feat: add automated CSV folder sync and guide screen

app/src/main/AndroidManifest.xml

@@ -71,6 +71,11 @@
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <intent-filter>
+                <action android:name="com.serranoie.app.minus.action.SYNC_NOW" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
         </activity>
 
         <service

app/src/main/java/com/serranoie/app/minus/MinusApplication.kt

@@ -3,6 +3,7 @@ package com.serranoie.app.minus
 import android.app.Application
 import androidx.hilt.work.HiltWorkerFactory
 import androidx.work.Configuration
+import com.serranoie.app.minus.data.csv.CsvSyncWorker
 import com.serranoie.app.minus.domain.usecase.BackfillOrphanedPeriodsUseCase
 import com.serranoie.app.minus.domain.usecase.FoldCarryIntoTotalBudgetUseCase
 import com.serranoie.app.minus.wearsync.PhoneWearMessageListener
@@ -40,6 +41,8 @@ class MinusApplication : Application(), Configuration.Provider {
 
         phoneWearMessageListener.start()
 
+        CsvSyncWorker.schedule(this)
+
         CoroutineScope(Dispatchers.IO).launch {
             backfillOrphanedPeriodsUseCase()
             foldCarryIntoTotalBudgetUseCase()

app/src/main/java/com/serranoie/app/minus/data/csv/CsvModels.kt

@@ -20,7 +20,8 @@ data class CsvTransactionRow(
     val subscriptionDay: Int?,
     val isCredit: Boolean,
     val isCreditPaid: Boolean,
-    val periodId: Long
+    val periodId: Long,
+    val createdAt: Long? = null
 )
 
 data class CsvBackupMetadata(
@@ -57,7 +58,8 @@ fun CsvTransactionRow.toDomainTransaction(categoryId: Long? = null): Transaction
         subscriptionDay = subscriptionDay,
         categoryId = categoryId,
         isCredit = isCredit,
-        isCreditPaid = isCreditPaid
+        isCreditPaid = isCreditPaid,
+        createdAt = createdAt ?: System.currentTimeMillis()
     )
 }
 

