Stupid live data

app/src/main/java/io/heckel/ntfy/MainActivity.kt

@@ -14,10 +14,7 @@ import androidx.core.app.NotificationCompat
 import androidx.core.app.NotificationManagerCompat
 import androidx.recyclerview.widget.RecyclerView
 import io.heckel.ntfy.add.AddTopicActivity
-import io.heckel.ntfy.data.Status
+import io.heckel.ntfy.data.*
-import io.heckel.ntfy.data.Topic
-import io.heckel.ntfy.data.topicShortUrl
-import io.heckel.ntfy.data.topicUrl
 import io.heckel.ntfy.detail.DetailActivity
 import kotlin.random.Random
 
@@ -27,8 +24,8 @@ const val TOPIC_BASE_URL = "base_url"
 
 class MainActivity : AppCompatActivity() {
     private val newTopicActivityRequestCode = 1
-    private val topicsViewModel by viewModels<TopicsViewModel> {
+    private val topicsViewModel by viewModels<SubscriptionViewModel> {
-        TopicsViewModelFactory()
+        SubscriptionsViewModelFactory()
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -48,17 +45,22 @@ class MainActivity : AppCompatActivity() {
 
         topicsViewModel.list().observe(this) {
             it?.let {
-                adapter.submitList(it as MutableList<Topic>)
+                println("new data arrived: $it")
+                adapter.submitList(it as MutableList<Subscription>)
             }
         }
 
         // Set up notification channel
         createNotificationChannel()
-        topicsViewModel.setNotificationListener { n -> displayNotification(n) }
+        topicsViewModel.setListener(object : NotificationListener {
+            override fun onNotification(subscriptionId: Long, notification: Notification) {
+                displayNotification(notification)
+            }
+        })
     }
 
     /* Opens TopicDetailActivity when RecyclerView item is clicked. */
-    private fun topicOnClick(topic: Topic) {
+    private fun topicOnClick(topic: Subscription) {
         val intent = Intent(this, DetailActivity()::class.java)
         intent.putExtra(TOPIC_ID, topic.id)
         startActivity(intent)
@@ -77,7 +79,7 @@ class MainActivity : AppCompatActivity() {
             intentData?.let { data ->
                 val name = data.getStringExtra(TOPIC_NAME) ?: return
                 val baseUrl = data.getStringExtra(TOPIC_BASE_URL) ?: return
-                val topic = Topic(Random.nextLong(), name, baseUrl, Status.CONNECTING, 0)
+                val topic = Subscription(Random.nextLong(), name, baseUrl, Status.CONNECTING, 0)
 
                 topicsViewModel.add(topic)
             }
@@ -88,7 +90,7 @@ class MainActivity : AppCompatActivity() {
         val channelId = getString(R.string.notification_channel_id)
         val notification = NotificationCompat.Builder(this, channelId)
             .setSmallIcon(R.drawable.ntfy)
-            .setContentTitle(topicShortUrl(n.topic))
+            .setContentTitle(topicShortUrl(n.subscription))
             .setContentText(n.message)
             .setPriority(NotificationCompat.PRIORITY_DEFAULT)
             .build()

