From 2d5f90ff9d0516cdc53ad4ade72623d02a3ce666 Mon Sep 17 00:00:00 2001
From: Denys Berkovskyy <berkovskyy@gmail.com>
Date: Sun, 26 Apr 2020 13:05:21 +0100
Subject: [PATCH] Implement per topic counting.

---
 counter.html |  1 +
 counter.js   | 52 +++++++++++++++++++++++++++++++++++++++-------------
 readme.md    |  4 +++-
 3 files changed, 43 insertions(+), 14 deletions(-)

diff --git a/counter.html b/counter.html
index ce4e0ff..037b76c 100644
--- a/counter.html
+++ b/counter.html
@@ -60,6 +60,7 @@
     <ul>
       <li><code>msg.increment</code>: counter will be incremented by the given value.</li>
       <li><code>msg.decrement</code>: counter will be decremented by the given value.</li>
+      <li><code>msg.topic</code>: if specified the counter will work on a per topic basis.</li>
       <li><code>msg.reset</code>: resets the counter to it's initial count, or to the given value, when it's a number.</li>
     </ul>
     </p>
diff --git a/counter.js b/counter.js
index 0ca4b31..aa798b2 100644
--- a/counter.js
+++ b/counter.js
@@ -11,12 +11,28 @@ module.exports = function(RED) {
         this.lower = config.lower || null;
         this.upper = config.upper || null;
         this.mode = config.mode || "increment";
-        this.count = this.init;
+        this.count_per_topic = {};
 
         this.on("input", function(msg) {
             var lowerLimitReached = false,
                 upperLimitReached = false;
 
+            // Extract topic
+            var topic = "";
+            if ( msg.hasOwnProperty("topic") ) {
+                if ( typeof msg.topic === "string" ) {
+                    topic = msg.topic;
+                }
+                else {
+                    this.error("topic is not a string", msg);
+                }
+            }
+
+            // Initialize counter if required
+            if ( !node.count_per_topic.hasOwnProperty(topic) ) {
+                node.count_per_topic[topic] = this.init
+            }
+
             // use message parameters
             if( msg.hasOwnProperty("increment") || msg.hasOwnProperty("decrement") ) {
                 var decremented = false;
@@ -26,7 +42,7 @@ module.exports = function(RED) {
                     var decrement = Number(msg.decrement);
 
                     if( !isNaN(decrement) && isFinite(decrement) ) {
-                        node.count -= decrement;
+                        node.count_per_topic[topic] -= decrement;
                         decremented = true;
                     }
                     else {
@@ -39,7 +55,7 @@ module.exports = function(RED) {
                     var increment = Number(msg.increment || 1);
 
                     if( !isNaN(increment) && isFinite(increment) ) {
-                        node.count += increment;
+                        node.count_per_topic[topic] += increment;
                     }
                     else {
                         this.error("increment is not a numeric value", msg);
@@ -54,10 +70,10 @@ module.exports = function(RED) {
                 }
 
                 if( node.mode === "increment" ) {
-                    node.count += node.step;
+                    node.count_per_topic[topic] += node.step;
                 }
                 else if( node.mode === "decrement" ) {
-                    node.count -= node.step;
+                    node.count_per_topic[topic] -= node.step;
                 }
                 else {
                     this.error("unknown mode '" + node.mode + "'", msg);
@@ -65,16 +81,26 @@ module.exports = function(RED) {
             }
 
             // handle reset
-            if( msg.hasOwnProperty("reset") && msg.reset ) {
-                node.count = typeof msg.reset === "number" ? msg.reset : node.init;
+            if( msg.hasOwnProperty("reset") && msg.reset !== false ) {
+                if ( topic !== "" ) {
+                    node.count_per_topic[topic] = typeof msg.reset === "number" ? msg.reset : node.init;
+                }
+                else {
+                    if (typeof msg.reset !== "number") {
+                        node.count_per_topic = {}
+                    }
+                    else {
+                        Object.keys(node.count_per_topic).forEach(v => node.count_per_topic[v] = msg.reset)
+                    }
+                }
             }
 
             // handle lower limit
             if( node.lower !== null ) {
                 var lower = Number(node.lower);
 
-                if( !isNaN(lower) && isFinite(lower) && node.count < lower ) {
-                    node.count = lower;
+                if( !isNaN(lower) && isFinite(lower) && node.count_per_topic[topic] < lower ) {
+                    node.count_per_topic[topic] = lower;
                     lowerLimitReached = true;
                 }
             }
@@ -83,15 +109,15 @@ module.exports = function(RED) {
             if( node.upper !== null ) {
                 var upper = Number(node.upper);
 
-                if( !isNaN(upper) && isFinite(upper) && node.count > upper ) {
-                    node.count = upper;
+                if( !isNaN(upper) && isFinite(upper) && node.count_per_topic[topic] > upper ) {
+                    node.count_per_topic[topic] = upper;
                     upperLimitReached = true;
                 }
             }
 
             // single output
             if( node.outputs === "single" ) {
-                msg.count = node.count;
+                msg.count = node.count_per_topic[topic];
 
                 if( lowerLimitReached ) {
                     msg.countLowerLimitReached = true;
@@ -106,7 +132,7 @@ module.exports = function(RED) {
 
             // split output
             else {
-                var obj = {payload: node.count};
+                var obj = {payload: node.count_per_topic[topic]};
 
                 if( lowerLimitReached ) {
                     obj.countLowerLimitReached = true;
diff --git a/readme.md b/readme.md
index 76f6107..6d12c61 100644
--- a/readme.md
+++ b/readme.md
@@ -35,6 +35,7 @@ npm install node-red-contrib-counter
 
 By default the counter will be incremented for every inbound message and append the current count to `msg.count`.
 
+This works on a per msg.topic basis. This means that a single counter node can handle multiple topics at the same time.
 
 ### Configuration
 
@@ -60,7 +61,8 @@ It's possible to control the counter with incoming `msg` properties:
 
 - `msg.increment`: counter will be incremented by the given value.
 - `msg.decrement`: counter will be decremented by the given value.
-- `msg.reset`: resets the counter to it's initial count, or to the given value, when it's a number.
+- `msg.topic`: if specified the counter will work on a per topic basis.
+- `msg.reset`: resets the counter to it's initial count, or to the given value, when it's a number (if msg.topic is not specified the counter will reset all known topics).
 
 
 ## Example Flows