Disable system relay if it is not on manual mode

Disable the usage of system relay 0 if it is set on any other mode than
manual. An approppriate warning and info on how to change the relay function
is shown below the relay select in this case. Trying to trigger a
previously deployed relay with any other mode than manual will show a
warning message on Node-RED's debug panel. Restructure the relay service
logic to get rid of regular expressions. Use more functional style.

src/nodes/input-battery.html

@@ -105,7 +105,7 @@
     .hidden {
         display: none
     }
-    #statusmessage {
+    .form-tips {
         margin-bottom: 12px;
     }
 </style>

src/nodes/output-relay.html

@@ -10,7 +10,9 @@
         <select id="node-input-service"></select>
     </div>
 
-    <div class="form-row">
+    <div class="form-warning hidden" id="warningmessage"></div>
+
+    <div class="form-row" id="relay-state">
         <label> State </label>
         <input type="radio" name="value" value="on">On</input>
         <input type="radio" name="value" value="off">Off</input>
@@ -41,7 +43,9 @@
             let altName = 'Relay';
             if (this.service) {
                 let svc = JSON.parse(this.service);
-                altName = `Relay - ${svc.name} - ${this.state}`
+                altName = svc.disabled
+                    ? `Relay - ${svc.name} - disabled`
+                    : `Relay - ${svc.name} - ${this.state}`
             }
             return this.name || altName;
         },
@@ -87,6 +91,21 @@
             $("input[name='value']").change(function() {
                 $("#node-input-state").val(this.value);
             });
+
+            selectElem.change((e) => {
+                let selected = $(e.target).val() || _this.service;
+                // Ensure, that the selected relay isn't disabled
+                if (selected) {
+                    let serviceObj = JSON.parse(selected);
+                    if (serviceObj.disabled) {
+                        $('#warningmessage').text(serviceObj.warning).show()
+                        $("input[name='value']").attr('disabled', true);
+                    } else {
+                        $('#warningmessage').hide();
+                        $("input[name='value']").attr('disabled', false);
+                    }
+                }
+            });
         }
     });
 
@@ -98,10 +117,15 @@
         clear: none;
         margin: -4px 4px 0px 12px;
     }
+    .form-warning {
+        color: red;
+        font-size: 0.9em;
+        max-width: 30em;
+    }
     .hidden {
         display: hidden;
     }
-    #statusmessage {
+    .form-tips, .form-warning {
         margin-bottom: 12px;
     }
 </style>

src/nodes/output-relay.js

@@ -2,6 +2,8 @@
 module.exports = function(RED) {
     "use strict";
 
+    const mapping = require('../services/servicemapping');
+
     function OutputRelay(config) {
         RED.nodes.createNode(this, config)
 
@@ -19,7 +21,6 @@ module.exports = function(RED) {
                 case 'off':
                     return 0
                 case 'toggle':
-                    // Ideally the initial state would be fetched from the relay itself
                     toggleState = 1 - toggleState
                     return toggleState
             }
@@ -28,7 +29,11 @@ module.exports = function(RED) {
         this.on("input", function(msg) {
             let path = this.service.paths[0].path
             let service = this.service.service
-            this.client.publish(service, path, stateToMessage(this.state))
+
+            if (!this.service.disabled)
+                this.client.publish(service, path, stateToMessage(this.state))
+            else
+                this.warn(mapping.RELAY_MODE_WARNING('another'))
         });
 
     }

src/services/servicemapping.js

@@ -68,8 +68,20 @@ const RELAY = (service, path, name) => {
         }
 }
 
+const RELAY_FUNCTIONS = {
+    0: 'alarm',
+    1: 'generator',
+    2: 'manual',
+    3: 'tank pump'
+}
+
+const RELAY_MODE_WARNING = (func) =>
+    `This relay is reserved for ${func} function. Please navigate to Settings > Relay and change it to manual.`
+
 module.exports = {
     BATTERY,
     BATTERY_PATHS,
-    RELAY
+    RELAY,
+    RELAY_FUNCTIONS,
+    RELAY_MODE_WARNING
 }

src/services/systemconfiguration.js

@@ -2,7 +2,7 @@
 
 const mapping = require('./servicemapping');
 const _ = require('lodash')
-const debug = require('debug')('node-red-contrib-victron:systemconfiguration')
+const debug = require('debug')('node-red-contrib-victron:systemconfiguartion')
 