app/src/main/java/io/heckel/ntfy/SubscriptionViewModel.kt

@@ -0,0 +1,67 @@
+package io.heckel.ntfy
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import io.heckel.ntfy.data.*
+import kotlin.collections.List
+
+
+class SubscriptionViewModel(private val repository: Repository, private val connectionManager: ConnectionManager) : ViewModel() {
+    fun add(topic: Subscription) {
+        repository.add(topic)
+        connectionManager.start(topic, viewModelScope)
+    }
+
+    fun get(id: Long) : Subscription? {
+        return repository.get(id)
+    }
+
+    fun list(): LiveData<List<Subscription>> {
+        return repository.list()
+    }
+
+    fun remove(topic: Subscription) {
+        repository.remove(topic)
+        connectionManager.stop(topic)
+    }
+
+    fun setListener(listener: NotificationListener) {
+        connectionManager.setListener(object : ConnectionListener {
+            override fun onStatusChanged(subcriptionId: Long, status: Status) {
+                println("onStatusChanged($subcriptionId, $status)")
+                val topic = repository.get(subcriptionId)
+                if (topic != null) {
+                    println("-> old topic: $topic")
+                    repository.update(topic.copy(status = status))
+                }
+            }
+
+            override fun onNotification(subscriptionId: Long, notification: Notification) {
+                println("onNotification($subscriptionId, $notification)")
+                val topic = repository.get(subscriptionId)
+                if (topic != null) {
+                    println("-> old topic: $topic")
+                    repository.update(topic.copy(messages = topic.messages + 1))
+                }
+                listener.onNotification(subscriptionId, notification) // Forward downstream
+            }
+        })
+    }
+}
+
+class SubscriptionsViewModelFactory : ViewModelProvider.Factory {
+    @Suppress("UNCHECKED_CAST")
+    override fun <T : ViewModel?> create(modelClass: Class<T>) =
+        with(modelClass){
+            when {
+                isAssignableFrom(SubscriptionViewModel::class.java) -> {
+                    val repository = Repository.getInstance()
+                    val connectionManager = ConnectionManager.getInstance()
+                    SubscriptionViewModel(repository, connectionManager) as T
+                }
+                else -> throw IllegalArgumentException("Unknown viewModel class $modelClass")
+            }
+        }
+}

app/src/main/java/io/heckel/ntfy/SubscriptionsAdapter.kt

@@ -9,16 +9,16 @@ import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import io.heckel.ntfy.data.Status
-import io.heckel.ntfy.data.Topic
+import io.heckel.ntfy.data.Subscription
 import io.heckel.ntfy.data.topicUrl
 
-class TopicsAdapter(private val onClick: (Topic) -> Unit) :
+class TopicsAdapter(private val onClick: (Subscription) -> Unit) :
-    ListAdapter<Topic, TopicsAdapter.TopicViewHolder>(TopicDiffCallback) {
+    ListAdapter<Subscription, TopicsAdapter.TopicViewHolder>(TopicDiffCallback) {
 
     /* ViewHolder for Topic, takes in the inflated view and the onClick behavior. */
-    class TopicViewHolder(itemView: View, val onClick: (Topic) -> Unit) :
+    class TopicViewHolder(itemView: View, val onClick: (Subscription) -> Unit) :
         RecyclerView.ViewHolder(itemView) {
-        private var topic: Topic? = null
+        private var topic: Subscription? = null
         private val context: Context = itemView.context
         private val nameView: TextView = itemView.findViewById(R.id.topic_text)
         private val statusView: TextView = itemView.findViewById(R.id.topic_status)
@@ -31,18 +31,19 @@ class TopicsAdapter(private val onClick: (Topic) -> Unit) :
             }
         }
 
-        fun bind(topic: Topic) {
+        fun bind(subscription: Subscription) {
-            this.topic = topic
+            println("bind sub: $subscription")
-            val statusText = when (topic.status) {
+            this.topic = subscription
+            val statusText = when (subscription.status) {
                 Status.CONNECTING -> context.getString(R.string.status_connecting)
-                else -> context.getString(R.string.status_subscribed)
+                else -> context.getString(R.string.status_connected)
             }
-            val statusMessage = if (topic.messages == 1) {
+            val statusMessage = if (subscription.messages == 1) {
-                context.getString(R.string.status_text_one, statusText, topic.messages)
+                context.getString(R.string.status_text_one, statusText, subscription.messages)
             } else {
-                context.getString(R.string.status_text_not_one, statusText, topic.messages)
+                context.getString(R.string.status_text_not_one, statusText, subscription.messages)
             }
-            nameView.text = topicUrl(topic)
+            nameView.text = topicUrl(subscription)
             statusView.text = statusMessage
         }
     }
@@ -61,12 +62,14 @@ class TopicsAdapter(private val onClick: (Topic) -> Unit) :
     }
 }
 
