task-d complate

src/features/crm/customers/api/types.ts

@@ -77,6 +77,15 @@ export interface CustomerActivityRecord {
   actorName: string | null;
 }
 
+export interface CustomerRelatedEnquiryItem {
+  id: string;
+  code: string;
+  title: string;
+  status: string;
+  productType: string;
+  updatedAt: string;
+}
+
 export interface CustomerReferenceData {
   branches: BranchOption[];
   customerTypes: CustomerOption[];

src/features/crm/customers/components/customer-detail.tsx

@@ -14,6 +14,7 @@ import type { CustomerReferenceData } from '../api/types';
 import { CustomerFormSheet } from './customer-form-sheet';
 import { CustomerContactsTab } from './customer-contacts-tab';
 import { CustomerStatusBadge } from './customer-status-badge';
+import type { CustomerRelatedEnquiryItem } from '../api/types';
 
 function FieldItem({ label, value }: { label: string; value: string | null | undefined }) {
   return (
@@ -28,7 +29,8 @@ export function CustomerDetail({
   customerId,
   referenceData,
   canUpdate,
-  canManageContacts
+  canManageContacts,
+  relatedEnquiries
 }: {
   customerId: string;
   referenceData: CustomerReferenceData;
@@ -38,6 +40,7 @@ export function CustomerDetail({
     update: boolean;
     delete: boolean;
   };
+  relatedEnquiries: CustomerRelatedEnquiryItem[];
 }) {
   const { data } = useSuspenseQuery(customerByIdOptions(customerId));
   const [editOpen, setEditOpen] = useState(false);
@@ -212,14 +215,36 @@ export function CustomerDetail({
                     <CardHeader>
                       <CardTitle>Related Documents</CardTitle>
                       <CardDescription>
-                        Task C stops at customer and contact scope, so downstream CRM documents stay
-                        intentionally deferred.
+                        Production enquiry links are now visible here, while quotation and approval
+                        modules stay deferred.
                       </CardDescription>
                     </CardHeader>
                     <CardContent>
-                      <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
-                        Enquiry, quotation, and approval links will land here in Task D and later.
-                      </div>
+                      {!relatedEnquiries.length ? (
+                        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                          No enquiries have been linked to this customer yet.
+                        </div>
+                      ) : (
+                        <div className='space-y-3'>
+                          {relatedEnquiries.map((enquiry) => (
+                            <Link
+                              key={enquiry.id}
+                              href={`/dashboard/crm/enquiries/${enquiry.id}`}
+                              className='block rounded-lg border p-4 transition-colors hover:bg-muted/40'
+                            >
+                              <div className='flex items-center justify-between gap-3'>
+                                <div className='space-y-1'>
+                                  <div className='font-medium'>{enquiry.title}</div>
+                                  <div className='text-muted-foreground font-mono text-xs'>
+                                    {enquiry.code}
+                                  </div>
+                                </div>
+                                <Icons.arrowRight className='text-muted-foreground h-4 w-4' />
+                              </div>
+                            </Link>
+                          ))}
+                        </div>
+                      )}
                     </CardContent>
                   </Card>
                 </TabsContent>

src/features/crm/enquiries/api/mutations.ts

@@ -0,0 +1,74 @@
+import { mutationOptions } from '@tanstack/react-query';
+import { getQueryClient } from '@/lib/query-client';
+import {
+  createEnquiry,
+  createEnquiryFollowup,
+  deleteEnquiry,
+  deleteEnquiryFollowup,
+  updateEnquiry,
+  updateEnquiryFollowup
+} from './service';
+import { enquiryKeys } from './queries';
+import type { EnquiryFollowupMutationPayload, EnquiryMutationPayload } from './types';
+
+export const createEnquiryMutation = mutationOptions({
+  mutationFn: (data: EnquiryMutationPayload) => createEnquiry(data),
+  onSuccess: () => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+  }
+});
+
+export const updateEnquiryMutation = mutationOptions({
+  mutationFn: ({ id, values }: { id: string; values: EnquiryMutationPayload }) =>
+    updateEnquiry(id, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.id) });
+  }
+});
+
+export const deleteEnquiryMutation = mutationOptions({
+  mutationFn: (id: string) => deleteEnquiry(id),
+  onSuccess: () => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.all });
+  }
+});
+
+export const createEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({
+    enquiryId,
+    values
+  }: {
+    enquiryId: string;
+    values: EnquiryFollowupMutationPayload;
+  }) => createEnquiryFollowup(enquiryId, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});
+
+export const updateEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({
+    enquiryId,
+    followupId,
+    values
+  }: {
+    enquiryId: string;
+    followupId: string;
+    values: EnquiryFollowupMutationPayload;
+  }) => updateEnquiryFollowup(enquiryId, followupId, values),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});
+
+export const deleteEnquiryFollowupMutation = mutationOptions({
+  mutationFn: ({ enquiryId, followupId }: { enquiryId: string; followupId: string }) =>
+    deleteEnquiryFollowup(enquiryId, followupId),
+  onSuccess: (_data, variables) => {
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.followups(variables.enquiryId) });
+    getQueryClient().invalidateQueries({ queryKey: enquiryKeys.detail(variables.enquiryId) });
+  }
+});

src/features/crm/enquiries/api/queries.ts

@@ -0,0 +1,28 @@
+import { queryOptions } from '@tanstack/react-query';
+import { getEnquiries, getEnquiryById, getEnquiryFollowups } from './service';
+import type { EnquiryFilters } from './types';
+
+export const enquiryKeys = {
+  all: ['crm-enquiries'] as const,
+  list: (filters: EnquiryFilters) => [...enquiryKeys.all, 'list', filters] as const,
+  detail: (id: string) => [...enquiryKeys.all, 'detail', id] as const,
+  followups: (id: string) => [...enquiryKeys.all, 'followups', id] as const
+};
+
+export const enquiriesQueryOptions = (filters: EnquiryFilters) =>
+  queryOptions({
+    queryKey: enquiryKeys.list(filters),
+    queryFn: () => getEnquiries(filters)
+  });
+
+export const enquiryByIdOptions = (id: string) =>
+  queryOptions({
+    queryKey: enquiryKeys.detail(id),
+    queryFn: () => getEnquiryById(id)
+  });
+
+export const enquiryFollowupsOptions = (id: string) =>
+  queryOptions({
+    queryKey: enquiryKeys.followups(id),
+    queryFn: () => getEnquiryFollowups(id)
+  });

src/features/crm/enquiries/api/service.ts

@@ -0,0 +1,83 @@
+import { apiClient } from '@/lib/api-client';
+import type {
+  EnquiryDetailResponse,
+  EnquiryFilters,
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupsResponse,
+  EnquiryListResponse,
+  EnquiryMutationPayload,
+  MutationSuccessResponse
+} from './types';
+
+export async function getEnquiries(filters: EnquiryFilters): Promise<EnquiryListResponse> {
+  const searchParams = new URLSearchParams();
+
+  if (filters.page) searchParams.set('page', String(filters.page));
+  if (filters.limit) searchParams.set('limit', String(filters.limit));
+  if (filters.search) searchParams.set('search', filters.search);
+  if (filters.status) searchParams.set('status', filters.status);
+  if (filters.productType) searchParams.set('productType', filters.productType);
+  if (filters.priority) searchParams.set('priority', filters.priority);
+  if (filters.branch) searchParams.set('branch', filters.branch);
+  if (filters.customer) searchParams.set('customer', filters.customer);
+  if (filters.sort) searchParams.set('sort', filters.sort);
+
+  const query = searchParams.toString();
+
+  return apiClient<EnquiryListResponse>(`/crm/enquiries${query ? `?${query}` : ''}`);
+}
+
+export async function getEnquiryById(id: string): Promise<EnquiryDetailResponse> {
+  return apiClient<EnquiryDetailResponse>(`/crm/enquiries/${id}`);
+}
+
+export async function createEnquiry(data: EnquiryMutationPayload) {
+  return apiClient<MutationSuccessResponse>('/crm/enquiries', {
+    method: 'POST',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function updateEnquiry(id: string, data: EnquiryMutationPayload) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${id}`, {
+    method: 'PATCH',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function deleteEnquiry(id: string) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${id}`, {
+    method: 'DELETE'
+  });
+}
+
+export async function getEnquiryFollowups(id: string): Promise<EnquiryFollowupsResponse> {
+  return apiClient<EnquiryFollowupsResponse>(`/crm/enquiries/${id}/followups`);
+}
+
+export async function createEnquiryFollowup(
+  enquiryId: string,
+  data: EnquiryFollowupMutationPayload
+) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups`, {
+    method: 'POST',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function updateEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  data: EnquiryFollowupMutationPayload
+) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups/${followupId}`, {
+    method: 'PATCH',
+    body: JSON.stringify(data)
+  });
+}
+
+export async function deleteEnquiryFollowup(enquiryId: string, followupId: string) {
+  return apiClient<MutationSuccessResponse>(`/crm/enquiries/${enquiryId}/followups/${followupId}`, {
+    method: 'DELETE'
+  });
+}

