Add gradle task to generate new days

build.gradle.kts

@@ -12,4 +12,39 @@ tasks {
     wrapper {
         gradleVersion = "8.5"
     }
+
+    // Adapted from https://github.com/kotlin-hands-on/advent-of-code-kotlin-template/pull/17
+    task("generateNextDay") {
+        doLast {
+            val prevDayNum = fileTree("$projectDir/src").matching {
+                include("Day*.kt")
+            }.maxOf {
+                val (prevDayNum) = Regex("Day(\\d\\d)").find(it.name)!!.destructured
+                prevDayNum.toInt()
+            }
+            val newDayNum = String.format("%02d", prevDayNum + 1)
+            File("$projectDir/src", "Day$newDayNum.kt").writeText(
+                """fun main() {
+    fun part1(input: List<String>): Int {
+        return input.size
+    }
+
+    fun part2(input: List<String>): Int {
+        return input.size  
+    }
+
+    // test if implementation meets criteria from the description, like:
+    val testInput = readInput("Day${newDayNum}_test")
+    check(part1(testInput) == 0)
+
+    val input = readInput("Day${newDayNum}")
+    part1(input).println()
+    part2(input).println()
+}
+"""
+            )
+            File("$projectDir/src", "Day$newDayNum.txt").createNewFile()
+            File("$projectDir/src", "Day${newDayNum}_test.txt").createNewFile()
+        }
+    }
 }