-object TopicDiffCallback : DiffUtil.ItemCallback<Topic>() {
+object TopicDiffCallback : DiffUtil.ItemCallback<Subscription>() {
-    override fun areItemsTheSame(oldItem: Topic, newItem: Topic): Boolean {
+    override fun areItemsTheSame(oldItem: Subscription, newItem: Subscription): Boolean {
+        println("areItemsTheSame: $oldItem.id ==? $newItem.id")
         return oldItem.id == newItem.id
     }
 
-    override fun areContentsTheSame(oldItem: Topic, newItem: Topic): Boolean {
+    override fun areContentsTheSame(oldItem: Subscription, newItem: Subscription): Boolean {
+        println("areContentsTheSame: $oldItem ==? $newItem")
         return oldItem == newItem
     }
 }

app/src/main/java/io/heckel/ntfy/TopicsViewModel.kt

@@ -1,45 +0,0 @@
-package io.heckel.ntfy
-
-import androidx.lifecycle.LiveData
-import androidx.lifecycle.ViewModel
-import androidx.lifecycle.ViewModelProvider
-import androidx.lifecycle.viewModelScope
-import io.heckel.ntfy.data.Repository
-import io.heckel.ntfy.data.Topic
-import kotlin.collections.List
-
-data class Notification(val topic: Topic, val message: String)
-typealias NotificationListener = (notification: Notification) -> Unit
-
-class TopicsViewModel(private val repository: Repository) : ViewModel() {
-    fun add(topic: Topic) {
-        repository.add(topic, viewModelScope)
-    }
-
-    fun get(id: Long) : Topic? {
-        return repository.get(id)
-    }
-
-    fun list(): LiveData<List<Topic>> {
-        return repository.list()
-    }
-
-    fun remove(topic: Topic) {
-        repository.remove(topic)
-    }
-
-    fun setNotificationListener(listener: NotificationListener) {
-        repository.setNotificationListener(listener)
-    }
-}
-
-class TopicsViewModelFactory() : ViewModelProvider.Factory {
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : ViewModel?> create(modelClass: Class<T>) =
-        with(modelClass){
-            when {
-                isAssignableFrom(TopicsViewModel::class.java) -> TopicsViewModel(Repository.getInstance()) as T
-                else -> throw IllegalArgumentException("Unknown viewModel class $modelClass")
-            }
-        }
-}

