hub/reducers: consolidate command in progress states

The Loaded state is not used anywhere else, so we can replace it with
the Unknown state. Then we can make all other command-in-progress
states (start repl/stop user program) the same as download and run.
When the command completes, the hub is in an unknown state until a
status message is received. The Disconnected states overrides all other
states.

src/hub/reducers.test.ts

@@ -16,6 +16,8 @@ import {
     didStartDownload,
     hubDidFailToStartRepl,
     hubDidFailToStopUserProgram,
+    hubDidStartRepl,
+    hubDidStopUserProgram,
     hubStartRepl,
     hubStopUserProgram,
 } from './actions';
@@ -111,7 +113,7 @@ describe('runtime', () => {
         expect(
             reducers({ runtime: HubRuntimeState.Loading } as State, didFinishDownload())
                 .runtime,
-        ).toBe(HubRuntimeState.Loaded);
+        ).toBe(HubRuntimeState.Unknown);
     });
 
     test('didFinishDownload', () => {
@@ -153,7 +155,7 @@ describe('runtime', () => {
         // normal operation - user program started
         expect(
             reducers(
-                { runtime: HubRuntimeState.Loaded } as State,
+                { runtime: HubRuntimeState.Unknown } as State,
                 didReceiveStatusReport(statusToFlag(Status.UserProgramRunning)),
             ).runtime,
         ).toBe(HubRuntimeState.Running);
@@ -161,7 +163,7 @@ describe('runtime', () => {
         // really short program run finished before receiving download finished
         expect(
             reducers(
-                { runtime: HubRuntimeState.Loaded } as State,
+                { runtime: HubRuntimeState.Unknown } as State,
                 didReceiveStatusReport(0),
             ).runtime,
         ).toBe(HubRuntimeState.Idle);
@@ -173,6 +175,22 @@ describe('runtime', () => {
                 didReceiveStatusReport(0),
             ).runtime,
         ).toBe(HubRuntimeState.Idle);
+
+        // ignored during start repl command
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.StartingRepl } as State,
+                didReceiveStatusReport(0),
+            ).runtime,
+        ).toBe(HubRuntimeState.StartingRepl);
+
+        // ignored during stop user program command
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.StoppingUserProgram } as State,
+                didReceiveStatusReport(0),
+            ).runtime,
+        ).toBe(HubRuntimeState.StoppingUserProgram);
     });
 
     test('hubStartRepl', () => {
@@ -182,6 +200,21 @@ describe('runtime', () => {
         ).toBe(HubRuntimeState.StartingRepl);
     });
 
+    test('hubDidStartRepl', () => {
+        expect(
+            reducers({ runtime: HubRuntimeState.Running } as State, hubDidStartRepl())
+                .runtime,
+        ).toBe(HubRuntimeState.Unknown);
+
+        // ignored if disconnected
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.Disconnected } as State,
+                hubDidStartRepl(),
+            ).runtime,
+        ).toBe(HubRuntimeState.Disconnected);
+    });
+
     test('hubDidFailToStartRepl', () => {
         expect(
             reducers(
@@ -189,6 +222,14 @@ describe('runtime', () => {
                 hubDidFailToStartRepl(),
             ).runtime,
         ).toBe(HubRuntimeState.Unknown);
+
+        // ignored if disconnected
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.Disconnected } as State,
+                hubDidFailToStartRepl(),
+            ).runtime,
+        ).toBe(HubRuntimeState.Disconnected);
     });
 
     test('hubStopUserProgram', () => {
@@ -200,6 +241,23 @@ describe('runtime', () => {
         ).toBe(HubRuntimeState.StoppingUserProgram);
     });
 
+    test('hubStopUserProgram', () => {
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.Running } as State,
+                hubDidStopUserProgram(),
+            ).runtime,
+        ).toBe(HubRuntimeState.Unknown);
+
+        // ignored if disconnected
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.Disconnected } as State,
+                hubDidStopUserProgram(),
+            ).runtime,
+        ).toBe(HubRuntimeState.Disconnected);
+    });
+
     test('hubDidFailToStopUserProgram', () => {
         expect(
             reducers(
@@ -207,5 +265,13 @@ describe('runtime', () => {
                 hubDidFailToStopUserProgram(),
             ).runtime,
         ).toBe(HubRuntimeState.Unknown);
+
+        // ignored if disconnected
+        expect(
+            reducers(
+                { runtime: HubRuntimeState.Disconnected } as State,
+                hubDidFailToStopUserProgram(),
+            ).runtime,
+        ).toBe(HubRuntimeState.Disconnected);
     });
 });

src/hub/reducers.ts

@@ -28,6 +28,8 @@ import {
     didStartDownload,
     hubDidFailToStartRepl,
     hubDidFailToStopUserProgram,
+    hubDidStartRepl,
+    hubDidStopUserProgram,
     hubStartRepl,
     hubStopUserProgram,
 } from './actions';
@@ -44,8 +46,6 @@ export enum HubRuntimeState {
     Idle = 'hub.runtime.idle',
     /** A user program is being copied to the hub. */
     Loading = 'hub.runtime.loading',
-    /** A user program has been copied to the hub. */
-    Loaded = 'hub.runtime.loaded',
     /** A user program is running. */
     Running = 'hub.runtime.running',
     /** Busy starting the REPL. */
@@ -84,7 +84,8 @@ const runtime: Reducer<HubRuntimeState> = (
         if (state === HubRuntimeState.Disconnected) {
             return state;
         }
-        return HubRuntimeState.Loaded;
+        // state is unknown until we receive a status event
+        return HubRuntimeState.Unknown;
     }
 
     if (didFailToFinishDownload.matches(action)) {
@@ -100,7 +101,9 @@ const runtime: Reducer<HubRuntimeState> = (
         // let the hub status interfere with it.
         if (
             state === HubRuntimeState.Disconnected ||
-            state === HubRuntimeState.Loading
+            state === HubRuntimeState.Loading ||
+            state === HubRuntimeState.StartingRepl ||
+            state === HubRuntimeState.StoppingUserProgram
         ) {
             return state;
         }
@@ -116,10 +119,19 @@ const runtime: Reducer<HubRuntimeState> = (
         return HubRuntimeState.StartingRepl;
     }
 
-    // NB: hubDidStartRepl will trigger user program running, so we don't
-    // change state for both to avoid race condition
+    if (hubDidStartRepl.matches(action)) {
+        if (state === HubRuntimeState.Disconnected) {
+            return state;
+        }
+        // state is unknown until we receive a status event
+        return HubRuntimeState.Unknown;
+    }
 
     if (hubDidFailToStartRepl.matches(action)) {
+        if (state === HubRuntimeState.Disconnected) {
+            return state;
+        }
+        // failed to communicate, so state is unknown
         return HubRuntimeState.Unknown;
     }
 
@@ -127,10 +139,19 @@ const runtime: Reducer<HubRuntimeState> = (
         return HubRuntimeState.StoppingUserProgram;
     }
 
-    // NB: hubDidStopUserProgram will trigger user program running flag to clear,
-    // so we don't change state for both to avoid race condition
+    if (hubDidStopUserProgram.matches(action)) {
+        if (state === HubRuntimeState.Disconnected) {
+            return state;
+        }
+        // state is unknown until we receive a status event
+        return HubRuntimeState.Unknown;
+    }
 
     if (hubDidFailToStopUserProgram.matches(action)) {
+        if (state === HubRuntimeState.Disconnected) {
+            return state;
+        }
+        // failed to communicate, so state is unknown
         return HubRuntimeState.Unknown;
     }