app/src/main/java/com/serranoie/app/minus/data/csv/CsvSyncWorker.kt

@@ -0,0 +1,302 @@
+package com.serranoie.app.minus.data.csv
+
+import android.content.ContentResolver
+import android.content.Context
+import android.net.Uri
+import android.provider.DocumentsContract
+import androidx.core.net.toUri
+import androidx.hilt.work.HiltWorker
+import androidx.work.CoroutineWorker
+import androidx.work.ExistingPeriodicWorkPolicy
+import androidx.work.ExistingWorkPolicy
+import androidx.work.OneTimeWorkRequestBuilder
+import androidx.work.PeriodicWorkRequestBuilder
+import androidx.work.WorkManager
+import androidx.work.WorkerParameters
+import com.serranoie.app.minus.data.repository.SettingsRepository
+import com.serranoie.app.minus.presentation.util.ErrorLogRecorder
+import dagger.assisted.Assisted
+import dagger.assisted.AssistedInject
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import java.time.LocalDateTime
+import java.time.format.DateTimeFormatter
+import java.util.concurrent.TimeUnit
+
+@HiltWorker
+class CsvSyncWorker @AssistedInject constructor(
+    @Assisted context: Context,
+    @Assisted params: WorkerParameters,
+    private val csvService: MinusCsvService,
+    private val settingsRepository: SettingsRepository,
+    private val errorLogRecorder: ErrorLogRecorder,
+) : CoroutineWorker(context, params) {
+
+    override suspend fun doWork(): Result = syncMutex.withLock { runSync() }
+
+    private suspend fun runSync(): Result {
+        val folder = settingsRepository.getString(SYNC_FOLDER_URI_KEY)
+            ?.ifBlank { null }
+            ?.toUri()
+            ?: return Result.success()
+
+        val resolver = applicationContext.contentResolver
+
+        return try {
+            val listing = childDocuments(folder)
+                ?: error("Could not list the sync folder")
+            val children = migrateLegacyMirror(resolver, folder, listing)
+
+            val restored = restoreFromMirror(resolver, children)
+            if (restored != null && restored.imported > 0) {
+                recordStatus(STATUS_RESTORED)
+                return Result.success()
+            }
+            if (restored != null && restored.errors.isNotEmpty()) {
+                recordStatus(STATUS_REJECTED, EXPORT_FILE_NAME)
+                return Result.success()
+            }
+
+            val outcome = ingest(resolver, children)
+            writeMirror(resolver, folder, children)
+
+            when {
+                outcome.rejectedFiles.isNotEmpty() -> recordStatus(
+                    STATUS_REJECTED,
+                    outcome.rejectedFiles.joinToString(", ")
+                )
+
+                else -> recordStatus(STATUS_OK, outcome.imported.toString())
+            }
+            Result.success()
+        } catch (e: CancellationException) {
+            throw e
+        } catch (e: SecurityException) {
+            settingsRepository.setString(SYNC_FOLDER_URI_KEY, "")
+            recordStatus(STATUS_NO_ACCESS)
+            errorLogRecorder.record("CsvSyncWorker.doWork", e)
+            Result.failure()
+        } catch (e: Exception) {
+            recordStatus(STATUS_ERROR, e.message.orEmpty())
+            errorLogRecorder.record("CsvSyncWorker.doWork", e)
+            Result.retry()
+        }
+    }
+
+    private fun migrateLegacyMirror(
+        resolver: ContentResolver,
+        folder: Uri,
+        children: List<Pair<Uri, String>>,
+    ): List<Pair<Uri, String>> {
+        if (children.any { (_, name) -> name == EXPORT_FILE_NAME }) return children
+
+        val legacy = children.firstOrNull { (_, name) -> name == LEGACY_EXPORT_FILE_NAME }?.first
+            ?: return children
+
+        DocumentsContract.renameDocument(resolver, legacy, EXPORT_FILE_NAME)
+            ?: error("Could not rename $LEGACY_EXPORT_FILE_NAME to $EXPORT_FILE_NAME")
+
+        return childDocuments(folder) ?: error("Could not list the sync folder")
+    }
+
+    private suspend fun restoreFromMirror(
+        resolver: ContentResolver,
+        children: List<Pair<Uri, String>>,
+    ): CsvImportResult? {
+        val mirror = children.firstOrNull { (_, name) -> name == EXPORT_FILE_NAME }?.first
+            ?: return null
+        if (!csvService.hasNoLocalData()) return null
+
+        return resolver.openInputStream(mirror)?.use { csvService.importTransactions(it) }
+            ?: error("Could not open $EXPORT_FILE_NAME for reading")
+    }
+
+    private suspend fun ingest(
+        resolver: ContentResolver,
+        children: List<Pair<Uri, String>>,
+    ): IngestOutcome {
+        var imported = 0
+        val rejected = mutableListOf<String>()
+
+        children.filter { (_, name) -> isIngestCandidate(name) }
+            .forEach { (document, name) ->
+                val claimed = DocumentsContract.renameDocument(
+                    resolver,
+                    document,
+                    name + SUFFIX_IN_PROGRESS
+                ) ?: error("Could not claim $name for import")
+
+                val result = try {
+                    resolver.openInputStream(claimed)?.use { csvService.importTransactions(it) }
+                        ?: error("Could not open $name for reading")
+                } catch (cancellation: CancellationException) {
+                    throw cancellation
+                } catch (failure: Exception) {
+                    DocumentsContract.renameDocument(resolver, claimed, name + SUFFIX_REJECTED)
+                    throw failure
+                }
+
+                imported += result.imported
+                val settledName = if (result.errors.isEmpty()) {
+                    name + SUFFIX_IMPORTED
+                } else {
+                    rejected += name
+                    name + SUFFIX_REJECTED
+                }
+
+                DocumentsContract.renameDocument(resolver, claimed, settledName)
