73014: MetadataPatchOperationService create patch in two steps to fix remove operation issue

src/app/+item-page/edit-item-page/item-metadata/edit-in-place-field/edit-in-place-field.component.ts

@@ -11,7 +11,6 @@ import { NgModel } from '@angular/forms';
 import { MetadatumViewModel } from '../../../../core/shared/metadata.models';
 import { MetadataField } from '../../../../core/metadata/metadata-field.model';
 import { InputSuggestion } from '../../../../shared/input-suggestions/input-suggestions.model';
-import { METADATA_PATCH_OPERATION_SERVICE_TOKEN } from '../../../../core/data/object-updates/patch-operation-service/metadata-patch-operation.service';
 
 @Component({
   // tslint:disable-next-line:component-selector
@@ -76,7 +75,7 @@ export class EditInPlaceFieldComponent implements OnInit, OnChanges {
    * Sends a new change update for this field to the object updates service
    */
   update(ngModel?: NgModel) {
-    this.objectUpdatesService.saveChangeFieldUpdate(this.url, cloneDeep(this.metadata), METADATA_PATCH_OPERATION_SERVICE_TOKEN);
+    this.objectUpdatesService.saveChangeFieldUpdate(this.url, cloneDeep(this.metadata));
     if (hasValue(ngModel)) {
       this.checkValidity(ngModel);
     }
@@ -104,7 +103,7 @@ export class EditInPlaceFieldComponent implements OnInit, OnChanges {
    * Sends a new remove update for this field to the object updates service
    */
   remove() {
-    this.objectUpdatesService.saveRemoveFieldUpdate(this.url, cloneDeep(this.metadata), METADATA_PATCH_OPERATION_SERVICE_TOKEN);
+    this.objectUpdatesService.saveRemoveFieldUpdate(this.url, cloneDeep(this.metadata));
   }
 
   /**

src/app/+item-page/edit-item-page/item-metadata/item-metadata.component.ts

@@ -94,14 +94,14 @@ export class ItemMetadataComponent extends AbstractItemUpdateComponent {
    * @param metadata The metadata to add, if no parameter is supplied, create a new Metadatum
    */
   add(metadata: MetadatumViewModel = new MetadatumViewModel()) {
-    this.objectUpdatesService.saveAddFieldUpdate(this.url, metadata, METADATA_PATCH_OPERATION_SERVICE_TOKEN);
+    this.objectUpdatesService.saveAddFieldUpdate(this.url, metadata);
   }
 
   /**
    * Sends all initial values of this item to the object updates service
    */
   public initializeOriginalFields() {
-    this.objectUpdatesService.initialize(this.url, this.item.metadataAsList, this.item.lastModified);
+    this.objectUpdatesService.initialize(this.url, this.item.metadataAsList, this.item.lastModified, METADATA_PATCH_OPERATION_SERVICE_TOKEN);
   }
 
   /**

src/app/core/data/object-updates/object-updates.actions.ts

@@ -40,7 +40,8 @@ export class InitializeFieldsAction implements Action {
   payload: {
     url: string,
     fields: Identifiable[],
-    lastModified: Date
+    lastModified: Date,
+    patchOperationServiceToken?: InjectionToken<PatchOperationService>
   };
 
   /**
@@ -50,16 +51,15 @@ export class InitializeFieldsAction implements Action {
    *    the unique url of the page for which the fields are being initialized
    * @param fields The identifiable fields of which the updates are kept track of
    * @param lastModified The last modified date of the object that belongs to the page
-   * @param order A custom order to keep track of objects moving around
-   * @param pageSize The page size used to fill empty pages for the custom order
-   * @param page The first page to populate in the custom order
+   * @param patchOperationServiceToken An InjectionToken referring to the {@link PatchOperationService} used for creating a patch
    */
   constructor(
     url: string,
     fields: Identifiable[],
-    lastModified: Date
+    lastModified: Date,
+    patchOperationServiceToken?: InjectionToken<PatchOperationService>
   ) {
-    this.payload = { url, fields, lastModified };
+    this.payload = { url, fields, lastModified, patchOperationServiceToken };
   }
 }
 
@@ -72,7 +72,6 @@ export class AddFieldUpdateAction implements Action {
     url: string,
     field: Identifiable,
     changeType: FieldChangeType,
-    patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>
   };
 
   /**
@@ -86,9 +85,8 @@ export class AddFieldUpdateAction implements Action {
   constructor(
     url: string,
     field: Identifiable,
-    changeType: FieldChangeType,
-    patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>) {
-    this.payload = { url, field, changeType, patchOperationServiceToken };
+    changeType: FieldChangeType) {
+    this.payload = { url, field, changeType };
   }
 }
 

src/app/core/data/object-updates/object-updates.reducer.ts

@@ -51,7 +51,6 @@ export interface Identifiable {
 export interface FieldUpdate {
   field: Identifiable,
   changeType: FieldChangeType,
-  patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>
 }
 
