VaultRepository.kt

1package com.peachpasswords.vault23import kotlinx.coroutines.flow.MutableStateFlow4import kotlinx.coroutines.flow.StateFlow5import kotlinx.coroutines.flow.asStateFlow6import kotlinx.coroutines.sync.Mutex7import kotlinx.coroutines.sync.withLock8import java.security.SecureRandom9import java.text.Normalizer10import java.util.Base6411import java.util.UUID12import javax.inject.Inject13import javax.inject.Singleton1415private fun b64(bytes: ByteArray): String = Base64.getEncoder().withoutPadding().encodeToString(bytes)16private fun unb64(s: String): ByteArray = Base64.getDecoder().decode(s)1718/** Cap on retained past passwords per entry. Mirrors the browser PASSWORD_HISTORY_MAX. */19private const val PASSWORD_HISTORY_MAX = 502021sealed interface UnlockResult {22    data object Success : UnlockResult23    data object WrongPassword : UnlockResult24    data class Error(val reason: String) : UnlockResult25}2627sealed interface CreateVaultResult {28    data object Success : CreateVaultResult29    data class Error(val reason: String) : CreateVaultResult30}3132/**33 * In-memory vault session backed by [VaultStore]. Faithful port of the browser34 * `vault.ts` semantics that matter for correctness:35 *36 *  - Two-slot at rest: slot A is the real (encrypted) vault, slot B a size-matched37 *    noise blob so a fresh install shows two similarly-shaped records.38 *  - Every modifiedAt/deletedAt uses [VaultCrypto.monotonicEntryTimestamp] so a39 *    deletion always wins last-write-wins against an in-flight edit.40 *  - Local writes bump the version counter; sync-applied writes do NOT (so a41 *    sync round never cascades into another outbound sync).42 *  - add/update/delete roll back in-memory state if the disk write fails.43 *  - destroyVault never touches the Pro license (separate store).44 */45@Singleton46class VaultRepository @Inject constructor(47    private val store: VaultStorage,48) {49    private val mutex = Mutex()50    private val rng = SecureRandom()5152    private var derivedKey: ByteArray? = null53    private var rootKey: ByteArray? = null54    private var entryList: MutableList<VaultEntry> = mutableListOf()55    private var duressConfigured: Boolean = false56    private var recoveryWordHash: String? = null57    private var recoveryWordsSet: Boolean = false58    /** True while a decoy (duress) session is active — persistence targets the decoy slot. */59    private var decoyMode: Boolean = false6061    private val _isUnlocked = MutableStateFlow(false)62    val isUnlocked: StateFlow<Boolean> = _isUnlocked.asStateFlow()6364    private val _entries = MutableStateFlow<List<VaultEntry>>(emptyList())65    /** Active (non-deleted) entryList. */66    val entries: StateFlow<List<VaultEntry>> = _entries.asStateFlow()6768    private val _settings = MutableStateFlow(VaultSettings())69    val settings: StateFlow<VaultSettings> = _settings.asStateFlow()7071    fun hasVault(): Boolean = store.hasVault()7273    // ---- Codex (printed paper backup) -------------------------------------7475    /**76     * The at-rest slot-A envelope as base64 JSON `{"a": <StoredVault>}` — the77     * Codex payload's vaultBlob. Slot B is noise, so it is omitted. Restorable78     * on any device that has the master password. Null when no vault exists.79     */80    fun codexVaultBlobBase64(): String? {81        val slotA = store.loadSlotA() ?: return null82        val wrapper = """{"a":${VaultCodec.encodeSlot(slotA)}}"""83        return Base64.getUrlEncoder().withoutPadding().encodeToString(wrapper.toByteArray(Charsets.UTF_8))84    }8586    /**87     * Replace the local vault from a Codex blob, then unlock with [password].88     * Writes slot A (and a size-matched noise slot B) before unlocking so the89     * restored vault is at rest exactly as a freshly-created one would be.90     */91    suspend fun restoreFromCodex(vaultBlobBase64: String, password: String): UnlockResult = mutex.withLock {92        return try {93            val wrapperJson = String(Base64.getUrlDecoder().decode(vaultBlobBase64), Charsets.UTF_8)94            val slotJson = Regex("\"a\"\\s*:\\s*(\\{.