do not override an existing collection with an empty one - except whe…

…n last podcast is deleted

app/build.gradle

@@ -63,8 +63,8 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion"
-    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.0"
-    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.0"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.4"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.4"
 
     implementation "com.google.android.material:material:1.2.0-beta01"
 

app/src/main/java/org/y20k/escapepod/Keys.kt

@@ -67,6 +67,7 @@ object Keys {
     const val PREF_ONE_TIME_HOUSEKEEPING_NECESSARY = "ONE_TIME_HOUSEKEEPING_NECESSARY_VERSIONCODE_26" // increment to current app version code to trigger housekeeping that runs only once
     const val PREF_THEME_SELECTION: String= "THEME_SELECTION"
     const val PREF_LAST_UPDATE_COLLECTION: String = "LAST_UPDATE_COLLECTION"
+    const val PREF_COLLECTION_SIZE: String = "COLLECTION_SIZE"
     const val PREF_COLLECTION_MODIFICATION_DATE: String = "COLLECTION_MODIFICATION_DATE"
     const val PREF_CURRENT_MEDIA_ID: String = "CURRENT_MEDIA_ID"
     const val PREF_CURRENT_PLAYBACK_STATE: String = "CURRENT_PLAYBACK_STATE"

app/src/main/java/org/y20k/escapepod/PlayerService.kt

@@ -611,7 +611,6 @@ class PlayerService(): MediaBrowserServiceCompat(), Player.EventListener, Corout
             }
         }
 
-
         override fun onFastForward() {
             LogHelper.d(TAG, "Skipping forward")
             // update position

app/src/main/java/org/y20k/escapepod/collection/CollectionViewModel.kt

@@ -45,7 +45,7 @@ class CollectionViewModel(application: Application) : AndroidViewModel(applicati
     private var collectionChangedReceiver: BroadcastReceiver
     private val backgroundJob = Job()
     private val uiScope = CoroutineScope(Dispatchers.Main + backgroundJob)
-    //private var collectionDatabase: CollectionDatabase
+//    private var collectionDatabase: CollectionDatabase
 
 
     /* Init constructor */
@@ -56,7 +56,7 @@ class CollectionViewModel(application: Application) : AndroidViewModel(applicati
         collectionChangedReceiver = createCollectionChangedReceiver()
         LocalBroadcastManager.getInstance(application).registerReceiver(collectionChangedReceiver, IntentFilter(Keys.ACTION_COLLECTION_CHANGED))
         // get instance of collection database // todo remove: just a database test
-        //collectionDatabase = CollectionDatabase.getInstance(application)
+//        collectionDatabase = CollectionDatabase.getInstance(application)
     }
 
 
@@ -98,17 +98,24 @@ class CollectionViewModel(application: Application) : AndroidViewModel(applicati
             // update collection view model
             collectionLiveData.value = collection
             // Todo remove: just a database test
-            //insertPodcasts(collection)
+//            insertPodcasts(collection)
     }
 }
 
+    // todo read this :-) https://itnext.io/room-persistence-library-using-mutablelivedata-observable-to-update-the-ui-after-a-database-6836d25e8267
 
-///* Todo remove: just a database test */
+
+/* Todo remove: just a database test */
 //private fun insertPodcasts(collection: Collection) {
 //    GlobalScope.launch {
-//        collectionDatabase.podcastDao().insertAll(DatabaseHelper.convertToPodcastEntityList(collection))
+//        //collectionDatabase.clearAllTables()
+//
+//        val result: Pair<List<PodcastEntity>, List<EpisodeEntity>> = DatabaseHelper.convertToPodcastEntityList(collection)
+//        collectionDatabase.podcastDao().insertAll(result.first)
+//        collectionDatabase.episodeDao().insertAll(result.second)
 //
-//        LogHelper.e(TAG, "${collectionDatabase.podcastDao().findByName("Subnet").pid}")
+//        val numberOfEpisodes = collectionDatabase.episodeDao().getSize()
+//        val numberOfPodcasts = collectionDatabase.podcastDao().getSize()
 //    }
 //}
 

app/src/main/java/org/y20k/escapepod/database/EpisodeDao.kt

@@ -1,30 +1,51 @@
 package org.y20k.escapepod.database
 
+import androidx.lifecycle.LiveData
 import androidx.room.*
 
 @Dao
 interface EpisodeDao {
-    @Query("SELECT * FROM episode")
-    fun getAll(): List<EpisodeEntity>
+    @Query("SELECT COUNT(*) FROM episodes")
+    fun getSize(): Int
 
