From a0313dad3467b7a09b853cc801b317b334b7b408 Mon Sep 17 00:00:00 2001
From: Michal <c00@wp.pl>
Date: Tue, 11 Dec 2018 16:08:05 +0100
Subject: [PATCH] Code does not work on real microbits (#1723)

Radio packets are not received when while() loop in button callback waits for health status of first infected. That results in master waiting in while loop forever.
Added "Infecting" state. Master sends infect messages in forever loop in non-blocking way.
Another bug is in call to Math.randomRange while selecting patientZero. randomRange returns number incusive with boundaries. This results in accessing players array beyond end.
---
 docs/projects/infection.md | 33 +++++++++++++++++++++------------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/docs/projects/infection.md b/docs/projects/infection.md
index ab9fc9b4..100a3bde 100644
--- a/docs/projects/infection.md
+++ b/docs/projects/infection.md
@@ -107,6 +107,7 @@ const TRANSMISSIONPROB = 40; // % probability to transfer disease
 enum GameState {
     Stopped,
     Pairing,
+    Infecting,
     Running,
     Over
 }
@@ -191,6 +192,7 @@ function gameFace() {
             else
                 basic.showIcon(paired ? GameIcons.Paired : GameIcons.Pairing, 1);
             break;
+        case GameState.Infecting:
         case GameState.Running:
             switch (health) {
                 case HealthState.Dead:
@@ -257,18 +259,11 @@ input.onButtonPressed(Button.AB, () => {
     // launch game
     if (state == GameState.Pairing) {
         // pick 1 player and infect him
-        patientZero = players[Math.randomRange(0, players.length)];
-        while (patientZero.health == HealthState.Healthy) {
-            radio.sendValue("infect", patientZero.id);
-            basic.pause(100);
-        }
-
-        // all ready
-        state = GameState.Running;
+        patientZero = players[Math.randomRange(0, players.length - 1)];
+        // infecting message needs to be confirmed by 
+        // the player
+        state = GameState.Infecting;
         serial.writeLine(`game started ${players.length} players`);
-
-        // show startup
-        basic.showIcon(GameIcons.Dead);
     } // end game 
     else if (state == GameState.Running) {
         gameOver();
@@ -360,6 +355,17 @@ basic.forever(() => {
                 serial.writeLine(`pairing ${players.length} players`);
                 basic.pause(500);
                 break;
+            case GameState.Infecting:
+                if (patientZero.health == HealthState.Healthy) {
+                    radio.sendValue("infect", patientZero.id);
+                    basic.pause(100);
+                } else {
+                    serial.writeLine(`patient ${patientZero.id} infected`);
+                    // show startup
+                    basic.showIcon(GameIcons.Dead);
+                    state = GameState.Running;
+                }
+                break;
             case GameState.Running:
                 for (const p of players) {
                     radio.sendValue("h" + p.id, p.health);
@@ -380,6 +386,9 @@ basic.forever(() => {
                 else if (infectedBy > -1)
                     radio.sendValue("health", health);
                 break;
+            case GameState.Infecting:
+                radio.sendValue("health", health);
+                break;
             case GameState.Running:
                 // update health status
                 if (health != HealthState.Healthy && input.runningTime() - infectedTime > DEATH)
@@ -402,4 +411,4 @@ basic.showIcon(GameIcons.Pairing)
 
 ```package
 radio
-```
\ No newline at end of file
+```