fix: nlp sample inconsistency when language is deleted

api/src/i18n/controllers/language.controller.spec.ts

@@ -9,6 +9,7 @@
 
 import { CACHE_MANAGER } from '@nestjs/cache-manager';
 import { BadRequestException, NotFoundException } from '@nestjs/common';
+import { EventEmitter2 } from '@nestjs/event-emitter';
 import { MongooseModule } from '@nestjs/mongoose';
 import { Test } from '@nestjs/testing';
 
@@ -63,6 +64,7 @@ describe('LanguageController', () => {
           },
         },
         LoggerService,
+        EventEmitter2,
       ],
     }).compile();
     languageService = module.get<LanguageService>(LanguageService);

api/src/i18n/repositories/language.repository.ts

@@ -8,16 +8,46 @@
  */
 
 import { Injectable } from '@nestjs/common';
+import { EventEmitter2 } from '@nestjs/event-emitter';
 import { InjectModel } from '@nestjs/mongoose';
-import { Model } from 'mongoose';
+import { Document, Model, Query, TFilterQuery } from 'mongoose';
 
-import { BaseRepository } from '@/utils/generics/base-repository';
+import { BaseRepository, DeleteResult } from '@/utils/generics/base-repository';
 
 import { Language } from '../schemas/language.schema';
 
 @Injectable()
 export class LanguageRepository extends BaseRepository<Language> {
-  constructor(@InjectModel(Language.name) readonly model: Model<Language>) {
+  constructor(
+    @InjectModel(Language.name) readonly model: Model<Language>,
+    private readonly eventEmitter: EventEmitter2,
+  ) {
     super(model, Language);
   }
+
+  /**
+   * Pre-delete hook that triggers before an language is deleted.
+   *
+   * @param query The query used to delete the language.
+   * @param criteria The filter criteria used to find the language for deletion.
+   */
+  async preDelete(
+    _query: Query<
+      DeleteResult,
+      Document<Language, any, any>,
+      unknown,
+      Language,
+      'deleteOne' | 'deleteMany'
+    >,
+    criteria: TFilterQuery<Language>,
+  ): Promise<void> {
+    if (criteria._id) {
+      const language = await this.findOne(
+        typeof criteria === 'string' ? { _id: criteria } : criteria,
+      );
+      this.eventEmitter.emit('hook:language:delete', language);
+    } else {
+      throw new Error('Attempted to delete language using unknown criteria');
+    }
+  }
 }

api/src/i18n/schemas/language.schema.ts

@@ -11,6 +11,7 @@ import { Prop, Schema, SchemaFactory, ModelDefinition } from '@nestjs/mongoose';
 import { THydratedDocument } from 'mongoose';
 
 import { BaseSchema } from '@/utils/generics/base-schema';
+import { LifecycleHookManager } from '@/utils/generics/lifecycle-hook-manager';
 
 @Schema({ timestamps: true })
 export class Language extends BaseSchema {
@@ -41,10 +42,10 @@ export class Language extends BaseSchema {
   isRTL?: boolean;
 }
 
-export const LanguageModel: ModelDefinition = {
+export const LanguageModel: ModelDefinition = LifecycleHookManager.attach({
   name: Language.name,
   schema: SchemaFactory.createForClass(Language),
-};
+});
 
 export type LanguageDocument = THydratedDocument<Language>;
 

api/src/nlp/schemas/nlp-sample.schema.ts

@@ -49,15 +49,15 @@ export class NlpSampleStub extends BaseSchema {
   @Prop({
     type: MongooseSchema.Types.ObjectId,
     ref: 'Language',
-    required: true,
+    required: false,
   })
-  language: unknown;
+  language: unknown | null;
 }
 
 @Schema({ timestamps: true })
 export class NlpSample extends NlpSampleStub {
   @Transform(({ obj }) => obj.language.toString())
-  language: string;
+  language: string | null;
 
   @Exclude()
   entities?: never;
@@ -66,7 +66,7 @@ export class NlpSample extends NlpSampleStub {
 @Schema({ timestamps: true })
 export class NlpSampleFull extends NlpSampleStub {
   @Type(() => Language)
-  language: Language;
+  language: Language | null;
 
   @Type(() => NlpSampleEntity)
   entities: NlpSampleEntity[];

api/src/nlp/services/nlp-sample.service.ts

@@ -8,6 +8,7 @@
  */
 
 import { Injectable } from '@nestjs/common';
+import { OnEvent } from '@nestjs/event-emitter';
 
 import {
   CommonExample,
@@ -16,6 +17,7 @@ import {
   ExampleEntity,
   LookupTable,
 } from '@/extensions/helpers/nlp/default/types';
+import { Language } from '@/i18n/schemas/language.schema';
 import { LanguageService } from '@/i18n/services/language.service';
 import { BaseService } from '@/utils/generics/base-service';
 
@@ -140,4 +142,21 @@ export class NlpSampleService extends BaseService<
       entity_synonyms,
     };
   }
+
+  /**
+   * When a language gets deleted, we need to set related samples to null
+   *
+   * @param language The language that has been deleted.
+   */
+  @OnEvent('hook:language:delete')
+  async handleLanguageDelete(language: Language) {
+    await this.updateMany(
+      {
+        language: language.id,
+      },
+      {
+        language: null,
+      },
+    );
+  }
 }