android/ui: add mdm key expiry notification window (#365)

Updates tailscale/corp#19743

Adjust the key expiry window and it's related notification based
on the keyExpiry MDM setting.  Default remains 24 hours.  Logic
moved to the viewModel.

unitTest package added.  It's a start!

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>

android/build.gradle

@@ -85,6 +85,7 @@ dependencies {
     // Kotlin dependencies.
     implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.3"
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.8.0"
+    implementation 'junit:junit:4.12'
     runtimeOnly "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.8.0"
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
@@ -92,7 +93,6 @@ dependencies {
     // Compose dependencies.
     def composeBom = platform('androidx.compose:compose-bom:2023.06.01')
     implementation composeBom
-    androidTestImplementation composeBom
     implementation 'androidx.compose.material3:material3:1.2.1'
     implementation 'androidx.compose.material:material-icons-core:1.6.3'
     implementation "androidx.compose.ui:ui:1.6.3"
@@ -115,18 +115,22 @@ dependencies {
     // Tailscale dependencies.
     implementation ':libtailscale@aar'
 
-    // Tests
+    // Integration Tests
-    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation composeBom
     androidTestImplementation 'androidx.test:runner:1.5.2'
     androidTestImplementation 'androidx.test.ext:junit-ktx:1.1.5'
     androidTestImplementation 'androidx.test.ext:junit:1.1.5'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
     implementation 'androidx.test.uiautomator:uiautomator:2.3.0'
 
+
     // Authentication only for tests
     androidTestImplementation 'dev.turingcomplete:kotlin-onetimepassword:2.4.0'
     androidTestImplementation 'commons-codec:commons-codec:1.16.1'
-    
+
+    // Unit Tests
+    testImplementation 'junit:junit:4.13.2'
+
     debugImplementation("androidx.compose.ui:ui-tooling")
     implementation("androidx.compose.ui:ui-tooling-preview")
 }
@@ -135,8 +139,8 @@ def getLocalProperty(key) {
     try {
         Properties properties = new Properties()
         properties.load(project.file('local.properties').newDataInputStream())
-        return properties.getProperty(key);
+        return properties.getProperty(key)
     } catch(Throwable ignored) {
         return ""
     }
-}
+}

android/src/main/java/com/tailscale/ipn/ui/util/TimeUtil.kt

@@ -3,12 +3,16 @@
 
 package com.tailscale.ipn.ui.util
 
+import android.util.Log
 import com.tailscale.ipn.R
+import java.time.Duration
 import java.time.Instant
 import java.time.format.DateTimeFormatter
 import java.util.Date
 
 object TimeUtil {
+  val TAG = "TimeUtil"
+
   fun keyExpiryFromGoTime(goTime: String?): ComposableStringFormatter {
 
     val time = goTime ?: return ComposableStringFormatter(R.string.empty)
@@ -70,10 +74,51 @@ object TimeUtil {
     return Date.from(i)
   }
 
-  // Returns true if the given time is within 24 hours from now or in the past.
+  // Returns true if the given Go time string is in the past, or will occur within the given
-  fun isWithin24Hours(goTime: String): Boolean {
+  // duration from now.
+  fun isWithinExpiryNotificationWindow(window: Duration, goTime: String): Boolean {
     val expTime = epochMillisFromGoTime(goTime)
     val now = Instant.now().toEpochMilli()
-    return (expTime - now) / 1000 < 86400
+    return (expTime - now) / 1000 < window.seconds
+  }
+
+  // Parses a Go duration string (e.g. "2h3.2m4s") and returns a Java Duration object.
+  // Returns null if the input string is not a valid Go duration or contains
+  // units other than y,w,d,h,m,s (ms and us are explicitly not supported).
+  fun duration(goDuration: String): Duration? {
+    if (goDuration.contains("ms") || goDuration.contains("us")) {
+      return null
+    }
+
+    var duration = 0.0
+    var valStr = ""
+    for (c in goDuration) {
+      // Scan digits and decimal points
+      if (c.isDigit() || c == '.') {
+        valStr += c
+      } else {
+        try {
+          val durationFragment = valStr.toDouble()
+          duration +=
+              when (c) {
+                'y' -> durationFragment * 31536000.0 // 365 days
+                'w' -> durationFragment * 604800.0
+                'd' -> durationFragment * 86400.0
+                'h' -> durationFragment * 3600.0
+                'm' -> durationFragment * 60.0
+                's' -> durationFragment
+                else -> {
+                  Log.e(TAG, "Invalid duration string: $goDuration")
+                  return null
+                }
+              }
+        } catch (e: NumberFormatException) {
+          Log.e(TAG, "Invalid duration string: $goDuration")
+          return null
+        }
+        valStr = ""
+      }
+    }
+    return Duration.ofSeconds(duration.toLong())
   }
 }

