feat: add brands and variant categories management

- Implemented CRUD operations for brands and variant categories in the API.
- Created UI components for managing brands and variant categories, including listing, creating, editing, and deleting.
- Enhanced the sidebar navigation to include links for brands and variant categories.
- Updated the categories API to support pagination and filtering.
- Added validation for brand and variant category names.
- Integrated toast notifications for user feedback on actions.

Frontend/erp-system/lib/api/brands.ts

@@ -0,0 +1,64 @@
+// One typed client method per Brand endpoint, mirroring lib/api/uoms.ts.
+// In-memory sample data (lib/api/mock-data.ts) — no backend API calls.
+import { PagedResponse } from "@/types/common"
+import { Brand, CreateBrandRequest, UpdateBrandRequest } from "@/types/master-data"
+import { allocateBrandId, mockBrands, mockDelay } from "@/lib/api/mock-data"
+
+export interface ListBrandsParams {
+  page?: number
+  pageSize?: number
+  q?: string
+  sortOrder?: "asc" | "desc"
+}
+
+export const brandsApi = {
+  list(params: ListBrandsParams = {}): Promise<PagedResponse<Brand>> {
+    const term = params.q?.trim().toLowerCase()
+    const sortOrder = params.sortOrder ?? "asc"
+    const filtered = mockBrands
+      .filter((b) => !term || b.name.toLowerCase().includes(term))
+      .sort((a, b) => (sortOrder === "asc" ? a.name.localeCompare(b.name) : b.name.localeCompare(a.name)))
+
+    const page = params.page ?? 1
+    const pageSize = params.pageSize ?? 5
+    const start = (page - 1) * pageSize
+    const items = filtered.slice(start, start + pageSize)
+    const totalItems = filtered.length
+    const totalPages = pageSize <= 0 ? 0 : Math.ceil(totalItems / pageSize)
+
+    return mockDelay({
+      items,
+      pagination: { page, pageSize, totalItems, totalPages },
+    })
+  },
+
+  create(request: CreateBrandRequest): Promise<Brand> {
+    const name = request.name.trim()
+    if (!name) return Promise.reject(new Error("Brand name is required."))
+    if (mockBrands.some((b) => b.name.toLowerCase() === name.toLowerCase())) {
+      return Promise.reject(new Error(`Brand "${name}" already exists.`))
+    }
+    const brand: Brand = { brandId: allocateBrandId(), name, createdAt: new Date().toISOString() }
+    mockBrands.push(brand)
+    return mockDelay(brand)
+  },
+
+  update(brandId: number, request: UpdateBrandRequest): Promise<Brand> {
+    const name = request.name.trim()
+    if (!name) return Promise.reject(new Error("Brand name is required."))
+    const brand = mockBrands.find((b) => b.brandId === brandId)
+    if (!brand) return Promise.reject(new Error("Brand not found."))
+    if (mockBrands.some((b) => b.brandId !== brandId && b.name.toLowerCase() === name.toLowerCase())) {
+      return Promise.reject(new Error(`Brand "${name}" already exists.`))
+    }
+    brand.name = name
+    return mockDelay(brand)
+  },
+
+  remove(brandId: number): Promise<void> {
+    const index = mockBrands.findIndex((b) => b.brandId === brandId)
+    if (index === -1) return Promise.reject(new Error("Brand not found."))
+    mockBrands.splice(index, 1)
+    return mockDelay(undefined)
+  },
+}

Frontend/erp-system/lib/api/categories.ts

@@ -1,35 +1,37 @@
 // One typed client method per Category endpoint (docs/11-BACKEND-PHASE1.md §2.3, FR-MD-04).
 // In-memory sample data (lib/api/mock-data.ts) — no backend API calls.
 import { PagedResponse } from "@/types/common"
-import { Category, CategoryTreeNode, CreateCategoryRequest } from "@/types/master-data"
+import { Category, CreateCategoryRequest, UpdateCategoryRequest } from "@/types/master-data"
 import { allocateCategoryId, mockCategories, mockDelay } from "@/lib/api/mock-data"
 
-function buildTree(categories: Category[]): CategoryTreeNode[] {
-  const nodes = new Map<number, CategoryTreeNode>(categories.map((c) => [c.categoryId, { ...c, children: [] }]))
-  const roots: CategoryTreeNode[] = []
-  for (const node of nodes.values()) {
-    if (node.parentId !== null && nodes.has(node.parentId)) {
-      nodes.get(node.parentId)!.children.push(node)
-    } else {
-      roots.push(node)
-    }
-  }
-  return roots
+export interface ListCategoriesParams {
+  page?: number
+  pageSize?: number
+  q?: string
+  sortOrder?: "asc" | "desc"
 }
 