 /**
@@ -92,6 +91,7 @@ export interface ObjectUpdatesEntry {
   fieldUpdates: FieldUpdates;
   virtualMetadataSources: VirtualMetadataSources;
   lastModified: Date;
+  patchOperationServiceToken?: InjectionToken<PatchOperationService>;
 }
 
 /**
@@ -166,6 +166,7 @@ function initializeFieldsUpdate(state: any, action: InitializeFieldsAction) {
   const url: string = action.payload.url;
   const fields: Identifiable[] = action.payload.fields;
   const lastModifiedServer: Date = action.payload.lastModified;
+  const patchOperationServiceToken: InjectionToken<PatchOperationService> = action.payload.patchOperationServiceToken;
   const fieldStates = createInitialFieldStates(fields);
   const newPageState = Object.assign(
     {},
@@ -173,7 +174,8 @@ function initializeFieldsUpdate(state: any, action: InitializeFieldsAction) {
     { fieldStates: fieldStates },
     { fieldUpdates: {} },
     { virtualMetadataSources: {} },
-    { lastModified: lastModifiedServer }
+    { lastModified: lastModifiedServer },
+    { patchOperationServiceToken }
   );
   return Object.assign({}, state, { [url]: newPageState });
 }
@@ -187,7 +189,6 @@ function addFieldUpdate(state: any, action: AddFieldUpdateAction) {
   const url: string = action.payload.url;
   const field: Identifiable = action.payload.field;
   const changeType: FieldChangeType = action.payload.changeType;
-  const patchOperationServiceToken: InjectionToken<PatchOperationService<Identifiable>> = action.payload.patchOperationServiceToken;
   const pageState: ObjectUpdatesEntry = state[url] || {};
 
   let states = pageState.fieldStates;
@@ -198,7 +199,7 @@ function addFieldUpdate(state: any, action: AddFieldUpdateAction) {
   let fieldUpdate: any = pageState.fieldUpdates[field.uuid] || {};
   const newChangeType = determineChangeType(fieldUpdate.changeType, changeType);
 
-  fieldUpdate = Object.assign({}, { field, changeType: newChangeType, patchOperationServiceToken });
+  fieldUpdate = Object.assign({}, { field, changeType: newChangeType });
 
   const fieldUpdates = Object.assign({}, pageState.fieldUpdates, { [field.uuid]: fieldUpdate });
 

src/app/core/data/object-updates/object-updates.service.ts

@@ -59,9 +59,10 @@ export class ObjectUpdatesService {
    * @param url The page's URL for which the changes are being mapped
    * @param fields The initial fields for the page's object
    * @param lastModified The date the object was last modified
+   * @param patchOperationServiceToken An InjectionToken referring to the {@link PatchOperationService} used for creating a patch
    */
-  initialize(url, fields: Identifiable[], lastModified: Date): void {
-    this.store.dispatch(new InitializeFieldsAction(url, fields, lastModified));
+  initialize(url, fields: Identifiable[], lastModified: Date, patchOperationServiceToken?: InjectionToken<PatchOperationService>): void {
+    this.store.dispatch(new InitializeFieldsAction(url, fields, lastModified, patchOperationServiceToken));
   }
 
   /**
@@ -70,8 +71,8 @@ export class ObjectUpdatesService {
    * @param field An updated field for the page's object
    * @param changeType The last type of change applied to this field
    */
-  private saveFieldUpdate(url: string, field: Identifiable, changeType: FieldChangeType, patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>) {
-    this.store.dispatch(new AddFieldUpdateAction(url, field, changeType, patchOperationServiceToken))
+  private saveFieldUpdate(url: string, field: Identifiable, changeType: FieldChangeType) {
+    this.store.dispatch(new AddFieldUpdateAction(url, field, changeType))
   }
 
   /**
@@ -188,8 +189,8 @@ export class ObjectUpdatesService {
    * @param url The page's URL for which the changes are saved
    * @param field An updated field for the page's object
    */
-  saveAddFieldUpdate(url: string, field: Identifiable, patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>) {
-    this.saveFieldUpdate(url, field, FieldChangeType.ADD, patchOperationServiceToken);
+  saveAddFieldUpdate(url: string, field: Identifiable) {
+    this.saveFieldUpdate(url, field, FieldChangeType.ADD);
   }
 
