Add support to save chapter to databases

src/db/interfaces.ts

@@ -0,0 +1,21 @@
+import { DbConfig, DbType } from "../config";
+import { IndexedDb } from "./indexedDb";
+import type { QdChapterInfo } from "../types";
+
+export interface Db {
+    init(): Promise<void>;
+    saveQdChapter(info: QdChapterInfo): Promise<void>;
+    close(): void;
+}
+
+export async function createDb(): Promise<Db> {
+    const config = new DbConfig();
+    await config.init();
+    switch (config.DbType) {
+        case DbType.IndexedDb:
+            const db = new IndexedDb(config.IndexedDb);
+            return db;
+        default:
+            throw new Error('Unsupported database type');
+    }
+}