Add document splitting functionality to the multi-tools page (#1808)

* Add a split button on top of the insert button in multitool viewer.

* Add placeholder splitFileButtonCallback method.

* Remove unused splitFileButtonContainer element.

* Add this binding to setActions for splitFileButtonCallback

* Add test log for adding separators.

* Add test log for adding separators.

* Remove test logs and add visual indicators to separators instead.

* Add splitting functionality to multi-tools.

* Prevent trying to split from index 0.

* Hide the split button for the first page to avoid confusion.

* Change the class name 'cutBefore' to 'split-before' to fall mroe in line with already existing classes.

* Add dummy methods for splitting and compressing documents.

* Remove form submission, begin work on client side splitting.

* Add client side document splitting.

* Add client side archiving for the split documents.

* Fix a bug that adds an empty page to splitted documents due to a sorting error.

* Add a 'Split All' button and the relevant functionality.

---------

Co-authored-by: kazandaki <ahmetfiratusta@gmail.com>
Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>

src/main/resources/static/css/multi-tool.css

@@ -127,6 +127,19 @@ label {
   margin-bottom: 16px;
 }
 
+.page-container.split-before {
+  border-left: 1px dashed var(--md-sys-color-on-surface);
+  padding-left: -1px;
+}
+
+.page-container.split-before:first-child {
+  border-left: none;
+}
+
+.page-container:first-child .pdf-actions_split-file-button {
+  display: none;
+}
+
 /* Pushes the last item to the left */
 .page-container:last-child {
   margin-right: auto;
@@ -171,6 +184,7 @@ label {
 .page-container:last-child:lang(nqo),
 /* N'Ko */
 .page-container:last-child:lang(bqi)
+
 /* Bakhtiari */
   {
   margin-left: auto !important;

src/main/resources/static/css/pdfActions.css

@@ -117,3 +117,12 @@ html[dir="rtl"] .pdf-actions_container:last-child>.pdf-actions_insert-file-butto
   aspect-ratio: 1;
   border-radius: 100px;
 }
+
+.pdf-actions_split-file-button {
+  position: absolute;
+  top: 25%;
+  right: 50%;
+  translate: 0 -50%;
+  aspect-ratio: 1;
+  border-radius: 100px;
+}

src/main/resources/static/js/multitool/PdfActionsManager.js

@@ -73,7 +73,12 @@ class PdfActionsManager {
     this.addFiles(imgContainer);
   }
 
-  setActions({ movePageTo, addFiles, rotateElement }) {
+  splitFileButtonCallback(e) {
+    var imgContainer = this.getPageContainer(e.target);
+    imgContainer.classList.toggle("split-before");
+  }
+
+  setActions({ movePageTo, addPdfs, rotateElement }) {
     this.movePageTo = movePageTo;
     this.addFiles = addFiles;
     this.rotateElement = rotateElement;
@@ -84,6 +89,7 @@ class PdfActionsManager {
     this.rotateCWButtonCallback = this.rotateCWButtonCallback.bind(this);
     this.deletePageButtonCallback = this.deletePageButtonCallback.bind(this);
     this.insertFileButtonCallback = this.insertFileButtonCallback.bind(this);
+    this.splitFileButtonCallback = this.splitFileButtonCallback.bind(this);
   }
 
   adapt(div) {
@@ -140,6 +146,12 @@ class PdfActionsManager {
     insertFileButton.onclick = this.insertFileButtonCallback;
     insertFileButtonContainer.appendChild(insertFileButton);
 
+    const splitFileButton = document.createElement("button");
+    splitFileButton.classList.add("btn", "btn-primary", "pdf-actions_split-file-button");
+    splitFileButton.innerHTML = `<span class="material-symbols-rounded">cut</span>`;
+    splitFileButton.onclick = this.splitFileButtonCallback;
+    insertFileButtonContainer.appendChild(splitFileButton);
+
     div.appendChild(insertFileButtonContainer);
 
     // add this button to every element, but only show it on the last one :D

src/main/resources/static/js/multitool/PdfContainer.js

@@ -19,6 +19,9 @@ class PdfContainer {
     this.setDownloadAttribute = this.setDownloadAttribute.bind(this);
     this.preventIllegalChars = this.preventIllegalChars.bind(this);
     this.addImageFile = this.addImageFile.bind(this);
+    this.nameAndArchiveFiles = this.nameAndArchiveFiles.bind(this);
+    this.splitPDF = this.splitPDF.bind(this);
+    this.splitAll = this.splitAll.bind(this);
 
     this.pdfAdapters = pdfAdapters;
 
@@ -34,6 +37,7 @@ class PdfContainer {
     window.addFiles = this.addFiles;
     window.exportPdf = this.exportPdf;
     window.rotateAll = this.rotateAll;
+    window.splitAll = this.splitAll;
 
     const filenameInput = document.getElementById("filename-input");
     const downloadBtn = document.getElementById("export-button");
@@ -212,6 +216,61 @@ class PdfContainer {
     }
   }
 