   /**
@@ -197,8 +198,8 @@ export class ObjectUpdatesService {
    * @param url The page's URL for which the changes are saved
    * @param field An updated field for the page's object
    */
-  saveRemoveFieldUpdate(url: string, field: Identifiable, patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>) {
-    this.saveFieldUpdate(url, field, FieldChangeType.REMOVE, patchOperationServiceToken);
+  saveRemoveFieldUpdate(url: string, field: Identifiable) {
+    this.saveFieldUpdate(url, field, FieldChangeType.REMOVE);
   }
 
   /**
@@ -206,8 +207,8 @@ export class ObjectUpdatesService {
    * @param url The page's URL for which the changes are saved
    * @param field An updated field for the page's object
    */
-  saveChangeFieldUpdate(url: string, field: Identifiable, patchOperationServiceToken?: InjectionToken<PatchOperationService<Identifiable>>) {
-    this.saveFieldUpdate(url, field, FieldChangeType.UPDATE, patchOperationServiceToken);
+  saveChangeFieldUpdate(url: string, field: Identifiable) {
+    this.saveFieldUpdate(url, field, FieldChangeType.UPDATE);
   }
 
   /**
@@ -345,18 +346,17 @@ export class ObjectUpdatesService {
 
   /**
    * Create a patch from the current object-updates state
+   * The {@link ObjectUpdatesEntry} should contain a patchOperationServiceToken, in order to define how a patch should
+   * be created. If it doesn't, an empty patch will be returned.
    * @param url The URL of the page for which the patch should be created
    */
   createPatch(url: string): Observable<Operation[]> {
     return this.getObjectEntry(url).pipe(
       map((entry) => {
-        const patch = [];
-        Object.keys(entry.fieldUpdates).forEach((uuid) => {
-          const update = entry.fieldUpdates[uuid];
-          if (hasValue(update.patchOperationServiceToken)) {
-            patch.push(this.injector.get(update.patchOperationServiceToken).fieldUpdateToPatchOperation(update));
+        let patch = [];
+        if (hasValue(entry.patchOperationServiceToken)) {
+          patch = this.injector.get(entry.patchOperationServiceToken).fieldUpdatesToPatchOperations(entry.fieldUpdates);
         }
-        });
         return patch;
       })
     );

src/app/core/data/object-updates/patch-operation-service/metadata-patch-operation.model.ts

@@ -0,0 +1,33 @@
+import { Operation } from 'fast-json-patch';
+import { hasValue } from '../../../../shared/empty.util';
+
+/**
+ * Wrapper object for metadata patch Operations
+ * It contains the operation type, metadata field, metadata place and patch value, as well as a method to transform it
+ * into a fast-json-patch Operation.
+ */
+export class MetadataPatchOperation {
+  op: string;
+  field: string;
+  place: number;
+  value: any;
+
+  constructor(op: string, field: string, place?: number, value?: any) {
+    this.op = op;
+    this.field = field;
+    this.place = place;
+    this.value = value;
+  }
+
+  /**
+   * Transform the MetadataPatchOperation into a fast-json-patch Operation by constructing its path and other properties
+   * using the information provided.
+   */
+  toOperation(): Operation {
+    let path = `/metadata/${this.field}`;
+    if (hasValue(this.place)) {
+      path += `/${this.place}`;
+    }
+    return { op: this.op as any, path, value: this.value };
+  }
+}

src/app/core/data/object-updates/patch-operation-service/metadata-patch-operation.service.ts

@@ -1,29 +1,103 @@
 import { PatchOperationService } from './patch-operation.service';
-import { MetadataValue, MetadatumViewModel } from '../../../shared/metadata.models';
-import { FieldUpdate } from '../object-updates.reducer';
+import { MetadatumViewModel } from '../../../shared/metadata.models';
+import { FieldUpdates } from '../object-updates.reducer';
 import { Operation } from 'fast-json-patch';
 import { FieldChangeType } from '../object-updates.actions';
 import { InjectionToken } from '@angular/core';
+import { MetadataPatchOperation } from './metadata-patch-operation.model';
+import { hasValue } from '../../../../shared/empty.util';
 
+/**
+ * Token to use for injecting this service anywhere you want
+ * This token can used to store in the object-updates store
+ */
 export const METADATA_PATCH_OPERATION_SERVICE_TOKEN = new InjectionToken<MetadataPatchOperationService>('MetadataPatchOperationService', {
   providedIn: 'root',
   factory: () => new MetadataPatchOperationService(),
 });
 
