fix(desktop): store preferences under Askimo home

desktop-shared/src/main/kotlin/io/askimo/ui/common/preferences/AccountPreferences.kt

@@ -5,50 +5,46 @@
 package io.askimo.ui.common.preferences
 
 import io.askimo.core.logging.logger
+import io.askimo.core.util.AskimoHome
 import java.time.Duration
 import java.time.LocalDate
 import java.time.LocalDateTime
 import java.time.format.DateTimeFormatter
-import java.util.prefs.Preferences
 
 /**
  * Per-account preferences scoped to a specific authenticated user.
  *
- * Stored under the Java Preferences path:
- *   `io/askimo/app/accounts/<accountId>/`
+ * Stored under `<AskimoHome>/prefs/accounts/<accountId>.properties`.
  *
  * Keeps sync cursors, default model, plan inputs, and user-behavior tracking
  * fully isolated between users on the same machine. These are NOT reset when
  * the user clears app preferences — they survive across settings resets.
  *
  * Obtain via [AccountPreferences.forAccount].
  */
-class AccountPreferences private constructor(private val prefs: Preferences) {
+class AccountPreferences private constructor(private val prefs: PropertyFilePreferences) {
 
     companion object {
-        private const val ROOT_NODE = "io/askimo/app/accounts"
-
         private const val MINIMUM_DAYS_BEFORE_PROMPT = 7L
         private const val MINIMUM_MESSAGES_BEFORE_PROMPT = 20
         private const val SNOOZE_DAYS = 30L
 
         /**
          * Returns [AccountPreferences] scoped to [accountId] (typically the user's email,
-         * lowercased and sanitized for use as a Preferences path segment).
-         * Safe to call multiple times — Preferences nodes are singletons per path.
+         * lowercased and sanitized for use as a file name).
          */
         fun forAccount(accountId: String): AccountPreferences {
             val safeId = accountId.trim().lowercase()
                 .replace(Regex("[^a-z0-9._@-]"), "_")
-            return AccountPreferences(Preferences.userRoot().node("$ROOT_NODE/$safeId"))
+            return AccountPreferences(PropertyFilePreferences(AskimoHome.base().resolve("prefs/accounts/$safeId.properties")))
         }
 
         /**
          * Returns a device-level (no account) [AccountPreferences] node for fields
          * that must persist even before the user logs in (e.g. first-use date,
          * launch count, analytics consent).
          */
-        fun device(): AccountPreferences = AccountPreferences(Preferences.userRoot().node("$ROOT_NODE/__device__"))
+        fun device(): AccountPreferences = AccountPreferences(PropertyFilePreferences(AskimoHome.base().resolve("prefs/accounts/__device__.properties")))
     }
 
     private val log = logger<AccountPreferences>()
@@ -61,26 +57,17 @@ class AccountPreferences private constructor(private val prefs: Preferences) {
         .onFailure { log.warn("AccountPreferences.get failed key='$key': ${it.message}") }
         .getOrDefault(default)
 
-    private fun safePutBoolean(key: String, value: Boolean) = runCatching { prefs.putBoolean(key, value) }
-        .onFailure { log.warn("AccountPreferences.putBoolean failed key='$key': ${it.message}") }
+    private fun safePutBoolean(key: String, value: Boolean) = safePut(key, value.toString())
 
-    private fun safeGetBoolean(key: String, default: Boolean): Boolean = runCatching { prefs.getBoolean(key, default) }
-        .onFailure { log.warn("AccountPreferences.getBoolean failed key='$key': ${it.message}") }
-        .getOrDefault(default)
+    private fun safeGetBoolean(key: String, default: Boolean): Boolean = safeGet(key, null)?.toBooleanStrictOrNull() ?: default
 
-    private fun safePutInt(key: String, value: Int) = runCatching { prefs.putInt(key, value) }
-        .onFailure { log.warn("AccountPreferences.putInt failed key='$key': ${it.message}") }
+    private fun safePutInt(key: String, value: Int) = safePut(key, value.toString())
 
-    private fun safeGetInt(key: String, default: Int): Int = runCatching { prefs.getInt(key, default) }
-        .onFailure { log.warn("AccountPreferences.getInt failed key='$key': ${it.message}") }
-        .getOrDefault(default)
+    private fun safeGetInt(key: String, default: Int): Int = safeGet(key, null)?.toIntOrNull() ?: default
 