src/features/crm/enquiries/api/types.ts

@@ -0,0 +1,189 @@
+export interface EnquiryOption {
+  id: string;
+  code: string;
+  label: string;
+  value: string | null;
+}
+
+export interface EnquiryBranchOption {
+  id: string;
+  code: string;
+  name: string;
+  value: string | null;
+}
+
+export interface EnquiryCustomerLookup {
+  id: string;
+  code: string;
+  name: string;
+  branchId: string | null;
+}
+
+export interface EnquiryContactLookup {
+  id: string;
+  customerId: string;
+  name: string;
+  email: string | null;
+  mobile: string | null;
+  isPrimary: boolean;
+}
+
+export interface EnquiryRecord {
+  id: string;
+  organizationId: string;
+  branchId: string | null;
+  code: string;
+  customerId: string;
+  contactId: string | null;
+  title: string;
+  description: string | null;
+  requirement: string | null;
+  projectName: string | null;
+  projectLocation: string | null;
+  productType: string;
+  status: string;
+  priority: string;
+  leadChannel: string | null;
+  estimatedValue: number | null;
+  chancePercent: number | null;
+  expectedCloseDate: string | null;
+  competitor: string | null;
+  source: string | null;
+  notes: string | null;
+  isHotProject: boolean;
+  isActive: boolean;
+  createdAt: string;
+  updatedAt: string;
+  deletedAt: string | null;
+  createdBy: string;
+  updatedBy: string;
+}
+
+export interface EnquiryListItem extends EnquiryRecord {
+  customerName: string;
+  contactName: string | null;
+  followupCount: number;
+}
+
+export interface EnquiryFollowupRecord {
+  id: string;
+  organizationId: string;
+  enquiryId: string;
+  followupDate: string;
+  followupType: string;
+  contactId: string | null;
+  outcome: string | null;
+  notes: string | null;
+  nextFollowupDate: string | null;
+  nextAction: string | null;
+  createdAt: string;
+  updatedAt: string;
+  deletedAt: string | null;
+  createdBy: string;
+  updatedBy: string;
+}
+
+export interface EnquiryActivityRecord {
+  id: string;
+  action: string;
+  entityType: string;
+  entityId: string;
+  createdAt: string;
+  userId: string;
+  actorName: string | null;
+}
+
+export interface EnquiryReferenceData {
+  branches: EnquiryBranchOption[];
+  statuses: EnquiryOption[];
+  productTypes: EnquiryOption[];
+  priorities: EnquiryOption[];
+  leadChannels: EnquiryOption[];
+  followupTypes: EnquiryOption[];
+  customers: EnquiryCustomerLookup[];
+  contacts: EnquiryContactLookup[];
+}
+
+export interface EnquiryFilters {
+  page?: number;
+  limit?: number;
+  search?: string;
+  status?: string;
+  productType?: string;
+  priority?: string;
+  branch?: string;
+  customer?: string;
+  sort?: string;
+}
+
+export interface EnquiryListResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  totalItems: number;
+  offset: number;
+  limit: number;
+  items: EnquiryListItem[];
+}
+
+export interface EnquiryDetailResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  enquiry: EnquiryRecord;
+  activity: EnquiryActivityRecord[];
+}
+
+export interface EnquiryFollowupsResponse {
+  success: boolean;
+  time: string;
+  message: string;
+  items: EnquiryFollowupRecord[];
+}
+
+export interface EnquiryMutationPayload {
+  customerId: string;
+  contactId?: string | null;
+  title: string;
+  description?: string;
+  requirement?: string;
+  projectName?: string;
+  projectLocation?: string;
+  branchId?: string | null;
+  productType: string;
+  status: string;
+  priority: string;
+  leadChannel?: string | null;
+  estimatedValue?: number | null;
+  chancePercent?: number | null;
+  expectedCloseDate?: string | null;
+  competitor?: string;
+  source?: string;
+  isHotProject?: boolean;
+  notes?: string;
+  isActive?: boolean;
+}
+
+export interface EnquiryFollowupMutationPayload {
+  followupDate: string;
+  followupType: string;
+  contactId?: string | null;
+  outcome?: string;
+  notes?: string;
+  nextFollowupDate?: string | null;
+  nextAction?: string;
+}
+
+export interface EnquiryCustomerRelationItem {
+  id: string;
+  code: string;
+  title: string;
+  status: string;
+  productType: string;
+  updatedAt: string;
+}
+
+export interface MutationSuccessResponse {
+  success: boolean;
+  message: string;
+}

src/features/crm/enquiries/components/enquiries-table.tsx

@@ -0,0 +1,70 @@
+'use client';
+
+import { useMemo } from 'react';
+import { parseAsInteger, parseAsString, useQueryStates } from 'nuqs';
+import { useSuspenseQuery } from '@tanstack/react-query';
+import { DataTable } from '@/components/ui/table/data-table';
+import { DataTableToolbar } from '@/components/ui/table/data-table-toolbar';
+import { useDataTable } from '@/hooks/use-data-table';
+import { getSortingStateParser } from '@/lib/parsers';
+import { enquiriesQueryOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { getEnquiryColumns } from './enquiry-columns';
+
+export function EnquiriesTable({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const columns = useMemo(
+    () => getEnquiryColumns({ referenceData, canUpdate, canDelete }),
+    [referenceData, canUpdate, canDelete]
+  );
+  const columnIds = columns.map((column) => column.id).filter(Boolean) as string[];
+  const [params] = useQueryStates({
+    page: parseAsInteger.withDefault(1),
+    perPage: parseAsInteger.withDefault(10),
+    name: parseAsString,
+    status: parseAsString,
+    productType: parseAsString,
+    priority: parseAsString,
+    branch: parseAsString,
+    customer: parseAsString,
+    sort: getSortingStateParser(columnIds).withDefault([])
+  });
+
+  const filters = {
+    page: params.page,
+    limit: params.perPage,
+    ...(params.name && { search: params.name }),
+    ...(params.status && { status: params.status }),
+    ...(params.productType && { productType: params.productType }),
+    ...(params.priority && { priority: params.priority }),
+    ...(params.branch && { branch: params.branch }),
+    ...(params.customer && { customer: params.customer }),
+    ...(params.sort.length > 0 && { sort: JSON.stringify(params.sort) })
+  };
+
+  const { data } = useSuspenseQuery(enquiriesQueryOptions(filters));
+  const pageCount = Math.ceil(data.totalItems / params.perPage);
+  const { table } = useDataTable({
+    data: data.items,
+    columns,
+    pageCount,
+    shallow: true,
+    debounceMs: 500,
+    initialState: {
+      columnPinning: { right: ['actions'] }
+    }
+  });
+
+  return (
+    <DataTable table={table}>
+      <DataTableToolbar table={table} />
+    </DataTable>
+  );
+}

src/features/crm/enquiries/components/enquiry-cell-action.tsx

@@ -0,0 +1,82 @@
+'use client';
+
+import { useState } from 'react';
+import { useRouter } from 'next/navigation';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { AlertModal } from '@/components/modal/alert-modal';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuLabel,
+  DropdownMenuTrigger
+} from '@/components/ui/dropdown-menu';
+import { deleteEnquiryMutation } from '../api/mutations';
+import type { EnquiryListItem, EnquiryReferenceData } from '../api/types';
+import { EnquiryFormSheet } from './enquiry-form-sheet';
+
+export function EnquiryCellAction({
+  data,
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  data: EnquiryListItem;
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const router = useRouter();
+  const [deleteOpen, setDeleteOpen] = useState(false);
+  const [editOpen, setEditOpen] = useState(false);
+
+  const deleteMutation = useMutation({
+    ...deleteEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry deleted successfully');
+      setDeleteOpen(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to delete enquiry')
+  });
+
+  return (
+    <>
+      <AlertModal
+        isOpen={deleteOpen}
+        onClose={() => setDeleteOpen(false)}
+        onConfirm={() => deleteMutation.mutate(data.id)}
+        loading={deleteMutation.isPending}
+      />
+      <EnquiryFormSheet
+        enquiry={data}
+        open={editOpen}
+        onOpenChange={setEditOpen}
+        referenceData={referenceData}
+      />
+      <DropdownMenu modal={false}>
+        <DropdownMenuTrigger asChild>
+          <Button variant='ghost' className='h-8 w-8 p-0'>
+            <span className='sr-only'>Open actions</span>
+            <Icons.ellipsis className='h-4 w-4' />
+          </Button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent align='end'>
+          <DropdownMenuLabel>Actions</DropdownMenuLabel>
+          <DropdownMenuItem onClick={() => router.push(`/dashboard/crm/enquiries/${data.id}`)}>
+            <Icons.arrowRight className='mr-2 h-4 w-4' /> View
+          </DropdownMenuItem>
+          <DropdownMenuItem onClick={() => setEditOpen(true)} disabled={!canUpdate}>
+            <Icons.edit className='mr-2 h-4 w-4' /> Edit
+          </DropdownMenuItem>
+          <DropdownMenuItem onClick={() => setDeleteOpen(true)} disabled={!canDelete}>
+            <Icons.trash className='mr-2 h-4 w-4' /> Delete
+          </DropdownMenuItem>
+        </DropdownMenuContent>
+      </DropdownMenu>
+    </>
+  );
+}

src/features/crm/enquiries/components/enquiry-columns.tsx

@@ -0,0 +1,176 @@
+'use client';
+
+import Link from 'next/link';
+import type { Column, ColumnDef } from '@tanstack/react-table';
+import { Badge } from '@/components/ui/badge';
+import { DataTableColumnHeader } from '@/components/ui/table/data-table-column-header';
+import { Icons } from '@/components/icons';
+import type { EnquiryListItem, EnquiryReferenceData } from '../api/types';
+import { EnquiryCellAction } from './enquiry-cell-action';
+import { EnquiryStatusBadge } from './enquiry-status-badge';
+
+export function getEnquiryColumns({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}): ColumnDef<EnquiryListItem>[] {
+  const statusMap = new Map(referenceData.statuses.map((item) => [item.id, item]));
+  const productTypeMap = new Map(referenceData.productTypes.map((item) => [item.id, item]));
+  const priorityMap = new Map(referenceData.priorities.map((item) => [item.id, item]));
+  const branchMap = new Map(referenceData.branches.map((item) => [item.id, item]));
+
+  return [
+    {
+      id: 'title',
+      accessorKey: 'title',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Enquiry' />
+      ),
+      cell: ({ row }) => (
+        <div className='flex flex-col'>
+          <Link
+            href={`/dashboard/crm/enquiries/${row.original.id}`}
+            className='font-medium hover:underline'
+          >
+            {row.original.title}
+          </Link>
+          <span className='text-muted-foreground text-xs'>
+            {row.original.code} • {row.original.customerName}
+          </span>
+        </div>
+      ),
+      meta: {
+        label: 'Enquiry',
+        placeholder: 'Search enquiries...',
+        variant: 'text' as const,
+        icon: Icons.search
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'status',
+      accessorKey: 'status',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Status' />
+      ),
+      cell: ({ row }) => {
+        const status = statusMap.get(row.original.status);
+        return <EnquiryStatusBadge code={status?.code} label={status?.label ?? 'Unknown'} />;
+      },
+      meta: {
+        label: 'Status',
+        variant: 'multiSelect' as const,
+        options: referenceData.statuses.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'productType',
+      accessorKey: 'productType',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Product Type' />
+      ),
+      cell: ({ row }) => (
+        <Badge variant='outline'>
+          {productTypeMap.get(row.original.productType)?.label ?? 'Unknown'}
+        </Badge>
+      ),
+      meta: {
+        label: 'Product Type',
+        variant: 'multiSelect' as const,
+        options: referenceData.productTypes.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'priority',
+      accessorKey: 'priority',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Priority' />
+      ),
+      cell: ({ row }) => (
+        <Badge variant='secondary'>
+          {priorityMap.get(row.original.priority)?.label ?? 'Unknown'}
+        </Badge>
+      ),
+      meta: {
+        label: 'Priority',
+        variant: 'multiSelect' as const,
+        options: referenceData.priorities.map((item) => ({
+          value: item.id,
+          label: item.label
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'branch',
+      accessorFn: (row) => row.branchId ?? '',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Branch' />
+      ),
+      cell: ({ row }) => (
+        <span>
+          {row.original.branchId
+            ? (branchMap.get(row.original.branchId)?.name ?? 'Unknown')
+            : 'Unassigned'}
+        </span>
+      ),
+      meta: {
+        label: 'Branch',
+        variant: 'multiSelect' as const,
+        options: referenceData.branches.map((item) => ({
+          value: item.id,
+          label: item.name
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'customer',
+      accessorFn: (row) => row.customerId,
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Customer' />
+      ),
+      cell: ({ row }) => <span>{row.original.customerName}</span>,
+      meta: {
+        label: 'Customer',
+        variant: 'multiSelect' as const,
+        options: referenceData.customers.map((item) => ({
+          value: item.id,
+          label: item.name
+        }))
+      },
+      enableColumnFilter: true
+    },
+    {
+      id: 'followupCount',
+      accessorKey: 'followupCount',
+      header: ({ column }: { column: Column<EnquiryListItem, unknown> }) => (
+        <DataTableColumnHeader column={column} title='Follow-ups' />
+      ),
+      cell: ({ row }) => <span>{row.original.followupCount}</span>
+    },
+    {
+      id: 'actions',
+      cell: ({ row }) => (
+        <EnquiryCellAction
+          data={row.original}
+          referenceData={referenceData}
+          canUpdate={canUpdate}
+          canDelete={canDelete}
+        />
+      )
+    }
+  ];
+}

