From f721f959f0cd4781eb68a03f64fdb40ac7b8af14 Mon Sep 17 00:00:00 2001
From: David Lechner <david@pybricks.com>
Date: Tue, 9 Jun 2020 10:06:33 -0500
Subject: [PATCH] do soft reset after connecting

When we first connect, we don't know what state the hub is in. This adds
a new state for that called Unknown and sends a stop request as soon
as we connect to try to get to a known state.
---
 src/actions/hub.ts  |  1 -
 src/epics/ble.ts    | 16 ++--------------
 src/reducers/hub.ts | 20 ++++++++++++--------
 src/services/ble.ts |  3 +++
 4 files changed, 17 insertions(+), 23 deletions(-)

diff --git a/src/actions/hub.ts b/src/actions/hub.ts
index c541cfca..f6cdf256 100644
--- a/src/actions/hub.ts
+++ b/src/actions/hub.ts
@@ -4,7 +4,6 @@
 import { Action } from 'redux';
 
 export enum HubRuntimeStatusType {
-    Disconnected = 'disconnected',
     Idle = 'idle',
     Loading = 'loading',
     Loaded = 'loaded',
diff --git a/src/epics/ble.ts b/src/epics/ble.ts
index a613588a..7448c620 100644
--- a/src/epics/ble.ts
+++ b/src/epics/ble.ts
@@ -4,7 +4,7 @@
 import { AnyAction } from 'redux';
 import { Epic, combineEpics, ofType } from 'redux-observable';
 import { map } from 'rxjs/operators';
-import { BLEConnectActionType, BLEDataAction, BLEDataActionType } from '../actions/ble';
+import { BLEDataAction, BLEDataActionType } from '../actions/ble';
 import { HubRuntimeStatusType, checksum, updateStatus } from '../actions/hub';
 import { sendData } from '../actions/terminal';
 import { RootState } from '../reducers';
@@ -12,18 +12,6 @@ import { HubRuntimeState } from '../reducers/hub';
 
 const decoder = new TextDecoder();
 
-const connect: Epic = (action$) =>
-    action$.pipe(
-        ofType(BLEConnectActionType.DidConnect),
-        map(() => updateStatus(HubRuntimeStatusType.Idle)),
-    );
-
-const disconnect: Epic = (action$) =>
-    action$.pipe(
-        ofType(BLEConnectActionType.DidDisconnect),
-        map(() => updateStatus(HubRuntimeStatusType.Disconnected)),
-    );
-
 const rxUartData: Epic<AnyAction, AnyAction, RootState> = (action$, state$) =>
     action$.pipe(
         ofType<AnyAction, BLEDataAction>(BLEDataActionType.Notify),
@@ -52,4 +40,4 @@ const rxUartData: Epic<AnyAction, AnyAction, RootState> = (action$, state$) =>
         }),
     );
 
-export default combineEpics(connect, disconnect, rxUartData);
+export default combineEpics(rxUartData);
diff --git a/src/reducers/hub.ts b/src/reducers/hub.ts
index 090d13d6..ffaf4b84 100644
--- a/src/reducers/hub.ts
+++ b/src/reducers/hub.ts
@@ -2,11 +2,9 @@
 // Copyright (c) 2020 The Pybricks Authors
 
 import { Reducer, combineReducers } from 'redux';
-import {
-    HubMessageActionType,
-    HubRuntimeStatusMessageAction,
-    HubRuntimeStatusType,
-} from '../actions/hub';
+import { Action } from '../actions';
+import { BLEConnectActionType } from '../actions/ble';
+import { HubMessageActionType, HubRuntimeStatusType } from '../actions/hub';
 
 /**
  * Describes the state of the MicroPython runtime on the hub.
@@ -16,6 +14,10 @@ export enum HubRuntimeState {
      * The hub is not connected.
      */
     Disconnected = 'hub.runtime.disconnected',
+    /**
+     * The hub is connected but the state is not known yet.
+     */
+    Unknown = 'hub.runtime.unknown',
     /**
      * The runtime is idle waiting for command after soft reboot.
      */
@@ -38,15 +40,17 @@ export enum HubRuntimeState {
     Error = 'hub.runtime.error',
 }
 
-const runtime: Reducer<HubRuntimeState, HubRuntimeStatusMessageAction> = (
+const runtime: Reducer<HubRuntimeState, Action> = (
     state = HubRuntimeState.Disconnected,
     action,
 ) => {
     switch (action.type) {
+        case BLEConnectActionType.DidDisconnect:
+            return HubRuntimeState.Disconnected;
+        case BLEConnectActionType.DidConnect:
+            return HubRuntimeState.Unknown;
         case HubMessageActionType.RuntimeStatus:
             switch (action.newStatus) {
-                case HubRuntimeStatusType.Disconnected:
-                    return HubRuntimeState.Disconnected;
                 case HubRuntimeStatusType.Idle:
                     return HubRuntimeState.Idle;
                 case HubRuntimeStatusType.Loading:
diff --git a/src/services/ble.ts b/src/services/ble.ts
index e4a5ee5a..aba7b9ed 100644
--- a/src/services/ble.ts
+++ b/src/services/ble.ts
@@ -12,6 +12,7 @@ import {
     disconnect as disconnectAction,
     notify,
 } from '../actions/ble';
+import { stop } from '../actions/hub';
 import * as notification from '../actions/notification';
 import { RootState } from '../reducers';
 import { BLEConnectionState } from '../reducers/ble';
@@ -104,6 +105,8 @@ async function connect(action: Action, dispatch: Dispatch): Promise<void> {
         return;
     }
     dispatch(didConnect());
+    // Try to force a soft reset so the hub is in a known state
+    dispatch(stop());
 }
 
 function disconnect(action: Action): void {