NGO-DB/ndb-core

import { Entity } from "../model/entity";
import { asArray } from "../../../utils/utils";
import { EntitySchemaService } from "../schema/entity-schema.service";
import { EntityMapperService } from "../entity-mapper/entity-mapper.service";

export class CascadingActionResult {
  /**
   * entities that have been updated in the process, in their original state
   * (can be used for undo action)
   */
  originalEntitiesBeforeChange: Entity[];

  /**
   * entities that may still contain PII related to the primary entity that could not be automatically removed
   * (may need manual review by the user)
   */
  potentiallyRetainingPII: Entity[];

  constructor(changedEntities?: Entity[], potentiallyRetainingPII?: Entity[]) {
    this.originalEntitiesBeforeChange = changedEntities ?? [];
    this.potentiallyRetainingPII = potentiallyRetainingPII ?? [];
  }

  mergeResults(otherResult: CascadingActionResult) {
    this.originalEntitiesBeforeChange = [
      ...this.originalEntitiesBeforeChange,
      ...otherResult.originalEntitiesBeforeChange.filter(
        (e) =>
          !this.originalEntitiesBeforeChange.some(
            (x) => x.getId() === e.getId(),
          ),
      ),
    ];
    this.potentiallyRetainingPII = [
      ...this.potentiallyRetainingPII,
      ...otherResult.potentiallyRetainingPII.filter(
        (e) =>
          !this.potentiallyRetainingPII.some((x) => x.getId() === e.getId()),
      ),
    ];

    return this;
  }
}

/**
 * extend this class to implement services that perform actions on an entity
 * that require recursive actions to related entities as well.
 */
export abstract class CascadingEntityAction {
  protected constructor(
    protected entityMapper: EntityMapperService,
    protected schemaService: EntitySchemaService,
  ) {}

  /**
   * Recursively call the given actions on all related entities that contain a reference to the given entity.
   *
   * Returns an array of all affected related entities (excluding the given entity) in their state before the action
   * to support an undo action.
   *
   * @param entity
   * @param compositeAction
   * @param aggregateAction
   * @private
   */
  protected async cascadeActionToRelatedEntities(
    entity: Entity,
    compositeAction: (
      relatedEntity: Entity,
      refField?: string,
      entity?: Entity,
    ) => Promise<CascadingActionResult>,
    aggregateAction: (
      relatedEntity: Entity,
      refField?: string,
      entity?: Entity,
    ) => Promise<CascadingActionResult>,
  ): Promise<CascadingActionResult> {
    const cascadeActionResult = new CascadingActionResult();

    const entityTypesWithReferences =
      this.schemaService.getEntityTypesReferencingType(entity.getType());

    for (const refType of entityTypesWithReferences) {
      const entities = await this.entityMapper.loadType(refType.entityType);

      for (const refField of refType.referencingProperties) {
        const affectedEntities = entities.filter((e) =>
          asArray(e[refField]).includes(entity.getId()),
        );

        for (const e of affectedEntities) {
          if (
            refType.entityType.schema.get(refField).entityReferenceRole ===
              "composite" &&
            asArray(e[refField]).length === 1
          ) {
            // is only composite
            const result = await compositeAction(e);
            cascadeActionResult.mergeResults(result);
          } else {
            const result = await aggregateAction(e, refField, entity);
            cascadeActionResult.mergeResults(result);
          }
        }
      }
    }

    return cascadeActionResult;
  }
}