Refactor alert/hazard system with timing and display improvements

- Replace magic numbers with seconds-based timing constants
- Switch from scrollTo() to hardware-accelerated transform
- Add scroll caching to prevent repeated DOM queries every scroll cycle
- Switch to safeJson() for centralized error handling across alert modules
- Horizontal alert scroll now goes edge-to-edge
- Integrate global speed settings into horizontal scroll timing
- Improve error handling flow with better fallback behavior for missing data
- Remvoe unused getCurrentData() function in hazards.mjs
- Move background color from scrolling element to container to avoid
    showing the underlying content when scrolling with trasnform

server/scripts/modules/currentweatherscroll.mjs

@@ -3,11 +3,14 @@ import { elemForEach } from './utils/elem.mjs';
 import getCurrentWeather from './currentweather.mjs';
 import { currentDisplay } from './navigation.mjs';
 import getHazards from './hazards.mjs';
+import settings from './settings.mjs';
 
 // constants
 const degree = String.fromCharCode(176);
-const SCROLL_SPEED = 75; // pixels/second
-const DEFAULT_UPDATE = 8; // 0.5s ticks
+const SCROLL_SPEED = 100; // pixels/second
+const TICK_INTERVAL_MS = 500; // milliseconds per tick
+const secondsToTicks = (seconds) => Math.ceil((seconds * 1000) / TICK_INTERVAL_MS);
+const DEFAULT_UPDATE = secondsToTicks(4.0); // 4 second default for each current conditions
 
 // local variables
 let interval;
@@ -28,7 +31,7 @@ const start = () => {
 	resetFlag = false;
 	// set up the interval if needed
 	if (!interval) {
-		interval = setInterval(incrementInterval, 500);
+		interval = setInterval(incrementInterval, TICK_INTERVAL_MS);
 	}
 
 	// draw the data
@@ -70,15 +73,21 @@ const drawScreen = async () => {
 	// get the conditions
 	const data = await getCurrentWeather();
 
+	// create a data object (empty if no valid current weather conditions)
+	const scrollData = data || {};
+
 	// add the hazards if on screen 0
 	if (screenIndex === 0) {
-		data.hazards = await getHazards(() => this.stillWaiting());
+		const hazards = await getHazards();
+		if (hazards && hazards.length > 0) {
+			scrollData.hazards = hazards;
+		}
 	}
 
-	// nothing to do if there's no data yet
-	if (!data) return;
+	// if we have no current weather and no hazards, there's nothing to display
+	if (!data && (!scrollData.hazards || scrollData.hazards.length === 0)) return;
 
-	const thisScreen = screens[screenIndex](data);
+	const thisScreen = screens[screenIndex](scrollData);
 
 	// update classes on the scroll area
 	elemForEach('.weather-display .scroll', (elem) => {
@@ -115,7 +124,9 @@ const hazards = (data) => {
 	// test for data
 	if (!data.hazards || data.hazards.length === 0) return false;
 
-	const hazard = `${data.hazards[0].properties.event} ${data.hazards[0].properties.description}`;
+	// since the hazard scroll element has no left/right margins, pad the beginning and end with non-breaking spaces
+	const padding = ' '.repeat(4);
+	const hazard = `${padding}${data.hazards[0].properties.event} ${data.hazards[0].properties.description}${padding}`;
 
 	return {
 		text: hazard,
@@ -210,25 +221,35 @@ const drawScrollCondition = (screen) => {
 
