PairedDeviceStore.kt

1package com.peachpasswords.sync23import android.content.Context4import androidx.security.crypto.EncryptedSharedPreferences5import androidx.security.crypto.MasterKey6import dagger.hilt.android.qualifiers.ApplicationContext7import kotlinx.coroutines.channels.awaitClose8import kotlinx.coroutines.flow.Flow9import kotlinx.coroutines.flow.callbackFlow10import kotlinx.serialization.builtins.ListSerializer11import kotlinx.serialization.json.Json12import javax.inject.Inject13import javax.inject.Singleton1415/**16 * Persistent registry of paired devices, encrypted at rest with17 * EncryptedSharedPreferences (same construction as DuressConfigStore /18 * LicenseRepository, v2.1.36). The whole list lives under a single key as a19 * kotlinx.serialization JSON array of the REAL [PairedDevice] (sync package).20 *21 * Reconciliation with the C7 brief:22 *  - The brief invents a fresh `PairedDevice(id, name, publicKey: ByteArray,23 *    lastSeen, trustStatus, lastSyncAt)`. That type does NOT exist in this24 *    shape. The real [PairedDevice] (PairedDevice.kt) keys on `deviceId`, holds25 *    the public key as `longTermPublicKeyHex` (hex, not ByteArray), and tracks26 *    `pairedAt` / `lastSyncedAt` / `lastKnownIp`. This store reuses it verbatim;27 *    Base64 publicKey storage is therefore unnecessary — the hex field is the28 *    canonical wire form already produced by ChirpPairing.frameToPairedDevice.29 *  - The brief's `TrustStatus` enum does not exist either. The real model uses a30 *    nullable `trustSource: String?` (e.g. "direct", "manifest"). Trust state is31 *    expressed there. See C7-INTEGRATION.md for the trust-status delta.32 *  - `updateLastSync` here maps to the real `lastSyncedAt` field. There is no33 *    `lastSeen` field on the real PairedDevice; [updateLastSeen] folds into34 *    `lastKnownIp` refresh + `lastSyncedAt` is left untouched. It is kept as a35 *    no-op-friendly hook so callers from the brief compile; see integration note.36 */37@Singleton38class PairedDeviceStore @Inject constructor(39    @ApplicationContext context: Context,40) : PairedDeviceRegistry {41    private val masterKey = MasterKey.Builder(context)42        .setKeyScheme(MasterKey.KeyScheme.AES256_GCM)43        .build()4445    private val prefs = EncryptedSharedPreferences.create(46        context,47        PREFS_FILE,48        masterKey,49        EncryptedSharedPreferences.PrefKeyEncryptionScheme.AES256_SIV,50        EncryptedSharedPreferences.PrefValueEncryptionScheme.AES256_GCM,51    )5253    private val listSerializer = ListSerializer(PairedDevice.serializer())54    private val revocationSerializer = ListSerializer(DeviceRevocation.serializer())5556    override fun getAll(): List<PairedDevice> {57        val raw = prefs.getString(KEY_DEVICES, null) ?: return emptyList()58        return runCatching { json.decodeFromString(listSerializer, raw) }.getOrDefault(emptyList())59    }6061    override fun get(id: String): PairedDevice? = getAll().firstOrNull { it.deviceId == id }6263    override fun getByPubkey(pubkeyHex: String): PairedDevice? =64        getAll().firstOrNull {65            it.longTermPublicKeyHex?.let { key -> CryptoCompare.hex(key, pubkeyHex) } == true66        }6768    /** Insert or replace by [PairedDevice.deviceId]. */69    override fun upsert(device: PairedDevice) {70        val next = getAll().filterNot { it.deviceId == device.deviceId } + device71        persist(next)72    }7374    override fun remove(deviceId: String) {75        persist(getAll().filterNot { it.deviceId == deviceId })76    }7778    // ── Device revocation (Part 5 §C) ────────────────────────────────────────7980    override fun listRevocations(): List<DeviceRevocation> {81        val raw = prefs.getString(KEY_REVOCATIONS, null) ?: return emptyList()82        return runCatching { json.decodeFromString(revocationSerializer, raw) }83            .getOrDefault(emptyList())84    }8586    fun isRevoked(deviceId: String): Boolean =87        listRevocations().any { it.deviceId == deviceId }8889    /**90     * Revoke a device: record it, then drop it from the registry. The record91     * rides out in every manifest this device signs from now on.92     */93    fun revoke(94        deviceId: String,95        revokedByDeviceId: