Expose FieldRegion.projects relationship in GraphQL API

Author: rdonigian

src/components/field-region/dto/field-region.dto.ts

@@ -3,19 +3,26 @@ import {
   DbUnique,
   NameField,
   Resource,
+  type ResourceRelationsShape,
   type Secured,
   SecuredProperty,
   SecuredPropertyList,
   SecuredString,
 } from '~/common';
 import { e } from '~/core/gel';
 import { type LinkTo, RegisterResource } from '~/core/resources';
+import { IProject } from '../../project/dto';
 
 @RegisterResource({ db: e.FieldRegion })
 @ObjectType({
   implements: [Resource],
 })
 export class FieldRegion extends Resource {
+  static readonly Relations = () =>
+    ({
+      projects: [IProject],
+    } satisfies ResourceRelationsShape);
+
   @NameField()
   @DbUnique()
   readonly name: SecuredString;

src/components/field-region/field-region-projects.resolver.ts

@@ -0,0 +1,25 @@
+import { Parent, ResolveField, Resolver } from '@nestjs/graphql';
+import { ListArg } from '~/common';
+import { Loader, type LoaderOf } from '~/core';
+import { ProjectListInput, SecuredProjectList } from '../project/dto';
+import { ProjectLoader } from '../project/project.loader';
+import { FieldRegion } from './dto';
+import { FieldRegionService } from './field-region.service';
+
+@Resolver(FieldRegion)
+export class FieldRegionProjectsResolver {
+  constructor(private readonly fieldRegionService: FieldRegionService) {}
+
+  @ResolveField(() => SecuredProjectList, {
+    description: 'The list of projects in this field region',
+  })
+  async projects(
+    @Parent() fieldRegion: FieldRegion,
+    @ListArg(ProjectListInput) input: ProjectListInput,
+    @Loader(ProjectLoader) projects: LoaderOf<ProjectLoader>,
+  ): Promise<SecuredProjectList> {
+    const list = await this.fieldRegionService.listProjects(fieldRegion, input);
+    projects.primeAll(list.items);
+    return list;
+  }
+}

src/components/field-region/field-region.module.ts

@@ -2,7 +2,9 @@ import { forwardRef, Module } from '@nestjs/common';
 import { splitDb } from '~/core';
 import { AuthorizationModule } from '../authorization/authorization.module';
 import { FieldZoneModule } from '../field-zone/field-zone.module';
+import { ProjectModule } from '../project/project.module';
 import { UserModule } from '../user/user.module';
+import { FieldRegionProjectsResolver } from './field-region-projects.resolver';
 import { FieldRegionGelRepository } from './field-region.gel.repository';
 import { FieldRegionLoader } from './field-region.loader';
 import { FieldRegionRepository } from './field-region.repository';
@@ -14,10 +16,12 @@ import { RestrictRegionDirectorRemovalHandler } from './handlers/restrict-region
   imports: [
     forwardRef(() => AuthorizationModule),
     FieldZoneModule,
+    forwardRef(() => ProjectModule),
     forwardRef(() => UserModule),
   ],
   providers: [
     FieldRegionResolver,
+    FieldRegionProjectsResolver,
     FieldRegionService,
     splitDb(FieldRegionRepository, FieldRegionGelRepository),
     FieldRegionLoader,

src/components/field-region/field-region.service.ts

@@ -10,6 +10,12 @@ import {
 import { HandleIdLookup } from '~/core';
 import { IEventBus } from '~/core/events';
 import { Privileges } from '../authorization';
+import {
+  IProject,
+  type ProjectListInput,
+  type SecuredProjectList,
+} from '../project/dto';
+import { ProjectService } from '../project/project.service';
 import { UserService } from '../user';
 import {
   type CreateFieldRegion,
@@ -28,6 +34,7 @@ export class FieldRegionService {
     private readonly events: IEventBus,
     private readonly users: UserService,
     private readonly repo: FieldRegionRepository,
+    private readonly projectService: ProjectService,
   ) {}
 
   async create(input: CreateFieldRegion): Promise<FieldRegion> {
@@ -115,4 +122,26 @@ export class FieldRegionService {
       items: results.items.map((dto) => this.secure(dto)),
     };
   }
+
+  async listProjects(
+    fieldRegion: FieldRegion,
+    input: ProjectListInput,
+  ): Promise<SecuredProjectList> {
+    const projectListOutput = await this.projectService.list({
+      ...input,
+      filter: {
+        ...input.filter,
+        fieldRegion: {
+          ...(input.filter?.fieldRegion ?? {}),
+          id: fieldRegion.id,
+        },
+      },
+    });
+
+    return {
+      ...projectListOutput,
+      canRead: true,
+      canCreate: this.privileges.for(IProject).can('create'),
+    };
+  }
 }