 	// calculate the scroll distance and set a minimum scroll
 	const scrollDistance = Math.max(scrollWidth - clientWidth, 0);
-	// calculate the scroll time
-	const scrollTime = scrollDistance / SCROLL_SPEED;
-	// calculate a new minimum on-screen time +1.0s at start and end
-	nextUpdate = Math.round(Math.ceil(scrollTime / 0.5) + 4);
+	// calculate the scroll time (scaled by global speed setting)
+	const scrollTime = scrollDistance / SCROLL_SPEED * settings.speed.value;
+	// add 1 second pause at the end of the scroll animation
+	const endPauseTime = 1.0;
+	const totalAnimationTime = scrollTime + endPauseTime;
+	// calculate total on-screen time: animation time + start delay + end pause
+	const startDelayTime = 1.0; // setTimeout delay below
+	const totalDisplayTime = totalAnimationTime + startDelayTime;
+	nextUpdate = secondsToTicks(totalDisplayTime);
+
+	// update the element with initial position and transition
+	scrollElement.style.transform = 'translateX(0px)';
+	scrollElement.style.transition = `transform ${scrollTime.toFixed(1)}s linear`;
+	scrollElement.style.willChange = 'transform'; // Hint to browser for hardware acceleration
+	scrollElement.style.backfaceVisibility = 'hidden'; // Force hardware acceleration
+	scrollElement.style.perspective = '1000px'; // Enable 3D rendering context
 
-	// update the element transition and set initial left position
-	scrollElement.style.left = '0px';
-	scrollElement.style.transition = `left linear ${scrollTime.toFixed(1)}s`;
 	elemForEach('.weather-display .scroll .fixed', (elem) => {
 		elem.innerHTML = '';
 		elem.append(scrollElement.cloneNode(true));
 	});
-	// start the scroll after a short delay
+
+	// start the scroll after the specified delay
 	setTimeout(() => {
-		// change the left position to trigger the scroll
+		// change the transform to trigger the scroll
 		elemForEach('.weather-display .scroll .fixed .scroll-area', (elem) => {
-			elem.style.left = `-${scrollDistance.toFixed(0)}px`;
+			elem.style.transform = `translateX(-${scrollDistance.toFixed(0)}px)`;
 		});
-	}, 1000);
+	}, startDelayTime * 1000);
 };
 
 const parseMessage = (event) => {

server/scripts/modules/hazards.mjs

@@ -1,9 +1,11 @@
 // hourly forecast list
 
 import STATUS from './status.mjs';
-import { json } from './utils/fetch.mjs';
+import { safeJson } from './utils/fetch.mjs';
 import WeatherDisplay from './weatherdisplay.mjs';
 import { registerDisplay } from './navigation.mjs';
+import calculateScrollTiming from './utils/scroll-timing.mjs';
+import { debugFlag } from './utils/debug.mjs';
 
 const hazardLevels = {
 	Extreme: 10,
@@ -32,6 +34,19 @@ class Hazards extends WeatherDisplay {
 		// take note of the already-shown alert ids
 		this.viewedAlerts = new Set();
 		this.viewedGetCount = 0;
+
+		// cache for scroll calculations
+		// This cache is essential because baseCountChange() is called 25 times per second (every 40ms)
+		// during scrolling. Hazard scrolls can vary greatly in length depending on active alerts, but
+		// without caching we'd perform hundreds of expensive DOM layout queries during each scroll cycle.
+		// The cache reduces this to one calculation when content changes, then reuses cached values to try
+		// and get smoother scrolling.
+		this.scrollCache = {
+			displayHeight: 0,
+			contentHeight: 0,
+			maxOffset: 0,
+			hazardLines: null,
+		};
 	}
 
 	async getData(weatherParameters, refresh) {
@@ -53,16 +68,24 @@ class Hazards extends WeatherDisplay {
 		}
 
