Add category update endpoint

backend/src/categories/categories.controller.ts

@@ -1,7 +1,8 @@
-import { Controller, Get, Post, Delete, Body, Param, UseGuards } from '@nestjs/common';
+import { Controller, Get, Post, Delete, Body, Param, UseGuards, Patch } from '@nestjs/common';
 import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { CategoriesService } from './categories.service';
 import { CreateCategoryDto } from './dto/create-category.dto';
+import { UpdateCategoryDto } from './dto/update-category.dto';
 import { JwtAuthGuard } from '../auth/guards/jwt-auth.guard';
 
 @ApiTags('Categories')
@@ -29,6 +30,12 @@ export class CategoriesController {
     return this.service.create(dto);
   }
 
+  @Patch(':id')
+  @ApiOperation({ summary: 'Update a category' })
+  update(@Param('id') id: string, @Body() dto: UpdateCategoryDto) {
+    return this.service.update(id, dto);
+  }
+
   @Delete(':id')
   @ApiOperation({ summary: 'Delete a category' })
   remove(@Param('id') id: string) {

backend/src/categories/categories.service.ts

@@ -1,8 +1,13 @@
-import { Injectable, NotFoundException, ConflictException } from '@nestjs/common';
+import {
+  ConflictException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 import { Category } from './category.entity';
 import { CreateCategoryDto } from './dto/create-category.dto';
+import { UpdateCategoryDto } from './dto/update-category.dto';
 
 export interface CategoryWithCount extends Category {
   assetCount: number;
@@ -33,13 +38,29 @@ export class CategoriesService {
   }
 
   async create(dto: CreateCategoryDto): Promise<Category> {
-    const existing = await this.repo.findOne({ where: { name: dto.name } });
-    if (existing) throw new ConflictException('A category with this name already exists');
+    await this.ensureNameUnique(dto.name);
     return this.repo.save(this.repo.create(dto));
   }
 
+  async update(id: string, dto: UpdateCategoryDto): Promise<Category> {
+    const category = await this.findOne(id);
+    if (dto.name && dto.name !== category.name) {
+      await this.ensureNameUnique(dto.name);
+    }
+
+    Object.assign(category, dto);
+    return this.repo.save(category);
+  }
+
   async remove(id: string): Promise<void> {
     const cat = await this.findOne(id);
     await this.repo.remove(cat);
   }
+
+  private async ensureNameUnique(name: string): Promise<void> {
+    const existing = await this.repo.findOne({ where: { name } });
+    if (existing) {
+      throw new ConflictException('A category with this name already exists');
+    }
+  }
 }

backend/src/categories/dto/update-category.dto.ts

@@ -0,0 +1,4 @@
+import { PartialType } from '@nestjs/mapped-types';
+import { CreateCategoryDto } from './create-category.dto';
+
+export class UpdateCategoryDto extends PartialType(CreateCategoryDto) {}