src/features/crm/enquiries/components/enquiry-detail.tsx

@@ -0,0 +1,288 @@
+'use client';
+
+import Link from 'next/link';
+import { useMemo, useState } from 'react';
+import { useSuspenseQuery } from '@tanstack/react-query';
+import { Icons } from '@/components/icons';
+import { Badge } from '@/components/ui/badge';
+import { Button } from '@/components/ui/button';
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
+import { Separator } from '@/components/ui/separator';
+import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs';
+import { enquiryByIdOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { EnquiryFormSheet } from './enquiry-form-sheet';
+import { EnquiryFollowupsTab } from './enquiry-followups-tab';
+import { EnquiryStatusBadge } from './enquiry-status-badge';
+
+function FieldItem({ label, value }: { label: string; value: string | null | undefined }) {
+  return (
+    <div className='space-y-1'>
+      <div className='text-muted-foreground text-xs'>{label}</div>
+      <div className='text-sm'>{value || '-'}</div>
+    </div>
+  );
+}
+
+export function EnquiryDetail({
+  enquiryId,
+  referenceData,
+  canUpdate,
+  canManageFollowups
+}: {
+  enquiryId: string;
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canManageFollowups: {
+    create: boolean;
+    update: boolean;
+    delete: boolean;
+  };
+}) {
+  const { data } = useSuspenseQuery(enquiryByIdOptions(enquiryId));
+  const [editOpen, setEditOpen] = useState(false);
+  const enquiry = data.enquiry;
+  const branchMap = useMemo(
+    () => new Map(referenceData.branches.map((item) => [item.id, item.name])),
+    [referenceData]
+  );
+  const customerMap = useMemo(
+    () => new Map(referenceData.customers.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const contactMap = useMemo(
+    () => new Map(referenceData.contacts.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const statusMap = useMemo(
+    () => new Map(referenceData.statuses.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const productTypeMap = useMemo(
+    () => new Map(referenceData.productTypes.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const priorityMap = useMemo(
+    () => new Map(referenceData.priorities.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const leadChannelMap = useMemo(
+    () => new Map(referenceData.leadChannels.map((item) => [item.id, item])),
+    [referenceData]
+  );
+  const customer = customerMap.get(enquiry.customerId);
+  const contact = enquiry.contactId ? contactMap.get(enquiry.contactId) : null;
+  const status = statusMap.get(enquiry.status);
+
+  return (
+    <div className='space-y-6'>
+      <div className='flex flex-col gap-4 rounded-xl border p-5 lg:flex-row lg:items-start lg:justify-between'>
+        <div className='space-y-3'>
+          <div className='flex items-center gap-2'>
+            <Button asChild variant='ghost' size='icon'>
+              <Link href='/dashboard/crm/enquiries'>
+                <Icons.chevronLeft className='h-4 w-4' />
+              </Link>
+            </Button>
+            <span className='text-muted-foreground font-mono text-sm'>{enquiry.code}</span>
+            <EnquiryStatusBadge code={status?.code} label={status?.label ?? 'Unknown'} />
+            {enquiry.isHotProject ? <Badge>Hot</Badge> : null}
+          </div>
+          <div>
+            <h2 className='text-2xl font-semibold'>{enquiry.title}</h2>
+            <p className='text-muted-foreground text-sm'>
+              {customer?.name ?? 'Unknown customer'}
+              {contact ? ` • ${contact.name}` : ''}
+            </p>
+          </div>
+        </div>
+        <div className='flex flex-wrap gap-2'>
+          {canUpdate ? (
+            <Button variant='outline' onClick={() => setEditOpen(true)}>
+              <Icons.edit className='mr-2 h-4 w-4' /> Edit Enquiry
+            </Button>
+          ) : null}
+        </div>
+      </div>
+
+      <div className='grid gap-6 lg:grid-cols-3'>
+        <div className='space-y-6 lg:col-span-2'>
+          <Card>
+            <CardContent className='pt-6'>
+              <Tabs defaultValue='overview' className='gap-4'>
+                <TabsList>
+                  <TabsTrigger value='overview'>Overview</TabsTrigger>
+                  <TabsTrigger value='followups'>Follow-ups</TabsTrigger>
+                  <TabsTrigger value='activity'>Activity</TabsTrigger>
+                  <TabsTrigger value='related'>Related Quotations</TabsTrigger>
+                </TabsList>
+                <TabsContent value='overview'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Overview</CardTitle>
+                      <CardDescription>
+                        Opportunity scope, project context, and commercial direction.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent className='grid gap-4 md:grid-cols-2 xl:grid-cols-4'>
+                      <FieldItem label='Customer' value={customer?.name} />
+                      <FieldItem label='Contact' value={contact?.name} />
+                      <FieldItem
+                        label='Branch'
+                        value={enquiry.branchId ? branchMap.get(enquiry.branchId) : null}
+                      />
+                      <FieldItem label='Active' value={enquiry.isActive ? 'Yes' : 'No'} />
+                      <FieldItem
+                        label='Product Type'
+                        value={productTypeMap.get(enquiry.productType)?.label}
+                      />
+                      <FieldItem
+                        label='Priority'
+                        value={priorityMap.get(enquiry.priority)?.label}
+                      />
+                      <FieldItem
+                        label='Lead Channel'
+                        value={leadChannelMap.get(enquiry.leadChannel ?? '')?.label}
+                      />
+                      <FieldItem
+                        label='Expected Close Date'
+                        value={
+                          enquiry.expectedCloseDate
+                            ? new Date(enquiry.expectedCloseDate).toLocaleDateString()
+                            : null
+                        }
+                      />
+                      <FieldItem
+                        label='Estimated Value'
+                        value={
+                          enquiry.estimatedValue !== null
+                            ? enquiry.estimatedValue.toLocaleString()
+                            : null
+                        }
+                      />
+                      <FieldItem
+                        label='Chance %'
+                        value={enquiry.chancePercent !== null ? `${enquiry.chancePercent}%` : null}
+                      />
+                      <FieldItem label='Competitor' value={enquiry.competitor} />
+                      <FieldItem label='Source' value={enquiry.source} />
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem
+                          label='Project'
+                          value={
+                            [enquiry.projectName, enquiry.projectLocation]
+                              .filter(Boolean)
+                              .join(' • ') || null
+                          }
+                        />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Description' value={enquiry.description} />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Requirement' value={enquiry.requirement} />
+                      </div>
+                      <div className='md:col-span-2 xl:col-span-4'>
+                        <FieldItem label='Notes' value={enquiry.notes} />
+                      </div>
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+                <TabsContent value='followups'>
+                  <EnquiryFollowupsTab
+                    enquiryId={enquiryId}
+                    customerId={enquiry.customerId}
+                    referenceData={referenceData}
+                    canCreate={canManageFollowups.create}
+                    canUpdate={canManageFollowups.update}
+                    canDelete={canManageFollowups.delete}
+                  />
+                </TabsContent>
+                <TabsContent value='activity'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Activity</CardTitle>
+                      <CardDescription>
+                        Audit events for the enquiry and its follow-up records.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent className='space-y-4'>
+                      {!data.activity.length ? (
+                        <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                          No activity recorded yet.
+                        </div>
+                      ) : (
+                        data.activity.map((item, index) => (
+                          <div key={item.id} className='space-y-4'>
+                            <div className='flex items-start gap-3'>
+                              <div className='bg-primary mt-2 h-2 w-2 rounded-full' />
+                              <div className='space-y-1'>
+                                <div className='flex items-center gap-2'>
+                                  <Badge variant='outline' className='capitalize'>
+                                    {item.action}
+                                  </Badge>
+                                  <Badge variant='secondary'>
+                                    {item.entityType.replaceAll('_', ' ')}
+                                  </Badge>
+                                  <span className='text-sm font-medium'>
+                                    {item.actorName ?? item.userId}
+                                  </span>
+                                </div>
+                                <div className='text-muted-foreground text-xs'>
+                                  {new Date(item.createdAt).toLocaleString()}
+                                </div>
+                              </div>
+                            </div>
+                            {index < data.activity.length - 1 ? <Separator /> : null}
+                          </div>
+                        ))
+                      )}
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+                <TabsContent value='related'>
+                  <Card>
+                    <CardHeader>
+                      <CardTitle>Related Quotations</CardTitle>
+                      <CardDescription>
+                        Task D ends at enquiry readiness, so quotation production stays
+                        intentionally deferred.
+                      </CardDescription>
+                    </CardHeader>
+                    <CardContent>
+                      <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+                        Quotation linkage will land here in Task E.
+                      </div>
+                    </CardContent>
+                  </Card>
+                </TabsContent>
+              </Tabs>
+            </CardContent>
+          </Card>
+        </div>
+
+        <div className='space-y-6'>
+          <Card>
+            <CardHeader>
+              <CardTitle>Record Snapshot</CardTitle>
+              <CardDescription>Operational metadata for this enquiry row.</CardDescription>
+            </CardHeader>
+            <CardContent className='space-y-4'>
+              <FieldItem label='Created By' value={enquiry.createdBy} />
+              <FieldItem label='Updated By' value={enquiry.updatedBy} />
+              <FieldItem label='Created At' value={new Date(enquiry.createdAt).toLocaleString()} />
+              <FieldItem label='Updated At' value={new Date(enquiry.updatedAt).toLocaleString()} />
+            </CardContent>
+          </Card>
+        </div>
+      </div>
+
+      <EnquiryFormSheet
+        enquiry={enquiry}
+        open={editOpen}
+        onOpenChange={setEditOpen}
+        referenceData={referenceData}
+      />
+    </div>
+  );
+}

