1 files changed, 78 insertions, 0 deletions
diff --git a/js/src/app/app.ts b/js/src/app/app.ts
new file mode 100644
index 000000000..0c6260bc7
--- /dev/null
+++ b/js/src/app/app.ts
@@ -0,0 +1,78 @@
+import fs from "fs/promises";
+import { AppPath } from "./path";
+import { Log } from "../util/log";
+import { Context } from "../util/context";
+
+export namespace App {
+  const log = Log.create({ service: "app" });
+
+  export type Info = Awaited<ReturnType<typeof create>>;
+
+  const ctx = Context.create<Info>("app");
+
+  async function create(input: { directory: string }) {
+    const dataDir = AppPath.data(input.directory);
+    await fs.mkdir(dataDir, { recursive: true });
+    await Log.file(input.directory);
+
+    log.info("created", { path: dataDir });
+
+    const services = new Map<
+      any,
+      {
+        state: any;
+        shutdown?: (input: any) => Promise<void>;
+      }
+    >();
+
+    const result = {
+      get services() {
+        return services;
+      },
+      get root() {
+        return input.directory;
+      },
+    };
+
+    return result;
+  }
+
+  export function state<State>(
+    key: any,
+    init: (app: Info) => State,
+    shutdown?: (state: Awaited<State>) => Promise<void>,
+  ) {
+    return () => {
+      const app = ctx.use();
+      const services = app.services;
+      if (!services.has(key)) {
+        log.info("registering service", { name: key });
+        services.set(key, {
+          state: init(app),
+          shutdown: shutdown,
+        });
+      }
+      return services.get(key)?.state as State;
+    };
+  }
+
+  export async function use() {
+    return ctx.use();
+  }
+
+  export async function provide<T extends (app: Info) => any>(
+    input: { directory: string },
+    cb: T,
+  ) {
+    const app = await create(input);
+
+    return ctx.provide(app, async () => {
+      const result = await cb(app);
+      for (const [key, entry] of app.services.entries()) {
+        log.info("shutdown", { name: key });
+        await entry.shutdown?.(await entry.state);
+      }
+      return result;
+    });
+  }
+}