From 0d377ba222edefe71a668d6b4249f318362b386c Mon Sep 17 00:00:00 2001
From: Dmitriy Pleshevskiy <dmitriy@ideascup.me>
Date: Sat, 21 Aug 2021 08:56:18 +0300
Subject: [PATCH] example: add full ood example with new version

---
 examples/ood.ts | 215 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 215 insertions(+)
 create mode 100644 examples/ood.ts

diff --git a/examples/ood.ts b/examples/ood.ts
new file mode 100644
index 0000000..2903944
--- /dev/null
+++ b/examples/ood.ts
@@ -0,0 +1,215 @@
+import { StateMachine, StateMachineBuilder } from "../fsm.ts";
+
+enum ProjectStatus {
+  Pending = "pending",
+  Active = "active",
+  Completed = "completed",
+  Archived = "archived",
+}
+
+interface ProjectStateMachineContext {
+  projectService: ProjectService;
+  projectId: Project["id"];
+}
+
+const smbProject = new StateMachineBuilder<
+  ProjectStateMachineContext,
+  ProjectStatus
+>()
+  .withStates(
+    [ProjectStatus.Pending, ProjectStatus.Archived, ProjectStatus.Completed],
+    {
+      async onEntry(_from, to, { projectService, projectId }) {
+        await projectService.updateProject(projectId, { status: to.name });
+      },
+    },
+  )
+  .withState(
+    ProjectStatus.Active,
+    {
+      async onEntry(_from, _to, { projectService, projectId }) {
+        await projectService.activateProject(projectId);
+      },
+    },
+  )
+  .withTransitions([
+    [ProjectStatus.Pending, [ProjectStatus.Active, ProjectStatus.Archived]],
+    [ProjectStatus.Active, [ProjectStatus.Completed]],
+  ]);
+
+async function main() {
+  await prepareExampleEnv();
+
+  const projectService = new ProjectService();
+
+  async function firstProjectPath() {
+    const project = await projectService.getProject(1);
+    const smProject = smbProject.build(project.status);
+
+    const projectId = project.id;
+    const context = { projectService, projectId };
+
+    await logProject("[project 1] initial", projectId);
+    logAllowedStates(smProject);
+
+    await smProject.tryChangeState(ProjectStatus.Active, context);
+    await logProject("[project 1] after activation", projectId);
+    logAllowedStates(smProject);
+
+    await smProject.tryChangeState(ProjectStatus.Completed, context);
+    await logProject("[project 1] after completed", projectId);
+    logAllowedStates(smProject);
+  }
+
+  async function secondProjectPath() {
+    const project = await projectService.getProject(2);
+    const smProject = smbProject.build(project.status);
+
+    const projectId = project.id;
+    const context = { projectService, projectId };
+
+    await logProject("[project 2] initial", projectId);
+    logAllowedStates(smProject);
+
+    await smProject.tryChangeState(ProjectStatus.Archived, context);
+    await logProject("[project 2] after activation", projectId);
+    logAllowedStates(smProject);
+  }
+
+  async function logProject(message: string, projectId: number) {
+    console.log(message, await projectService.getProject(projectId));
+  }
+
+  function logAllowedStates<C, N extends string>(sm: StateMachine<C, N>) {
+    console.log("[fsm] transitions", sm.allowedTransitionStateNames());
+  }
+
+  await firstProjectPath();
+  console.log("---------");
+  await secondProjectPath();
+}
+
+async function prepareExampleEnv() {
+  const projectService = new ProjectService();
+
+  await projectService.createProject({ name: "my first project" });
+  await projectService.createProject({ name: "my second project" });
+}
+
+class ProjectService {
+  private readonly projectStorage = new ProjectStorage();
+
+  createProject(insertData: CreateProjectData) {
+    return this.projectStorage.createProject(insertData);
+  }
+
+  updateProject(id: Project["id"], patchData: UpdateProjectData) {
+    return this.projectStorage.updateProject(id, patchData);
+  }
+
+  async activateProject(id: Project["id"]) {
+    const project = await this.getProject(id);
+
+    await this.projectStorage.updateProject(
+      project.id,
+      { status: ProjectStatus.Active },
+    );
+  }
+
+  async getProject(id: Project["id"]) {
+    const project = await this.getProjectUnchecked(id);
+    if (!project) throw new Error("Project does not exist");
+    return project;
+  }
+
+  getProjectUnchecked(id: Project["id"]) {
+    return this.projectStorage.getProject(id);
+  }
+}
+
+interface CreateProjectData {
+  name: string;
+}
+
+interface UpdateProjectData {
+  name?: string;
+  status?: ProjectStatus;
+}
+
+class ProjectStorage {
+  createProject(insertData: CreateProjectData) {
+    return randomDebounced(() => {
+      const createdData: Project = {
+        ...insertData,
+        id: genProjectId(),
+        status: ProjectStatus.Pending,
+        createdAt: new Date(),
+        updatedAt: new Date(),
+      };
+      _projectStore.set(createdData.id, createdData);
+      return createdData;
+    });
+  }
+
+  updateProject(id: Project["id"], patchData: UpdateProjectData) {
+    return randomDebounced(() => {
+      const currentData = _projectStore.get(id);
+      if (!currentData) return null;
+
+      const updatedData: Project = {
+        ...currentData,
+        ...patchData,
+        updatedAt: new Date(),
+      };
+
+      if (
+        currentData.activatedAt == null &&
+        patchData.status === ProjectStatus.Active
+      ) {
+        updatedData.activatedAt = new Date();
+      }
+
+      _projectStore.set(id, updatedData);
+      return updatedData;
+    });
+  }
+
+  getProject(id: Project["id"]) {
+    return randomDebounced(() => _projectStore.get(id));
+  }
+}
+
+interface Project {
+  id: number;
+  name: string;
+  status: ProjectStatus;
+  createdAt: Date;
+  updatedAt: Date;
+  activatedAt?: Date;
+}
+
+function genProjectId() {
+  return _projectStore.size + 1;
+}
+
+const _projectStore = new Map<Project["id"], Project>();
+
+function randomDebounced<T>(fn: () => T): Promise<T> {
+  return debounced(fn, randomWaitMs());
+}
+
+function debounced<T>(fn: () => T, wait: number): Promise<T> {
+  return delay(wait).then(fn);
+}
+
+function delay(wait: number) {
+  return new Promise((resolve) => setTimeout(resolve, wait));
+}
+
+function randomWaitMs() {
+  return Math.round(Math.random() * 1000) + 1000;
+}
+
+if (import.meta.main) {
+  await main();
+}