Log the light bar and count rumble changes

So a console test can tell a game that never rumbled from a phone that
never buzzed: each light-bar change is logged as it happens, and the
heartbeat says how many rumble changes arrived in the last minute.

src/web.c

@@ -81,6 +81,7 @@ typedef struct {
     C4fNet net;
     C4fWebPad pads[C4F_MAX_PADS];
     int klogFd, stop, changed, creationBlocked, feedbackMissing;
+    unsigned rumbleChanges;   /* since the last heartbeat, to tell a silent game from a silent phone */
     char klogLine[1024];
     size_t klogUsed;
     C4fAdd add;
@@ -264,8 +265,13 @@ static void c4fPollFeedback(C4fWeb *app, uint64_t now)
             p->feedbackFailed = 1;
             continue;
         }
-        if (!p->feedbackKnown || f.r != p->feedback.r || f.g != p->feedback.g || f.b != p->feedback.b)
+        if (!p->feedbackKnown || f.r != p->feedback.r || f.g != p->feedback.g || f.b != p->feedback.b) {
+            /* Rare: a sign-in, or a game setting its colour. */
+            c4fLog("web controller %d light bar %02x %02x %02x\n", i + 1, f.r, f.g, f.b);
             app->changed = 1;
+        }
+        if (p->feedbackKnown && (f.large != p->feedback.large || f.small != p->feedback.small))
+            app->rumbleChanges++;
         p->feedback = f;
         p->feedbackKnown = 1;
         if (p->owner && (!p->rumbleSentValid || f.large != p->rumbleSent[0] || f.small != p->rumbleSent[1])) {
@@ -740,8 +746,9 @@ int c4fWebRun(int klogFd)
         if (now >= app->heartbeatAt) {
             int active = 0;
             for (int i = 0; i < C4F_MAX_PADS; i++) active += app->pads[i].active;
-            c4fLog("heartbeat: listener=%d controllers=%d klog=%d connecting=%d\n",
-                   app->net.fd >= 0, active, app->klogFd >= 0, app->add.state);
+            c4fLog("heartbeat: listener=%d controllers=%d klog=%d connecting=%d rumble-changes=%u\n",
+                   app->net.fd >= 0, active, app->klogFd >= 0, app->add.state, app->rumbleChanges);
+            app->rumbleChanges = 0;
             app->heartbeatAt = now + 60000;
         }
         if (app->changed || now >= app->broadcastAt) {

tests/test_web.py

@@ -378,6 +378,7 @@ def main():
         c.wait_for(rumble(0, 200, 40))
         time.sleep(.05)
         assert c.request('status')['result']['pads'][0]['color'] == [255, 0, 0], 'player 2 red, at full'
+        assert 'web controller 1 light bar 40 00 00' in server.rows(), 'the colour is logged for diagnosis'
         watcher = Client()
         os.write(server.log, b'C4F-TEST-FEEDBACK 11030d 0 0 0 64 0\n')
         c.wait_for(rumble(0, 0, 0))