CodeYourFuture · DamianDL · Mar 17, 2026 · Mar 24, 2026 · Mar 24, 2026 · Mar 24, 2026
diff --git a/Sprint-3/alarmclock/alarmclock.js b/Sprint-3/alarmclock/alarmclock.js
@@ -1,4 +1,70 @@
-function setAlarm() {}
+let countdownId = null;
+const originalBackgroundColor = document.body.style.backgroundColor || "white"; // Store the original background color
+let timeRemainingHeading = null;
+
+function getTimeRemainingHeading() {
+  if (timeRemainingHeading === null) {
+    timeRemainingHeading = document.getElementById("timeRemaining");
+  }
+
+  return timeRemainingHeading;
+}
+
+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 = getTimeRemainingHeading(); // Query once, then reuse the cached DOM node on each tick
+  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
+
+  // Guard against edge cases: empty input, non-numeric, negative values, and 0
+  if (!Number.isFinite(remainingSeconds) || remainingSeconds <= 0) {
+    // Check if the input is a valid number and strictly greater than 0
+    alert("Please enter a positive number greater than 0");
+    return; // Exit early without starting the countdown
+  }
+
+  if (countdownId !== null) {
+    // If there is an existing countdown, clear it before starting a new one
+
+    clearInterval(countdownId);
+  }
+
+
+  // Reset background and stop alarm sound when setting a new alarm
+  document.body.style.backgroundColor = originalBackgroundColor;
+
+  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; // Exit the function to prevent further execution
+    }
+
+    updateHeading(remainingSeconds);
+  }, 1000);
+}
 
 // DO NOT EDIT BELOW HERE
 

diff --git a/Sprint-3/alarmclock/index.html b/Sprint-3/alarmclock/index.html
@@ -4,7 +4,7 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <link rel="stylesheet" href="style.css" />
-    <title>Title here</title>
+    <title>Alarm Clock App</title>
   </head>
   <body>
     <div class="centre">