-    private fun safePutLong(key: String, value: Long) = runCatching { prefs.putLong(key, value) }
-        .onFailure { log.warn("AccountPreferences.putLong failed key='$key': ${it.message}") }
+    private fun safePutLong(key: String, value: Long) = safePut(key, value.toString())
 
-    private fun safeGetLong(key: String, default: Long): Long = runCatching { prefs.getLong(key, default) }
-        .onFailure { log.warn("AccountPreferences.getLong failed key='$key': ${it.message}") }
-        .getOrDefault(default)
+    private fun safeGetLong(key: String, default: Long): Long = safeGet(key, null)?.toLongOrNull() ?: default
 
     // ── Conversation sync ─────────────────────────────────────────────────────
 
@@ -132,11 +119,7 @@ class AccountPreferences private constructor(private val prefs: Preferences) {
         }
         safePut(
             "plan.inputs.$planId",
-            if (raw.length > Preferences.MAX_VALUE_LENGTH) {
-                raw.substring(0, Preferences.MAX_VALUE_LENGTH)
-            } else {
-                raw
-            },
+            raw,
         )
     }
 

desktop-shared/src/main/kotlin/io/askimo/ui/common/preferences/ApplicationPreferences.kt

@@ -5,44 +5,38 @@
 package io.askimo.ui.common.preferences
 
 import io.askimo.core.logging.logger
-import java.util.prefs.Preferences
-import kotlin.jvm.java
+import io.askimo.core.util.AskimoHome
 
 /**
  * Resettable application preferences — UI layout, onboarding state, and device identity.
  */
 object ApplicationPreferences {
-    private val prefs = Preferences.userNodeForPackage(ApplicationPreferences::class.java)
     private val log = logger<ApplicationPreferences>()
 
+    private fun prefs() = PropertyFilePreferences(AskimoHome.base().resolve("prefs/app.properties"))
+
     // ── Safe preference accessors ─────────────────────────────────────────────
 
     private fun safePut(key: String, value: String) {
-        runCatching { prefs.put(key, value) }
+        runCatching { prefs().put(key, value) }
             .onFailure { log.warn("Preferences.put failed for key='$key': ${it.message}") }
     }
 
-    private fun safeGet(key: String, default: String?): String? = runCatching { prefs.get(key, default) }
+    private fun safeGet(key: String, default: String?): String? = runCatching { prefs().get(key, default) }
         .onFailure { log.warn("Preferences.get failed for key='$key': ${it.message}") }
         .getOrDefault(default)
 
     private fun safePutBoolean(key: String, value: Boolean) {
-        runCatching { prefs.putBoolean(key, value) }
-            .onFailure { log.warn("Preferences.putBoolean failed for key='$key': ${it.message}") }
+        safePut(key, value.toString())
     }
 
-    private fun safeGetBoolean(key: String, default: Boolean): Boolean = runCatching { prefs.getBoolean(key, default) }
-        .onFailure { log.warn("Preferences.getBoolean failed for key='$key': ${it.message}") }
-        .getOrDefault(default)
+    private fun safeGetBoolean(key: String, default: Boolean): Boolean = safeGet(key, null)?.toBooleanStrictOrNull() ?: default
 
     private fun safePutInt(key: String, value: Int) {
-        runCatching { prefs.putInt(key, value) }
-            .onFailure { log.warn("Preferences.putInt failed for key='$key': ${it.message}") }
+        safePut(key, value.toString())
     }
 
-    private fun safeGetInt(key: String, default: Int): Int = runCatching { prefs.getInt(key, default) }
-        .onFailure { log.warn("Preferences.getInt failed for key='$key': ${it.message}") }
-        .getOrDefault(default)
+    private fun safeGetInt(key: String, default: Int): Int = safeGet(key, null)?.toIntOrNull() ?: default
 
     // ============================================================
     // TUTORIAL & ONBOARDING  (resettable — re-shows on clearAll)
@@ -136,7 +130,7 @@ object ApplicationPreferences {
      * update dismissals) are stored in [AccountPreferences] and are NOT affected.
      */
     fun clearAll() {
-        runCatching { prefs.clear() }
+        runCatching { prefs().clear() }
             .onFailure { log.warn("Preferences.clear() failed: ${it.message}") }
         log.info("All resettable application preferences cleared")
     }

desktop-shared/src/main/kotlin/io/askimo/ui/common/preferences/PropertyFilePreferences.kt

