From 15ad2ea91f375eaa75dcef8c58c2f084291ad573 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?marcin=20miko=C5=82ajczak?= <git@mkljczk.pl>
Date: Sat, 18 May 2024 15:47:36 +0200
Subject: [PATCH] Client-side language detection
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>
---
 package.json                                  |  1 +
 src/actions/compose.ts                        | 18 +++++++--
 .../compose/components/language-dropdown.tsx  | 11 +++++-
 .../compose/editor/plugins/state-plugin.tsx   | 38 ++++++++++++++++---
 src/reducers/compose.ts                       |  5 +++
 src/schemas/instance.ts                       |  4 --
 src/utils/features.ts                         | 10 ++++-
 vite.config.ts                                |  6 +++
 yarn.lock                                     | 12 ++++++
 9 files changed, 89 insertions(+), 16 deletions(-)

diff --git a/package.json b/package.json
index 292a83633..6f7283225 100644
--- a/package.json
+++ b/package.json
@@ -117,6 +117,7 @@
     "escape-html": "^1.0.3",
     "eslint-plugin-formatjs": "^4.12.2",
     "exifr": "^7.1.3",
+    "fasttext.wasm.js": "^1.0.0",
     "fuzzysort": "^3.0.0",
     "graphemesplit": "^2.4.4",
     "html-react-parser": "^5.0.0",
diff --git a/src/actions/compose.ts b/src/actions/compose.ts
index ba736151e..2bc67c8e6 100644
--- a/src/actions/compose.ts
+++ b/src/actions/compose.ts
@@ -90,7 +90,8 @@ const COMPOSE_EDITOR_STATE_SET = 'COMPOSE_EDITOR_STATE_SET' as const;
 
 const COMPOSE_CHANGE_MEDIA_ORDER = 'COMPOSE_CHANGE_MEDIA_ORDER' as const;
 
-const COMPOSE_ADD_SUGGESTED_QUOTE      = 'COMPOSE_ADD_SUGGESTED_QUOTE' as const;
+const COMPOSE_ADD_SUGGESTED_QUOTE    = 'COMPOSE_ADD_SUGGESTED_QUOTE' as const;
+const COMPOSE_ADD_SUGGESTED_LANGUAGE = 'COMPOSE_ADD_SUGGESTED_LANGUAGE' as const;
 
 const getAccount = makeGetAccount();
 
@@ -380,7 +381,7 @@ const submitCompose = (composeId: string, opts: SubmitComposeOpts = {}) =>
       content_type: contentType,
       poll: compose.poll,
       scheduled_at: compose.schedule,
-      language: compose.language,
+      language: compose.language || compose.suggested_language,
       to,
     };
 
@@ -875,7 +876,7 @@ const eventDiscussionCompose = (composeId: string, status: Status) =>
 const setEditorState = (composeId: string, editorState: EditorState | string | null, text?: string) => ({
   type: COMPOSE_EDITOR_STATE_SET,
   id: composeId,
-  editorState: editorState,
+  editorState,
   text,
 });
 
@@ -889,7 +890,13 @@ const changeMediaOrder = (composeId: string, a: string, b: string) => ({
 const addSuggestedQuote = (composeId: string, quoteId: string) => ({
   type: COMPOSE_ADD_SUGGESTED_QUOTE,
   id: composeId,
-  quoteId: quoteId,
+  quoteId,
+});
+
+const addSuggestedLanguage = (composeId: string, language: string) => ({
+  type: COMPOSE_ADD_SUGGESTED_LANGUAGE,
+  id: composeId,
+  language,
 });
 
 type ComposeAction =
@@ -940,6 +947,7 @@ type ComposeAction =
   | ReturnType<typeof setEditorState>
   | ReturnType<typeof changeMediaOrder>
   | ReturnType<typeof addSuggestedQuote>
+  | ReturnType<typeof addSuggestedLanguage>
 