+                    ?: error("Imported $name but could not mark it as processed")
+            }
+
+        return IngestOutcome(imported, rejected)
+    }
+
+    private suspend fun writeMirror(
+        resolver: ContentResolver,
+        folder: Uri,
+        children: List<Pair<Uri, String>>,
+    ) {
+        val treeDocument = DocumentsContract.buildDocumentUriUsingTree(
+            folder,
+            DocumentsContract.getTreeDocumentId(folder)
+        )
+
+        val staging = children.firstOrNull { (_, name) -> name == STAGING_FILE_NAME }?.first
+            ?: DocumentsContract.createDocument(
+                resolver,
+                treeDocument,
+                MIME_TYPE_CSV,
+                STAGING_FILE_NAME
+            )
+            ?: error("Could not create $STAGING_FILE_NAME in the sync folder")
+
+        resolver.openOutputStream(staging, "wt")?.use { output ->
+            csvService.exportAllTransactions(output)
+        } ?: error("Could not open $STAGING_FILE_NAME for writing")
+
+        children.firstOrNull { (_, name) -> name == EXPORT_FILE_NAME }?.first?.let { previous ->
+            val stamp = LocalDateTime.now().format(BACKUP_STAMP)
+            DocumentsContract.renameDocument(resolver, previous, "$BACKUP_PREFIX$stamp.csv")
+                ?: error("Could not rotate the previous $EXPORT_FILE_NAME")
+        }
+
+        DocumentsContract.renameDocument(resolver, staging, EXPORT_FILE_NAME)
+            ?: error("Exported data but could not publish it as $EXPORT_FILE_NAME")
+
+        pruneBackups(resolver, folder)
+    }
+
+    private fun pruneBackups(resolver: ContentResolver, folder: Uri) {
+        val backups = childDocuments(folder)
+            ?.filter { (_, name) -> isRotatedBackup(name) }
+            ?.sortedByDescending { (_, name) -> name }
+            ?: return
+
+        backups.drop(BACKUPS_KEPT).forEach { (document, _) ->
+            runCatching { DocumentsContract.deleteDocument(resolver, document) }
+        }
+    }
+
+    private suspend fun recordStatus(code: String, detail: String = "") {
+        settingsRepository.setString(
+            SYNC_STATUS_KEY,
+            listOf(code, System.currentTimeMillis().toString(), detail)
+                .joinToString(STATUS_SEPARATOR)
+        )
+    }
+
+    private fun childDocuments(folder: Uri): List<Pair<Uri, String>>? {
+        val children = DocumentsContract.buildChildDocumentsUriUsingTree(
+            folder,
+            DocumentsContract.getTreeDocumentId(folder)
+        )
+
+        return applicationContext.contentResolver.query(
+            children,
+            arrayOf(
+                DocumentsContract.Document.COLUMN_DOCUMENT_ID,
+                DocumentsContract.Document.COLUMN_DISPLAY_NAME,
+            ),
+            null,
+            null,
+            null
+        )?.use { cursor ->
+            buildList {
+                while (cursor.moveToNext()) {
+                    val documentId = cursor.getString(0) ?: continue
+                    val displayName = cursor.getString(1) ?: continue
+                    add(
+                        DocumentsContract.buildDocumentUriUsingTree(folder, documentId)
+                                to displayName
+                    )
+                }
+            }
+        }
+    }
+
+    private data class IngestOutcome(
+        val imported: Int,
+        val rejectedFiles: List<String>,
+    )
+
+    companion object {
+        const val SYNC_FOLDER_URI_KEY = "sync_folder_uri"
+        const val SYNC_STATUS_KEY = "sync_last_status"
+        const val EXPORT_FILE_NAME = "minus_synced.csv"
+        const val STAGING_FILE_NAME = "minus_synced.csv.writing"
+        const val LEGACY_EXPORT_FILE_NAME = "minus_latest.csv"
+        const val UNIQUE_WORK_NAME = "csv_folder_sync"
+        const val IMMEDIATE_WORK_NAME = "csv_folder_sync_now"
+        const val ACTION_SYNC_NOW = "com.serranoie.app.minus.action.SYNC_NOW"
+        const val SYNC_INTERVAL_HOURS = 2L
+
+        const val STATUS_SEPARATOR = "|"
+        const val STATUS_OK = "ok"
+        const val STATUS_RESTORED = "restored"
+        const val STATUS_REJECTED = "rejected"
+        const val STATUS_ERROR = "error"
+        const val STATUS_NO_ACCESS = "no_access"
+
+        const val IMPORT_PREFIX = "minus_import_"
+        const val BACKUP_PREFIX = "minus_backup-"
+        const val BACKUPS_KEPT = 5
+        const val SUFFIX_IN_PROGRESS = ".importing"
+        const val SUFFIX_IMPORTED = ".imported"
+        const val SUFFIX_REJECTED = ".rejected"
+
+        private const val MIME_TYPE_CSV = "text/csv"
+        private val BACKUP_STAMP = DateTimeFormatter.ofPattern("yyyyMMdd-HHmmss")
+
+        private val syncMutex = Mutex()
+
+        fun isIngestCandidate(displayName: String): Boolean {
+            return displayName.startsWith(IMPORT_PREFIX, ignoreCase = true) &&
+                    displayName.endsWith(".csv", ignoreCase = true)
+        }
+
+        fun isRotatedBackup(displayName: String): Boolean {
+            return displayName.startsWith(BACKUP_PREFIX, ignoreCase = true) &&
+                    displayName.endsWith(".csv", ignoreCase = true)
+        }
+
+        fun schedule(context: Context) {
+            WorkManager.getInstance(context).enqueueUniquePeriodicWork(
+                UNIQUE_WORK_NAME,
+                ExistingPeriodicWorkPolicy.KEEP,
+                PeriodicWorkRequestBuilder<CsvSyncWorker>(
+                    SYNC_INTERVAL_HOURS,
+                    TimeUnit.HOURS
+                ).build()
+            )
+        }
+
+        fun syncNow(context: Context) {
+            WorkManager.getInstance(context).enqueueUniqueWork(
+                IMMEDIATE_WORK_NAME,
+                ExistingWorkPolicy.KEEP,
+                OneTimeWorkRequestBuilder<CsvSyncWorker>().build()
+            )
+        }
+    }
+}