app/src/main/java/io/heckel/ntfy/data/ConnectionManager.kt

@@ -0,0 +1,84 @@
+package io.heckel.ntfy.data
+
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonObject
+import com.google.gson.JsonSyntaxException
+import kotlinx.coroutines.*
+import java.io.IOException
+import java.net.HttpURLConnection
+import java.net.URL
+
+const val READ_TIMEOUT = 60_000 // Keep alive every 30s assumed
+
+class ConnectionManager {
+    private val jobs = mutableMapOf<Long, Job>()
+    private val gson = GsonBuilder().create()
+    private var listener: ConnectionListener? = null;
+
+    fun start(subscription: Subscription, scope: CoroutineScope) {
+        jobs[subscription.id] = launchConnection(subscription, scope)
+    }
+
+    fun stop(subscription: Subscription) {
+        jobs.remove(subscription.id)?.cancel() // Cancel coroutine and remove
+    }
+
+    fun setListener(listener: ConnectionListener) {
+        this.listener = listener
+    }
+
+    private fun launchConnection(subscription: Subscription, scope: CoroutineScope): Job {
+        return scope.launch(Dispatchers.IO) {
+            while (isActive) {
+                openConnection(this, subscription)
+                delay(5000) // TODO exponential back-off
+            }
+        }
+    }
+
+    private fun openConnection(scope: CoroutineScope, subscription: Subscription) {
+        val url = "${subscription.baseUrl}/${subscription.topic}/json"
+        println("Connecting to $url ...")
+        val conn = (URL(url).openConnection() as HttpURLConnection).also {
+            it.doInput = true
+            it.readTimeout = READ_TIMEOUT
+        }
+        try {
+            listener?.onStatusChanged(subscription.id, Status.CONNECTED)
+            val input = conn.inputStream.bufferedReader()
+            while (scope.isActive) {
+                val line = input.readLine() ?: break // Break if EOF is reached, i.e. readLine is null
+                if (!scope.isActive) {
+                    break // Break if scope is not active anymore; readLine blocks for a while, so we want to be sure
+                }
+                try {
+                    val json = gson.fromJson(line, JsonObject::class.java) ?: break // Break on unexpected line
+                    if (!json.isJsonNull && !json.has("event") && json.has("message")) {
+                        val message = json.get("message").asString
+                        listener?.onNotification(subscription.id, Notification(subscription, message))
+                    }
+                } catch (e: JsonSyntaxException) {
+                    break // Break on unexpected line
+                }
+            }
+        } catch (e: IOException) {
+            println("Connection error: " + e.message)
+        } finally {
+            conn.disconnect()
+        }
+        listener?.onStatusChanged(subscription.id, Status.CONNECTING)
+        println("Connection terminated: $url")
+    }
+
+    companion object {
+        private var instance: ConnectionManager? = null
+
+        fun getInstance(): ConnectionManager {
+            return synchronized(ConnectionManager::class) {
+                val newInstance = instance ?: ConnectionManager()
+                instance = newInstance
+                newInstance
+            }
+        }
+    }
+}

app/src/main/java/io/heckel/ntfy/data/Models.kt

@@ -0,0 +1,29 @@
+package io.heckel.ntfy.data
+
+enum class Status {
+    CONNECTED, CONNECTING
+}
+
+data class Subscription(
+    val id: Long, // Internal ID, only used in Repository and activities
+    val topic: String,
+    val baseUrl: String,
+    val status: Status,
+    val messages: Int
+)
+
+data class Notification(
+    val subscription: Subscription,
+    val message: String
+)
+
+interface NotificationListener {
+    fun onNotification(subscriptionId: Long, notification: Notification)
+}
+
+interface ConnectionListener : NotificationListener {
+    fun onStatusChanged(subcriptionId: Long, status: Status)
+}
+
+fun topicUrl(s: Subscription) = "${s.baseUrl}/${s.topic}"
+fun topicShortUrl(s: Subscription) = topicUrl(s).replace("http://", "").replace("https://", "")

app/src/main/java/io/heckel/ntfy/data/Repository.kt

@@ -2,133 +2,43 @@ package io.heckel.ntfy.data
 
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
-import com.google.gson.GsonBuilder
-import com.google.gson.JsonObject
-import com.google.gson.JsonSyntaxException
-import io.heckel.ntfy.Notification
-import io.heckel.ntfy.NotificationListener
-import kotlinx.coroutines.*
-import java.io.IOException
-import java.net.HttpURLConnection
-import java.net.URL
-
-const val READ_TIMEOUT = 60_000 // Keep alive every 30s assumed
 
 class Repository {
-    private val topics: MutableLiveData<List<Topic>> = MutableLiveData(mutableListOf())
+    private val subscriptions = mutableListOf<Subscription>()
-    private val jobs = mutableMapOf<Long, Job>()
+    private val subscriptionsLiveData: MutableLiveData<List<Subscription>> = MutableLiveData(subscriptions)
-    private val gson = GsonBuilder().create()
-    private var notificationListener: NotificationListener? = null;
 
-    fun add(topic: Topic, scope: CoroutineScope) {
+    fun add(subscription: Subscription) {
-        val currentList = topics.value
+        synchronized(subscriptions) {
-        if (currentList == null) {
+            subscriptions.add(subscription)
-            topics.postValue(listOf(topic))
+            subscriptionsLiveData.postValue(ArrayList(subscriptions)) // Copy!
-        } else {
-            val updatedList = currentList.toMutableList()
-            updatedList.add(0, topic)
-            topics.postValue(updatedList)
         }
-        jobs[topic.id] = subscribeTopic(topic, scope)
     }
 
