Updated Whisper Push Notifications (markdown)

Whisper-Push-Notifications.md

@@ -178,10 +178,69 @@ Now, why do we have distinct client and chat keys? The reason is simple: client
 Here is how you create chat session key might look like (remember we are still using `web3` object connected to `Device A` node):
 
 ```js
+var newChatSessionTopic = '0x509579a2'; // NEW_CHAT_SESSION
+var ackNewChatSessionTopic = '0xd012aae8'; // ACK_NEW_CHAT_SESSION
+var createChatSession = function (subscriptionKey) {
+    var chatId = '0xdeadbeef';
+    // subscriptionKey is key shared by server that allows us to communicate with server privately
+    var keyname = 'SUBSCRIPTION_KEY';
+    web3.shh.deleteSymKey(keyname);
+    web3.shh.addSymKey(keyname, subscriptionKey);
+
+    console.log("subscription key: ", subscriptionKey);
+
+    // before sending new chat request, let's start waiting for response
+    var filter = web3.shh.filter({
+        to: identity,
+        topics: [ackNewChatSessionTopic]
+    });
+    filter.watch(function (error, result) {
+        if (!error) {
+            console.log("Chat Creation ACK received: ", result);
+            // response will be in JSON, e.g. {"server": "0xdeadbeef", "key": "0xdeadbeef"}
+            // which will give you serverID
+            var payload = JSON.parse(web3.toAscii(result.payload));
+
+            // no need to watch for the filter any more
+            filter.stopWatching();
+
+            // ok, at this point we have Chat Session SymKey, and we can:
+            // 1. register our device with that chat
+            // 2. share that key with others, so that they can register themselves
+            // 3. use chat key to trigger notifications
+            shareAndUseChatKey(payload.key)
+        }
+    });
+
+    var err = web3.shh.post({
+        from: identity,
+        topics: [newChatSessionTopic],
+        payload: '{"chat": "' + chatId + '"}', // globally unique chat ID
+        ttl: 20,
+        keyname: keyname
+    });
+    if (err !== null) {
+        console.log("message NOT sent")
+    } else {
+        console.log("message sent OK")
+    }
+};
 ```
+Now, we have Chat Session Key, which we can use to register our device id (to be used as target by FCM), and allow others to register themselves.
 
 ### 3. Sharing Chat session key, and allowing notifications
 
+So, all we need to review is device registration and key sharing. Let's continue with `Device A` web3 object:
+
+```js
+```
+
+Now, on `Device B` side, we need to wait for shared key, and then once we register `Device B`, we will be able to send notifications:
+
+```js
+```
+
+### 4. Triggering Push Notifications
 
 # Implementation notes I: One-to-One Chats