 export {
   COMPOSE_CHANGE,
@@ -990,6 +998,7 @@ export {
   COMPOSE_EDITOR_STATE_SET,
   COMPOSE_CHANGE_MEDIA_ORDER,
   COMPOSE_ADD_SUGGESTED_QUOTE,
+  COMPOSE_ADD_SUGGESTED_LANGUAGE,
   setComposeToStatus,
   changeCompose,
   replyCompose,
@@ -1047,5 +1056,6 @@ export {
   setEditorState,
   changeMediaOrder,
   addSuggestedQuote,
+  addSuggestedLanguage,
   type ComposeAction,
 };
diff --git a/src/features/compose/components/language-dropdown.tsx b/src/features/compose/components/language-dropdown.tsx
index 99a157bd3..8ed307393 100644
--- a/src/features/compose/components/language-dropdown.tsx
+++ b/src/features/compose/components/language-dropdown.tsx
@@ -27,6 +27,7 @@ const languages = Object.entries(languagesObject) as Array<[Language, string]>;
 
 const messages = defineMessages({
   languagePrompt: { id: 'compose.language_dropdown.prompt', defaultMessage: 'Select language' },
+  languageSuggestion: { id: 'compose.language_dropdown.suggestion', defaultMessage: '{language} (detected)' },
   search: { id: 'compose.language_dropdown.search', defaultMessage: 'Search language…' },
 });
 
@@ -61,7 +62,7 @@ const LanguageDropdown: React.FC<ILanguageDropdown> = ({ composeId }) => {
     ],
   });
 
-  const language = useCompose(composeId).language;
+  const { language, suggested_language: suggestedLanguage } = useCompose(composeId);
 
   const handleClick: React.EventHandler<
     React.MouseEvent<HTMLButtonElement> | React.KeyboardEvent<HTMLButtonElement>
@@ -253,12 +254,18 @@ const LanguageDropdown: React.FC<ILanguageDropdown> = ({ composeId }) => {
   const isSearching = searchValue !== '';
   const results = search();
 
+  let buttonLabel = intl.formatMessage(messages.languagePrompt);
+  if (language) buttonLabel = languagesObject[language];
+  else if (suggestedLanguage) buttonLabel = intl.formatMessage(messages.languageSuggestion, {
+    language: languagesObject[suggestedLanguage as Language] || suggestedLanguage,
+  });
+
   return (
     <>
       <Button
         theme='muted'
         size='xs'
-        text={language ? languagesObject[language] : intl.formatMessage(messages.languagePrompt)}
+        text={buttonLabel}
         icon={require('@tabler/icons/outline/language.svg')}
         secondaryIcon={require('@tabler/icons/outline/chevron-down.svg')}
         title={intl.formatMessage(messages.languagePrompt)}
diff --git a/src/features/compose/editor/plugins/state-plugin.tsx b/src/features/compose/editor/plugins/state-plugin.tsx
index d07d4859a..7a8262262 100644
--- a/src/features/compose/editor/plugins/state-plugin.tsx
+++ b/src/features/compose/editor/plugins/state-plugin.tsx
@@ -1,14 +1,17 @@
 import { useLexicalComposerContext } from '@lexical/react/LexicalComposerContext';
 import { $createRemarkExport } from '@mkljczk/lexical-remark';
+import { type LanguageIdentificationModel } from 'fasttext.wasm.js/dist/models/language-identification/common.js';
 import { $getRoot } from 'lexical';
 import debounce from 'lodash/debounce';
 import { useCallback, useEffect } from 'react';
 
-import { addSuggestedQuote, setEditorState } from 'soapbox/actions/compose';
+import { addSuggestedLanguage, addSuggestedQuote, setEditorState } from 'soapbox/actions/compose';
 import { fetchStatus } from 'soapbox/actions/statuses';
 import { useAppDispatch, useFeatures } from 'soapbox/hooks';
 import { getStatusIdsFromLinksInContent } from 'soapbox/utils/status';
 
