1 files changed, 53 insertions, 5 deletions
diff --git a/diller/mq.lua b/diller/mq.lua
index 0b4a884..74f3ef8 100644
--- a/diller/mq.lua
+++ b/diller/mq.lua
@@ -1,12 +1,48 @@
 local P = {}
 local m, topic, cid
+local active_subscriptions = {}
+local pending_subscriptions = {}
+local pending_subcsription
 
 local function p(msg)
   print("MQTT: "..msg)
 end
 
+-- Subscribe to all registered subscriptions
+-- TODO: subscriptions that are not successfull will remain in state = 1. Might not be a real problem if it happens, the server probably disallowed the subscription.
+local function create_subscriptions()
+  print("create_subscriptions, pending count "..table.getn(pending_subscriptions)..", pending: "..tostring(pending_subscription))
+
+  if (pending_subscription) then
+    return
+  end
+
+  pending_subcsription = table.remove(pending_subscriptions)
+
+  -- The API claims that the callback has this signature: function(client, topic, message)
+  -- but that doesn't seems right from the source code. The code doesn't
+  -- remember the topics that is being subscribed to.
+  m:subscribe(pending_subcsription, 0, function(client)
+    print("success: "..pending_subcsription)
+    table.insert(active_subscriptions, pending_subscription)
+    pending_subscription = nil
+    create_subscriptions()
+  end)
+end
+
 local function mq_client_connected(con)
   p("connected")
+
+  create_subscriptions()
+end
+
+local function disconnect()
+  p("Lost wifi connection, disconnecting")
+  m:close()
+  m = nil
+
+  -- append active_subscriptions to pending_subscriptions
+  active_subscriptions = {}
 end
 
 function mq_on_timer()
@@ -30,9 +66,7 @@ function mq_on_timer()
     end
   else
     if m then
-      p("Lost wifi connection, disconnecting")
-      m:close()
-      m = nil
+	  disconnect()
     end
   end
 end
@@ -45,17 +79,31 @@ function P.init(timer_id, client_id)
   tmr.alarm(timer_id, 3 * 1000, 1, mq_on_timer)
 end 
 
+function P.subscribe(path, cb)
+  subscription = subscriptions[path]
+  if subscription then
+    print("subscription on "..path.." already registered, state="..tostring(subscription.state))
+    return
+  end
+
+  print("Registering subscription on "..path)
+
+  pending_subscriptions[path] = true
+
+  create_subscriptions()
+end
+
 function P.publish(path, payload)
   if not m then
 	print("Not connected, dropping message to "..path)
-	return
+	return false, 'not connected'
   end
 
   path = topic.."/"..path
   print("path="..path)
   m:publish(path, payload, 0, 0)
 
-  return true, "yo?"
+  return true, 'ok'
 end
 
 return P