London |ITP- Jan-2026| Damian Dunkley |Sprint 3 |Alarm Clock

Sprint-3/alarmclock/alarmclock.js

@@ -1,4 +1,47 @@
-function setAlarm() {}
+let countdownId = null;
+
+function formatTime(totalSeconds) {// Convert total seconds to minutes and seconds
+  const minutes = Math.floor(totalSeconds / 60);
+  const seconds = totalSeconds % 60;
+
+  return `${String(minutes).padStart(2, "0")}:${String(seconds).padStart(2, "0")}`;
+}
+
+function updateHeading(totalSeconds) {// Update the heading with the formatted time remaining
+  const heading = document.getElementById("timeRemaining");// Get the heading element using its DOM ID
+  heading.innerText = `Time Remaining: ${formatTime(totalSeconds)}`;// Set the text of the heading to show the time remaining in the format "Time Remaining: MM:SS"
+}
+
+function setAlarm() {
+  const input = document.getElementById("alarmSet");// Get the input element using its DOM ID
+  let remainingSeconds = Number(input.value);// Convert the input value to a number representing the total seconds for the countdown
+
+  if (!Number.isFinite(remainingSeconds) || remainingSeconds < 0) {// Check if the input is a valid number and non-negative
+    remainingSeconds = 0;// If the input is invalid, set remainingSeconds to 0
+  }
+
+  if (countdownId !== null) {// If there is an existing countdown, clear it before starting a new one  
+
+    clearInterval(countdownId);
+  }
+
+  updateHeading(remainingSeconds);// Update the heading to show the initial time remaining before starting the countdown
+
+  countdownId = setInterval(() => {// Start a new interval that will execute the provided function every 1000 milliseconds (1 second)
+    remainingSeconds -= 1;
+
+    if (remainingSeconds <= 0) {// If the remaining seconds reach 0 or below, stop the countdown and play the alarm
+      updateHeading(0);
+      clearInterval(countdownId);
+      countdownId = null;
+      playAlarm();
+      document.body.style.backgroundColor = "red"; // change background colour
+      return;
+    }
+
+    updateHeading(remainingSeconds);
+  }, 1000);
+}
 
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