feat: Categories Create and Delete (#34)

# Description

* Deletion of categories
* Creation of new categories

## Checklist

- [x] This PR can be reviewed in under 30 minutes
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] I have assigned reviewers to this PR.

src/categories/categories.resolver.ts

@@ -6,6 +6,8 @@ import { DampLabService } from '../services/models/damplab-service.model';
 import { CategoryPipe } from './categories.pipe';
 import { CategoryChange } from './dtos/update.dto';
 import { CategoryUpdatePipe } from './update.pipe';
+import { CreateCategory } from './dtos/create.dto';
+import { CreateCategoryPipe } from './create.pipe';
 
 @Resolver(() => Category)
 export class CategoryResolver {
@@ -24,6 +26,17 @@ export class CategoryResolver {
     return this.categoryService.update(category, changes);
   }
 
+  @Mutation(() => Boolean)
+  async deleteCategory(@Args('category', { type: () => ID }, CategoryPipe) category: Category): Promise<boolean> {
+    await this.categoryService.delete(category);
+    return true;
+  }
+
+  @Mutation(() => Category)
+  async createCategory(@Args('category', CreateCategoryPipe) category: CreateCategory): Promise<Category> {
+    return this.categoryService.create(category);
+  }
+
   /**
    * Resolver for the services field of the Category type
    */

src/categories/categories.service.ts

@@ -3,6 +3,7 @@ import { InjectModel } from '@nestjs/mongoose';
 import { Category, CategoryDocument } from './category.model';
 import { Model } from 'mongoose';
 import { CategoryChange } from './dtos/update.dto';
+import { CreateCategory } from './dtos/create.dto';
 
 @Injectable()
 export class CategoryService {
@@ -20,4 +21,12 @@ export class CategoryService {
     await this.categoryModel.updateOne({ _id: category._id }, change);
     return (await this.find(category._id))!;
   }
+
+  async delete(category: Category): Promise<void> {
+    await this.categoryModel.deleteOne({ _id: category._id });
+  }
+
+  async create(category: CreateCategory): Promise<Category> {
+    return this.categoryModel.create(category);
+  }
 }

src/categories/create.pipe.ts

@@ -0,0 +1,17 @@
+import { Injectable, PipeTransform } from '@nestjs/common';
+import { DampLabServicePipe } from '../services/damplab-services.pipe';
+import { CreateCategory } from './dtos/create.dto';
+
+@Injectable()
+export class CreateCategoryPipe implements PipeTransform<CreateCategory, Promise<CreateCategory>> {
+  constructor(private readonly damplabServicePipe: DampLabServicePipe) {}
+
+  async transform(value: CreateCategory): Promise<CreateCategory> {
+    // Ensure the services are valid
+    for (const service of value.services) {
+      await this.damplabServicePipe.transform(service);
+    }
+
+    return value;
+  }
+}

src/categories/dtos/create.dto.ts

@@ -0,0 +1,8 @@
+import { ID, InputType, OmitType, Field } from '@nestjs/graphql';
+import { Category } from '../category.model';
+
+@InputType()
+export class CreateCategory extends OmitType(Category, ['_id', 'services'] as const, InputType) {
+  @Field(() => [ID])
+  services: string[];
+}