demo: add user settings repository

demo/android/src/main/kotlin/im/molly/monero/demo/data/SettingsRepository.kt

@@ -0,0 +1,34 @@
+package im.molly.monero.demo.data
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.stringPreferencesKey
+import im.molly.monero.demo.data.model.SocksProxy
+import im.molly.monero.demo.data.model.UserSettings
+import im.molly.monero.demo.data.model.toSocketAddress
+import kotlinx.coroutines.flow.map
+
+class SettingsRepository(
+    private val dataStore: DataStore<Preferences>,
+) {
+    companion object {
+        val PREF_SOCKS_PROXY = stringPreferencesKey("socks_proxy")
+    }
+
+    fun getUserSettings() = dataStore.data.map { prefs ->
+        UserSettings(
+            socksProxy = prefs[PREF_SOCKS_PROXY]?.let { SocksProxy(it.toSocketAddress()) }
+        )
+    }
+
+    suspend fun setSocksProxy(socksProxy: SocksProxy?) {
+        dataStore.edit { prefs ->
+            if (socksProxy != null) {
+                prefs[PREF_SOCKS_PROXY] = socksProxy.address().toString()
+            } else {
+                prefs.remove(PREF_SOCKS_PROXY)
+            }
+        }
+    }
+}

demo/android/src/main/kotlin/im/molly/monero/demo/data/model/SocksProxy.kt

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+package im.molly.monero.demo.data.model
+
+import java.net.InetSocketAddress
+import java.net.Proxy
+import java.net.SocketAddress
+
+data class SocksProxy(val socketAddress: SocketAddress) : Proxy(Type.SOCKS, socketAddress)
+
+fun String.toSocketAddress(): SocketAddress =
+    try {
+        val index = lastIndexOf(':')
+        val host = substring(0, index)
+        val port = substring(index + 1).toInt()
+        InetSocketAddress.createUnresolved(host, port)
+    } catch (t: IndexOutOfBoundsException) {
+        throw IllegalArgumentException()
+    }

demo/android/src/main/kotlin/im/molly/monero/demo/data/model/UserSettings.kt

@@ -0,0 +1,9 @@
+package im.molly.monero.demo.data.model
+
+import java.net.Proxy
+
+data class UserSettings(
+    val socksProxy: SocksProxy?,
+) {
+    val activeProxy: Proxy = socksProxy ?: Proxy.NO_PROXY
+}