 /**
  * SystemConfiguration contains information on the given Venus system.
@@ -17,8 +17,8 @@ class SystemConfiguration {
     }
 
     /**
-     * Builds the edit form layout for the battery node.
-     * Filters the dbus cache for available battery services.
+     * Build the edit form layout for the battery node.
+     * Filter the dbus cache for available battery services.
      */
     getBatteryServices() {
         // filter the dbus cache for battery services
@@ -40,40 +40,54 @@ class SystemConfiguration {
 
     }
     /**
-     * Builds the edit form for the relay node.
-     * Filters the cache for system and battery relays.
+     * Build the edit form for the relay node.
+     * Filter the cache for system and battery relays.
      */
     getRelayServices() {
-        // Iterate over previously found devices and look for /Relay/X paths
-        let services = [];
-        Object.keys(this.cache).forEach(svc => {
-            Object.keys(this.cache[svc]).forEach(path => {
-                if (_.startsWith(path, '/Relay')) {
-
-                    // Node label is based on the given service
-                    let name = ''
-                    if (_.startsWith(svc, 'com.victronenergy.battery')) {
-                        let batteryRe = /\bbattery\.(.*)/
-                        let batterySvc = batteryRe.exec(svc)
-
-                        name = this.cache[svc]['/CustomName'] || this.cache[svc]['/ProductName'] || batterySvc[1]
-                    }
-                    else if (_.startsWith(svc, 'com.victronenergy.system')) {
-                        let relayPathRe = /\/Relay\/(\d)+\/State/
-                        let systemRelayIdx = relayPathRe.exec(path)
-                        name = systemRelayIdx !== null ? `Venus device (${systemRelayIdx[1]})` : ''
-                    }
 
-                    services.push(mapping.RELAY(svc, path, name))
+        // Build a relay object representing the relay node settings in node-red UI
+        const buildRelayObject = (service, path) => {
+            if (service.startsWith('com.victronenergy.system')) {
+                const relayIndex = path.split('/')[2] || ''
+                const name = `Venus device (${relayIndex})`
+
+                let relayObject = mapping.RELAY(service, path, name)
+
+                // Special case for system relay 0 - only allow usage if relay function is set to manual
+                if (relayIndex === '0') {
+                    const systemRelayFunction = this.cache['com.victronenergy.settings']['/Settings/Relay/Function']
+                    if (systemRelayFunction !== 2) { // manual
+                        relayObject["disabled"] = true
+                        relayObject["warning"] = mapping.RELAY_MODE_WARNING(mapping.RELAY_FUNCTIONS[systemRelayFunction])
+                    }
                 }
-            })
-        })
 
-        return services;
+                return relayObject
+            }
+            if (service.startsWith('com.victronenergy.battery')) {
+                const name = this.cache[service]['/CustomName']
+                    || this.cache[service]['/ProductName']
+                    || service.split('.').pop()
+
+                return mapping.RELAY(service, path, name)
+            }
+        }
+
+        // Filter all paths that begin with '/Relay'.
+        // Construct and return an array of relay nodes representing their settings.
+        return Object.entries(this.cache)
+            .reduce((acc, [service, pathObj]) => {
+                Object.keys(pathObj)
+                    .filter(path => path.startsWith('/Relay'))
+                    .map(relayPath => acc.push(
+                        buildRelayObject(service, relayPath))
+                    )
+                return acc
+            }, []);
     }
 
     /**
-     * Lists all currently available services. This list is used to populate the nodes' edit dialog.
+     * List all currently available services. This list is used to populate the nodes' edit dialog.
      * E.g. if a battery monitor is available, all the given battery monitor services are listed
      * in the input-battery node.
      * 
@@ -82,7 +96,8 @@ class SystemConfiguration {
     listAvailableServices(device=null) {
         let services = {
             "battery": this.getBatteryServices(),
-            "relay": this.getRelayServices()
+            "relay": this.getRelayServices(),
+            "cache": this.cache
         };
 
         return device !== null

src/services/victronclient.js

@@ -67,7 +67,6 @@ class VictronClient {
                 {
                     onError: msg => debug(`[ERROR] ${msg}`),
                     onServiceChange: (changeType, serviceName) => {
-                        debug(`[SERVICE ${changeType}] ${serviceName}`)
                         if (changeType === 'DELETE' && serviceName !== null) {
                             delete this.system.cache[serviceName]
                         }