src/features/crm/enquiries/components/enquiry-followups-tab.tsx

@@ -0,0 +1,150 @@
+'use client';
+
+import { useState } from 'react';
+import { useMutation, useSuspenseQuery } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { AlertModal } from '@/components/modal/alert-modal';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
+import { Badge } from '@/components/ui/badge';
+import { deleteEnquiryFollowupMutation } from '../api/mutations';
+import { enquiryFollowupsOptions } from '../api/queries';
+import type { EnquiryReferenceData } from '../api/types';
+import { FollowupFormSheet } from './followup-form-sheet';
+
+export function EnquiryFollowupsTab({
+  enquiryId,
+  customerId,
+  referenceData,
+  canCreate,
+  canUpdate,
+  canDelete
+}: {
+  enquiryId: string;
+  customerId: string;
+  referenceData: EnquiryReferenceData;
+  canCreate: boolean;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const { data } = useSuspenseQuery(enquiryFollowupsOptions(enquiryId));
+  const [selectedId, setSelectedId] = useState<string | null>(null);
+  const [open, setOpen] = useState(false);
+  const [deleteOpen, setDeleteOpen] = useState(false);
+  const selected = data.items.find((item) => item.id === selectedId);
+  const followupTypeMap = new Map(referenceData.followupTypes.map((item) => [item.id, item.label]));
+
+  const deleteMutation = useMutation({
+    ...deleteEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up deleted successfully');
+      setDeleteOpen(false);
+      setSelectedId(null);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to delete follow-up')
+  });
+
+  return (
+    <Card>
+      <CardHeader className='flex flex-row items-start justify-between gap-4'>
+        <div>
+          <CardTitle>Follow-ups</CardTitle>
+          <CardDescription>
+            Track the latest contact moments, outcomes, and next steps for this enquiry.
+          </CardDescription>
+        </div>
+        {canCreate ? (
+          <Button
+            size='sm'
+            onClick={() => {
+              setSelectedId(null);
+              setOpen(true);
+            }}
+          >
+            <Icons.add className='mr-2 h-4 w-4' /> Add Follow-up
+          </Button>
+        ) : null}
+      </CardHeader>
+      <CardContent className='space-y-4'>
+        {!data.items.length ? (
+          <div className='text-muted-foreground rounded-lg border border-dashed p-8 text-center text-sm'>
+            No follow-ups recorded yet.
+          </div>
+        ) : (
+          data.items.map((item) => (
+            <div
+              key={item.id}
+              className='flex flex-col gap-3 rounded-lg border p-4 md:flex-row md:items-start md:justify-between'
+            >
+              <div className='space-y-2'>
+                <div className='flex flex-wrap items-center gap-2'>
+                  <Badge variant='outline'>
+                    {followupTypeMap.get(item.followupType) ?? 'Unknown type'}
+                  </Badge>
+                  <span className='text-sm font-medium'>
+                    {new Date(item.followupDate).toLocaleDateString()}
+                  </span>
+                </div>
+                {item.outcome ? <p className='text-sm'>{item.outcome}</p> : null}
+                {item.nextAction ? (
+                  <p className='text-muted-foreground text-sm'>Next action: {item.nextAction}</p>
+                ) : null}
+                {item.nextFollowupDate ? (
+                  <p className='text-muted-foreground text-sm'>
+                    Next follow-up: {new Date(item.nextFollowupDate).toLocaleDateString()}
+                  </p>
+                ) : null}
+                {item.notes ? <p className='text-muted-foreground text-sm'>{item.notes}</p> : null}
+              </div>
+              <div className='flex gap-2'>
+                <Button
+                  variant='outline'
+                  size='sm'
+                  disabled={!canUpdate}
+                  onClick={() => {
+                    setSelectedId(item.id);
+                    setOpen(true);
+                  }}
+                >
+                  <Icons.edit className='mr-2 h-4 w-4' /> Edit
+                </Button>
+                <Button
+                  variant='outline'
+                  size='sm'
+                  disabled={!canDelete}
+                  onClick={() => {
+                    setSelectedId(item.id);
+                    setDeleteOpen(true);
+                  }}
+                >
+                  <Icons.trash className='mr-2 h-4 w-4' /> Delete
+                </Button>
+              </div>
+            </div>
+          ))
+        )}
+      </CardContent>
+
+      <FollowupFormSheet
+        enquiryId={enquiryId}
+        followup={selected}
+        open={open}
+        onOpenChange={setOpen}
+        referenceData={referenceData}
+        customerId={customerId}
+      />
+      <AlertModal
+        isOpen={deleteOpen}
+        onClose={() => setDeleteOpen(false)}
+        onConfirm={() => {
+          if (selectedId) {
+            deleteMutation.mutate({ enquiryId, followupId: selectedId });
+          }
+        }}
+        loading={deleteMutation.isPending}
+      />
+    </Card>
+  );
+}