 		try {
-			// get the forecast
+			// get the forecast using centralized safe handling
 			const url = new URL('https://api.weather.gov/alerts/active');
 			url.searchParams.append('point', `${this.weatherParameters.latitude},${this.weatherParameters.longitude}`);
-			const alerts = await json(url, { retryCount: 3, stillWaiting: () => this.stillWaiting() });
-			const allUnsortedAlerts = alerts.features ?? [];
-			const unsortedAlerts = allUnsortedAlerts.slice(0, 5);
-			const hasImmediate = unsortedAlerts.reduce((acc, hazard) => acc || hazard.properties.urgency === 'Immediate', false);
-			const sortedAlerts = unsortedAlerts.sort((a, b) => (calcSeverity(b.properties.severity, b.properties.event)) - (calcSeverity(a.properties.severity, a.properties.event)));
-			const filteredAlerts = sortedAlerts.filter((hazard) => hazard.properties.severity !== 'Unknown' && (!hasImmediate || (hazard.properties.urgency === 'Immediate')));
-			this.data = filteredAlerts;
+			const alerts = await safeJson(url, { retryCount: 3, stillWaiting: () => this.stillWaiting() });
+
+			if (!alerts) {
+				if (debugFlag('verbose-failures')) {
+					console.warn('Active Alerts request failed; assuming no active alerts');
+				}
+				this.data = [];
+			} else {
+				const allUnsortedAlerts = alerts.features ?? [];
+				const unsortedAlerts = allUnsortedAlerts.slice(0, 5);
+				const hasImmediate = unsortedAlerts.reduce((acc, hazard) => acc || hazard.properties.urgency === 'Immediate', false);
+				const sortedAlerts = unsortedAlerts.sort((a, b) => (calcSeverity(b.properties.severity, b.properties.event)) - (calcSeverity(a.properties.severity, a.properties.event)));
+				const filteredAlerts = sortedAlerts.filter((hazard) => hazard.properties.severity !== 'Unknown' && (!hasImmediate || (hazard.properties.urgency === 'Immediate')));
+				this.data = filteredAlerts;
+			}
 
 			// every 10 times through the get process (10 minutes), reset the viewed messages
 			if (this.viewedGetCount >= 10) {
@@ -82,8 +105,7 @@ class Hazards extends WeatherDisplay {
 			// draw the canvas to calculate the new timings and activate hazards in the slide deck again
 			this.drawLongCanvas();
 		} catch (error) {
-			console.error('Get hazards failed');
-			console.error(error.status, error.responseJSON);
+			console.error(`Unexpected Active Alerts error: ${error.message}`);
 			if (this.isEnabled) this.setStatus(STATUS.failed);
 			// return undefined to other subscribers
 			this.getDataCallback(undefined);
@@ -109,8 +131,12 @@ class Hazards extends WeatherDisplay {
 
 		const lines = unViewed.map((data) => {
 			const fillValues = {};
-			// text
-			fillValues['hazard-text'] = `${data.properties.event}<br/><br/>${data.properties.description.replaceAll('\n\n', '<br/><br/>').replaceAll('\n', ' ')}`;
+			const description = data.properties.description
+				.replaceAll('\n\n', '<br/><br/>')
+				.replaceAll('\n', ' ')
+				.replace(/(\S)\.\.\.(\S)/g, '$1... $2'); // Add space after ... when surrounded by non-whitespace to improve text-wrappability
+
+			fillValues['hazard-text'] = `${data.properties.event}<br/><br/>${description}<br/><br/><br/><br/>`; // Add some padding to scroll off the bottom a bit
 
 			return this.fillTemplate('hazard', fillValues);
 		});
@@ -131,16 +157,16 @@ class Hazards extends WeatherDisplay {
 	}
 
 	setTiming(list) {
-		// set up the timing
-		this.timing.baseDelay = 20;
-		// 24 hours = 6 pages
-		const pages = Math.max(Math.ceil(list.scrollHeight / 480) - 4);
-		const timingStep = 480;
-		this.timing.delay = [150 + timingStep];
-		// add additional pages
-		for (let i = 0; i < pages; i += 1) this.timing.delay.push(timingStep);
-		// add the final 3 second delay
-		this.timing.delay.push(250);
+		const container = this.elem.querySelector('.main');
+		const timingConfig = calculateScrollTiming(list, container, {
+			finalPause: 2.0, // shorter final pause for hazards
+		});
+
+		// Apply the calculated timing
+		this.timing.baseDelay = timingConfig.baseDelay;
+		this.timing.delay = timingConfig.delay;
+		this.scrollTiming = timingConfig.scrollTiming;
+
 		this.calcNavTiming();
 	}
 
