Warn if logout/delete would impact unsynced data

app/src/main/java/net/helcel/cowspent/android/account/AccountActivity.kt

@@ -109,8 +109,7 @@ class AccountActivity : AppCompatActivity() {
                                 viewModel.useSso = false
                                 preferences.edit { putBoolean(SETTINGS_USE_SSO, false) }
                             }
-                        },
+                        }
-                        onLogout = { viewModel.logout() }
                     )
                 }
 

app/src/main/java/net/helcel/cowspent/android/account/AccountScreen.kt

@@ -14,6 +14,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.input.PasswordVisualTransformation
@@ -28,8 +29,7 @@ fun AccountScreen(
     viewModel: AccountViewModel,
     onBack: () -> Unit,
     onConnect: () -> Unit,
-    onSsoClick: (Boolean) -> Unit,
+    onSsoClick: (Boolean) -> Unit
-    onLogout: () -> Unit
 ) {
     AccountScreenContent(
         isLoggedIn = viewModel.isLoggedIn,
@@ -51,7 +51,57 @@ fun AccountScreen(
         onBack = onBack,
         onConnect = onConnect,
         onSsoClick = onSsoClick,
-        onLogout = onLogout
+        onLogout = { viewModel.requestLogout() }
+    )
+
+    viewModel.logoutImpact?.let { impact ->
+        LogoutConfirmationDialog(
+            impact = impact,
+            onDismiss = { viewModel.cancelLogout() },
+            onConfirm = { viewModel.confirmLogout() }
+        )
+    }
+}
+
+@Composable
+fun LogoutConfirmationDialog(
+    impact: AccountViewModel.LogoutImpact,
+    onDismiss: () -> Unit,
+    onConfirm: () -> Unit
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.logout_confirm_title)) },
+        text = {
+            Column {
+                Text(
+                    if (impact.projects > 0) {
+                        pluralStringResource(
+                            R.plurals.logout_confirm_projects, impact.projects, impact.projects
+                        )
+                    } else {
+                        stringResource(R.string.logout_confirm_no_projects)
+                    }
+                )
+                if (impact.unsyncedBills > 0) {
+                    Spacer(Modifier.height(12.dp))
+                    Text(
+                        text = pluralStringResource(
+                            R.plurals.warning_unsynced_bills,
+                            impact.unsyncedBills,
+                            impact.unsyncedBills
+                        ),
+                        fontWeight = FontWeight.Bold
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onConfirm) { Text(stringResource(R.string.action_logout)) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.simple_cancel)) }
+        }
     )
 }
 

app/src/main/java/net/helcel/cowspent/android/account/AccountViewModel.kt

@@ -6,6 +6,7 @@ import android.util.Log
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
+import androidx.annotation.VisibleForTesting
 import androidx.core.content.edit
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
@@ -13,11 +14,17 @@ import androidx.preference.PreferenceManager
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import net.helcel.cowspent.model.DBProject
 import net.helcel.cowspent.persistence.CowspentSQLiteOpenHelper
 import net.helcel.cowspent.util.CospendClientUtil
 import net.helcel.cowspent.util.SecureStorage
 
 class AccountViewModel(application: Application) : AndroidViewModel(application) {
+
+    private companion object {
+        const val TAG = "AccountViewModel"
+    }
+
     private val preferences: SharedPreferences = PreferenceManager.getDefaultSharedPreferences(application)
 
     var useSso by mutableStateOf(preferences.getBoolean(AccountActivity.SETTINGS_USE_SSO, false))
@@ -43,6 +50,9 @@ class AccountViewModel(application: Application) : AndroidViewModel(application)
     var showWebView by mutableStateOf(false)
 
     var isLoggedIn by mutableStateOf(false)
+
+    /** Non-null while the logout confirmation is up, carrying what it would cost. */
+    var logoutImpact by mutableStateOf<LogoutImpact?>(null)
         private set
 
     var isValidatingLogin by mutableStateOf(false)
@@ -90,25 +100,60 @@ class AccountViewModel(application: Application) : AndroidViewModel(application)
         }
     }
 
-    private fun forgetProjectsTheAccountProvided() {
+    private fun projectsTheAccountProvided(db: CowspentSQLiteOpenHelper): List<DBProject> {
-        try {
-            val db = CowspentSQLiteOpenHelper.getInstance(getApplication())
         val offered = db.accountProjects
         val cospendPath = "/index.php/apps/cospend"
-            for (project in db.projects) {
+        return db.projects.filter { project ->
-                val matches = offered.any {
+            offered.any {
                 it.remoteId == project.remoteId &&
                         project.serverUrl?.replace("/+$".toRegex(), "") ==
                         it.ncUrl.replace("/+$".toRegex(), "") + cospendPath
             }
-                if (matches) db.deleteProject(project.id)
         }
-            db.clearAccountProjects()
+    }
+    data class LogoutImpact(val projects: Int, val unsyncedBills: Int)
+
+    private fun measureLogoutImpact(): LogoutImpact {
+        val db = CowspentSQLiteOpenHelper.getInstance(getApplication())
+        val projects = projectsTheAccountProvided(db)
+        val unsynced = projects.sumOf { db.countUnsyncedBills(it.id) }
+        return LogoutImpact(projects.size, unsynced)
+    }
+
+    fun requestLogout() {
+        viewModelScope.launch {
+            logoutImpact = withContext(Dispatchers.IO) {
+                try {
+                    measureLogoutImpact()
                 } catch (e: Exception) {
-            Log.e("AccountViewModel", "Could not remove the account's projects on logout", e)
+                    // Never let a failed count block signing out - just ask without the detail.
+                    Log.e(TAG, "Could not measure what logging out would remove", e)
+                    LogoutImpact(0, 0)
+                }
+            }
         }
     }
 