src/features/crm/enquiries/components/enquiry-form-sheet.tsx

@@ -0,0 +1,377 @@
+'use client';
+
+import * as React from 'react';
+import { useEffect, useMemo, useState } from 'react';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue
+} from '@/components/ui/select';
+import {
+  Sheet,
+  SheetContent,
+  SheetDescription,
+  SheetFooter,
+  SheetHeader,
+  SheetTitle
+} from '@/components/ui/sheet';
+import { useAppForm, useFormFields } from '@/components/ui/tanstack-form';
+import { createEnquiryMutation, updateEnquiryMutation } from '../api/mutations';
+import type { EnquiryMutationPayload, EnquiryRecord, EnquiryReferenceData } from '../api/types';
+import { enquirySchema, type EnquiryFormValues } from '../schemas/enquiry.schema';
+
+function toDefaultValues(
+  enquiry: EnquiryRecord | undefined,
+  referenceData: EnquiryReferenceData
+): EnquiryFormValues {
+  return {
+    customerId: enquiry?.customerId ?? referenceData.customers[0]?.id ?? '',
+    contactId: enquiry?.contactId ?? undefined,
+    title: enquiry?.title ?? '',
+    description: enquiry?.description ?? '',
+    requirement: enquiry?.requirement ?? '',
+    projectName: enquiry?.projectName ?? '',
+    projectLocation: enquiry?.projectLocation ?? '',
+    branchId: enquiry?.branchId ?? undefined,
+    productType: enquiry?.productType ?? referenceData.productTypes[0]?.id ?? '',
+    status: enquiry?.status ?? referenceData.statuses[0]?.id ?? '',
+    priority:
+      enquiry?.priority ?? referenceData.priorities[1]?.id ?? referenceData.priorities[0]?.id ?? '',
+    leadChannel: enquiry?.leadChannel ?? undefined,
+    estimatedValue: enquiry?.estimatedValue ? String(enquiry.estimatedValue) : '',
+    chancePercent:
+      enquiry?.chancePercent !== null && enquiry?.chancePercent !== undefined
+        ? String(enquiry.chancePercent)
+        : '',
+    expectedCloseDate: enquiry?.expectedCloseDate ? enquiry.expectedCloseDate.slice(0, 10) : '',
+    competitor: enquiry?.competitor ?? '',
+    source: enquiry?.source ?? '',
+    isHotProject: enquiry?.isHotProject ?? false,
+    notes: enquiry?.notes ?? '',
+    isActive: enquiry?.isActive ?? true
+  };
+}
+
+export function EnquiryFormSheet({
+  enquiry,
+  open,
+  onOpenChange,
+  referenceData
+}: {
+  enquiry?: EnquiryRecord;
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+  referenceData: EnquiryReferenceData;
+}) {
+  const isEdit = !!enquiry;
+  const defaultValues = useMemo(
+    () => toDefaultValues(enquiry, referenceData),
+    [enquiry, referenceData]
+  );
+  const [selectedCustomerId, setSelectedCustomerId] = useState(defaultValues.customerId);
+  const { FormTextField, FormTextareaField, FormSelectField, FormSwitchField } =
+    useFormFields<EnquiryFormValues>();
+
+  const createMutation = useMutation({
+    ...createEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry created successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to create enquiry')
+  });
+
+  const updateMutation = useMutation({
+    ...updateEnquiryMutation,
+    onSuccess: () => {
+      toast.success('Enquiry updated successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to update enquiry')
+  });
+
+  const contactsForCustomer = referenceData.contacts.filter(
+    (contact) => contact.customerId === selectedCustomerId
+  );
+
+  const form = useAppForm({
+    defaultValues,
+    validators: {
+      onSubmit: enquirySchema
+    },
+    onSubmit: async ({ value }) => {
+      const payload: EnquiryMutationPayload = {
+        customerId: value.customerId,
+        contactId: value.contactId || null,
+        title: value.title,
+        description: value.description,
+        requirement: value.requirement,
+        projectName: value.projectName,
+        projectLocation: value.projectLocation,
+        branchId: value.branchId || null,
+        productType: value.productType,
+        status: value.status,
+        priority: value.priority,
+        leadChannel: value.leadChannel || null,
+        estimatedValue: value.estimatedValue ? Number(value.estimatedValue) : null,
+        chancePercent: value.chancePercent ? Number(value.chancePercent) : null,
+        expectedCloseDate: value.expectedCloseDate || null,
+        competitor: value.competitor,
+        source: value.source,
+        isHotProject: value.isHotProject ?? false,
+        notes: value.notes,
+        isActive: value.isActive ?? true
+      };
+
+      if (isEdit && enquiry) {
+        await updateMutation.mutateAsync({ id: enquiry.id, values: payload });
+        return;
+      }
+
+      await createMutation.mutateAsync(payload);
+    }
+  });
+
+  useEffect(() => {
+    if (!open) {
+      return;
+    }
+
+    setSelectedCustomerId(defaultValues.customerId);
+    form.reset(defaultValues);
+  }, [defaultValues, form, open]);
+
+  const isPending = createMutation.isPending || updateMutation.isPending;
+
+  return (
+    <Sheet open={open} onOpenChange={onOpenChange}>
+      <SheetContent className='flex flex-col sm:max-w-4xl'>
+        <SheetHeader>
+          <SheetTitle>{isEdit ? 'Edit Enquiry' : 'New Enquiry'}</SheetTitle>
+          <SheetDescription>
+            Capture the opportunity details before quotation and approval stages begin.
+          </SheetDescription>
+        </SheetHeader>
+
+        <div className='flex-1 overflow-auto'>
+          <form.AppForm>
+            <form.Form id='enquiry-form-sheet' className='grid gap-4 md:grid-cols-2'>
+              <form.AppField
+                name='customerId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Customer *</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value);
+                          field.handleBlur();
+                          setSelectedCustomerId(value);
+                          form.setFieldValue('contactId', '');
+                        }}
+                      >
+                        <SelectTrigger aria-label='Customer'>
+                          <SelectValue placeholder='Select customer' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {referenceData.customers.map((customer) => (
+                            <SelectItem key={customer.id} value={customer.id}>
+                              {customer.name} ({customer.code})
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+
+              <form.AppField
+                name='contactId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Contact</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value === '__none__' ? '' : value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Contact'>
+                          <SelectValue placeholder='Select contact' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {contactsForCustomer.length ? (
+                            contactsForCustomer.map((contact) => (
+                              <SelectItem key={contact.id} value={contact.id}>
+                                {contact.name}
+                                {contact.isPrimary ? ' (Primary)' : ''}
+                              </SelectItem>
+                            ))
+                          ) : (
+                            <SelectItem value='__none__'>No contact selected</SelectItem>
+                          )}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+
+              <FormTextField
+                name='title'
+                label='Title'
+                required
+                placeholder='Warehouse crane upgrade opportunity'
+              />
+              <FormTextField
+                name='projectName'
+                label='Project Name'
+                placeholder='Bangna Warehouse Expansion'
+              />
+              <FormTextField
+                name='projectLocation'
+                label='Project Location'
+                placeholder='Bangkok'
+              />
+              <FormTextField
+                name='source'
+                label='Source'
+                placeholder='Existing customer referral'
+              />
+              <FormSelectField
+                name='branchId'
+                label='Branch'
+                options={referenceData.branches.map((branch) => ({
+                  value: branch.id,
+                  label: branch.name
+                }))}
+              />
+              <FormSelectField
+                name='productType'
+                label='Product Type'
+                required
+                options={referenceData.productTypes.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='status'
+                label='Status'
+                required
+                options={referenceData.statuses.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='priority'
+                label='Priority'
+                required
+                options={referenceData.priorities.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormSelectField
+                name='leadChannel'
+                label='Lead Channel'
+                options={referenceData.leadChannels.map((item) => ({
+                  value: item.id,
+                  label: item.label
+                }))}
+              />
+              <FormTextField
+                name='estimatedValue'
+                label='Estimated Value'
+                type='number'
+                placeholder='2500000'
+              />
+              <FormTextField name='chancePercent' label='Chance %' type='number' placeholder='60' />
+              <FormTextField
+                name='expectedCloseDate'
+                label='Expected Close Date'
+                placeholder='YYYY-MM-DD'
+              />
+              <FormTextField name='competitor' label='Competitor' placeholder='Other vendor name' />
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='description'
+                  label='Description'
+                  placeholder='High-level summary of the opportunity'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='requirement'
+                  label='Requirement'
+                  placeholder='Specific technical or commercial requirements'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='notes'
+                  label='Notes'
+                  placeholder='Internal notes, blockers, or guidance for the sales team'
+                />
+              </div>
+              <div className='md:col-span-2 grid gap-4 md:grid-cols-2'>
+                <FormSwitchField
+                  name='isHotProject'
+                  label='Hot Project'
+                  description='Use for urgent or highly strategic opportunities.'
+                />
+                <FormSwitchField
+                  name='isActive'
+                  label='Active Record'
+                  description='Inactive enquiries stay in history but should not progress further.'
+                />
+              </div>
+            </form.Form>
+          </form.AppForm>
+        </div>
+
+        <SheetFooter>
+          <Button type='button' variant='outline' onClick={() => onOpenChange(false)}>
+            Cancel
+          </Button>
+          <Button type='submit' form='enquiry-form-sheet' isLoading={isPending}>
+            <Icons.check className='mr-2 h-4 w-4' />
+            {isEdit ? 'Update Enquiry' : 'Create Enquiry'}
+          </Button>
+        </SheetFooter>
+      </SheetContent>
+    </Sheet>
+  );
+}
+
+export function EnquiryFormSheetTrigger({
+  referenceData
+}: {
+  referenceData: EnquiryReferenceData;
+}) {
+  const [open, setOpen] = React.useState(false);
+
+  return (
+    <>
+      <Button onClick={() => setOpen(true)}>
+        <Icons.add className='mr-2 h-4 w-4' /> Add Enquiry
+      </Button>
+      <EnquiryFormSheet open={open} onOpenChange={setOpen} referenceData={referenceData} />
+    </>
+  );
+}

src/features/crm/enquiries/components/enquiry-listing.tsx

@@ -0,0 +1,46 @@
+import { HydrationBoundary, dehydrate } from '@tanstack/react-query';
+import { getQueryClient } from '@/lib/query-client';
+import { searchParamsCache } from '@/lib/searchparams';
+import type { EnquiryReferenceData } from '../api/types';
+import { enquiriesQueryOptions } from '../api/queries';
+import { EnquiriesTable } from './enquiries-table';
+
+export default function EnquiryListing({
+  referenceData,
+  canUpdate,
+  canDelete
+}: {
+  referenceData: EnquiryReferenceData;
+  canUpdate: boolean;
+  canDelete: boolean;
+}) {
+  const page = searchParamsCache.get('page');
+  const limit = searchParamsCache.get('perPage');
+  const search = searchParamsCache.get('name');
+  const status = searchParamsCache.get('status');
+  const productType = searchParamsCache.get('productType');
+  const priority = searchParamsCache.get('priority');
+  const branch = searchParamsCache.get('branch');
+  const customer = searchParamsCache.get('customer');
+  const sort = searchParamsCache.get('sort');
+  const filters = {
+    page,
+    limit,
+    ...(search && { search }),
+    ...(status && { status }),
+    ...(productType && { productType }),
+    ...(priority && { priority }),
+    ...(branch && { branch }),
+    ...(customer && { customer }),
+    ...(sort && { sort })
+  };
+  const queryClient = getQueryClient();
+
+  void queryClient.prefetchQuery(enquiriesQueryOptions(filters));
+
+  return (
+    <HydrationBoundary state={dehydrate(queryClient)}>
+      <EnquiriesTable referenceData={referenceData} canUpdate={canUpdate} canDelete={canDelete} />
+    </HydrationBoundary>
+  );
+}

src/features/crm/enquiries/components/enquiry-status-badge.tsx

@@ -0,0 +1,31 @@
+'use client';
+
+import { Badge } from '@/components/ui/badge';
+import { Icons } from '@/components/icons';
+
+export function EnquiryStatusBadge({ code, label }: { code?: string | null; label: string }) {
+  const normalized = code?.toLowerCase() ?? '';
+  const variant =
+    normalized === 'closed_lost' || normalized === 'cancelled'
+      ? 'outline'
+      : normalized === 'converted'
+        ? 'default'
+        : normalized === 'follow_up'
+          ? 'secondary'
+          : 'secondary';
+  const Icon =
+    normalized === 'converted'
+      ? Icons.circleCheck
+      : normalized === 'closed_lost' || normalized === 'cancelled'
+        ? Icons.warning
+        : normalized === 'follow_up'
+          ? Icons.clock
+          : Icons.circle;
+
+  return (
+    <Badge variant={variant} className='capitalize'>
+      <Icon className='h-3 w-3' />
+      {label}
+    </Badge>
+  );
+}

