Expose FieldZone.projects relationship in GraphQL API

Author: rdonigian

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

@@ -3,18 +3,25 @@ import {
   DbUnique,
   NameField,
   Resource,
+  type ResourceRelationsShape,
   type Secured,
   SecuredProperty,
   SecuredString,
 } from '~/common';
 import { e } from '~/core/gel';
 import { type LinkTo, RegisterResource } from '~/core/resources';
+import { IProject } from '../../project/dto';
 
 @RegisterResource({ db: e.FieldZone })
 @ObjectType({
   implements: [Resource],
 })
 export class FieldZone extends Resource {
+  static readonly Relations = () =>
+    ({
+      projects: [IProject],
+    } satisfies ResourceRelationsShape);
+
   @NameField()
   @DbUnique()
   readonly name: SecuredString;

src/components/field-zone/field-zone-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 { FieldZone } from './dto';
+import { FieldZoneService } from './field-zone.service';
+
+@Resolver(FieldZone)
+export class FieldZoneProjectsResolver {
+  constructor(private readonly fieldZoneService: FieldZoneService) {}
+
+  @ResolveField(() => SecuredProjectList, {
+    description: 'The list of projects in regions within this field zone',
+  })
+  async projects(
+    @Parent() fieldZone: FieldZone,
+    @ListArg(ProjectListInput) input: ProjectListInput,
+    @Loader(ProjectLoader) projects: LoaderOf<ProjectLoader>,
+  ): Promise<SecuredProjectList> {
+    const list = await this.fieldZoneService.listProjects(fieldZone, input);
+    projects.primeAll(list.items);
+    return list;
+  }
+}

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

@@ -1,7 +1,9 @@
 import { forwardRef, Module } from '@nestjs/common';
 import { splitDb } from '~/core';
 import { AuthorizationModule } from '../authorization/authorization.module';
+import { ProjectModule } from '../project/project.module';
 import { UserModule } from '../user/user.module';
+import { FieldZoneProjectsResolver } from './field-zone-projects.resolver';
 import { FieldZoneGelRepository } from './field-zone.gel.repository';
 import { FieldZoneLoader } from './field-zone.loader';
 import { FieldZoneRepository } from './field-zone.repository';
@@ -12,10 +14,12 @@ import { RestrictZoneDirectorRemovalHandler } from './handlers/restrict-zone-dir
 @Module({
   imports: [
     forwardRef(() => AuthorizationModule),
+    forwardRef(() => ProjectModule),
     forwardRef(() => UserModule),
   ],
   providers: [
     FieldZoneResolver,
+    FieldZoneProjectsResolver,
     FieldZoneService,
     splitDb(FieldZoneRepository, FieldZoneGelRepository),
     FieldZoneLoader,

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

@@ -10,6 +10,8 @@ import {
 import { HandleIdLookup } from '~/core';
 import { IEventBus } from '~/core/events';
 import { Privileges } from '../authorization';
+import { type ProjectListInput, type SecuredProjectList } from '../project/dto';
+import { ProjectService } from '../project/project.service';
 import { UserService } from '../user';
 import {
   type CreateFieldZone,
@@ -28,6 +30,7 @@ export class FieldZoneService {
     private readonly events: IEventBus,
     private readonly users: UserService,
     private readonly repo: FieldZoneRepository,
+    private readonly projectService: ProjectService,
   ) {}
 
   async create(input: CreateFieldZone): Promise<FieldZone> {
@@ -115,4 +118,29 @@ export class FieldZoneService {
       items: results.items.map((dto) => this.secure(dto)),
     };
   }
+
+  async listProjects(
+    fieldZone: FieldZone,
+    input: ProjectListInput,
+  ): Promise<SecuredProjectList> {
+    const projectListOutput = await this.projectService.list({
+      ...input,
+      filter: {
+        ...input.filter,
+        fieldRegion: {
+          ...(input.filter?.fieldRegion ?? {}),
+          fieldZone: {
+            ...(input.filter?.fieldRegion?.fieldZone ?? {}),
+            id: fieldZone.id,
+          },
+        },
+      },
+    });
+
+    return {
+      ...projectListOutput,
+      canRead: true,
+      canCreate: false, // Field zone doesn't own project creation
+    };
+  }
 }