Added utility class to export and share database's data

radar-commons-android/src/main/java/org/radarbase/android/storage/extract/DatabaseToCSVExtractor.kt

@@ -0,0 +1,154 @@
+package org.radarbase.android.storage.extract
+
+import android.content.Context
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.supervisorScope
+import kotlinx.coroutines.withContext
+import org.radarbase.android.storage.dao.NetworkStatusDao
+import org.radarbase.android.storage.dao.SourceStatusDao
+import org.radarbase.android.storage.db.RadarApplicationDatabase
+import org.radarbase.android.storage.entity.NetworkStatusLog
+import org.radarbase.android.storage.entity.SourceStatusLog
+import org.slf4j.Logger
+import org.slf4j.LoggerFactory
+import java.io.File
+
+@Suppress("unused")
+class DatabaseToCSVExtractor {
+    private var database: RadarApplicationDatabase? = null
+    private var sourceStatusDao: SourceStatusDao? = null
+    private var networkStatusDao: NetworkStatusDao? = null
+    private var exportsDir: File? = null
+
+    fun initialize(context: Context) {
+        database = RadarApplicationDatabase.getInstance(context).also {
+            this.sourceStatusDao = it.sourceStatusDao()
+            this.networkStatusDao = it.networkStatusDao()
+        }
+        prepareExportDirectory(context)
+    }
+
+    @Throws(IllegalStateException::class)
+    suspend fun exportEntities() {
+        val sDao = sourceStatusDao
+        val nDao = networkStatusDao
+        check(sDao != null && nDao != null) { "Data Access Objects are not initialized yet." }
+
+        clearExportDirectoryFiles()
+        supervisorScope {
+            launch {
+                exportSourceEntitiesToCsvFile(
+                    withContext(Dispatchers.IO) {
+                        sDao.loadAllStatuses()
+                    }
+                )
+            }
+            launch {
+                exportNetworkEntitiesToCSVFile(
+                    withContext(Dispatchers.IO) {
+                        nDao.loadAllNetworkLogs()
+                    }
+                )
+            }
+        }
+    }
+
+    /**
+     * Exports the given list of SourceStatusLog entities directly to a CSV file using
+     * a buffered stream, which minimizes memory overhead.
+     *
+     * @param sourceEntities List of [SourceStatusLog] objects to export.
+     */
+    private fun exportSourceEntitiesToCsvFile(sourceEntities: List<SourceStatusLog>) {
+        val sourceStatusFile = SOURCE_STATUS_FILE
+        val file = File(exportsDir, sourceStatusFile)
+
+        file.bufferedWriter().use { writer ->
+            writer.write("id,time,plugin,source_status")
+            writer.newLine()
+
+            sourceEntities.forEach { entity ->
+                writer.write(
+                    buildString {
+                        append(entity.id)
+                        append(',')
+                        append(entity.time)
+                        append(',')
+                        append(entity.plugin)
+                        append(',')
+                        append(entity.sourceStatus)
+                    }
+                )
+                writer.newLine()
+            }
+        }
+        logger.info("Source CSV file exported to: ${file.absolutePath}")
+    }
+
+    /**
+     * Exports the given list of NetworkStatusLog entities directly to a CSV file using
+     * a buffered stream, which minimizes memory overhead.
+     *
+     * @param networkEntities List of [NetworkStatusLog] objects to export.
+     */
+    private fun exportNetworkEntitiesToCSVFile(networkEntities: List<NetworkStatusLog>) {
+        val networkStatusFile = NETWORK_STATUS_FILE
+        val file = File(exportsDir, networkStatusFile)
+
+        file.bufferedWriter().use { writer ->
+            writer.write("id,time,connectionStatus")
+            writer.newLine()
+
+            networkEntities.forEach { entity ->
+                writer.write(
+                    buildString {
+                        append(entity.id)
+                        append(',')
+                        append(entity.time)
+                        append(',')
+                        append(entity.connectionStatus)
+                    }
+                )
+                writer.newLine()
+            }
+        }
+        logger.info("Network CSV file exported to: ${file.absolutePath}")
+    }
+
+    /**
+     * Prepares the export directory within the internal cache directory.
+     */
+    private fun prepareExportDirectory(context: Context) {
+        val internalDir: File = context.filesDir
+        exportsDir = File(internalDir, APPLICATION_PLUGIN_EXPORT_PATH).also {
+            if (!it.exists()) {
+                it.mkdirs()
+            }
+        }
+    }
+
+    private fun clearExportDirectoryFiles() {
+        exportsDir?.let { exports ->
+            exports.listFiles { file ->
+                file.name.startsWith(FILE_NAME_PREFIX) && file.name.endsWith(FILE_EXTENSION)
+            }?.forEach { file ->
+                if (file.delete()) {
+                    logger.info("Deleted file: ${file.name}")
+                } else {
+                    logger.warn("Failed to delete file: ${file.name}")
+                }
+            }
+        }
+    }
+
+    companion object {
+        private val logger: Logger = LoggerFactory.getLogger(DatabaseToCSVExtractor::class.java)
+
+        private const val FILE_NAME_PREFIX = "application_status_"
+        private const val FILE_EXTENSION = ".csv"
+        private const val SOURCE_STATUS_FILE = "${FILE_NAME_PREFIX}source${FILE_EXTENSION}"
+        private const val NETWORK_STATUS_FILE = "${FILE_NAME_PREFIX}network${FILE_EXTENSION}"
+        private const val APPLICATION_PLUGIN_EXPORT_PATH = "org.radarbase.monitor.application.exports"
+    }
+}