src/features/crm/enquiries/components/followup-form-sheet.tsx

@@ -0,0 +1,249 @@
+'use client';
+
+import { useEffect, useMemo } from 'react';
+import { useMutation } from '@tanstack/react-query';
+import { toast } from 'sonner';
+import { Icons } from '@/components/icons';
+import { Button } from '@/components/ui/button';
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue
+} from '@/components/ui/select';
+import {
+  Sheet,
+  SheetContent,
+  SheetDescription,
+  SheetFooter,
+  SheetHeader,
+  SheetTitle
+} from '@/components/ui/sheet';
+import { useAppForm, useFormFields } from '@/components/ui/tanstack-form';
+import { createEnquiryFollowupMutation, updateEnquiryFollowupMutation } from '../api/mutations';
+import type {
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupRecord,
+  EnquiryReferenceData
+} from '../api/types';
+import { enquiryFollowupSchema, type EnquiryFollowupFormValues } from '../schemas/enquiry.schema';
+
+function toDefaultValues(followup: EnquiryFollowupRecord | undefined): EnquiryFollowupFormValues {
+  return {
+    followupDate: followup?.followupDate ? followup.followupDate.slice(0, 10) : '',
+    followupType: followup?.followupType ?? '',
+    contactId: followup?.contactId ?? undefined,
+    outcome: followup?.outcome ?? '',
+    notes: followup?.notes ?? '',
+    nextFollowupDate: followup?.nextFollowupDate ? followup.nextFollowupDate.slice(0, 10) : '',
+    nextAction: followup?.nextAction ?? ''
+  };
+}
+
+export function FollowupFormSheet({
+  enquiryId,
+  followup,
+  open,
+  onOpenChange,
+  referenceData,
+  customerId
+}: {
+  enquiryId: string;
+  followup?: EnquiryFollowupRecord;
+  open: boolean;
+  onOpenChange: (open: boolean) => void;
+  referenceData: EnquiryReferenceData;
+  customerId: string;
+}) {
+  const isEdit = !!followup;
+  const defaultValues = useMemo(() => toDefaultValues(followup), [followup]);
+  const { FormTextField, FormTextareaField } = useFormFields<EnquiryFollowupFormValues>();
+  const contactOptions = referenceData.contacts.filter((item) => item.customerId === customerId);
+
+  const createMutation = useMutation({
+    ...createEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up created successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to create follow-up')
+  });
+
+  const updateMutation = useMutation({
+    ...updateEnquiryFollowupMutation,
+    onSuccess: () => {
+      toast.success('Follow-up updated successfully');
+      onOpenChange(false);
+    },
+    onError: (error) =>
+      toast.error(error instanceof Error ? error.message : 'Failed to update follow-up')
+  });
+
+  const form = useAppForm({
+    defaultValues,
+    validators: {
+      onSubmit: enquiryFollowupSchema
+    },
+    onSubmit: async ({ value }) => {
+      const payload: EnquiryFollowupMutationPayload = {
+        followupDate: value.followupDate,
+        followupType: value.followupType,
+        contactId: value.contactId || null,
+        outcome: value.outcome,
+        notes: value.notes,
+        nextFollowupDate: value.nextFollowupDate || null,
+        nextAction: value.nextAction
+      };
+
+      if (isEdit && followup) {
+        await updateMutation.mutateAsync({
+          enquiryId,
+          followupId: followup.id,
+          values: payload
+        });
+        return;
+      }
+
+      await createMutation.mutateAsync({
+        enquiryId,
+        values: payload
+      });
+    }
+  });
+
+  useEffect(() => {
+    if (!open) {
+      return;
+    }
+
+    form.reset(defaultValues);
+  }, [defaultValues, form, open]);
+
+  const isPending = createMutation.isPending || updateMutation.isPending;
+
+  return (
+    <Sheet open={open} onOpenChange={onOpenChange}>
+      <SheetContent className='flex flex-col sm:max-w-2xl'>
+        <SheetHeader>
+          <SheetTitle>{isEdit ? 'Edit Follow-up' : 'New Follow-up'}</SheetTitle>
+          <SheetDescription>
+            Keep the enquiry timeline current with the latest customer interaction and next step.
+          </SheetDescription>
+        </SheetHeader>
+
+        <div className='flex-1 overflow-auto'>
+          <form.AppForm>
+            <form.Form id='enquiry-followup-form' className='grid gap-4 md:grid-cols-2'>
+              <FormTextField
+                name='followupDate'
+                label='Follow-up Date'
+                required
+                placeholder='YYYY-MM-DD'
+              />
+              <form.AppField
+                name='followupType'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Follow-up Type *</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value === '__none__' ? '' : value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Follow-up type'>
+                          <SelectValue placeholder='Select follow-up type' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {referenceData.followupTypes.map((item) => (
+                            <SelectItem key={item.id} value={item.id}>
+                              {item.label}
+                            </SelectItem>
+                          ))}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+              <form.AppField
+                name='contactId'
+                children={(field) => (
+                  <field.FieldSet>
+                    <field.Field>
+                      <field.FieldLabel>Contact</field.FieldLabel>
+                      <Select
+                        value={field.state.value ?? ''}
+                        onValueChange={(value) => {
+                          field.handleChange(value);
+                          field.handleBlur();
+                        }}
+                      >
+                        <SelectTrigger aria-label='Follow-up contact'>
+                          <SelectValue placeholder='Select contact' />
+                        </SelectTrigger>
+                        <SelectContent>
+                          {contactOptions.length ? (
+                            contactOptions.map((item) => (
+                              <SelectItem key={item.id} value={item.id}>
+                                {item.name}
+                              </SelectItem>
+                            ))
+                          ) : (
+                            <SelectItem value='__none__'>No contact selected</SelectItem>
+                          )}
+                        </SelectContent>
+                      </Select>
+                    </field.Field>
+                    <field.FieldError />
+                  </field.FieldSet>
+                )}
+              />
+              <FormTextField
+                name='nextFollowupDate'
+                label='Next Follow-up Date'
+                placeholder='YYYY-MM-DD'
+              />
+              <div className='md:col-span-2'>
+                <FormTextField
+                  name='nextAction'
+                  label='Next Action'
+                  placeholder='Prepare revised technical proposal'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='outcome'
+                  label='Outcome'
+                  placeholder='Customer asked for revised dimensions and a site survey'
+                />
+              </div>
+              <div className='md:col-span-2'>
+                <FormTextareaField
+                  name='notes'
+                  label='Notes'
+                  placeholder='Internal notes from the follow-up session'
+                />
+              </div>
+            </form.Form>
+          </form.AppForm>
+        </div>
+
+        <SheetFooter>
+          <Button type='button' variant='outline' onClick={() => onOpenChange(false)}>
+            Cancel
+          </Button>
+          <Button type='submit' form='enquiry-followup-form' isLoading={isPending}>
+            <Icons.check className='mr-2 h-4 w-4' />
+            {isEdit ? 'Update Follow-up' : 'Create Follow-up'}
+          </Button>
+        </SheetFooter>
+      </SheetContent>
+    </Sheet>
+  );
+}

src/features/crm/enquiries/schemas/enquiry.schema.ts

@@ -0,0 +1,47 @@
+import * as z from 'zod';
+
+export const enquirySchema = z.object({
+  customerId: z.string().min(1, 'Please select a customer'),
+  contactId: z.string().optional().nullable(),
+  title: z.string().min(2, 'Title must be at least 2 characters'),
+  description: z.string().optional(),
+  requirement: z.string().optional(),
+  projectName: z.string().optional(),
+  projectLocation: z.string().optional(),
+  branchId: z.string().optional().nullable(),
+  productType: z.string().min(1, 'Please select a product type'),
+  status: z.string().min(1, 'Please select a status'),
+  priority: z.string().min(1, 'Please select a priority'),
+  leadChannel: z.string().optional().nullable(),
+  estimatedValue: z
+    .string()
+    .optional()
+    .refine((value) => !value || !Number.isNaN(Number(value)), 'Estimated value must be a number'),
+  chancePercent: z
+    .string()
+    .optional()
+    .refine((value) => !value || !Number.isNaN(Number(value)), 'Chance percent must be a number')
+    .refine(
+      (value) => !value || (Number(value) >= 0 && Number(value) <= 100),
+      'Chance percent must be between 0 and 100'
+    ),
+  expectedCloseDate: z.string().optional().nullable(),
+  competitor: z.string().optional(),
+  source: z.string().optional(),
+  isHotProject: z.boolean().default(false),
+  notes: z.string().optional(),
+  isActive: z.boolean().default(true)
+});
+
+export const enquiryFollowupSchema = z.object({
+  followupDate: z.string().min(1, 'Follow-up date is required'),
+  followupType: z.string().min(1, 'Please select a follow-up type'),
+  contactId: z.string().optional().nullable(),
+  outcome: z.string().optional(),
+  notes: z.string().optional(),
+  nextFollowupDate: z.string().optional().nullable(),
+  nextAction: z.string().optional()
+});
+
+export type EnquiryFormValues = z.input<typeof enquirySchema>;
+export type EnquiryFollowupFormValues = z.input<typeof enquiryFollowupSchema>;

