refactor: Use i18next for language resolution

Due to https://github.com/i18next/i18next/issues/1564 we still have to
implement our own language resolution, but we can rely on
resolvedLanguage to determine which language to pass through to the
renderer.

We will use the language detected by chromium as the system locale, so
there is no need to use os-locale for detection any more.

We use i18next in the main process do resolve the language, then set the
resolve (not requested!) language in the renderer process to avoid doing
resolution twice. This avoids the need in the renderer process to know
the list of supported languages.

We set the language and the writing direction in HTML in the renderer.

Signed-off-by: Kristóf Marussy <kristof@marussy.com>

3 files changed, 36 insertions, 0 deletions

diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index c4de885..95af73a 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -80,3 +80,5 @@ export {
   defineSharedStoreModel,
   FALLBACK_LOCALE,
 } from './stores/SharedStoreBase';
+
+export { default as WritingDirection } from './stores/WritingDirection';
diff --git a/packages/shared/src/stores/SharedStoreBase.ts b/packages/shared/src/stores/SharedStoreBase.ts
index a576a0e..bd71cea 100644
--- a/packages/shared/src/stores/SharedStoreBase.ts
+++ b/packages/shared/src/stores/SharedStoreBase.ts
@@ -30,6 +30,7 @@ import {
 import GlobalSettingsBase from './GlobalSettingsBase';
 import ProfileBase from './Profile';
 import ServiceBase from './ServiceBase';
+import WritingDirection from './WritingDirection';
 
 export const FALLBACK_LOCALE = 'en';
 
@@ -46,6 +47,7 @@ export function defineSharedStoreModel<
     services: types.array(types.reference(service)),
     shouldUseDarkColors: false,
     language: FALLBACK_LOCALE,
+    writingDirection: types.optional(WritingDirection, 'ltr'),
   });
 }
 
diff --git a/packages/shared/src/stores/WritingDirection.ts b/packages/shared/src/stores/WritingDirection.ts
new file mode 100644
index 0000000..561a86b
--- /dev/null
+++ b/packages/shared/src/stores/WritingDirection.ts
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C)  2022 Kristóf Marussy <kristof@marussy.com>
+ *
+ * This file is part of Sophie.
+ *
+ * Sophie 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, version 3.
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Instance, types } from 'mobx-state-tree';
+
+const WritingDirection = /* @__PURE__ */ (() =>
+  types.enumeration('WritingDirection', ['ltr', 'rtl']))();
+
+/*
+  eslint-disable-next-line @typescript-eslint/no-redeclare --
+  Intentionally naming the type the same as the store definition.
+*/
+type WritingDirection = Instance<typeof WritingDirection>;
+
+export default WritingDirection;