-    @Query("SELECT * FROM episode WHERE eid IN (:eids)")
+    @Query("SELECT * FROM episodes")
+    fun getAll(): LiveData<List<EpisodeEntity>>
+
+    @Query("SELECT * FROM episodes WHERE eid IN (:eids)")
     fun loadAllByIds(eids: IntArray): List<EpisodeEntity>
 
-    @Query("SELECT * FROM episode WHERE episode_title LIKE :title LIMIT 1")
+    @Query("SELECT * FROM episodes WHERE episode_title LIKE :title LIMIT 1")
     fun findByTitle(title: String): EpisodeEntity
 
-    @Query("SELECT * FROM episode WHERE episode_guid IS :guid LIMIT 1")
+    @Query("SELECT * FROM episodes WHERE episode_guid IS :guid LIMIT 1")
     fun findByGuid(guid: String): EpisodeEntity
 
-    @Insert(onConflict = OnConflictStrategy.REPLACE)
-    fun insert(episode: EpisodeEntity)
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    fun insert(episode: EpisodeEntity): Long
 
-    @Insert(onConflict = OnConflictStrategy.REPLACE)
-    fun insertAll(vararg episodes: EpisodeEntity)
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    fun insertAll(episodes: List<EpisodeEntity>): List< Long>
 
-    @Update
-    fun add(episode: EpisodeEntity)
+    @Update(onConflict = OnConflictStrategy.REPLACE)
+    fun update(episode: EpisodeEntity)
 
     @Delete
     fun delete(episode: EpisodeEntity)
+
+    @Transaction
+    fun upsert(episode: EpisodeEntity) {
+        val rowId = insert(episode)
+        if (rowId == -1L) {
+            update(episode)
+        }
+    }
+
+    @Transaction
+    fun upsertAll(episodes: List<EpisodeEntity>) {
+        val rowIds = insertAll(episodes)
+        val episodesToUpdate = rowIds.mapIndexedNotNull { index, rowId ->
+            if (rowId == -1L) null else episodes[index] }
+        episodesToUpdate.forEach { update(it) }
+    }
+
 }

app/src/main/java/org/y20k/escapepod/database/EpisodeEntity.kt

@@ -2,12 +2,12 @@ package org.y20k.escapepod.database
 
 import androidx.room.ColumnInfo
 import androidx.room.Entity
+import androidx.room.Index
 import androidx.room.PrimaryKey
 
-@Entity(tableName = "episode")
+@Entity(tableName = "episodes", indices = arrayOf(Index(value = ["episode_guid"], unique = true)))
 data class EpisodeEntity (
 
-        @PrimaryKey (autoGenerate = true) val eid: Long,
         @ColumnInfo (name = "podcast_id") val podcastId: Long,
         @ColumnInfo (name = "episode_guid") val guid: String,
         @ColumnInfo (name = "episode_title") val title: String,
@@ -24,4 +24,6 @@ data class EpisodeEntity (
         @ColumnInfo (name = "episode_remote_cover_file_location") val remoteCoverFileLocation: String,
         @ColumnInfo (name = "episode_remote_audio_file_location") val remoteAudioFileLocation: String
 
