From 72a01cdc176191d2af165baae126b2a4bbb7a7c8 Mon Sep 17 00:00:00 2001
From: Sebastian Malton <sebastian@malton.name>
Date: Mon, 17 Apr 2023 15:47:57 -0400
Subject: [PATCH] chore: Introduce competition for InitializableState

Signed-off-by: Sebastian Malton <sebastian@malton.name>
---
 .../common/initializable-state/create.test.ts | 78 ++++++++++++++++++-
 .../src/common/initializable-state/create.ts  | 65 +++++++++++++++-
 2 files changed, 139 insertions(+), 4 deletions(-)

diff --git a/packages/core/src/common/initializable-state/create.test.ts b/packages/core/src/common/initializable-state/create.test.ts
index 8241aa1612..5bd1d6d461 100644
--- a/packages/core/src/common/initializable-state/create.test.ts
+++ b/packages/core/src/common/initializable-state/create.test.ts
@@ -5,11 +5,14 @@
 
 import type { AsyncFnMock } from "@async-fn/jest";
 import asyncFn from "@async-fn/jest";
-import type { DiContainer, Injectable } from "@ogre-tools/injectable";
+import type { Runnable } from "@k8slens/run-many";
+import { runManyFor } from "@k8slens/run-many";
+import type { DiContainer, Injectable, InjectionToken } from "@ogre-tools/injectable";
+import { createContainer, getInjectionToken } from "@ogre-tools/injectable";
 import { runInAction } from "mobx";
 import { getDiForUnitTesting } from "../../main/getDiForUnitTesting";
-import type { InitializableState } from "./create";
-import { createInitializableState } from "./create";
+import type { ImplInitializableInjectionTokensArgs, Initializable, InitializableState } from "./create";
+import { getInjectablesForInitializable, getInitializable, createInitializableState } from "./create";
 
 describe("InitializableState tests", () => {
   let di: DiContainer;
@@ -75,3 +78,72 @@ describe("InitializableState tests", () => {
     });
   });
 });
+
+describe("InitializableTokens technical tests", () => {
+  let di: DiContainer;
+  let initializableToken: Initializable<number>;
+  let phase: InjectionToken<Runnable<void>, void>;
+
+  beforeEach(() => {
+    di = createContainer("irrelevant");
+
+    initializableToken = getInitializable("some-root-id");
+    phase = getInjectionToken({ id: "some-runnable-phase" });
+  });
+
+  it("throws given attempting to inject the state token", () => {
+    expect(() => di.inject(initializableToken.stateToken)).toThrowErrorMatchingInlineSnapshot(
+      `"Tried to inject non-registered injectable "irrelevant" -> "some-root-id-state-token"."`,
+    );
+  });
+
+  describe("given some implementation for initializableToken is registered", () => {
+    let mockInit: AsyncFnMock<ImplInitializableInjectionTokensArgs<number>["init"]>;
+
+    beforeEach(() => {
+      mockInit = asyncFn();
+
+      const { initializationInjectable, stateInjectable } = getInjectablesForInitializable({
+        init: mockInit,
+        phase,
+        token: initializableToken,
+      });
+
+      di.register(initializationInjectable, stateInjectable);
+    });
+
+    it("throws given attempting to inject the state token", () => {
+      expect(() => di.inject(initializableToken.stateToken)).toThrowErrorMatchingInlineSnapshot(
+        `"Tried to inject "some-root-id" before initialization was complete"`,
+      );
+    });
+
+    describe("given the phase is started to be run", () => {
+      let runManyPromise: Promise<void>;
+
+      beforeEach(() => {
+        runManyPromise = runManyFor(di)(phase)();
+      });
+
+      it("throws given attempting to inject the state token", () => {
+        expect(() => di.inject(initializableToken.stateToken)).toThrowErrorMatchingInlineSnapshot(
+          `"Tried to inject "some-root-id" before initialization was complete"`,
+        );
+      });
+
+      describe("when initialization is complete", () => {
+        beforeEach(async () => {
+          await mockInit.resolve(10);
+        });
+
+        it("initializes the state", () => {
+          expect(di.inject(initializableToken.stateToken)).toBe(10);
+        });
+
+        it("allows the runMany to complete", async () => {
+          await runManyPromise;
+        });
+      });
+    });
+  });
+});
diff --git a/packages/core/src/common/initializable-state/create.ts b/packages/core/src/common/initializable-state/create.ts
index 829de57d94..bb45d878b5 100644
--- a/packages/core/src/common/initializable-state/create.ts
+++ b/packages/core/src/common/initializable-state/create.ts
@@ -3,8 +3,10 @@
  * Licensed under MIT License. See LICENSE in root directory for more information.
  */
 
+import type { Runnable } from "@k8slens/run-many";
 import type { DiContainerForInjection, Injectable, InjectionToken } from "@ogre-tools/injectable";
-import { getInjectable } from "@ogre-tools/injectable";
+import { getInjectionToken, getInjectable } from "@ogre-tools/injectable";
+import assert from "assert";
 
 export interface CreateInitializableStateArgs<T> {
   id: string;
@@ -21,6 +23,67 @@ type InitializableStateValue<T> =
   | { set: false }
   | { set: true; value: T } ;
 
+export interface Initializable<T> {
+  readonly rootId: string;
+  readonly stateToken: InjectionToken<T, void>;
+}
+
+export const getInitializable = <T>(rootId: string): Initializable<T> => ({
+  rootId,
+  stateToken: getInjectionToken<T>({
+    id: `${rootId}-state-token`,
+  }),
+});
+
+type InitState<T> = { set: true; value: T } | { set: false };
+
+export interface ImplInitializableInjectionTokensArgs<T> {
+  token: Initializable<T>;
+  init: (di: DiContainerForInjection) => T | Promise<T>;
+  phase: InjectionToken<Runnable<void>, void>;
+  runAfter?: Runnable<void>["runAfter"];
+}
+
+export const getInjectablesForInitializable = <T>({
+  init,
+  phase,
+  token: {
+    rootId,
+    stateToken,
+  },
+  runAfter,
+}: ImplInitializableInjectionTokensArgs<T>) => {
+  let state: InitState<T> = { set: false };
+
+  const stateInjectable = getInjectable({
+    id: `${rootId}-state`,
+    instantiate: () => {
+      assert(state.set, `Tried to inject "${rootId}" before initialization was complete`);
+
+      return state.value;
+    },
+    injectionToken: stateToken,
+  });
+  const initializationInjectable = getInjectable({
+    id: `${rootId}-initialization`,
+    instantiate: (di) => ({
+      run: async () => {
+        state = {
+          set: true,
+          value: await init(di),
+        };
+      },
+      runAfter,
+    }),
+    injectionToken: phase,
+  });
+
+  return {
+    stateInjectable,
+    initializationInjectable,
+  };
+};
+
 export function createInitializableState<T>(args: CreateInitializableStateArgs<T>): Injectable<InitializableState<T>, unknown, void> {
   const { id, init, injectionToken } = args;