Add Redux and reducers.

Load i18n files and add dayjs.

src/redux/reducers/sync.ts

@@ -0,0 +1,85 @@
+import { AppearanceOptions } from "./settings";
+import { Language } from "../../context/Locale";
+import { ThemeOptions } from "../../context/Theme";
+
+export type SyncKeys = 'theme' | 'appearance' | 'locale';
+
+export interface SyncData {
+    locale?: Language;
+    theme?: ThemeOptions;
+    appearance?: AppearanceOptions;
+}
+
+export const DEFAULT_ENABLED_SYNC: SyncKeys[] = [ 'theme', 'appearance', 'locale' ];
+export interface SyncOptions {
+    disabled?: SyncKeys[]
+    revision?: {
+        [key: string]: number
+    }
+}
+
+export type SyncUpdateAction = {
+    type: "SYNC_UPDATE";
+    update: { [key in SyncKeys]?: [ number, SyncData[key] ] }
+};
+
+export type SyncAction =
+    | { type: undefined }
+    | {
+          type: "SYNC_ENABLE_KEY";
+          key: SyncKeys;
+      }
+    | {
+          type: "SYNC_DISABLE_KEY";
+          key: SyncKeys;
+      }
+    | {
+          type: "SYNC_SET_REVISION";
+          key: SyncKeys;
+          timestamp: number;
+      }
+    | SyncUpdateAction;
+
+export function sync(
+    state = {} as SyncOptions,
+    action: SyncAction
+): SyncOptions {
+    switch (action.type) {
+        case "SYNC_DISABLE_KEY":
+            return {
+                ...state,
+                disabled: [
+                    ...(state.disabled ?? []).filter(v => v !== action.key),
+                    action.key
+                ]
+            };
+        case "SYNC_ENABLE_KEY":
+            return {
+                ...state,
+                disabled: state.disabled?.filter(v => v !== action.key)
+            };
+        case "SYNC_SET_REVISION":
+            return {
+                ...state,
+                revision: {
+                    ...state.revision,
+                    [action.key]: action.timestamp
+                }
+            };
+        case "SYNC_UPDATE":
+            const revision = { ...state.revision };
+            for (const key of Object.keys(action.update)) {
+                const value = action.update[key as SyncKeys];
+                if (value) {
+                    revision[key] = value[0];
+                }
+            }
+
+            return {
+                ...state,
+                revision
+            }
+        default:
+            return state;
+    }
+}