-export class MetadataPatchOperationService implements PatchOperationService<MetadatumViewModel> {
-  fieldUpdateToPatchOperation(fieldUpdate: FieldUpdate): Operation {
-    const metadatum = fieldUpdate.field as MetadatumViewModel;
-    const path = `/metadata/${metadatum.key}`;
+/**
+ * Service transforming {@link FieldUpdates} into {@link Operation}s for metadata values
+ * This expects the fields within every {@link FieldUpdate} to be {@link MetadatumViewModel}s
+ */
+export class MetadataPatchOperationService implements PatchOperationService {
+
+  /**
+   * Transform a {@link FieldUpdates} object into an array of fast-json-patch Operations for metadata values
+   * This method first creates an array of {@link MetadataPatchOperation} wrapper operations, which are then
+   * iterated over to create the actual patch operations. While iterating, it has the ability to check for previous
+   * operations that would modify the operation's position and act accordingly.
+   * @param fieldUpdates
+   */
+  fieldUpdatesToPatchOperations(fieldUpdates: FieldUpdates): Operation[] {
+    const metadataPatch = this.fieldUpdatesToMetadataPatchOperations(fieldUpdates);
+
+    // This map stores what metadata fields had a value deleted at which places
+    // This is used to modify the place of operations to match previous operations
+    const metadataRemoveMap = new Map<string, number[]>();
+    const patch = [];
+    metadataPatch.forEach((operation) => {
+      // If this operation is removing or editing an existing value, first check the map for previous operations
+      // If the map contains remove operations before this operation's place, lower the place by 1 for each
+      if ((operation.op === 'remove' || operation.op === 'replace') && hasValue(operation.place)) {
+        if (metadataRemoveMap.has(operation.field)) {
+          metadataRemoveMap.get(operation.field).forEach((index) => {
+            if (index < operation.place) {
+              operation.place--;
+            }
+          });
+        }
+      }
+
+      // If this is a remove operation, add its (updated) place to the map, so we can adjust following operations accordingly
+      if (operation.op === 'remove' && hasValue(operation.place)) {
+        if (!metadataRemoveMap.has(operation.field)) {
+          metadataRemoveMap.set(operation.field, []);
+        }
+        metadataRemoveMap.get(operation.field).push(operation.place);
+      }
+
+      // Transform the updated operation into a fast-json-patch Operation and add it to the patch
+      patch.push(operation.toOperation());
+    });
+
+    return patch;
+  }
+
+  /**
+   * Transform a {@link FieldUpdates} object into an array of {@link MetadataPatchOperation} wrapper objects
+   * These wrapper objects contain detailed information about the patch operation that needs to be creates for each update
+   * This information can then be modified before creating the actual patch
+   * @param fieldUpdates
+   */
+  fieldUpdatesToMetadataPatchOperations(fieldUpdates: FieldUpdates): MetadataPatchOperation[] {
+    const metadataPatch = [];
+
+    Object.keys(fieldUpdates).forEach((uuid) => {
+      const update = fieldUpdates[uuid];
+      const metadatum = update.field as MetadatumViewModel;
       const val = {
         value: metadatum.value,
         language: metadatum.language
       }
 
-    switch (fieldUpdate.changeType) {
-      case FieldChangeType.ADD: return { op: 'add', path, value: [ val ] };
-      case FieldChangeType.REMOVE: return { op: 'remove', path: `${path}/${metadatum.place}` };
-      case FieldChangeType.UPDATE: return { op: 'replace', path: `${path}/${metadatum.place}`, value: val };
-      default: return undefined;
+      let operation: MetadataPatchOperation;
+      switch (update.changeType) {
+        case FieldChangeType.ADD:
+          operation = new MetadataPatchOperation('add', metadatum.key, undefined, [ val ]);
+          break;
+        case FieldChangeType.REMOVE:
+          operation = new MetadataPatchOperation('remove', metadatum.key, metadatum.place);
+          break;
+        case FieldChangeType.UPDATE:
+          operation = new MetadataPatchOperation('replace', metadatum.key, metadatum.place, val);
+          break;
       }
+
+      metadataPatch.push(operation);
+    });
+
+    return metadataPatch;
   }
+
 }

src/app/core/data/object-updates/patch-operation-service/patch-operation.service.ts

@@ -1,6 +1,15 @@
-import { FieldUpdate, Identifiable } from '../object-updates.reducer';
+import { FieldUpdates } from '../object-updates.reducer';
 import { Operation } from 'fast-json-patch';
 
-export interface PatchOperationService<T extends Identifiable> {
-  fieldUpdateToPatchOperation(fieldUpdate: FieldUpdate): Operation;
+/**
+ * Interface for a service dealing with the transformations of patch operations from the object-updates store
+ * The implementations of this service know how to deal with the fields of a FieldUpdate and how to transform them
+ * into patch Operations.
+ */
+export interface PatchOperationService {
+  /**
+   * Transform a {@link FieldUpdates} object into an array of fast-json-patch Operations
+   * @param fieldUpdates
+   */
+  fieldUpdatesToPatchOperations(fieldUpdates: FieldUpdates): Operation[];
 }