Validate single port or range endpoint is between 0 and 65535

src/main/kotlin/com/coder/jetbrains/matcher/PortMatcher.kt

@@ -28,12 +28,16 @@ class PortMatcher(private val rule: String) {
         return when {
             // Try parsing as single port
             portPart.all { it.isDigit() } -> {
-                MatchRule.SinglePort(portPart.toInt())
+                val port = portPart.toInt()
+                validatePort(port)
+                MatchRule.SinglePort(port)
             }
             // Try parsing as port range (e.g., "40000-55000")
             portPart.matches("^\\d+-\\d+$".toRegex()) -> {
                 val (start, end) = portPart.split('-')
                     .map { it.trim().toInt() }
+                validatePort(start)
+                validatePort(end)
                 require(start <= end) { "Invalid port range: start must be less than or equal to end" }
                 MatchRule.PortRange(start, end)
             }
@@ -47,4 +51,12 @@ class PortMatcher(private val rule: String) {
             }
         }
     }
+
+    private fun validatePort(port: Int) {
+        require(port in 0..65535) { "Port number must be between 0 and 65535, got: $port" }
+    }
+
+    companion object {
+        const val MAX_PORT = 65535
+    }
 }

src/test/kotlin/com/coder/jetbrains/matcher/PortMatcherTest.kt

@@ -3,6 +3,7 @@ package com.coder.jetbrains.matcher
 import org.junit.Test
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
+import org.junit.Assert.assertThrows
 
 class PortMatcherTest {
 
@@ -40,4 +41,24 @@ class PortMatcherTest {
         assertTrue(matcher.matches(8009))
         assertFalse(matcher.matches(8010))
     }
+
+    @Test
+    fun `test invalid port numbers`() {
+        assertThrows(IllegalArgumentException::class.java) { PortMatcher("65536") }
+        assertThrows(IllegalArgumentException::class.java) { PortMatcher("0-65536") }
+        assertThrows(IllegalArgumentException::class.java) { PortMatcher("70000") }
+    }
+
+    @Test
+    fun `test edge case port numbers`() {
+        // These should work
+        PortMatcher("0")
+        PortMatcher("65535")
+        PortMatcher("0-65535")
+
+        // These combinations should work
+        val matcher = PortMatcher("0-65535")
+        assertTrue(matcher.matches(0))
+        assertTrue(matcher.matches(65535))
+    }
 }