User management improvements (#1101)

* Show more descriptive success messages for User actions

* Check username uniqueness when creating/updating User

* Adjust translations

* Add tests for `validateUsernameUnique()`

Co-authored-by: Deluan <deluan@navidrome.org>

ui/src/user/UserCreate.js

@@ -1,4 +1,4 @@
-import React from 'react'
+import React, { useCallback } from 'react'
 import {
   BooleanInput,
   Create,
@@ -8,18 +8,49 @@ import {
   email,
   SimpleForm,
   useTranslate,
+  useMutation,
+  useNotify,
+  useRedirect,
 } from 'react-admin'
 import { Title } from '../common'
 
 const UserCreate = (props) => {
   const translate = useTranslate()
+  const [mutate] = useMutation()
+  const notify = useNotify()
+  const redirect = useRedirect()
   const resourceName = translate('resources.user.name', { smart_count: 1 })
   const title = translate('ra.page.create', {
     name: `${resourceName}`,
   })
+
+  const save = useCallback(
+    async (values) => {
+      try {
+        await mutate(
+          {
+            type: 'create',
+            resource: 'user',
+            payload: { data: values },
+          },
+          { returnPromise: true }
+        )
+        notify('resources.user.notifications.created', 'info', {
+          smart_count: 1,
+        })
+        redirect('/user')
+      } catch (error) {
+        if (error.body.errors) {
+          return error.body.errors
+        }
+      }
+    },
+    [mutate, notify, redirect]
+  )
+
   return (
     <Create title={<Title subTitle={title} />} {...props}>
-      <SimpleForm redirect="list" variant={'outlined'}>
+      <SimpleForm save={save} variant={'outlined'}>
         <TextInput source="userName" validate={[required()]} />
         <TextInput source="name" validate={[required()]} />
         <TextInput source="email" validate={[email()]} />