app/src/main/java/com/serranoie/app/minus/data/csv/MinusCsvParser.kt

@@ -125,6 +125,7 @@ class MinusCsvParser {
             isCredit = isCredit,
             isCreditPaid = isCreditPaid,
             periodId = periodId,
+            createdAt = raw.valueOf(MinusCsvContract.COL_CREATED_AT).toLongOrNull(),
         )
     }
 
@@ -187,9 +188,9 @@ class MinusCsvParser {
                 try {
                     BudgetSplitMode.valueOf(it)
                 } catch (_: Exception) {
-                    BudgetSplitMode.STATIC
+                    BudgetSplitMode.DYNAMIC
                 }
-            } ?: BudgetSplitMode.STATIC
+            } ?: BudgetSplitMode.DYNAMIC
 
         return CsvBackupMetadata(
             budgetSettings = BudgetSettings(

app/src/main/java/com/serranoie/app/minus/data/csv/MinusCsvService.kt

@@ -49,6 +49,11 @@ class MinusCsvService @Inject constructor(
         exporter.export(transactions, archivedBudgets, metadata, outputStream)
     }
 
+    suspend fun hasNoLocalData(): Boolean {
+        return repository.getBudgetSettingsSync() == null &&
+                repository.getRecentTransactions(1).isEmpty()
+    }
+
     suspend fun importTransactions(inputStream: InputStream): CsvImportResult {
         val payload = parser.parse(inputStream)
         val rows = payload.rows

app/src/main/java/com/serranoie/app/minus/data/repository/SettingsRepository.kt

@@ -118,6 +118,8 @@ interface SettingsRepository {
 
     suspend fun resetTutorials()
 
+    fun observeString(key: String): Flow<String?>
+
     suspend fun getString(key: String): String?
 
     suspend fun setString(key: String, value: String)