luci-app-statistics: add watt-ups for nut and skip unsupported values

Only render NUT charts for actually available data and add a chart
definition for `watt-ups` values while we're at it.

Ref: https://forum.openwrt.org/t/x/156246
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

applications/luci-app-statistics/htdocs/luci-static/resources/statistics/rrdtool/definitions/nut.js

@@ -7,125 +7,150 @@ return baseclass.extend({
 	title: _('UPS'),
 
 	rrdargs: function(graph, host, plugin, plugin_instance, dtype) {
-		var voltages_ac = {
+		var definitions = [];
+		var instances;
+
+		function find_instances(dtype, wanted) {
+			var matching = graph.dataInstances(host, plugin, plugin_instance, dtype).filter(function(instance) {
+				return wanted.indexOf(instance) > -1;
+			});
+
+			return matching.length ? { [dtype]: matching } : null;
+		}
+
+		if ((instances = find_instances('voltage', [ 'input', 'output' ])) != null) {
+			definitions.push({
 				title: "%H: AC voltages on UPS \"%pi\"",
 				vlabel: "V",
 				number_format: "%5.1lfV",
 				data: {
-				instances: {
+					instances: instances,
-					voltage: [ "input", "output" ]
-				},
 					options: {
 						voltage_output : { color: "00e000", title: "Output voltage", noarea: true, overlay: true },
 						voltage_input  : { color: "ffb000", title: "Input voltage", noarea: true, overlay: true }
 					}
 				}
-		};
+			});
+		}
 
-		var voltages_dc = {
+		if ((instances = find_instances('voltage', [ 'battery' ])) != null) {
+			definitions.push({
 				title: "%H: Battery voltage on UPS \"%pi\"",
 				vlabel: "V",
 				number_format: "%5.1lfV",
 				data: {
-				instances: {
+					instances: instances,
-					voltage: [ "battery" ]
-				},
 					options: {
 						voltage: { color: "0000ff", title: "Battery voltage", noarea: true, overlay: true }
 					}
 				}
-		};
+			});
+		}
 
-		var currents = {
+		if ((instances = find_instances('current', [ 'battery', 'output' ])) != null) {
+			definitions.push({
 				title: "%H: Current on UPS \"%pi\"",
 				vlabel: "A",
 				number_format: "%5.3lfA",
 				data: {
-				instances: {
+					instances: instances,
-					current: [ "battery", "output" ]
-				},
 					options: {
 						current_output : { color: "00e000", title: "Output current", noarea: true, overlay: true },
 						current_battery: { color: "0000ff", title: "Battery current", noarea: true, overlay: true }
 					}
 				}
-		};
+			});
+		}
 
-		var percentage = {
+		if ((instances = find_instances('percent', [ 'charge', 'load' ])) != null) {
+			definitions.push({
 				title: "%H: Battery charge/load on UPS \"%pi\"",
 				vlabel: "Percent",
 				y_min: "0",
 				y_max: "100",
 				number_format: "%5.1lf%%",
 				data: {
-				instances: {
+					instances: instances,
-					percent: [ "charge", "load" ]
-				},
 					options: {
 						percent_charge: { color: "00ff00", title: "Charge level", noarea: true, overlay: true },
 						percent_load: { color: "ff0000", title: "Load", noarea: true, overlay: true }
 					}
 				}
-		};
+			});
+		}
 
+		if ((instances = find_instances('temperature', [ 'battery' ])) != null) {
 			/* Note: This is in ISO8859-1 for rrdtool. Welcome to the 20th century. */
-		var temperature = {
+			definitions.push({
 				title: "%H: Battery temperature on UPS \"%pi\"",
 				vlabel: "\u00b0C",
 				number_format: "%5.1lf\u00b0C",
 				data: {
-				instances: {
+					instances: instances,
-					temperature: "battery"
-				},
 					options: {
 						temperature_battery: { color: "ffb000", title: "Battery temperature", noarea: true }
 					}
 				}
-		};
+			});
+		}
 
-		var timeleft = {
+		if ((instances = find_instances('timeleft', [ 'battery' ])) != null) {
+			definitions.push({
 				title: "%H: Time left on UPS \"%pi\"",
 				vlabel: "Minutes",
 				number_format: "%.1lfm",
 				data: {
-				instances: {
+					instances: instances,
-					timeleft: [ "battery" ]
-				},
 					options: {
 						timeleft_battery: { color: "0000ff", title: "Time left", transform_rpn: "60,/", noarea: true }
 					}
 				}
-		};
+			});
+		}
 
-		var power = {
+		if ((instances = find_instances('power', [ 'watt-ups' ])) != null) {
+			definitions.push({
 				title: "%H: Power on UPS \"%pi\"",
-			vlabel: "Power",
+				vlabel: "Watt",
 				number_format: "%5.1lf%%",
 				data: {
-				instances: {
+					instances: instances,
-					power: [ "ups" ]
-				},
 					options: {
-					power_ups: { color: "00ff00", title: "Power level"  }
+						['power_watt-ups']: { color: "00ff00", title: "Power level (Watt)"  }
 					}
 				}
-		};
+			});
+		}
 
-		var frequencies = {
+		if ((instances = find_instances('power', [ 'ups' ])) != null) {
+			definitions.push({
+				title: "%H: Power on UPS \"%pi\"",
+				vlabel: "VA",
+				number_format: "%5.1lf%%",
+				data: {
+					instances: instances,
+					options: {
+						power_ups: { color: "00ff00", title: "Power level (VA)"  }
+					}
+				}
+			});
+		}
+
+		if ((instances = find_instances('frequency', [ 'input', 'output' ])) != null) {
+			definitions.push({
 				title: "%H: Frequencies on UPS \"%pi\"",
 				vlabel: "Hz",
 				number_format: "%5.1lfHz",
 				data: {
-				instances: {
+					instances: instances,
-					frequency: [ "input", "output" ]
-				},
 					options: {
 						frequency_output : { color: "00e000", title: "Output frequency", noarea: true, overlay: true },
 						frequency_input  : { color: "ffb000", title: "Input frequency", noarea: true, overlay: true }
 					}
 				}
-		};
+			});
+		}
 
-		return [ voltages_ac, voltages_dc, currents, percentage, temperature, timeleft, power, frequencies ];
+		return definitions;
 	}
 });