[feature] Self-serve email change for users (#2957)

* [feature] Email change

* frontend stuff for changing email

* docs

* tests etc

* differentiate more clearly between local user+account and account

* populate user

3 files changed, 154 insertions, 1 deletions

diff --git a/web/source/settings/lib/query/user/index.ts b/web/source/settings/lib/query/user/index.ts
index 8c4e5215b..1f9070bfb 100644
--- a/web/source/settings/lib/query/user/index.ts
+++ b/web/source/settings/lib/query/user/index.ts
@@ -24,6 +24,7 @@ import type {
 	UpdateAliasesFormData
 } from "../../types/migration";
 import type { Theme } from "../../types/theme";
+import { User } from "../../types/user";
 
 const extended = gtsApi.injectEndpoints({
 	endpoints: (build) => ({
@@ -37,6 +38,9 @@ const extended = gtsApi.injectEndpoints({
 			}),
 			...replaceCacheOnMutation("verifyCredentials")
 		}),
+		user: build.query<User, void>({
+			query: () => ({url: `/api/v1/user`})
+		}),
 		passwordChange: build.mutation({
 			query: (data) => ({
 				method: "POST",
@@ -44,6 +48,14 @@ const extended = gtsApi.injectEndpoints({
 				body: data
 			})
 		}),
+		emailChange: build.mutation<User, { password: string, new_email: string }>({
+			query: (data) => ({
+				method: "POST",
+				url: `/api/v1/user/email_change`,
+				body: data
+			}),
+			...replaceCacheOnMutation("user")
+		}),
 		aliasAccount: build.mutation<any, UpdateAliasesFormData>({
 			async queryFn(formData, _api, _extraOpts, fetchWithBQ) {
 				// Pull entries out from the hooked form.
@@ -78,7 +90,9 @@ const extended = gtsApi.injectEndpoints({
 
 export const {
 	useUpdateCredentialsMutation,
+	useUserQuery,
 	usePasswordChangeMutation,
+	useEmailChangeMutation,
 	useAliasAccountMutation,
 	useMoveAccountMutation,
 	useAccountThemesQuery,
diff --git a/web/source/settings/lib/types/user.ts b/web/source/settings/lib/types/user.ts
new file mode 100644
index 000000000..92210d5d3
--- /dev/null
+++ b/web/source/settings/lib/types/user.ts
@@ -0,0 +1,34 @@
+/*
+	GoToSocial
+	Copyright (C) GoToSocial Authors admin@gotosocial.org
+	SPDX-License-Identifier: AGPL-3.0-or-later
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+export interface User {
+	id: string;
+	created_at: string;
+	email?: string;
+	unconfirmed_email?: string;
+	reason?: string;
+	last_emailed_at?: string;
+	confirmed_at?: string;
+	confirmation_sent_at?: string;
+	moderator: boolean;
+	admin: boolean;
+	disabled: boolean;
+	approved: boolean;
+	reset_password_sent_at?: string;
+}
diff --git a/web/source/settings/views/user/settings.tsx b/web/source/settings/views/user/settings.tsx
index cbd973706..a27cc1ba3 100644
--- a/web/source/settings/views/user/settings.tsx
+++ b/web/source/settings/views/user/settings.tsx
@@ -25,7 +25,9 @@ import FormWithData from "../../lib/form/form-with-data";
 import Languages from "../../components/languages";
 import MutationButton from "../../components/form/mutation-button";
 import { useVerifyCredentialsQuery } from "../../lib/query/oauth";
-import { usePasswordChangeMutation, useUpdateCredentialsMutation } from "../../lib/query/user";
+import { useEmailChangeMutation, usePasswordChangeMutation, useUpdateCredentialsMutation, useUserQuery } from "../../lib/query/user";
+import Loading from "../../components/loading";
+import { User } from "../../lib/types/user";
 
 export default function UserSettings() {
 	return (
@@ -98,6 +100,7 @@ function UserSettingsForm({ data }) {
 				/>
 			</form>
 			<PasswordChange />
+			<EmailChange />
 		</>
 	);
 }
@@ -168,3 +171,105 @@ function PasswordChange() {
 		</form>
 	);
 }
+
+function EmailChange() {
+	// Load existing user data.
+	const { data: user, isFetching, isLoading } = useUserQuery();
+	if (isFetching || isLoading) {
+		return <Loading />;
+	}
+
+	if (user === undefined) {
+		throw "could not fetch user";
+	}
+
+	return <EmailChangeForm user={user} />;
+}
+
+function EmailChangeForm({user}: {user: User}) {
+	const form = {
+		currentEmail: useTextInput("current_email", {
+			defaultValue: user.email,
+			nosubmit: true
+		}),
+		newEmail: useTextInput("new_email", {
+			validator: (value: string | undefined) => {
+				if (!value) {
+					return "";
+				}
+
+				if (value.toLowerCase() === user.email?.toLowerCase()) {
+					return "cannot change to your existing address";
+				}
+
+				if (value.toLowerCase() === user.unconfirmed_email?.toLowerCase()) {
+					return "you already have a pending email address change to this address";
+				}
+
+				return "";
+			},
+		}),
+		password: useTextInput("password"),
+	};
+	const [submitForm, result] = useFormSubmit(form, useEmailChangeMutation());
+
+	return (
+		<form className="change-email" onSubmit={submitForm}>
+			<div className="form-section-docs">
+				<h3>Change Email</h3>
+				<a
+					href="https://docs.gotosocial.org/en/latest/user_guide/settings/#email-change"
+					target="_blank"
+					className="docslink"
+					rel="noreferrer"
+				>
+					Learn more about this (opens in a new tab)
+				</a>
+			</div>
+
+			{ user.unconfirmed_email && <>
+				<div className="info">
+					<i className="fa fa-fw fa-info-circle" aria-hidden="true"></i>
+					<b>
+						You currently have a pending email address
+						change to the address: {user.unconfirmed_email}
+						<br />
+						To confirm {user.unconfirmed_email} as your new
+						address for this account, please check your email inbox.
+					</b>
+				</div>
+			</> }
+
+			<TextInput
+				type="email"
+				name="current-email"
+				field={form.currentEmail}
+				label="Current email address"
+				autoComplete="none"
+				disabled={true}
+			/>
+
+			<TextInput
+				type="password"
+				name="password"
+				field={form.password}
+				label="Current password"
+				autoComplete="current-password"
+			/>
+
+			<TextInput
+				type="email"
+				name="new-email"
+				field={form.newEmail}
+				label="New email address"
+				autoComplete="none"
+			/>
+			
+			<MutationButton
+				disabled={!form.password || !form.newEmail || !form.newEmail.valid}
+				label="Change email address"
+				result={result}
+			/>
+		</form>
+	);
+}