-)
+) {
+    @PrimaryKey (autoGenerate = true) var eid: Long = 0L
+}

app/src/main/java/org/y20k/escapepod/database/PodcastDao.kt

@@ -1,32 +1,58 @@
 package org.y20k.escapepod.database
 
+import androidx.lifecycle.LiveData
 import androidx.room.*
 
 @Dao
 interface PodcastDao {
-    @Query("SELECT * FROM podcast")
-    fun getAll(): List<PodcastEntity>
+    @Query("SELECT COUNT(*) FROM podcasts")
+    fun getSize(): Int
 
-    @Query("SELECT * FROM podcast WHERE pid IN (:pids)")
+    @Query("SELECT * FROM podcasts")
+    fun getAll(): LiveData<List<PodcastEntity>>
+
+    @Query("SELECT * FROM podcasts WHERE pid IN (:pids)")
     fun loadAllByIds(pids: IntArray): List<PodcastEntity>
 
-    @Query("SELECT * FROM podcast WHERE podcast_name LIKE :name LIMIT 1")
+    @Query("SELECT * FROM podcasts WHERE podcast_name LIKE :name LIMIT 1")
     fun findByName(name: String): PodcastEntity
 
-    @Insert
-    fun insert(podcast: PodcastEntity)
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    fun insert(podcast: PodcastEntity): Long
 
-    @Insert
-    fun insertAll(podcasts: List<PodcastEntity>)
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    fun insertAll(podcasts: List<PodcastEntity>): List<Long>
 
-    @Update
-    fun add(podcast: PodcastEntity)
+    @Update(onConflict = OnConflictStrategy.REPLACE)
+    fun update(podcast: PodcastEntity)
 
     @Delete
     fun delete(user: PodcastEntity)
 
     @Transaction
-    @Query("SELECT * FROM podcast")
+    fun upsert(podcast: PodcastEntity) {
+        val rowId = insert(podcast)
+        if (rowId == -1L) {
+            update(podcast)
+        }
+    }
+
+    @Transaction
+    fun upsertAll(podcasts: List<PodcastEntity>) {
+        val rowIds = insertAll(podcasts)
+        val podcastsToUpdate = rowIds.mapIndexedNotNull { index, rowId ->
+            if (rowId == -1L) null else podcasts[index] }
+        podcastsToUpdate.forEach { update(it) }
+    }
+
+
+    /**
+     * This query will tell Room to query both the Podcast and Episode tables and handle
+     * the object mapping.
+     */
+    @Transaction
+    //@Query("SELECT * FROM episodes WHERE podcast_id IN (SELECT DISTINCT(pid) FROM podcasts)")
+    @Query("SELECT * FROM podcasts")
     fun getPodcastsWithEpisodes(): List<PodcastWithEpisodesEntity>
 
 }

app/src/main/java/org/y20k/escapepod/database/PodcastEntity.kt

@@ -2,10 +2,11 @@ package org.y20k.escapepod.database
 
 import androidx.room.ColumnInfo
 import androidx.room.Entity
+import androidx.room.Index
 import androidx.room.PrimaryKey
 
 
-@Entity(tableName = "podcast")
+@Entity(tableName = "podcasts", indices = arrayOf(Index(value = ["podcast_remote_podcast_feed_location"], unique = true)))
 data class PodcastEntity(
 
         @ColumnInfo (name = "podcast_name") val name: String,

app/src/main/java/org/y20k/escapepod/helpers/DatabaseHelper.kt

@@ -1,12 +1,14 @@
 package org.y20k.escapepod.helpers
 
 import org.y20k.escapepod.core.Collection
+import org.y20k.escapepod.database.EpisodeEntity
 import org.y20k.escapepod.database.PodcastEntity
 