@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: AGPLv3
+ *
+ * Copyright (c) 2026 Askimo
+ */
+package io.askimo.ui.common.preferences
+
+import java.nio.file.AtomicMoveNotSupportedException
+import java.nio.file.Files
+import java.nio.file.Path
+import java.nio.file.StandardCopyOption
+import java.util.Properties
+import java.util.concurrent.ConcurrentHashMap
+
+/** Small thread-safe preference store backed by a plain Java properties file. */
+internal class PropertyFilePreferences(private val path: Path) {
+    private val lock = locks.computeIfAbsent(path.toAbsolutePath().normalize()) { Any() }
+
+    fun get(key: String, default: String?): String? = synchronized(lock) {
+        load().getProperty(key, default)
+    }
+
+    fun put(key: String, value: String) = synchronized(lock) {
+        val properties = load()
+        properties.setProperty(key, value)
+        save(properties)
+    }
+
+    fun remove(key: String) = synchronized(lock) {
+        val properties = load()
+        properties.remove(key)
+        save(properties)
+    }
+
+    fun clear() = synchronized(lock) {
+        save(Properties())
+    }
+
+    private fun load(): Properties = Properties().also { properties ->
+        if (Files.isRegularFile(path)) {
+            Files.newInputStream(path).buffered().use(properties::load)
+        }
+    }
+
+    private fun save(properties: Properties) {
+        val parent = path.parent
+        Files.createDirectories(parent)
+        val temporary = Files.createTempFile(parent, ".${path.fileName}", ".tmp")
+        try {
+            Files.newOutputStream(temporary).buffered().use { output ->
+                properties.store(output, "Askimo preferences")
+            }
+            try {
+                Files.move(
+                    temporary,
+                    path,
+                    StandardCopyOption.ATOMIC_MOVE,
+                    StandardCopyOption.REPLACE_EXISTING,
+                )
+            } catch (_: AtomicMoveNotSupportedException) {
+                Files.move(temporary, path, StandardCopyOption.REPLACE_EXISTING)
+            }
+        } finally {
+            Files.deleteIfExists(temporary)
+        }
+    }
+
+    private companion object {
+        val locks = ConcurrentHashMap<Path, Any>()
+    }
+}

desktop-shared/src/test/kotlin/io/askimo/ui/common/preferences/PreferencesStorageTest.kt

@@ -0,0 +1,53 @@
+/* SPDX-License-Identifier: AGPLv3
+ *
+ * Copyright (c) 2026 Askimo
+ */
+package io.askimo.ui.common.preferences
+
+import io.askimo.core.util.AskimoHome
+import java.nio.file.Files
+import java.util.Properties
+import kotlin.io.path.inputStream
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class PreferencesStorageTest {
+    @Test
+    fun `application preferences use Askimo home property file`() {
+        val root = Files.createTempDirectory("askimo-app-prefs")
+
+        AskimoHome.withTestBase(root).use {
+            ApplicationPreferences.clearAll()
+            ApplicationPreferences.setProjectSidePanelWidth(512)
+
+            val file = AskimoHome.base().resolve("prefs/app.properties")
+            assertTrue(Files.isRegularFile(file))
+            assertEquals("512", load(file).getProperty("ui.project_side_panel_width"))
+            assertEquals(512, ApplicationPreferences.getProjectSidePanelWidth())
+        }
+    }
+
+    @Test
+    fun `account and device preferences use isolated property files`() {
+        val root = Files.createTempDirectory("askimo-account-prefs")
+
+        AskimoHome.withTestBase(root).use {
+            val account = AccountPreferences.forAccount("User Name@example.com")
+            account.saveLastSyncSeq(42)
+            AccountPreferences.device().setHardwareAccelerationEnabled(false)
+
+            val accountsDir = AskimoHome.base().resolve("prefs/accounts")
+            val accountFile = accountsDir.resolve("user_name@example.com.properties")
+            val deviceFile = accountsDir.resolve("__device__.properties")
+            assertEquals("42", load(accountFile).getProperty("sync.last_seq"))
+            assertEquals("false", load(deviceFile).getProperty("perf.hardware_acceleration_enabled"))
+            assertFalse(AccountPreferences.device().getHardwareAccelerationEnabled())
+        }
+    }
+
+    private fun load(path: java.nio.file.Path): Properties = Properties().also { properties ->
+        path.inputStream().use(properties::load)
+    }
+}