-    fun update(topic: Topic) {
+    fun update(subscription: Subscription) {
-        val currentList = topics.value
+        synchronized(subscriptions) {
-        if (currentList == null) {
+            val index = subscriptions.indexOfFirst { it.id == subscription.id } // Find index by Topic ID
-            topics.postValue(listOf(topic))
+            if (index == -1) return
-        } else {
+            subscriptions[index] = subscription
-            val index = currentList.indexOfFirst { it.id == topic.id } // Find index by Topic ID
+            subscriptionsLiveData.postValue(ArrayList(subscriptions)) // Copy!
-            if (index == -1) {
+        }
-                return // TODO race?
+    }
-            } else {
+
-                val updatedList = currentList.toMutableList()
+    fun remove(subscription: Subscription) {
-                updatedList[index] = topic
+        synchronized(subscriptions) {
-                println("PHIL updated list:")
+            if (subscriptions.remove(subscription)) {
-                println(updatedList)
+                subscriptionsLiveData.postValue(ArrayList(subscriptions)) // Copy!
-                topics.postValue(updatedList)
             }
         }
     }
 
-    fun remove(topic: Topic) {
+    fun get(id: Long): Subscription? {
-        val currentList = topics.value
+        synchronized(subscriptions) {
-        if (currentList != null) {
+            return subscriptions.firstOrNull { it.id == id } // Find index by Topic ID
-            val updatedList = currentList.toMutableList()
-            updatedList.remove(topic)
-            topics.postValue(updatedList)
-        }
-        jobs.remove(topic.id)?.cancel() // Cancel coroutine and remove
-    }
-
-    fun get(id: Long): Topic? {
-        topics.value?.let { topics ->
-            return topics.firstOrNull{ it.id == id}
-        }
-        return null
-    }
-
-    fun list(): LiveData<List<Topic>> {
-        return topics
-    }
-
-    fun setNotificationListener(listener: NotificationListener) {
-        notificationListener = listener
-    }
-
-    private fun subscribeTopic(topic: Topic, scope: CoroutineScope): Job {
-        return scope.launch(Dispatchers.IO) {
-            while (isActive) {
-                openConnection(this, topic)
-                delay(5000) // TODO exponential back-off
-            }
         }
     }
 
-    private fun openConnection(scope: CoroutineScope, topic: Topic) {
+    fun list(): LiveData<List<Subscription>> {
-        val url = "${topic.baseUrl}/${topic.name}/json"
+        return subscriptionsLiveData
-        println("Connecting to $url ...")
-        val conn = (URL(url).openConnection() as HttpURLConnection).also {
-            it.doInput = true
-            it.readTimeout = READ_TIMEOUT
-        }
-        // TODO ugly
-        val currentTopic = get(topic.id)
-        if (currentTopic != null) {
-            update(currentTopic.copy(status = Status.SUBSCRIBED))
-        }
-        try {
-            val input = conn.inputStream.bufferedReader()
-            while (scope.isActive) {
-                val line = input.readLine() ?: break // Break if EOF is reached, i.e. readLine is null
-                if (!scope.isActive) {
-                    break // Break if scope is not active anymore; readLine blocks for a while, so we want to be sure
-                }
-                try {
-                    val json = gson.fromJson(line, JsonObject::class.java) ?: break // Break on unexpected line
-                    if (!json.isJsonNull && json.has("message")) {
-                        val message = json.get("message").asString
-                        notificationListener?.let { it(Notification(topic, message)) }
-
-                        // TODO ugly
-                        val currentTopic = get(topic.id)
-                        if (currentTopic != null) {
-                            update(currentTopic.copy(messages = currentTopic.messages+1))
-                        }
-                    }
-                } catch (e: JsonSyntaxException) {
-                    break // Break on unexpected line
-                }
-            }
-        } catch (e: IOException) {
-            println("Connection error: " + e.message)
-        } finally {
-            conn.disconnect()
-        }
-        val currentTopic2 = get(topic.id)
-        if (currentTopic2 != null) {
-            update(currentTopic2.copy(status = Status.CONNECTING))
-        }
-        println("Connection terminated: $url")
     }
 