android/src/main/java/com/tailscale/ipn/ui/view/MainView.kt

@@ -85,7 +85,6 @@ import com.tailscale.ipn.ui.util.AutoResizingText
 import com.tailscale.ipn.ui.util.Lists
 import com.tailscale.ipn.ui.util.LoadingIndicator
 import com.tailscale.ipn.ui.util.PeerSet
-import com.tailscale.ipn.ui.util.TimeUtil
 import com.tailscale.ipn.ui.util.flag
 import com.tailscale.ipn.ui.util.itemsWithDividers
 import com.tailscale.ipn.ui.viewModel.MainViewModel
@@ -110,24 +109,25 @@ fun MainView(
       Column(
           modifier = Modifier.fillMaxWidth().padding(paddingInsets),
           verticalArrangement = Arrangement.Center) {
-            val state = viewModel.ipnState.collectAsState(initial = Ipn.State.NoState).value
+            val state by viewModel.ipnState.collectAsState(initial = Ipn.State.NoState)
-            val user = viewModel.loggedInUser.collectAsState(initial = null).value
+            val user by viewModel.loggedInUser.collectAsState(initial = null)
-            val stateVal = viewModel.stateRes.collectAsState(initial = R.string.placeholder).value
+            val stateVal by viewModel.stateRes.collectAsState(initial = R.string.placeholder)
             val stateStr = stringResource(id = stateVal)
-            val netmap = viewModel.netmap.collectAsState(initial = null).value
+            val netmap by viewModel.netmap.collectAsState(initial = null)
-            val showExitNodePicker = MDMSettings.exitNodesPicker.flow.collectAsState().value
+            val showExitNodePicker by MDMSettings.exitNodesPicker.flow.collectAsState()
-            val allowToggle = MDMSettings.forceEnabled.flow.collectAsState().value
+            val disableToggle by MDMSettings.forceEnabled.flow.collectAsState(initial = true)
+            val showKeyExpiry by viewModel.showExpiry.collectAsState(initial = false)
 
             ListItem(
                 colors = MaterialTheme.colorScheme.surfaceContainerListItem,
                 leadingContent = {
                   TintedSwitch(
                       onCheckedChange = {
-                        if (allowToggle) {
+                        if (!disableToggle) {
                           viewModel.toggleVpn()
                         }
                       },
-                      enabled = !allowToggle,
+                      enabled = !disableToggle,
                       checked = isOn.value)
                 },
                 headlineContent = {
@@ -166,7 +166,9 @@ fun MainView(
 
                 PromptPermissionsIfNecessary()
 
-                ExpiryNotificationIfNecessary(netmap = netmap, action = { viewModel.login() })
+                if (showKeyExpiry) {
+                  ExpiryNotification(netmap = netmap, action = { viewModel.login() })
+                }
 
                 if (showExitNodePicker == ShowHide.Show) {
                   ExitNodeStatus(
@@ -397,6 +399,7 @@ fun PeerList(
   val searchTermStr by viewModel.searchTerm.collectAsState(initial = "")
   val showNoResults =
       remember { derivedStateOf { searchTermStr.isNotEmpty() && peerList.value.isEmpty() } }.value
+
   val netmap = viewModel.netmap.collectAsState()
 
   val focusManager = LocalFocusManager.current
@@ -505,13 +508,8 @@ fun PeerList(
 }
 
 @Composable
-fun ExpiryNotificationIfNecessary(netmap: Netmap.NetworkMap?, action: () -> Unit = {}) {
+fun ExpiryNotification(netmap: Netmap.NetworkMap?, action: () -> Unit = {}) {
-  // Key expiry warning shown only if the key is expiring within 24 hours (or has already expired)
+  if (netmap == null) return
-  val networkMap = netmap ?: return
-  if (!TimeUtil.isWithin24Hours(networkMap.SelfNode.KeyExpiry) ||
-      networkMap.SelfNode.keyDoesNotExpire) {
-    return
-  }
 