 export const categoriesApi = {
-  list(): Promise<PagedResponse<Category>> {
-    const items = [...mockCategories].sort((a, b) => a.name.localeCompare(b.name))
+  list(params: ListCategoriesParams = {}): Promise<PagedResponse<Category>> {
+    const term = params.q?.trim().toLowerCase()
+    const sortOrder = params.sortOrder ?? "asc"
+    const filtered = mockCategories
+      .filter((c) => !term || c.name.toLowerCase().includes(term))
+      .sort((a, b) => (sortOrder === "asc" ? a.name.localeCompare(b.name) : b.name.localeCompare(a.name)))
+
+    const page = params.page ?? 1
+    const pageSize = params.pageSize ?? 5
+    const start = (page - 1) * pageSize
+    const items = filtered.slice(start, start + pageSize)
+    const totalItems = filtered.length
+    const totalPages = pageSize <= 0 ? 0 : Math.ceil(totalItems / pageSize)
+
     return mockDelay({
       items,
-      pagination: { page: 1, pageSize: 200, totalItems: items.length, totalPages: 1 },
+      pagination: { page, pageSize, totalItems, totalPages },
     })
   },
 
-  tree(): Promise<CategoryTreeNode[]> {
-    return mockDelay(buildTree(mockCategories))
-  },
-
   create(request: CreateCategoryRequest): Promise<Category> {
     const name = request.name.trim()
     if (!name) return Promise.reject(new Error("Category name is required."))
@@ -37,8 +39,24 @@ export const categoriesApi = {
     if (parentId !== null && !mockCategories.some((c) => c.categoryId === parentId)) {
       return Promise.reject(new Error("Selected parent category does not exist."))
     }
-    const category: Category = { categoryId: allocateCategoryId(), name, parentId }
+    const category: Category = { categoryId: allocateCategoryId(), name, parentId, createdAt: new Date().toISOString() }
     mockCategories.push(category)
     return mockDelay(category)
   },
+
+  update(categoryId: number, request: UpdateCategoryRequest): Promise<Category> {
+    const name = request.name.trim()
+    if (!name) return Promise.reject(new Error("Category name is required."))
+    const category = mockCategories.find((c) => c.categoryId === categoryId)
+    if (!category) return Promise.reject(new Error("Category not found."))
+    category.name = name
+    return mockDelay(category)
+  },
+
+  remove(categoryId: number): Promise<void> {
+    const index = mockCategories.findIndex((c) => c.categoryId === categoryId)
+    if (index === -1) return Promise.reject(new Error("Category not found."))
+    mockCategories.splice(index, 1)
+    return mockDelay(undefined)
+  },
 }

Frontend/erp-system/lib/api/items.ts

@@ -36,6 +36,7 @@ function toListItem(item: Item): ItemListItem {
     sku: item.sku,
     name: item.name,
     categoryId: item.categoryId,
+    brandId: item.brandId ?? null,
     baseUomId: item.baseUomId,
     defaultVendorId: item.defaultVendorId,
     itemType: item.itemType,
@@ -89,6 +90,7 @@ export const itemsApi = {
       name: request.name.trim(),
       description: request.description?.trim() || null,
       categoryId: request.categoryId,
+      brandId: request.brandId ?? null,
       baseUomId: request.baseUomId,
       defaultVendorId: request.defaultVendorId ?? null,
       itemType: request.itemType,
@@ -97,6 +99,7 @@ export const itemsApi = {
       status: "Active",
       reorder: [],
       conversions: [],
+      initialQty: request.initialQty ?? null,
       createdAt: new Date().toISOString(),
       updatedAt: null,
     }
@@ -121,6 +124,7 @@ export const itemsApi = {
     item.name = request.name.trim()
     item.description = request.description?.trim() || null
     item.categoryId = request.categoryId
+    item.brandId = request.brandId ?? null
     item.baseUomId = request.baseUomId
     item.defaultVendorId = request.defaultVendorId ?? null
     item.itemType = request.itemType

Frontend/erp-system/lib/api/mock-data.ts

@@ -1,7 +1,7 @@
 // In-memory sample data backing every lib/api/*.ts module — the app has no
 // fetch-based backend connection (lib/api-client.ts and lib/auth-token.ts were
 // removed). Shapes mirror docs/11-BACKEND-PHASE1.md.
-import { Bin, Category, Item, Uom, Vendor, Warehouse } from "@/types/master-data"
+import { Bin, Brand, Category, Item, Uom, Vendor, VariantCategory, Warehouse } from "@/types/master-data"
 import { PurchaseOrder, Quotation, Requisition, Rfq, PurchaseReturn } from "@/types/procurement"
 import { Grn } from "@/types/grn"
 import {
@@ -51,9 +51,9 @@ export function allocateUomId() {
 }
 
 export const mockCategories: Category[] = [
-  { categoryId: 3, name: "Hardware", parentId: null },
-  { categoryId: 12, name: "Fasteners", parentId: 3 },
-  { categoryId: 20, name: "Power Tools", parentId: null },
+  { categoryId: 3, name: "Hardware", parentId: null, createdAt: "2026-06-01T08:00:00Z" },
+  { categoryId: 12, name: "Fasteners", parentId: 3, createdAt: "2026-06-01T08:05:00Z" },
+  { categoryId: 20, name: "Power Tools", parentId: null, createdAt: "2026-06-02T09:00:00Z" },
 ]
 
 let nextCategoryId = 21
@@ -62,6 +62,28 @@ export function allocateCategoryId() {
   return nextCategoryId++
 }
 