+    fun cancelLogout() {
+        logoutImpact = null
+    }
+
+    fun confirmLogout() {
+        logoutImpact = null
+        logout()
+    }
+
+    private fun forgetProjectsTheAccountProvided() {
+        try {
+            val db = CowspentSQLiteOpenHelper.getInstance(getApplication())
+            projectsTheAccountProvided(db).forEach { db.deleteProject(it.id) }
+            db.clearAccountProjects()
+        } catch (e: Exception) {
+            Log.e(TAG, "Could not remove the account's projects on logout", e)
+        }
+    }
+
+    @VisibleForTesting
     fun logout() {
         viewModelScope.launch {
             withContext(Dispatchers.IO) { forgetProjectsTheAccountProvided() }

app/src/main/java/net/helcel/cowspent/android/main/BillsListViewActivity.kt

@@ -408,11 +408,26 @@ class BillsListViewActivity :
     private fun onRemoveProjectClick(projectId: Long) {
         if (projectId == 0L) return
         lifecycleScope.launch {
-            val proj = withContext(Dispatchers.IO) { db.getProject(projectId) } ?: return@launch
+            val (proj, unsyncedBills) = withContext(Dispatchers.IO) {
+                val p = db.getProject(projectId) ?: return@withContext null
+                p to db.countUnsyncedBills(projectId)
+            } ?: return@launch
+
+            val message = buildString {
+                if (!proj.isLocal) append(getString(R.string.dialog_confirm_remove_project_msg))
+                if (unsyncedBills > 0) {
+                    if (isNotEmpty()) append("\n\n")
+                    append(
+                        resources.getQuantityString(
+                            R.plurals.warning_unsynced_bills, unsyncedBills, unsyncedBills
+                        )
+                    )
+                }
+            }
 
             viewModel.showDialog(
                 title = getString(R.string.title_confirm),
-                message = if (!proj.isLocal) getString(R.string.dialog_confirm_remove_project_msg) else null,
+                message = message.ifEmpty { null },
                 positiveText = getString(R.string.simple_yes),
                 onConfirm = {
                     lifecycleScope.launch {

app/src/main/java/net/helcel/cowspent/persistence/CowspentSQLiteOpenHelper.kt

@@ -4,6 +4,7 @@ import android.annotation.SuppressLint
 import android.content.ContentValues
 import android.content.Context
 import android.database.Cursor
+import android.database.DatabaseUtils
 import android.database.sqlite.SQLiteDatabase
 import android.database.sqlite.SQLiteOpenHelper
 import android.text.TextUtils
@@ -554,6 +555,14 @@ class CowspentSQLiteOpenHelper private constructor(val context: Context) :
         return getBillsCustom("$key_projectid = ?", arrayOf(projId.toString()), "$key_timestamp ASC")
     }
     
+    @WorkerThread
+    fun countUnsyncedBills(projId: Long): Int = DatabaseUtils.queryNumEntries(
+        readableDatabase,
+        table_bills,
+        "$key_projectid = ? AND $key_state != ?",
+        arrayOf(projId.toString(), DBBill.STATE_OK.toString())
+    ).toInt()
+
     fun getBillsOfProjectWithState(projId: Long, state: Int): List<DBBill> {
         return getBillsCustom(
             "$key_projectid = ? AND $key_state = ?",

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

@@ -25,6 +25,8 @@
     <string name="action_settings">Settings</string>
     <string name="action_label_bills">Label missing categories</string>
     <string name="action_logout">Logout</string>
+    <string name="logout_confirm_title">Log out?</string>
+    <string name="logout_confirm_no_projects">You can sign back in at any time.</string>
     <string name="action_connect">Connect</string>
     <string name="action_discard">Discard</string>
     <string name="action_members">Members</string>
@@ -299,4 +301,14 @@
         <item quantity="one">%d project the account offers is kept off this device.</item>
         <item quantity="other">%d projects the account offers are kept off this device.</item>
     </plurals>
+
+    <plurals name="logout_confirm_projects">
+        <item quantity="one">%d project from this account will be removed from this device. It comes back when you sign in again.</item>
+        <item quantity="other">%d projects from this account will be removed from this device. They come back when you sign in again.</item>
+    </plurals>
+
+    <plurals name="warning_unsynced_bills">
+        <item quantity="one">%d bill has not reached the server yet and will be lost.</item>
+        <item quantity="other">%d bills have not reached the server yet and will be lost.</item>
+    </plurals>
 </resources>