String,96        nowMs: Long = System.currentTimeMillis(),97    ): DeviceRevocation? {98        val existing = listRevocations()99        if (existing.any { it.deviceId == deviceId }) return null100        val record = DeviceRevocation(101            deviceId = deviceId,102            longTermPublicKeyHex = get(deviceId)?.longTermPublicKeyHex ?: "0".repeat(64),103            revokedAt = nowMs,104            revokedByDeviceId = revokedByDeviceId,105        )106        persistRevocations(existing + record)107        remove(deviceId)108        return record109    }110111    /**112     * `revokedAt` is peer-supplied and is NOT used for ordering — revocation is113     * terminal, so an incoming record can never displace one already held.114     */115    override fun mergeRevocations(incoming: List<DeviceRevocation>): List<String> {116        val existing = listRevocations()117        val known = existing.map { it.deviceId }.toSet()118        val fresh = incoming.filterNot { known.contains(it.deviceId) }119        if (fresh.isEmpty()) return emptyList()120        persistRevocations((existing + fresh).takeLast(MAX_REVOCATIONS))121        return fresh.map { it.deviceId }122    }123124    /**125     * Clear a revocation. The ONLY legitimate caller is a direct, SAS-confirmed126     * re-pair — a physically present user on both devices. Never call this from127     * a path a remote peer can reach.128     */129    override fun clearRevocation(deviceId: String) {130        val existing = listRevocations()131        val filtered = existing.filterNot { it.deviceId == deviceId }132        if (filtered.size != existing.size) persistRevocations(filtered)133    }134135    fun clear() {136        prefs.edit().remove(KEY_DEVICES).apply()137    }138139    /**140     * Refresh the device's `lastKnownIp` (the closest real analogue to the141     * brief's `lastSeen`). No-op when the id is unknown or [ip] is null.142     */143    fun updateLastSeen(id: String, ip: String? = null) {144        val current = get(id) ?: return145        if (ip == null) return146        upsert(current.copy(lastKnownIp = ip))147    }148149    fun updateLastSync(id: String, at: Long = System.currentTimeMillis()) {150        val current = get(id) ?: return151        upsert(current.copy(lastSyncedAt = at))152    }153154    /**155     * Reconnect prefers each pair's relay over the global fallback. Rewrite all156     * established pairs when the user changes the mesh relay in Settings.157     */158    fun setRelayUrlForAll(relayUrl: String) {159        persist(withRelayUrl(getAll(), relayUrl))160    }161162    /**163     * Observe the full list. EncryptedSharedPreferences supports164     * OnSharedPreferenceChangeListener, so this emits on every persist —165     * including writes from other components in-process.166     */167    fun observeAll(): Flow<List<PairedDevice>> = callbackFlow {168        trySend(getAll())169        val listener = android.content.SharedPreferences.OnSharedPreferenceChangeListener { _, key ->170            if (key == KEY_DEVICES || key == null) trySend(getAll())171        }172        prefs.registerOnSharedPreferenceChangeListener(listener)173        awaitClose { prefs.unregisterOnSharedPreferenceChangeListener(listener) }174    }175176    private fun persistRevocations(records: List<DeviceRevocation>) {177        prefs.edit()178            .putString(KEY_REVOCATIONS, json.encodeToString(revocationSerializer, records))179            .apply()180    }181182    private fun persist(devices: List<PairedDevice>) {183        prefs.edit()184            .putString(KEY_DEVICES, json.encodeToString(listSerializer, devices))185            .apply()186    }187188    private companion object {189        const val PREFS_FILE = "peach_paired_devices"190        const val KEY_DEVICES = "paired_devices"191        const val KEY_REVOCATIONS = "device_revocations"192        /** Bound the list so a hostile peer cannot grow storage without limit. */193        const val MAX_REVOCATIONS = 500194        val json = Json { encodeDefaults = true; ignoreUnknownKeys = true }195    }196}197198internal fun withRelayUrl(199    devices: List<PairedDevice>,200    relayUrl: String,201): List<PairedDevice> = devices.map { it.copy(relayUrl = relayUrl) }