src/features/crm/enquiries/server/service.ts

@@ -0,0 +1,734 @@
+import { and, asc, count, desc, eq, ilike, inArray, isNull, or, type SQL } from 'drizzle-orm';
+import {
+  crmCustomerContacts,
+  crmCustomers,
+  crmEnquiries,
+  crmEnquiryFollowups,
+  users
+} from '@/db/schema';
+import { db } from '@/lib/db';
+import { AuthError } from '@/lib/auth/session';
+import { listAuditLogs } from '@/features/foundation/audit-log/service';
+import { getUserBranches, validateBranchAccess } from '@/features/foundation/branch-scope/service';
+import { generateNextDocumentCode } from '@/features/foundation/document-sequence/service';
+import { getActiveOptionsByCategory } from '@/features/foundation/master-options/service';
+import type {
+  EnquiryActivityRecord,
+  EnquiryBranchOption,
+  EnquiryContactLookup,
+  EnquiryCustomerLookup,
+  EnquiryCustomerRelationItem,
+  EnquiryFilters,
+  EnquiryFollowupMutationPayload,
+  EnquiryFollowupRecord,
+  EnquiryListItem,
+  EnquiryMutationPayload,
+  EnquiryOption,
+  EnquiryRecord,
+  EnquiryReferenceData
+} from '../api/types';
+
+const ENQUIRY_OPTION_CATEGORIES = {
+  status: 'crm_enquiry_status',
+  productType: 'crm_product_type',
+  priority: 'crm_priority',
+  leadChannel: 'crm_lead_channel',
+  followupType: 'crm_followup_type'
+} as const;
+
+function mapOption(
+  option: Awaited<ReturnType<typeof getActiveOptionsByCategory>>[number]
+): EnquiryOption {
+  return {
+    id: option.id,
+    code: option.code,
+    label: option.label,
+    value: option.value
+  };
+}
+
+function mapBranch(
+  branch: Awaited<ReturnType<typeof getUserBranches>>[number]
+): EnquiryBranchOption {
+  return {
+    id: branch.id,
+    code: branch.code,
+    name: branch.name,
+    value: branch.value
+  };
+}
+
+function mapEnquiryRecord(row: typeof crmEnquiries.$inferSelect): EnquiryRecord {
+  return {
+    id: row.id,
+    organizationId: row.organizationId,
+    branchId: row.branchId,
+    code: row.code,
+    customerId: row.customerId,
+    contactId: row.contactId,
+    title: row.title,
+    description: row.description,
+    requirement: row.requirement,
+    projectName: row.projectName,
+    projectLocation: row.projectLocation,
+    productType: row.productType,
+    status: row.status,
+    priority: row.priority,
+    leadChannel: row.leadChannel,
+    estimatedValue: row.estimatedValue,
+    chancePercent: row.chancePercent,
+    expectedCloseDate: row.expectedCloseDate?.toISOString() ?? null,
+    competitor: row.competitor,
+    source: row.source,
+    notes: row.notes,
+    isHotProject: row.isHotProject,
+    isActive: row.isActive,
+    createdAt: row.createdAt.toISOString(),
+    updatedAt: row.updatedAt.toISOString(),
+    deletedAt: row.deletedAt?.toISOString() ?? null,
+    createdBy: row.createdBy,
+    updatedBy: row.updatedBy
+  };
+}
+
+function mapFollowupRecord(row: typeof crmEnquiryFollowups.$inferSelect): EnquiryFollowupRecord {
+  return {
+    id: row.id,
+    organizationId: row.organizationId,
+    enquiryId: row.enquiryId,
+    followupDate: row.followupDate.toISOString(),
+    followupType: row.followupType,
+    contactId: row.contactId,
+    outcome: row.outcome,
+    notes: row.notes,
+    nextFollowupDate: row.nextFollowupDate?.toISOString() ?? null,
+    nextAction: row.nextAction,
+    createdAt: row.createdAt.toISOString(),
+    updatedAt: row.updatedAt.toISOString(),
+    deletedAt: row.deletedAt?.toISOString() ?? null,
+    createdBy: row.createdBy,
+    updatedBy: row.updatedBy
+  };
+}
+
+function parseSort(sort?: string) {
+  if (!sort) {
+    return desc(crmEnquiries.updatedAt);
+  }
+
+  try {
+    const parsed = JSON.parse(sort) as Array<{ id: string; desc?: boolean }>;
+    const [rule] = parsed;
+
+    if (!rule) {
+      return desc(crmEnquiries.updatedAt);
+    }
+
+    const sortMap = {
+      code: crmEnquiries.code,
+      title: crmEnquiries.title,
+      status: crmEnquiries.status,
+      priority: crmEnquiries.priority,
+      productType: crmEnquiries.productType,
+      branch: crmEnquiries.branchId,
+      customer: crmEnquiries.customerId,
+      updatedAt: crmEnquiries.updatedAt
+    } as const;
+
+    const column = sortMap[rule.id as keyof typeof sortMap];
+
+    if (!column) {
+      return desc(crmEnquiries.updatedAt);
+    }
+
+    return rule.desc ? desc(column) : asc(column);
+  } catch {
+    return desc(crmEnquiries.updatedAt);
+  }
+}
+
+function splitFilterValue(value?: string) {
+  return value
+    ? value
+        .split(/[.,]/)
+        .map((item) => item.trim())
+        .filter(Boolean)
+    : [];
+}
+
+async function resolveValidOptionIds(category: string, organizationId: string) {
+  const options = await getActiveOptionsByCategory(category, { organizationId });
+  return new Set(options.map((option) => option.id));
+}
+
+async function assertMasterOptionValue(
+  organizationId: string,
+  category: string,
+  optionId?: string | null
+) {
+  if (!optionId) {
+    return;
+  }
+
+  const validIds = await resolveValidOptionIds(category, organizationId);
+
+  if (!validIds.has(optionId)) {
+    throw new AuthError(`Invalid option for ${category}`, 400);
+  }
+}
+
+export async function assertCustomerBelongsToOrganization(id: string, organizationId: string) {
+  const customer = await db.query.crmCustomers.findFirst({
+    where: and(
+      eq(crmCustomers.id, id),
+      eq(crmCustomers.organizationId, organizationId),
+      isNull(crmCustomers.deletedAt)
+    )
+  });
+
+  if (!customer) {
+    throw new AuthError('Customer not found', 404);
+  }
+
+  return customer;
+}
+
+export async function assertContactBelongsToOrganization(
+  contactId: string,
+  organizationId: string,
+  customerId?: string | null
+) {
+  const contact = await db.query.crmCustomerContacts.findFirst({
+    where: and(
+      eq(crmCustomerContacts.id, contactId),
+      eq(crmCustomerContacts.organizationId, organizationId),
+      isNull(crmCustomerContacts.deletedAt),
+      ...(customerId ? [eq(crmCustomerContacts.customerId, customerId)] : [])
+    )
+  });
+
+  if (!contact) {
+    throw new AuthError('Contact not found', 404);
+  }
+
+  return contact;
+}
+
+async function assertEnquiryBelongsToOrganization(id: string, organizationId: string) {
+  const enquiry = await db.query.crmEnquiries.findFirst({
+    where: and(
+      eq(crmEnquiries.id, id),
+      eq(crmEnquiries.organizationId, organizationId),
+      isNull(crmEnquiries.deletedAt)
+    )
+  });
+
+  if (!enquiry) {
+    throw new AuthError('Enquiry not found', 404);
+  }
+
+  return enquiry;
+}
+
+async function assertFollowupBelongsToEnquiry(
+  followupId: string,
+  enquiryId: string,
+  organizationId: string
+) {
+  const followup = await db.query.crmEnquiryFollowups.findFirst({
+    where: and(
+      eq(crmEnquiryFollowups.id, followupId),
+      eq(crmEnquiryFollowups.enquiryId, enquiryId),
+      eq(crmEnquiryFollowups.organizationId, organizationId),
+      isNull(crmEnquiryFollowups.deletedAt)
+    )
+  });
+
+  if (!followup) {
+    throw new AuthError('Follow-up not found', 404);
+  }
+
+  return followup;
+}
+
+async function validateEnquiryPayload(organizationId: string, payload: EnquiryMutationPayload) {
+  await assertCustomerBelongsToOrganization(payload.customerId, organizationId);
+
+  if (payload.contactId) {
+    await assertContactBelongsToOrganization(payload.contactId, organizationId, payload.customerId);
+  }
+
+  await assertMasterOptionValue(organizationId, ENQUIRY_OPTION_CATEGORIES.status, payload.status);
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.productType,
+    payload.productType
+  );
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.priority,
+    payload.priority
+  );
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.leadChannel,
+    payload.leadChannel ?? null
+  );
+
+  if (payload.branchId) {
+    await validateBranchAccess(payload.branchId);
+  }
+}
+
+async function validateFollowupPayload(
+  organizationId: string,
+  enquiryId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  const enquiry = await assertEnquiryBelongsToOrganization(enquiryId, organizationId);
+
+  await assertMasterOptionValue(
+    organizationId,
+    ENQUIRY_OPTION_CATEGORIES.followupType,
+    payload.followupType
+  );
+
+  if (payload.contactId) {
+    await assertContactBelongsToOrganization(payload.contactId, organizationId, enquiry.customerId);
+  }
+}
+
+function buildEnquiryFilters(organizationId: string, filters: EnquiryFilters): SQL[] {
+  const statuses = splitFilterValue(filters.status);
+  const productTypes = splitFilterValue(filters.productType);
+  const priorities = splitFilterValue(filters.priority);
+  const branches = splitFilterValue(filters.branch);
+  const customers = splitFilterValue(filters.customer);
+
+  return [
+    eq(crmEnquiries.organizationId, organizationId),
+    isNull(crmEnquiries.deletedAt),
+    ...(statuses.length ? [inArray(crmEnquiries.status, statuses)] : []),
+    ...(productTypes.length ? [inArray(crmEnquiries.productType, productTypes)] : []),
+    ...(priorities.length ? [inArray(crmEnquiries.priority, priorities)] : []),
+    ...(branches.length ? [inArray(crmEnquiries.branchId, branches)] : []),
+    ...(customers.length ? [inArray(crmEnquiries.customerId, customers)] : []),
+    ...(filters.search
+      ? [
+          or(
+            ilike(crmEnquiries.code, `%${filters.search}%`),
+            ilike(crmEnquiries.title, `%${filters.search}%`),
+            ilike(crmEnquiries.projectName, `%${filters.search}%`),
+            ilike(crmEnquiries.competitor, `%${filters.search}%`)
+          )!
+        ]
+      : [])
+  ];
+}
+
+export async function getEnquiryReferenceData(
+  organizationId: string
+): Promise<EnquiryReferenceData> {
+  const [
+    branches,
+    statuses,
+    productTypes,
+    priorities,
+    leadChannels,
+    followupTypes,
+    customers,
+    contacts
+  ] = await Promise.all([
+    getUserBranches(),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.status, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.productType, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.priority, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.leadChannel, { organizationId }),
+    getActiveOptionsByCategory(ENQUIRY_OPTION_CATEGORIES.followupType, { organizationId }),
+    db.query.crmCustomers.findMany({
+      where: and(eq(crmCustomers.organizationId, organizationId), isNull(crmCustomers.deletedAt)),
+      orderBy: [asc(crmCustomers.name)]
+    }),
+    db.query.crmCustomerContacts.findMany({
+      where: and(
+        eq(crmCustomerContacts.organizationId, organizationId),
+        isNull(crmCustomerContacts.deletedAt)
+      ),
+      orderBy: [desc(crmCustomerContacts.isPrimary), asc(crmCustomerContacts.name)]
+    })
+  ]);
+
+  return {
+    branches: branches.map(mapBranch),
+    statuses: statuses.map(mapOption),
+    productTypes: productTypes.map(mapOption),
+    priorities: priorities.map(mapOption),
+    leadChannels: leadChannels.map(mapOption),
+    followupTypes: followupTypes.map(mapOption),
+    customers: customers.map((customer) => ({
+      id: customer.id,
+      code: customer.code,
+      name: customer.name,
+      branchId: customer.branchId
+    })),
+    contacts: contacts.map((contact) => ({