+let lidModel: LanguageIdentificationModel;
+
 interface IStatePlugin {
   composeId: string;
   isWysiwyg?: boolean;
@@ -50,9 +53,35 @@ const StatePlugin: React.FC<IStatePlugin> = ({ composeId, isWysiwyg }) => {
     });
   }, 2000), []);
 
+  const detectLanguage = useCallback(debounce(async (text: string) => {
+    dispatch(async (dispatch, getState) => {
+      const state = getState();
+      const compose = state.compose.get(composeId);
+
+      if (!features.postLanguages || features.languageDetection || compose?.language) return;
+
+      const wordsLength = text.split(/\s+/).length;
+
+      if (wordsLength < 4) return;
+
+      if (!lidModel) {
+        // eslint-disable-next-line import/extensions
+        const { getLIDModel } = await import('fasttext.wasm.js/common');
+        lidModel = await getLIDModel();
+      }
+      if (!lidModel.model) await lidModel.load();
+      const { alpha2, possibility } = await lidModel.identify(text.replace(/\s+/i, ' '));
+
+      if (alpha2 && possibility > 0.5) {
+        dispatch(addSuggestedLanguage(composeId, alpha2));
+      }
+    });
+  }, 750), []);
+
   useEffect(() => {
     editor.registerUpdateListener(({ editorState }) => {
-      let text;
+      const plainText = editorState.read(() => $getRoot().getTextContent());
+      let text = plainText;
       if (isWysiwyg) {
         text = editorState.read($createRemarkExport({
           handlers: {
@@ -60,13 +89,12 @@ const StatePlugin: React.FC<IStatePlugin> = ({ composeId, isWysiwyg }) => {
             mention: (node) => ({ type: 'text', value: node.getTextContent() }),
           },
         }));
-      } else {
-        text = editorState.read(() => $getRoot().getTextContent());
       }
       const isEmpty = text === '';
       const data = isEmpty ? null : JSON.stringify(editorState.toJSON());
       dispatch(setEditorState(composeId, data, text));
-      getQuoteSuggestions(text);
+      getQuoteSuggestions(plainText);
+      detectLanguage(plainText);
     });
   }, [editor]);
 
diff --git a/src/reducers/compose.ts b/src/reducers/compose.ts
index f3611257e..2b5eeb02c 100644
--- a/src/reducers/compose.ts
+++ b/src/reducers/compose.ts
@@ -56,6 +56,7 @@ import {
   COMPOSE_CHANGE_MEDIA_ORDER,
   COMPOSE_ADD_SUGGESTED_QUOTE,
   ComposeAction,
+  COMPOSE_ADD_SUGGESTED_LANGUAGE,
 } from '../actions/compose';
 import { EVENT_COMPOSE_CANCEL, EVENT_FORM_SET, type EventsAction } from '../actions/events';
 import { ME_FETCH_SUCCESS, ME_PATCH_SUCCESS, MeAction } from '../actions/me';
@@ -114,6 +115,7 @@ const ReducerCompose = ImmutableRecord({
   parent_reblogged_by: null as string | null,
   dismissed_quotes: ImmutableOrderedSet<string>(),
   language: null as Language | null,
+  suggested_language: null as string | null,
 });
 
 type State = ImmutableMap<string, Compose>;
@@ -553,6 +555,9 @@ const compose = (state = initialState, action: ComposeAction | EventsAction | Me
     case COMPOSE_ADD_SUGGESTED_QUOTE:
       return updateCompose(state, action.id, compose => compose
         .set('quote', action.quoteId));
+    case COMPOSE_ADD_SUGGESTED_LANGUAGE:
+      return updateCompose(state, action.id, compose => compose
+        .set('suggested_language', action.language));
     case COMPOSE_QUOTE_CANCEL:
       return updateCompose(state, action.id, compose => compose
         .update('dismissed_quotes', quotes => compose.quote ? quotes.add(compose.quote) : quotes)
diff --git a/src/schemas/instance.ts b/src/schemas/instance.ts
index 4082dd06b..50d1f5c84 100644
--- a/src/schemas/instance.ts
+++ b/src/schemas/instance.ts
@@ -21,10 +21,6 @@ const fixVersion = (version: string) => {
     version = '2.7.2 (compatible; Pleroma 2.4.50+akkoma)';
   }
 
