colIndex) => cellXml(row[colIndex], excelRowIndex - 1, colIndex, numericColumnStyle(data.columnTypes?.[colIndex], rightAlignEnabled), data.columnTypes?.[colIndex])).join("");
-      return `<row r="${excelRowIndex}">${cells}</row>`;
-    })
-    .join("");
+  const bodyXml = Array.from({ length: segment.rowEnd - segment.rowStart }, (_, rowIndex) => {
+    const row = rows[segment.rowStart + rowIndex]!;
+    const excelRowIndex = rowIndex + 2;
+    const cells = columns.map((_, colIndex) => cellXml(row[colIndex], excelRowIndex - 1, colIndex, numericColumnStyle(data.columnTypes?.[colIndex], rightAlignEnabled), data.columnTypes?.[colIndex])).join("");
+    return `<row r="${excelRowIndex}">${cells}</row>`;
+  }).join("");
 
   return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 <worksheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main">
@@ -171,6 +184,30 @@ function worksheetXml(data: XlsxWorksheetData): string {
 </worksheet>`;
 }
 
+function splitWorksheetsForMaxRows(sheets: readonly XlsxWorksheetData[], maxDataRowsPerSheet: number): XlsxWorksheetSegment[] {
+  const maxRows = Number.isFinite(maxDataRowsPerSheet) ? Math.max(1, Math.floor(maxDataRowsPerSheet)) : XLSX_MAX_DATA_ROWS;
+  const segments: XlsxWorksheetSegment[] = [];
+
+  for (const worksheet of sheets) {
+    if (worksheet.rows.length <= maxRows) {
+      segments.push({ worksheet, sheetName: worksheet.sheetName, rowStart: 0, rowEnd: worksheet.rows.length });
+      continue;
+    }
+
+    const baseName = normalizeSheetName(worksheet.sheetName);
+    for (let rowStart = 0, chunkIndex = 0; rowStart < worksheet.rows.length; rowStart += maxRows, chunkIndex += 1) {
+      segments.push({
+        worksheet,
+        sheetName: chunkIndex === 0 ? baseName : appendSheetSuffix(baseName, chunkIndex + 1),
+        rowStart,
+        rowEnd: Math.min(rowStart + maxRows, worksheet.rows.length),
+      });
+    }
+  }
+
+  return segments;
+}
+
 function contentTypesXml(sheetCount = 1): string {
   const worksheetOverrides = Array.from({ length: sheetCount }, (_, index) => `  <Override PartName="/xl/worksheets/sheet${index + 1}.xml" ContentType="application/vnd.openxmlformats-officedocument.spreadsheetml.worksheet+xml"/>`).join("\n");
   return `<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
@@ -278,14 +315,19 @@ export function buildXlsxWorkbook(data: XlsxWorksheetData): Uint8Array {
 }
 
 export function buildXlsxWorkbookMulti(sheets: readonly XlsxWorksheetData[]): Uint8Array {
+  return buildXlsxWorkbookMultiWithMaxRows(sheets, XLSX_MAX_DATA_ROWS);
+}
+
+export function buildXlsxWorkbookMultiWithMaxRows(sheets: readonly XlsxWorksheetData[], maxDataRowsPerSheet: number): Uint8Array {
   if (sheets.length === 0) throw new Error("At least one worksheet is required");
-  const sheetNames = normalizeUniqueSheetNames(sheets);
+  const segments = splitWorksheetsForMaxRows(sheets, maxDataRowsPerSheet);
+  const sheetNames = normalizeUniqueSheetNames(segments);
   return createZip([
-    { path: "[Content_Types].xml", content: contentTypesXml(sheets.length) },
+    { path: "[Content_Types].xml", content: contentTypesXml(segments.length) },
     { path: "_rels/.rels", content: rootRelsXml() },
     { path: "xl/workbook.xml", content: workbookXml(sheetNames) },
-    { path: "xl/_rels/workbook.xml.rels", content: workbookRelsXml(sheets.length) },
+    { path: "xl/_rels/workbook.xml.rels", content: workbookRelsXml(segments.length) },
     { path: "xl/styles.xml", content: stylesXml() },
-    ...sheets.map((sheet, index) => ({ path: `xl/worksheets/sheet${index + 1}.xml`, content: worksheetXml(sheet) })),
+    ...segments.map((segment, index) => ({ path: `xl/worksheets/sheet${index + 1}.xml`, content: worksheetXml(segment) })),
   ]);
 }