     companion object {

app/src/main/java/io/heckel/ntfy/data/Topic.kt

@@ -1,16 +0,0 @@
-package io.heckel.ntfy.data
-
-enum class Status {
-    SUBSCRIBED, CONNECTING
-}
-
-data class Topic(
-    val id: Long, // Internal ID, only used in Repository and activities
-    val name: String,
-    val baseUrl: String,
-    val status: Status,
-    val messages: Int
-)
-
-fun topicUrl(t: Topic) = "${t.baseUrl}/${t.name}"
-fun topicShortUrl(t: Topic) = topicUrl(t).replace("http://", "").replace("https://", "")

app/src/main/java/io/heckel/ntfy/detail/DetailActivity.kt

@@ -23,19 +23,20 @@ import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
 import io.heckel.ntfy.R
 import io.heckel.ntfy.TOPIC_ID
-import io.heckel.ntfy.TopicsViewModel
+import io.heckel.ntfy.SubscriptionViewModel
-import io.heckel.ntfy.TopicsViewModelFactory
+import io.heckel.ntfy.SubscriptionsViewModelFactory
+import io.heckel.ntfy.data.topicShortUrl
 
 class DetailActivity : AppCompatActivity() {
-    private val topicsViewModel by viewModels<TopicsViewModel> {
+    private val subscriptionsViewModel by viewModels<SubscriptionViewModel> {
-        TopicsViewModelFactory()
+        SubscriptionsViewModelFactory()
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.topic_detail_activity)
 
-        var topicId: Long? = null
+        var subscriptionId: Long? = null
 
         /* Connect variables to UI elements. */
         val topicText: TextView = findViewById(R.id.topic_detail_url)
@@ -43,20 +44,20 @@ class DetailActivity : AppCompatActivity() {
 
         val bundle: Bundle? = intent.extras
         if (bundle != null) {
-            topicId = bundle.getLong(TOPIC_ID)
+            subscriptionId = bundle.getLong(TOPIC_ID)
         }
 
         // TODO This should probably fail hard if topicId is null
 
         /* If currentTopicId is not null, get corresponding topic and set name, image and
         description */
-        topicId?.let {
+        subscriptionId?.let {
-            val topic = topicsViewModel.get(it)
+            val subscription = subscriptionsViewModel.get(it)
-            topicText.text = "${topic?.baseUrl}/${topic?.name}"
+            topicText.text = subscription?.let { s -> topicShortUrl(s) }
 
             removeButton.setOnClickListener {
-                if (topic != null) {
+                if (subscription != null) {
-                    topicsViewModel.remove(topic)
+                    subscriptionsViewModel.remove(subscription)
                 }
                 finish()
             }

app/src/main/res/values/strings.xml

@@ -2,12 +2,12 @@
     <string name="app_name">Ntfy</string>
     <string name="add_topic">Add Topic</string>
 
-    <string name="topic_string">Topics</string>
+
     <string name="topic_name_edit_text">Topic Name</string>
     <string name="topic_base_url_edit_text">Service URL</string>
     <string name="topic_base_url_default_value">https://ntfy.sh</string>
     <string name="subscribe_button_text">Subscribe</string>
-    <string name="status_subscribed">Subscribed</string>
+    <string name="status_connected">Connected</string>
     <string name="status_connecting">Connecting</string>
     <string name="status_text_one">%1$s, %2$d notification</string>
     <string name="status_text_not_one">%1$s, %2$d notifications</string>