 object DatabaseHelper {
 
-    fun convertToPodcastEntityList(collection: Collection): List<PodcastEntity> {
-        val list: MutableList<PodcastEntity> = mutableListOf()
+    fun convertToPodcastEntityList(collection: Collection): Pair<List<PodcastEntity>, List<EpisodeEntity>> {
+        val podcastList: MutableList<PodcastEntity> = mutableListOf()
+        val episodeList: MutableList<EpisodeEntity> = mutableListOf()
         collection.podcasts.forEach { podcast ->
             val podcastEntity: PodcastEntity = PodcastEntity(
                     name = podcast.name,
@@ -18,9 +20,32 @@ object DatabaseHelper {
                     remoteImageFileLocation = podcast.remoteImageFileLocation,
                     remotePodcastFeedLocation = podcast.remotePodcastFeedLocation
             )
-            list.add(podcastEntity)
+            podcastList.add(podcastEntity)
+
+            podcast.episodes.forEach { episode ->
+                val episodeEntity: EpisodeEntity = EpisodeEntity(
+                        podcastId = podcastEntity.pid,
+                        guid = episode.guid,
+                        title = episode.title,
+                        description = episode.description,
+                        audio = episode.audio,
+                        cover = episode.cover,
+                        smallCover = episode.smallCover,
+                        publicationDate = episode.publicationDate.time,
+                        playbackState = episode.playbackState,
+                        playbackPosition = episode.playbackPosition,
+                        duration = episode.duration,
+                        manuallyDownloaded = episode.manuallyDownloaded,
+                        manuallyDeleted = episode.manuallyDeleted,
+                        remoteCoverFileLocation = episode.remoteCoverFileLocation,
+                        remoteAudioFileLocation = episode.remoteAudioFileLocation
+                )
+                episodeList.add(episodeEntity)
+            }
+
+
         }
-        return list
+        return Pair(podcastList, episodeList)
     }
 
 }

app/src/main/java/org/y20k/escapepod/helpers/FileHelper.kt

@@ -181,23 +181,28 @@ object FileHelper {
     /* Saves podcast collection as JSON text file */
     fun saveCollection(context: Context, collection: Collection, lastSave: Date) {
         LogHelper.v(TAG, "Saving collection - Thread: ${Thread.currentThread().name}")
-        // convert to JSON
-        val gson: Gson = getCustomGson()
-        var json: String = String()
-        try {
-            json = gson.toJson(collection)
-        } catch (e: Exception) {
-            e.printStackTrace()
-        }
-        if (json.isNotBlank()) {
-            // save modification date
-            PreferencesHelper.saveCollectionModificationDate(context, lastSave)
-            // write text file
-            writeTextFile(context, json, Keys.FOLDER_COLLECTION, Keys.COLLECTION_FILE)
+        val collectionSize: Int = collection.podcasts.size
+        // do not override an existing collection with an empty one - except when last podcast is deleted
+        if (collectionSize > 0 || PreferencesHelper.loadCollectionSize(context) == 1) {
+            // convert to JSON
+            val gson: Gson = getCustomGson()
+            var json: String = String()
+            try {
+                json = gson.toJson(collection)
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+            if (json.isNotBlank()) {
+                // save modification date
+                PreferencesHelper.saveCollectionModificationDate(context, lastSave)
+                // write text file
+                writeTextFile(context, json, Keys.FOLDER_COLLECTION, Keys.COLLECTION_FILE)
+            }
+        } else {
+            LogHelper.w(TAG, "Not saving collection. Collection is empty.")
         }
     }
 
-
     /* Reads podcast collection from storage using GSON */
     fun readCollection(context: Context): Collection {
         LogHelper.v(TAG, "Reading collection - Thread: ${Thread.currentThread().name}")

app/src/main/java/org/y20k/escapepod/helpers/PreferencesHelper.kt

@@ -132,6 +132,22 @@ object PreferencesHelper {
     }
 
 
+    /* Loads size of collection from shared preferences */
+    fun loadCollectionSize(context: Context): Int {
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        return settings.getInt(Keys.PREF_COLLECTION_SIZE, -1)
+    }
+
+
+    /* Saves site of collection to shared preferences */
+    fun saveCollectionSize(context: Context, size: Int) {
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        editor.putInt(Keys.PREF_COLLECTION_SIZE, size)
+        editor.apply()
+    }
+
+
     /* Loads date of last save operation from shared preferences */
     fun loadCollectionModificationDate(context: Context): Date {
         val settings = PreferenceManager.getDefaultSharedPreferences(context)