+export const mockBrands: Brand[] = [
+  { brandId: 1, name: "Bosch", createdAt: "2026-06-01T08:00:00Z" },
+  { brandId: 2, name: "Makita", createdAt: "2026-06-02T09:00:00Z" },
+]
+
+let nextBrandId = 3
+
+export function allocateBrandId() {
+  return nextBrandId++
+}
+
+export const mockVariantCategories: VariantCategory[] = [
+  { variantCategoryId: 1, name: "Color", createdAt: "2026-06-01T08:00:00Z" },
+  { variantCategoryId: 2, name: "Size", createdAt: "2026-06-01T08:00:00Z" },
+]
+
+let nextVariantCategoryId = 3
+
+export function allocateVariantCategoryId() {
+  return nextVariantCategoryId++
+}
+
 export const mockVendors: Vendor[] = [
   {
     vendorId: 5,

Frontend/erp-system/lib/api/variants.ts

@@ -0,0 +1,49 @@
+// One typed client method per Variant Category endpoint, mirroring lib/api/brands.ts.
+// In-memory sample data (lib/api/mock-data.ts) — no backend API calls.
+import { PagedResponse } from "@/types/common"
+import { CreateVariantCategoryRequest, UpdateVariantCategoryRequest, VariantCategory } from "@/types/master-data"
+import { allocateVariantCategoryId, mockVariantCategories, mockDelay } from "@/lib/api/mock-data"
+
+export const variantCategoriesApi = {
+  list(): Promise<PagedResponse<VariantCategory>> {
+    const items = [...mockVariantCategories].sort((a, b) => a.name.localeCompare(b.name))
+    return mockDelay({
+      items,
+      pagination: { page: 1, pageSize: items.length || 1, totalItems: items.length, totalPages: 1 },
+    })
+  },
+
+  create(request: CreateVariantCategoryRequest): Promise<VariantCategory> {
+    const name = request.name.trim()
+    if (!name) return Promise.reject(new Error("Category name is required."))
+    if (mockVariantCategories.some((c) => c.name.toLowerCase() === name.toLowerCase())) {
+      return Promise.reject(new Error(`Variant category "${name}" already exists.`))
+    }
+    const category: VariantCategory = {
+      variantCategoryId: allocateVariantCategoryId(),
+      name,
+      createdAt: new Date().toISOString(),
+    }
+    mockVariantCategories.push(category)
+    return mockDelay(category)
+  },
+
+  update(variantCategoryId: number, request: UpdateVariantCategoryRequest): Promise<VariantCategory> {
+    const name = request.name.trim()
+    if (!name) return Promise.reject(new Error("Category name is required."))
+    const category = mockVariantCategories.find((c) => c.variantCategoryId === variantCategoryId)
+    if (!category) return Promise.reject(new Error("Variant category not found."))
+    if (mockVariantCategories.some((c) => c.variantCategoryId !== variantCategoryId && c.name.toLowerCase() === name.toLowerCase())) {
+      return Promise.reject(new Error(`Variant category "${name}" already exists.`))
+    }
+    category.name = name
+    return mockDelay(category)
+  },
+
+  remove(variantCategoryId: number): Promise<void> {
+    const index = mockVariantCategories.findIndex((c) => c.variantCategoryId === variantCategoryId)
+    if (index === -1) return Promise.reject(new Error("Variant category not found."))
+    mockVariantCategories.splice(index, 1)
+    return mockDelay(undefined)
+  },
+}

Frontend/erp-system/lib/validations/master-data.ts

@@ -50,3 +50,25 @@ export function validateCategoryName(name: string): Record<string, string> {
   if (!name.trim()) errors.name = "Category name is required"
   return errors
 }
+
+export function validateBrandName(name: string): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!name.trim()) errors.name = "Brand name is required"
+  return errors
+}
+
+export function validateVariantCategoryName(name: string): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!name.trim()) errors.name = "Category name is required"
+  return errors
+}
+
+export function validateVariantItemForm(input: {
+  categoryId: number | null
+  hasVariants: boolean
+}): Record<string, string> {
+  const errors: Record<string, string> = {}
+  if (!input.categoryId) errors.categoryId = "Select a category"
+  if (!input.hasVariants) errors.variants = "Check at least one variant category and add its values"
+  return errors
+}