+  splitAll() {
+    const allPages = this.pagesContainer.querySelectorAll(".page-container");
+    if (this.pagesContainer.querySelectorAll(".split-before").length > 0) {
+      allPages.forEach(page => {
+        page.classList.remove("split-before");
+      });
+    } else {
+      allPages.forEach(page => {
+        page.classList.add("split-before");
+      });
+    }
+  }
+
+  async splitPDF(baseDocBytes, splitters) {
+    const baseDocument = await PDFLib.PDFDocument.load(baseDocBytes);
+    const pageNum = baseDocument.getPages().length;
+
+    splitters.sort((a, b) => a - b);; // We'll sort the separator indexes just in case querySelectorAll does something funny.
+    splitters.push(pageNum); // We'll also add a faux separator at the end in order to get the pages after the last separator.
+
+    const splitDocuments = [];
+    for (const splitterPosition of splitters) {
+      const subDocument = await PDFLib.PDFDocument.create();
+
+      const splitterIndex = splitters.indexOf(splitterPosition);
+
+      let firstPage = splitterIndex === 0 ? 0 : splitters[splitterIndex - 1];
+
+      const pageIndices = Array.from({ length: splitterPosition - firstPage }, (value, key) => firstPage + key);
+
+      const copiedPages = await subDocument.copyPages(baseDocument, pageIndices);
+
+      copiedPages.forEach(copiedPage => {
+        subDocument.addPage(copiedPage);
+      });
+
+      const subDocumentBytes = await subDocument.save();
+
+      splitDocuments.push(subDocumentBytes);
+    };
+
+    return splitDocuments;
+  }
+
+  async nameAndArchiveFiles(pdfBytesArray, baseNameString) {
+    const zip = new JSZip();
+
+    for (let i = 0; i < pdfBytesArray.length; i++) {
+      const documentBlob = new Blob([pdfBytesArray[i]], { type: "application/pdf" });
+      zip.file(baseNameString + "-" + (i + 1) + ".pdf", documentBlob);
+    }
+
+    return zip;
+  }
+
   async exportPdf() {
     const pdfDoc = await PDFLib.PDFDocument.create();
     const pageContainers = this.pagesContainer.querySelectorAll(".page-container"); // Select all .page-container elements
@@ -262,8 +321,6 @@ class PdfContainer {
     }
     const pdfBytes = await pdfDoc.save();
     const pdfBlob = new Blob([pdfBytes], { type: "application/pdf" });
-    const url = URL.createObjectURL(pdfBlob);
-    const downloadOption = localStorage.getItem("downloadOption");
 
     const filenameInput = document.getElementById("filename-input");
 
@@ -280,6 +337,37 @@ class PdfContainer {
       this.fileName = filenameInput.value;
     }
 
+    const separators = this.pagesContainer.querySelectorAll(".split-before");
+    if (separators.length !== 0) { // Split the pdf if there are separators.
+      const baseName = this.fileName ? this.fileName : "managed";
+
+      const pagesArray = Array.from(this.pagesContainer.children);
+      const splitters = [];
+      separators.forEach(page => {
+        const pageIndex = pagesArray.indexOf(page);
+        if (pageIndex !== 0) {
+          splitters.push(pageIndex);
+        }
+      });
+
+      const splitDocuments = await this.splitPDF(pdfBytes, splitters);
+      const archivedDocuments = await this.nameAndArchiveFiles(splitDocuments, baseName);
+
+      const self = this;
+      archivedDocuments.generateAsync({ type: "base64" }).then(function (base64) {
+        const url = "data:application/zip;base64," + base64;
+        self.downloadLink = document.createElement("a");
+        self.downloadLink.href = url;
+        self.downloadLink.setAttribute("download", baseName + ".zip");
+        self.downloadLink.setAttribute("target", "_blank");
+        self.downloadLink.click();
+      });
+
+    } else { // Continue normally if there are no separators
+
+      const url = URL.createObjectURL(pdfBlob);
+      const downloadOption = localStorage.getItem("downloadOption");
+
       if (!filenameInput.value.includes(".pdf")) {
         filenameInput.value = filenameInput.value + ".pdf";
         this.fileName = filenameInput.value;
@@ -304,6 +392,7 @@ class PdfContainer {
         this.downloadLink.click();
       }
     }
+  }
 
 
   setDownloadAttribute() {

src/main/resources/templates/multi-tool.html

@@ -42,6 +42,11 @@
                       rotate_right
                     </span>
                   </button>
+                  <button class="btn btn-secondary enable-on-file" onclick="splitAll()" disabled>
+                    <span class="material-symbols-rounded">
+                      cut
+                    </span>
+                  </button>
                   <button id="export-button" class="btn btn-primary enable-on-file" onclick="exportPdf()" disabled>
                     <span class="material-symbols-rounded">
                       download