add sqlite middleware

src/middleware/sqlite.ts

+/*
+ * Sqlite中间件
+ *
+ * 用于获取卡牌数据
+ *
+ * */
+
+import initSqlJs, { Database } from "sql.js";
+
+export enum sqliteCmd {
+  // 初始化
+  INIT,
+  // 读取操作
+  SELECT,
+}
+
+export interface sqliteAction {
+  cmd: sqliteCmd;
+  // 初始化DB需要业务方传入的数据
+  initInfo?: {
+    dbUrl: string;
+  };
+  // 需要读取卡牌数据的ID
+  payload?: number;
+}
+
+let YGODB: Database | null = null;
+const sqlPromise = initSqlJs({
+  locateFile: (file) => `/node_modules/sql.js/dist/${file}`,
+});
+
+// FIXME: 应该有个返回值，告诉业务方本次请求的结果，比如初始化DB失败
+export default async function (action: sqliteAction) {
+  switch (action.cmd) {
+    case sqliteCmd.INIT: {
+      const info = action.initInfo;
+      if (info) {
+        const dataPromise = fetch(info.dbUrl).then((res) => res.arrayBuffer()); // TODO: i18n
+
+        const [SQL, buffer] = await Promise.all([sqlPromise, dataPromise]);
+        YGODB = new SQL.Database(new Uint8Array(buffer));
+      }
+
+      break;
+    }
+    case sqliteCmd.SELECT: {
+      if (YGODB) {
+        // TDOO
+      } else {
+        console.warn("ygo db not init!");
+      }
+
+      break;
+    }
+    default: {
+      console.warn(`Unhandled sqlite command: ${action.cmd}`);
+
+      break;
+    }
+  }
+}