feat: add browser implementations for advanced tools

frontend/src/utils/pdfOperations/split.ts

@@ -0,0 +1,75 @@
+import { PDFDocument } from 'pdf-lib';
+import type { SplitParameters } from '../../hooks/tools/split/useSplitParameters';
+import { resolvePageNumbers, validatePageNumbers } from '../pageSelection';
+import { createFileFromApiResponse } from '../fileResponseUtils';
+
+const PDF_MIME_TYPE = 'application/pdf';
+
+const getSplitPoints = (pages: string, totalPages: number): number[] | null => {
+  if (!pages.trim()) {
+    return Array.from({ length: totalPages }, (_, idx) => idx);
+  }
+
+  if (!validatePageNumbers(pages)) {
+    return null;
+  }
+
+  const resolved = resolvePageNumbers(pages, totalPages);
+  if (!resolved) {
+    return null;
+  }
+
+  const sorted = Array.from(new Set(resolved)).sort((a, b) => a - b);
+  if (sorted[sorted.length - 1] !== totalPages - 1) {
+    sorted.push(totalPages - 1);
+  }
+  return sorted;
+};
+
+export async function splitPdfClientSide(
+  params: SplitParameters,
+  files: File[]
+): Promise<File[]> {
+  return Promise.all(
+    files.flatMap(async (file) => {
+      const bytes = await file.arrayBuffer();
+      const pdfDoc = await PDFDocument.load(bytes, { ignoreEncryption: true });
+      const totalPages = pdfDoc.getPageCount();
+      const splitPoints = getSplitPoints(params.pages, totalPages);
+
+      if (!splitPoints || splitPoints.length === 0) {
+        throw new Error('Invalid page selection for split');
+      }
+
+      const outputs: File[] = [];
+      let previous = 0;
+      let partIndex = 1;
+
+      for (const splitPoint of splitPoints) {
+        if (splitPoint < previous) continue;
+        const segment = await PDFDocument.create();
+        const indexes: number[] = [];
+        for (let i = previous; i <= Math.min(splitPoint, totalPages - 1); i += 1) {
+          indexes.push(i);
+        }
+
+        if (indexes.length === 0) {
+          continue;
+        }
+
+        const copiedPages = await segment.copyPages(pdfDoc, indexes);
+        copiedPages.forEach((p) => segment.addPage(p));
+        const segmentBytes = await segment.save();
+        const baseName = file.name.replace(/\.[^.]+$/, '');
+        const outputName = `${baseName}_${partIndex}.pdf`;
+        outputs.push(
+          createFileFromApiResponse(segmentBytes, { 'content-type': PDF_MIME_TYPE }, outputName)
+        );
+        previous = splitPoint + 1;
+        partIndex += 1;
+      }
+
+      return outputs;
+    })
+  ).then((nested) => nested.flat());
+}