@@ -162,25 +188,30 @@ class Hazards extends WeatherDisplay {
 
 	// base count change callback
 	baseCountChange(count) {
+		// get the hazard lines element and cache measurements if needed
+		const hazardLines = this.elem.querySelector('.hazard-lines');
+		if (!hazardLines) return;
+
+		// update cache if needed (when content changes or first run)
+		if (this.scrollCache.hazardLines !== hazardLines || this.scrollCache.displayHeight === 0) {
+			this.scrollCache.displayHeight = this.elem.querySelector('.main').offsetHeight;
+			this.scrollCache.contentHeight = hazardLines.offsetHeight;
+			this.scrollCache.maxOffset = Math.max(0, this.scrollCache.contentHeight - this.scrollCache.displayHeight);
+			this.scrollCache.hazardLines = hazardLines;
+
+			// Set up hardware acceleration on the hazard lines element
+			hazardLines.style.willChange = 'transform';
+			hazardLines.style.backfaceVisibility = 'hidden';
+		}
+
 		// calculate scroll offset and don't go past end
-		let offsetY = Math.min(this.elem.querySelector('.hazard-lines').offsetHeight - 390, (count - 150));
+		let offsetY = Math.min(this.scrollCache.maxOffset, (count - this.scrollTiming.initialCounts) * this.scrollTiming.pixelsPerCount);
 
 		// don't let offset go negative
 		if (offsetY < 0) offsetY = 0;
 
-		// move the element
-		this.elem.querySelector('.main').scrollTo(0, offsetY);
-	}
-
-	// make data available outside this class
-	// promise allows for data to be requested before it is available
-	async getCurrentData(stillWaiting) {
-		if (stillWaiting) this.stillWaitingCallbacks.push(stillWaiting);
-		return new Promise((resolve) => {
-			if (this.data) resolve(this.data);
-			// data not available, put it into the data callback queue
-			this.getDataCallbacks.push(() => resolve(this.data));
-		});
+		// use transform instead of scrollTo for hardware acceleration
+		hazardLines.style.transform = `translateY(-${Math.round(offsetY)}px)`;
 	}
 
 	// after we roll through the hazards once, don't display again until the next refresh (10 minutes)

server/styles/scss/_hazards.scss

@@ -1,17 +1,16 @@
-@use 'shared/_colors'as c;
-@use 'shared/_utils'as u;
+@use 'shared/_colors' as c;
+@use 'shared/_utils' as u;
 
 .weather-display .main.hazards {
 	&.main {
 		overflow-y: hidden;
 		height: 480px;
+		background-color: rgb(112, 35, 35);
 
 		.hazard-lines {
 			min-height: 400px;
 			padding-top: 10px;
 
-			background-color: rgb(112, 35, 35);
-
 			.hazard {
 				font-family: 'Star4000';
 				font-size: 24pt;
@@ -26,4 +25,4 @@
 			}
 		}
 	}
-}
+}

server/styles/scss/_weather-display.scss

@@ -1,5 +1,5 @@
-@use 'shared/_colors'as c;
-@use 'shared/_utils'as u;
+@use 'shared/_colors' as c;
+@use 'shared/_utils' as u;
 
 .weather-display {
 	width: 640px;
@@ -129,6 +129,12 @@
 			overflow: hidden;
 		}
 
+		// Remove margins for hazard scrolls to maximize text space
+		&.hazard .fixed {
+			margin-left: 0;
+			margin-right: 0;
+		}
+
 		.scroll-header {
 			height: 26px;
 			font-family: "Star4000 Small";
@@ -150,4 +156,4 @@
 		}
 
 	}
-}
+}