Provide a way to remove unsupported devices from settings

smartapps/smartthings/gentle-wake-up.src/gentle-wake-up.groovy

@@ -39,6 +39,7 @@ preferences {
 	page(name: "completionPage")
 	page(name: "numbersPage")
 	page(name: "controllerExplanationPage")
+	page(name: "unsupportedDevicesPage")
 }
 
 def rootPage() {
@@ -47,6 +48,9 @@ def rootPage() {
 		section("What to dim") {
 			input(name: "dimmers", type: "capability.switchLevel", title: "Dimmers", description: null, multiple: true, required: true, submitOnChange: true)
 			if (dimmers) {
+				if (dimmersContainUnsupportedDevices()) {
+					href(name: "toUnsupportedDevicesPage", page: "unsupportedDevicesPage", title: "Some of your selected dimmers don't seem to be supported", description: "Tap here to fix it", required: true)
+				}
 				href(name: "toNumbersPage", page: "numbersPage", title: "Duration & Direction", description: numbersPageHrefDescription(), state: "complete")
 			}
 		}
@@ -71,6 +75,31 @@ def rootPage() {
 	}
 }
 
+def unsupportedDevicesPage() {
+
+	def unsupportedDimmers = dimmers.findAll { !hasSetLevelCommand(it) }
+
+	dynamicPage(name: "unsupportedDevicesPage") {
+		if (unsupportedDimmers) {
+			section("These devices do not support the setLevel command") {
+				unsupportedDimmers.each {
+					paragraph deviceLabel(it)
+				}
+			}
+			section {
+				input(name: "dimmers", type: "capability.sensor", title: "Please remove the above devices from this list.", submitOnChange: true, multiple: true)
+			}
+			section {
+				paragraph "If you think there is a mistake here, please contact support."
+			}
+		} else {
+			section {
+				paragraph "You're all set. You can hit the back button, now. Thanks for cleaning up your settings :)"
+			}
+		}
+	}
+}
+
 def controllerExplanationPage() {
 	dynamicPage(name: "controllerExplanationPage", title: "How To Control Gentle Wake Up") {
 
@@ -819,6 +848,11 @@ private getRedHue(level) {
 	if (level >= 96) return 17
 }
 
+private dimmersContainUnsupportedDevices() {
+	def found = dimmers.find { hasSetLevelCommand(it) == false }
+	return found != null
+}
+
 private hasSetLevelCommand(device) {
 	return hasCommand(device, "setLevel")
 }
@@ -1067,4 +1101,4 @@ def hasStartLevel() {
 
 def hasEndLevel() {
 	return (endLevel != null && endLevel != "")
-}
+}