Add reminder when about to post without alt text in web UI (#33760)

app/javascript/mastodon/features/ui/components/confirmation_modals/confirmation_modal.tsx

@@ -56,14 +56,6 @@ export const ConfirmationModal: React.FC<
 
       <div className='safety-action-modal__bottom'>
         <div className='safety-action-modal__actions'>
-          {secondary && (
-            <>
-              <Button onClick={handleSecondary}>{secondary}</Button>
-
-              <div className='spacer' />
-            </>
-          )}
-
           <button onClick={handleCancel} className='link-button'>
             <FormattedMessage
               id='confirmation_modal.cancel'
@@ -71,6 +63,15 @@ export const ConfirmationModal: React.FC<
             />
           </button>
 
+          {secondary && (
+            <>
+              <div className='spacer' />
+              <button onClick={handleSecondary} className='link-button'>
+                {secondary}
+              </button>
+            </>
+          )}
+
           {/* eslint-disable-next-line jsx-a11y/no-autofocus -- we are in a modal and thus autofocusing is justified */}
           <Button onClick={handleClick} autoFocus>
             {confirm}

app/javascript/mastodon/features/ui/components/confirmation_modals/index.ts

@@ -7,3 +7,4 @@ export { ConfirmUnfollowModal } from './unfollow';
 export { ConfirmClearNotificationsModal } from './clear_notifications';
 export { ConfirmLogOutModal } from './log_out';
 export { ConfirmFollowToListModal } from './follow_to_list';
+export { ConfirmMissingAltTextModal } from './missing_alt_text';

app/javascript/mastodon/features/ui/components/confirmation_modals/missing_alt_text.tsx

@@ -0,0 +1,81 @@
+import { useCallback } from 'react';
+
+import { defineMessages, useIntl } from 'react-intl';
+
+import type { Map as ImmutableMap, List as ImmutableList } from 'immutable';
+
+import { submitCompose } from 'mastodon/actions/compose';
+import { openModal } from 'mastodon/actions/modal';
+import type { MediaAttachment } from 'mastodon/models/media_attachment';
+import { useAppDispatch, useAppSelector } from 'mastodon/store';
+
+import type { BaseConfirmationModalProps } from './confirmation_modal';
+import { ConfirmationModal } from './confirmation_modal';
+
+const messages = defineMessages({
+  title: {
+    id: 'confirmations.missing_alt_text.title',
+    defaultMessage: 'Add alt text?',
+  },
+  confirm: {
+    id: 'confirmations.missing_alt_text.confirm',
+    defaultMessage: 'Add alt text',
+  },
+  message: {
+    id: 'confirmations.missing_alt_text.message',
+    defaultMessage:
+      'Your post contains media without alt text. Adding descriptions helps make your content accessible to more people.',
+  },
+  secondary: {
+    id: 'confirmations.missing_alt_text.secondary',
+    defaultMessage: 'Post anyway',
+  },
+});
+
+export const ConfirmMissingAltTextModal: React.FC<
+  BaseConfirmationModalProps
+> = ({ onClose }) => {
+  const intl = useIntl();
+  const dispatch = useAppDispatch();
+  const mediaId = useAppSelector(
+    (state) =>
+      (
+        (state.compose as ImmutableMap<string, unknown>).get(
+          'media_attachments',
+        ) as ImmutableList<MediaAttachment>
+      )
+        .find(
+          (media) =>
+            ['image', 'gifv'].includes(media.get('type') as string) &&
+            ((media.get('description') ?? '') as string).length === 0,
+        )
+        ?.get('id') as string,
+  );
+
+  const handleConfirm = useCallback(() => {
+    dispatch(
+      openModal({
+        modalType: 'FOCAL_POINT',
+        modalProps: {
+          mediaId,
+        },
+      }),
+    );
+  }, [dispatch, mediaId]);
+
+  const handleSecondary = useCallback(() => {
+    dispatch(submitCompose());
+  }, [dispatch]);
+
+  return (
+    <ConfirmationModal
+      title={intl.formatMessage(messages.title)}
+      message={intl.formatMessage(messages.message)}
+      confirm={intl.formatMessage(messages.confirm)}
+      secondary={intl.formatMessage(messages.secondary)}
+      onConfirm={handleConfirm}
+      onSecondary={handleSecondary}
+      onClose={onClose}
+    />
+  );
+};

app/javascript/mastodon/features/ui/components/modal_root.jsx

@@ -37,6 +37,7 @@ import {
   ConfirmClearNotificationsModal,
   ConfirmLogOutModal,
   ConfirmFollowToListModal,
+  ConfirmMissingAltTextModal,
 } from './confirmation_modals';
 import ImageModal from './image_modal';
 import MediaModal from './media_modal';
@@ -58,6 +59,7 @@ export const MODAL_COMPONENTS = {
   'CONFIRM_CLEAR_NOTIFICATIONS': () => Promise.resolve({ default: ConfirmClearNotificationsModal }),
   'CONFIRM_LOG_OUT': () => Promise.resolve({ default: ConfirmLogOutModal }),
   'CONFIRM_FOLLOW_TO_LIST': () => Promise.resolve({ default: ConfirmFollowToListModal }),
+  'CONFIRM_MISSING_ALT_TEXT': () => Promise.resolve({ default: ConfirmMissingAltTextModal }),
   'MUTE': MuteModal,
   'BLOCK': BlockModal,
   'DOMAIN_BLOCK': DomainBlockModal,