-  if (version.endsWith('+pl)')) {
-    version = version.slice(0, -3) + 'soapbox)';
-  }
-
   // Set Takahē version to a Pleroma-like string
   if (version.startsWith('takahe/')) {
     version = `0.0.0 (compatible; Takahe ${version.slice(7)})`;
diff --git a/src/utils/features.ts b/src/utils/features.ts
index 0ef55ea28..404966e6d 100644
--- a/src/utils/features.ts
+++ b/src/utils/features.ts
@@ -567,6 +567,11 @@ const getInstanceFeatures = (instance: Instance) => {
       v.software === PLEROMA && v.build === REBASED && gte(v.version, '2.5.54'),
     ]),
 
+    /**
+     * TODO: Replace with proper feature gate.
+     */
+    languageDetection: v.software === PLEROMA && v.build === REBASED,
+
     /**
      * Can create, view, and manage lists.
      * @see {@link https://docs.joinmastodon.org/methods/lists/}
@@ -909,8 +914,11 @@ const parseVersion = (version: string): Backend => {
   }) : null;
   const compat = match ? semverParse(match[1]) || semverCoerce(match[1]) : null;
   if (match && semver && compat) {
+    let build = semver.build[0];
+    if (build === 'pl') build = 'soapbox';
+
     return {
-      build: semver.build[0],
+      build,
       compatVersion: compat.version,
       software: match[2] || MASTODON,
       version: semver.version.split('-')[0],
diff --git a/vite.config.ts b/vite.config.ts
index d5ecaab5e..3643ec78e 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -82,6 +82,12 @@ const config =  defineConfig(({ command }) => ({
       }, {
         src: './custom/instance',
         dest: '.',
+      }, {
+        src: './node_modules/fasttext.wasm.js/dist/models/language-identification/assets/lid.176.ftz',
+        dest: 'fastText/models/',
+      }, {
+        src: './node_modules/fasttext.wasm.js/dist/core/fastText.common.wasm',
+        dest: 'fastText/',
       }],
     }),
     visualizer({
diff --git a/yarn.lock b/yarn.lock
index 6451df0cc..af1c5bb89 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2585,6 +2585,11 @@
   dependencies:
     "@types/trusted-types" "*"
 
+"@types/emscripten@^1.39.10":
+  version "1.39.12"
+  resolved "https://registry.yarnpkg.com/@types/emscripten/-/emscripten-1.39.12.tgz#e43b4fdd4b389861897d6cbb9665532f3afd5abd"
+  integrity sha512-AQImDBgudQfMqUBfrjZYilRxoHDzTBp+ejh+g1fY67eSMalwIKtBXofjpyI0JBgNpHGzxeGAR2QDya0wxW9zbA==
+
 "@types/escape-html@^1.0.1":
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/@types/escape-html/-/escape-html-1.0.1.tgz#b19b4646915f0ae2c306bf984dc0a59c5cfc97ba"
@@ -5769,6 +5774,13 @@ fastq@^1.6.0:
   dependencies:
     reusify "^1.0.4"
 
+fasttext.wasm.js@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/fasttext.wasm.js/-/fasttext.wasm.js-1.0.0.tgz#3f89dfc024386af6c0a070ab5b65f0a62a0a79d2"
+  integrity sha512-Rv2DyM9ZaJ/r09FRIYeVXxsSRFu45CVH3Zu7nheTe/EPCH0Sew1wKf0zQ4VCBmibGRBpeHlpMuRdsp+VC/YwZw==
+  dependencies:
+    "@types/emscripten" "^1.39.10"
+
 file-entry-cache@^6.0.1:
   version "6.0.1"
   resolved "https://registry.yarnpkg.com/file-entry-cache/-/file-entry-cache-6.0.1.tgz#211b2dd9659cb0394b073e7323ac3c933d522027"