Restructure frontend code to allow for extensions (#4721)

# Description of Changes
Move frontend code into `core` folder and add infrastructure for
`proprietary` folder to include premium, non-OSS features

frontend/src/core/hooks/tools/addWatermark/useAddWatermarkOperation.ts

@@ -0,0 +1,52 @@
+import { useTranslation } from 'react-i18next';
+import { ToolType, useToolOperation } from '@app/hooks/tools/shared/useToolOperation';
+import { createStandardErrorHandler } from '@app/utils/toolErrorHandler';
+import { AddWatermarkParameters, defaultParameters } from '@app/hooks/tools/addWatermark/useAddWatermarkParameters';
+
+// Static function that can be used by both the hook and automation executor
+export const buildAddWatermarkFormData = (parameters: AddWatermarkParameters, file: File): FormData => {
+  const formData = new FormData();
+  formData.append("fileInput", file);
+
+  // Required: watermarkType as string
+  formData.append("watermarkType", parameters.watermarkType || "text");
+
+  // Add watermark content based on type
+  if (parameters.watermarkType === 'text') {
+    formData.append("watermarkText", parameters.watermarkText);
+  } else if (parameters.watermarkType === 'image' && parameters.watermarkImage) {
+    formData.append("watermarkImage", parameters.watermarkImage);
+  }
+
+  // Required parameters with correct formatting
+  formData.append("fontSize", parameters.fontSize.toString());
+  formData.append("rotation", parameters.rotation.toString());
+  formData.append("opacity", (parameters.opacity / 100).toString()); // Convert percentage to decimal
+  formData.append("widthSpacer", parameters.widthSpacer.toString());
+  formData.append("heightSpacer", parameters.heightSpacer.toString());
+
+  // Backend-expected parameters from user input
+  formData.append("alphabet", parameters.alphabet);
+  formData.append("customColor", parameters.customColor);
+  formData.append("convertPDFToImage", parameters.convertPDFToImage.toString());
+
+  return formData;
+};
+
+// Static configuration object
+export const addWatermarkOperationConfig = {
+  toolType: ToolType.singleFile,
+  buildFormData: buildAddWatermarkFormData,
+  operationType: 'watermark',
+  endpoint: '/api/v1/security/add-watermark',
+  defaultParameters,
+} as const;
+
+export const useAddWatermarkOperation = () => {
+  const { t } = useTranslation();
+
+  return useToolOperation<AddWatermarkParameters>({
+    ...addWatermarkOperationConfig,
+    getErrorMessage: createStandardErrorHandler(t('watermark.error.failed', 'An error occurred while adding watermark to the PDF.'))
+  });
+};

frontend/src/core/hooks/tools/addWatermark/useAddWatermarkParameters.ts

@@ -0,0 +1,49 @@
+import { BaseParameters } from '@app/types/parameters';
+import { useBaseParameters, BaseParametersHook } from '@app/hooks/tools/shared/useBaseParameters';
+
+export interface AddWatermarkParameters extends BaseParameters {
+  watermarkType?: 'text' | 'image';
+  watermarkText: string;
+  watermarkImage?: File;
+  fontSize: number; // Used for both text size and image size
+  rotation: number;
+  opacity: number;
+  widthSpacer: number;
+  heightSpacer: number;
+  alphabet: string;
+  customColor: string;
+  convertPDFToImage: boolean;
+}
+
+export const defaultParameters: AddWatermarkParameters = {
+  watermarkType: undefined,
+  watermarkText: '',
+  fontSize: 12,
+  rotation: 0,
+  opacity: 50,
+  widthSpacer: 50,
+  heightSpacer: 50,
+  alphabet: 'roman',
+  customColor: '#d3d3d3',
+  convertPDFToImage: false
+};
+
+export type AddWatermarkParametersHook = BaseParametersHook<AddWatermarkParameters>;
+
+export const useAddWatermarkParameters = (): AddWatermarkParametersHook => {
+  return useBaseParameters({
+    defaultParameters: defaultParameters,
+    endpointName: 'add-watermark',
+    validateFn: (params): boolean => {
+      if (!params.watermarkType) {
+        return false;
+      }
+      if (params.watermarkType === 'text') {
+        return params.watermarkText.trim().length > 0;
+      } else {
+        return params.watermarkImage !== undefined;
+      }
+    },
+  });
+};
+