+      id: contact.id,
+      customerId: contact.customerId,
+      name: contact.name,
+      email: contact.email,
+      mobile: contact.mobile,
+      isPrimary: contact.isPrimary
+    }))
+  };
+}
+
+export async function listEnquiries(
+  organizationId: string,
+  filters: EnquiryFilters
+): Promise<{ items: EnquiryListItem[]; totalItems: number }> {
+  const page = filters.page ?? 1;
+  const limit = filters.limit ?? 10;
+  const whereFilters = buildEnquiryFilters(organizationId, filters);
+  const where = whereFilters.length === 1 ? whereFilters[0] : and(...whereFilters);
+  const offset = (page - 1) * limit;
+
+  const [totalResult] = await db.select({ value: count() }).from(crmEnquiries).where(where);
+  const rows = await db
+    .select()
+    .from(crmEnquiries)
+    .where(where)
+    .orderBy(parseSort(filters.sort))
+    .limit(limit)
+    .offset(offset);
+
+  const customerIds = [...new Set(rows.map((row) => row.customerId))];
+  const contactIds = [...new Set(rows.map((row) => row.contactId).filter(Boolean) as string[])];
+  const enquiryIds = rows.map((row) => row.id);
+
+  const [customers, contacts, followupCounts] = await Promise.all([
+    customerIds.length
+      ? db.query.crmCustomers.findMany({
+          where: and(
+            eq(crmCustomers.organizationId, organizationId),
+            inArray(crmCustomers.id, customerIds)
+          )
+        })
+      : [],
+    contactIds.length
+      ? db.query.crmCustomerContacts.findMany({
+          where: and(
+            eq(crmCustomerContacts.organizationId, organizationId),
+            inArray(crmCustomerContacts.id, contactIds)
+          )
+        })
+      : [],
+    enquiryIds.length
+      ? db
+          .select({
+            enquiryId: crmEnquiryFollowups.enquiryId,
+            value: count()
+          })
+          .from(crmEnquiryFollowups)
+          .where(
+            and(
+              eq(crmEnquiryFollowups.organizationId, organizationId),
+              inArray(crmEnquiryFollowups.enquiryId, enquiryIds),
+              isNull(crmEnquiryFollowups.deletedAt)
+            )
+          )
+          .groupBy(crmEnquiryFollowups.enquiryId)
+      : []
+  ]);
+
+  const customerMap = new Map(customers.map((customer) => [customer.id, customer.name]));
+  const contactMap = new Map(contacts.map((contact) => [contact.id, contact.name]));
+  const followupCountMap = new Map(followupCounts.map((item) => [item.enquiryId, item.value]));
+
+  return {
+    items: rows.map((row) => ({
+      ...mapEnquiryRecord(row),
+      customerName: customerMap.get(row.customerId) ?? 'Unknown customer',
+      contactName: row.contactId ? (contactMap.get(row.contactId) ?? null) : null,
+      followupCount: followupCountMap.get(row.id) ?? 0
+    })),
+    totalItems: totalResult?.value ?? 0
+  };
+}
+
+export async function getEnquiryDetail(id: string, organizationId: string): Promise<EnquiryRecord> {
+  const enquiry = await assertEnquiryBelongsToOrganization(id, organizationId);
+  return mapEnquiryRecord(enquiry);
+}
+
+export async function getEnquiryActivity(
+  id: string,
+  organizationId: string
+): Promise<EnquiryActivityRecord[]> {
+  const auditLogs = await listAuditLogs({
+    organizationId,
+    entityId: id,
+    limit: 30
+  });
+  const filteredLogs = auditLogs.filter(
+    (log) =>
+      (log.entityType === 'crm_enquiry' && log.entityId === id) ||
+      (log.entityType === 'crm_enquiry_followup' &&
+        ((log.afterData as { enquiryId?: string } | null)?.enquiryId === id ||
+          (log.beforeData as { enquiryId?: string } | null)?.enquiryId === id))
+  );
+  const userIds = [...new Set(filteredLogs.map((log) => log.userId))];
+  const actorRows = userIds.length
+    ? await db
+        .select({ id: users.id, name: users.name })
+        .from(users)
+        .where(inArray(users.id, userIds))
+    : [];
+  const actorMap = new Map(actorRows.map((row) => [row.id, row.name]));
+
+  return filteredLogs.map((log) => ({
+    id: log.id,
+    action: log.action,
+    entityType: log.entityType,
+    entityId: log.entityId,
+    createdAt: log.createdAt,
+    userId: log.userId,
+    actorName: actorMap.get(log.userId) ?? null
+  }));
+}
+
+export async function createEnquiry(
+  organizationId: string,
+  userId: string,
+  payload: EnquiryMutationPayload
+) {
+  await validateEnquiryPayload(organizationId, payload);
+
+  const documentCode = await generateNextDocumentCode({
+    organizationId,
+    documentType: 'enquiry',
+    branchId: payload.branchId ?? ''
+  });
+
+  const [created] = await db
+    .insert(crmEnquiries)
+    .values({
+      id: crypto.randomUUID(),
+      organizationId,
+      branchId: payload.branchId ?? null,
+      code: documentCode.code,
+      customerId: payload.customerId,
+      contactId: payload.contactId ?? null,
+      title: payload.title.trim(),
+      description: payload.description?.trim() || null,
+      requirement: payload.requirement?.trim() || null,
+      projectName: payload.projectName?.trim() || null,
+      projectLocation: payload.projectLocation?.trim() || null,
+      productType: payload.productType,
+      status: payload.status,
+      priority: payload.priority,
+      leadChannel: payload.leadChannel ?? null,
+      estimatedValue: payload.estimatedValue ?? null,
+      chancePercent: payload.chancePercent ?? null,
+      expectedCloseDate: payload.expectedCloseDate ? new Date(payload.expectedCloseDate) : null,
+      competitor: payload.competitor?.trim() || null,
+      source: payload.source?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      isHotProject: payload.isHotProject ?? false,
+      isActive: payload.isActive ?? true,
+      createdBy: userId,
+      updatedBy: userId
+    })
+    .returning();
+
+  return created;
+}
+
+export async function updateEnquiry(
+  id: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryMutationPayload
+) {
+  await validateEnquiryPayload(organizationId, payload);
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiries)
+    .set({
+      branchId: payload.branchId ?? null,
+      customerId: payload.customerId,
+      contactId: payload.contactId ?? null,
+      title: payload.title.trim(),
+      description: payload.description?.trim() || null,
+      requirement: payload.requirement?.trim() || null,
+      projectName: payload.projectName?.trim() || null,
+      projectLocation: payload.projectLocation?.trim() || null,
+      productType: payload.productType,
+      status: payload.status,
+      priority: payload.priority,
+      leadChannel: payload.leadChannel ?? null,
+      estimatedValue: payload.estimatedValue ?? null,
+      chancePercent: payload.chancePercent ?? null,
+      expectedCloseDate: payload.expectedCloseDate ? new Date(payload.expectedCloseDate) : null,
+      competitor: payload.competitor?.trim() || null,
+      source: payload.source?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      isHotProject: payload.isHotProject ?? false,
+      isActive: payload.isActive ?? true,
+      updatedBy: userId,
+      updatedAt: new Date()
+    })
+    .where(eq(crmEnquiries.id, id))
+    .returning();
+
+  return updated;
+}
+
+export async function softDeleteEnquiry(id: string, organizationId: string, userId: string) {
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+  const now = new Date();
+
+  const [updated] = await db
+    .update(crmEnquiries)
+    .set({
+      deletedAt: now,
+      updatedAt: now,
+      updatedBy: userId,
+      isActive: false
+    })
+    .where(eq(crmEnquiries.id, id))
+    .returning();
+
+  await db
+    .update(crmEnquiryFollowups)
+    .set({
+      deletedAt: now,
+      updatedAt: now,
+      updatedBy: userId
+    })
+    .where(
+      and(
+        eq(crmEnquiryFollowups.enquiryId, id),
+        eq(crmEnquiryFollowups.organizationId, organizationId)
+      )
+    );
+
+  return updated;
+}
+
+export async function listEnquiryFollowups(id: string, organizationId: string) {
+  await assertEnquiryBelongsToOrganization(id, organizationId);
+  const rows = await db.query.crmEnquiryFollowups.findMany({
+    where: and(
+      eq(crmEnquiryFollowups.enquiryId, id),
+      eq(crmEnquiryFollowups.organizationId, organizationId),
+      isNull(crmEnquiryFollowups.deletedAt)
+    ),
+    orderBy: [desc(crmEnquiryFollowups.followupDate)]
+  });
+
+  return rows.map(mapFollowupRecord);
+}
+
+export async function createEnquiryFollowup(
+  enquiryId: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  await validateFollowupPayload(organizationId, enquiryId, payload);
+
+  const [created] = await db
+    .insert(crmEnquiryFollowups)
+    .values({
+      id: crypto.randomUUID(),
+      organizationId,
+      enquiryId,
+      followupDate: new Date(payload.followupDate),
+      followupType: payload.followupType,
+      contactId: payload.contactId ?? null,
+      outcome: payload.outcome?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      nextFollowupDate: payload.nextFollowupDate ? new Date(payload.nextFollowupDate) : null,
+      nextAction: payload.nextAction?.trim() || null,
+      createdBy: userId,
+      updatedBy: userId
+    })
+    .returning();
+
+  return created;
+}
+
+export async function updateEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  organizationId: string,
+  userId: string,
+  payload: EnquiryFollowupMutationPayload
+) {
+  await validateFollowupPayload(organizationId, enquiryId, payload);
+  await assertFollowupBelongsToEnquiry(followupId, enquiryId, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiryFollowups)
+    .set({
+      followupDate: new Date(payload.followupDate),
+      followupType: payload.followupType,
+      contactId: payload.contactId ?? null,
+      outcome: payload.outcome?.trim() || null,
+      notes: payload.notes?.trim() || null,
+      nextFollowupDate: payload.nextFollowupDate ? new Date(payload.nextFollowupDate) : null,
+      nextAction: payload.nextAction?.trim() || null,
+      updatedAt: new Date(),
+      updatedBy: userId
+    })
+    .where(eq(crmEnquiryFollowups.id, followupId))
+    .returning();
+
+  return updated;
+}
+
+export async function softDeleteEnquiryFollowup(
+  enquiryId: string,
+  followupId: string,
+  organizationId: string,
+  userId: string
+) {
+  await assertFollowupBelongsToEnquiry(followupId, enquiryId, organizationId);
+
+  const [updated] = await db
+    .update(crmEnquiryFollowups)
+    .set({
+      deletedAt: new Date(),
+      updatedAt: new Date(),
+      updatedBy: userId
+    })
+    .where(eq(crmEnquiryFollowups.id, followupId))
+    .returning();
+
+  return updated;
+}
+
+export async function listCustomerEnquiryRelations(
+  customerId: string,
+  organizationId: string
+): Promise<EnquiryCustomerRelationItem[]> {
+  const rows = await db.query.crmEnquiries.findMany({
+    where: and(
+      eq(crmEnquiries.customerId, customerId),
+      eq(crmEnquiries.organizationId, organizationId),
+      isNull(crmEnquiries.deletedAt)
+    ),
+    orderBy: [desc(crmEnquiries.updatedAt)],
+    limit: 10
+  });
+
+  return rows.map((row) => ({
+    id: row.id,
+    code: row.code,
+    title: row.title,
+    status: row.status,
+    productType: row.productType,
+    updatedAt: row.updatedAt.toISOString()
+  }));
+}