   Box(modifier = Modifier.background(color = MaterialTheme.colorScheme.surfaceContainer)) {
     Box(
@@ -524,7 +522,7 @@ fun ExpiryNotificationIfNecessary(netmap: Netmap.NetworkMap?, action: () -> Unit
               colors = MaterialTheme.colorScheme.warningListItem,
               headlineContent = {
                 Text(
-                    networkMap.SelfNode.expiryLabel(),
+                    netmap.SelfNode.expiryLabel(),
                     style = MaterialTheme.typography.titleMedium,
                 )
               },

android/src/main/java/com/tailscale/ipn/ui/viewModel/MainViewModel.kt

@@ -6,14 +6,17 @@ package com.tailscale.ipn.ui.viewModel
 import android.util.Log
 import androidx.lifecycle.viewModelScope
 import com.tailscale.ipn.R
+import com.tailscale.ipn.mdm.MDMSettings
 import com.tailscale.ipn.ui.model.Ipn.State
 import com.tailscale.ipn.ui.notifier.Notifier
 import com.tailscale.ipn.ui.util.PeerCategorizer
 import com.tailscale.ipn.ui.util.PeerSet
+import com.tailscale.ipn.ui.util.TimeUtil
 import com.tailscale.ipn.ui.util.set
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
+import java.time.Duration
 
 class MainViewModel : IpnViewModel() {
 
@@ -35,6 +38,9 @@ class MainViewModel : IpnViewModel() {
   // The active search term for filtering peers
   val searchTerm: StateFlow<String> = MutableStateFlow("")
 
+  // True if we should render the key expiry bannder
+  val showExpiry: StateFlow<Boolean> = MutableStateFlow(false)
+
   private val peerCategorizer = PeerCategorizer()
 
   init {
@@ -51,6 +57,18 @@ class MainViewModel : IpnViewModel() {
         it?.let { netmap ->
           peerCategorizer.regenerateGroupedPeers(netmap)
           peers.set(peerCategorizer.groupedAndFilteredPeers(searchTerm.value))
+
+          if (netmap.SelfNode.keyDoesNotExpire) {
+            showExpiry.set(false)
+            return@let
+          } else {
+            val expiryNotificationWindowMDM = MDMSettings.keyExpirationNotice.flow.value
+            val window =
+                expiryNotificationWindowMDM?.let { TimeUtil.duration(it) } ?: Duration.ofHours(24)
+            val expiresSoon =
+                TimeUtil.isWithinExpiryNotificationWindow(window, it.SelfNode.KeyExpiry)
+            showExpiry.set(expiresSoon)
+          }
         }
       }
     }

android/src/test/java/android/util/Log.java

@@ -0,0 +1,30 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package android.util;
+
+/**
+ * This is a mock class for the android.util.Log class. It is used to print log messages to the console.
+ */
+public class Log {
+    public static int d(String tag, String msg) {
+        System.out.println("DEBUG: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int i(String tag, String msg) {
+        System.out.println("INFO: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int w(String tag, String msg) {
+        System.out.println("WARN: " + tag + ": " + msg);
+        return 0;
+    }
+
+    public static int e(String tag, String msg) {
+        System.out.println("ERROR: " + tag + ": " + msg);
+        return 0;
+    }
+
+}

android/src/test/kotlin/com/tailcale/ipn/ui/util/TimeUtilTest.kt

@@ -0,0 +1,60 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package com.tailcale.ipn.ui.util
+
+import com.tailscale.ipn.ui.util.TimeUtil
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+import java.time.Duration
+
+class TimeUtilTest {
+
+  @Test
+  fun durationInvalidMsUnits() {
+    val input = "5s10ms"
+    val actual = TimeUtil.duration(input)
+    assertNull("Should return null", actual)
+  }
+
+  @Test
+  fun durationInvalidUsUnits() {
+    val input = "5s10us"
+    val actual = TimeUtil.duration(input)
+    assertNull("Should return null", actual)
+  }
+
+  @Test
+  fun durationTestHappyPath() {
+    val input = arrayOf("1.0y1.0w1.0d1.0h1.0m1.0s", "1s", "1m", "1h", "1d", "1w", "1y")
+    val expectedSeconds =
+        arrayOf((31536000 + 604800 + 86400 + 3600 + 60 + 1), 1, 60, 3600, 86400, 604800, 31536000)
+    val expected = expectedSeconds.map { Duration.ofSeconds(it.toLong()) }
+    val actual = input.map { TimeUtil.duration(it) }
+    assertEquals("Incorrect conversion", expected, actual)
+  }
+
+  @Test
+  fun testBadDurationString() {
+    val input = "1..0y1.0w1.0d1.0h1.0m1.0s"
+    val actual = TimeUtil.duration(input)
+    assertNull("Should return null", actual)
+  }
+
+  @Test
+  fun testBadDInputString() {
+    val input = "1.0yy1.0w1.0d1.0h1.0m1.0s"
+    val actual = TimeUtil.duration(input)
+    assertNull("Should return null", actual)
+  }
+
+  @Test
+  fun testIgnoreFractionalSeconds() {
+    val input = "10.9s"
+    val expectedSeconds = 10
+    val expected = Duration.ofSeconds(expectedSeconds.toLong())
+    val actual = TimeUtil.duration(input)
+    assertEquals("Should return $expectedSeconds seconds", expected, actual)
+  }
+}