*\\})\\s*}\\s*$").find(wrapperJson)?.groupValues?.get(1)95                ?: return UnlockResult.Error("invalid_codex_blob")96            val slotA = VaultCodec.decodeSlot(slotJson) ?: return UnlockResult.Error("invalid_codex_blob")97            if (!store.writeSlotA(slotA)) return UnlockResult.Error("storage_write_failed")98            writeMatchingNoiseSlotB(slotA)99            store.stampLocalMutation()100            unlockLocked(password)101        } catch (e: Exception) {102            UnlockResult.Error(e.message ?: "restore_failed")103        }104    }105106    suspend fun createVault(password: String): CreateVaultResult = mutex.withLock {107        return try {108            val salt = VaultCrypto.generateSalt()109            val key = VaultCrypto.deriveKey(password, salt)110            entryList = mutableListOf()111            duressConfigured = false112            recoveryWordHash = null113            recoveryWordsSet = false114            decoyMode = false115            rootKey = generateRecoverableRootKey()116            val slotA = sealSlotA(key, salt)117            if (!store.writeSlotA(slotA)) return CreateVaultResult.Error("storage_write_failed")118            writeMatchingNoiseSlotB(slotA)119            store.stampLocalMutation()120            store.writeSettings(_settings.value)121            derivedKey = key122            publish()123            _isUnlocked.value = true124            CreateVaultResult.Success125        } catch (e: Exception) {126            CreateVaultResult.Error(e.message ?: "create_failed")127        }128    }129130    suspend fun unlock(password: String): UnlockResult = mutex.withLock { unlockLocked(password) }131132    /** Unlock body without acquiring the mutex — callers must already hold it. */133    private fun unlockLocked(password: String): UnlockResult {134        val slotA = store.loadSlotA() ?: return UnlockResult.Error("no_vault")135        val key = VaultCrypto.deriveKey(password, unb64(slotA.salt))136        val payload = try {137            VaultCodec.decode(VaultCrypto.decrypt(unb64(slotA.blob), key, VaultCrypto.AAD_SLOT_A))138        } catch (_: Exception) {139            VaultCrypto.zero(key)140            // LV-1: a vault sealed before NFC normalization with a non-NFC141            // password derives a different key now. If the supplied password is142            // not already in NFC form, retry with the raw (un-normalized) bytes.143            if (password != Normalizer.normalize(password, Normalizer.Form.NFC)) {144                val legacy = tryLegacyRawUnlock(password, slotA)145                if (legacy != null) return legacy146            }147            return UnlockResult.WrongPassword148        }149        return adoptSlotA(key, payload)150    }151152    /**153     * LV-1 legacy fallback: unlock a slot-A vault that was sealed under the raw154     * (un-normalized) password bytes. On success the slot is HEALED — re-sealed155     * under the NFC-normalized key — so every future unlock takes the normal156     * path. Returns null when the raw key also fails (genuinely wrong password).157     */158    private fun tryLegacyRawUnlock(password: String, slotA: StoredVault): UnlockResult? {159        val rawKey = VaultCrypto.deriveKeyRaw(password, unb64(slotA.salt))160        val payload = try {161            VaultCodec.decode(VaultCrypto.decrypt(unb64(slotA.blob), rawKey, VaultCrypto.AAD_SLOT_A))162        } catch (_: Exception) {163            VaultCrypto.zero(rawKey)164            return null165        }166        // Heal: re-seal slot A under the NFC key (mirrors changePassword's167        // re-seal). Escrows carry forward unchanged — only the wrapping rotates.168        val newSalt = VaultCrypto.generateSalt()169        val newKey = VaultCrypto.deriveKey(password, newSalt)170        val healed = try {171            val blob = b64(VaultCrypto.encrypt(VaultCodec.encode(payload), newKey, VaultCrypto.AAD_SLOT_A))172            val next = StoredVault(173                version = slotA.version,174                salt = b64(newSalt),175                blob = blob,176                recoveryEscrow = slotA.recoveryEscrow,177                rootKeyEscrow = slotA.rootKeyEscrow,178            )179            if (store.writeSlotA(next)) {180                writeMatchingNoiseSlotB(next)181                store.stampLocalMutation()182                true183            } else {184                false185            }186        } catch (_: Exception) {187            false188        }189        return if (healed) {190            VaultCrypto.zero(rawKey)191            adoptSlotA(newKey, payload) // session key now matches the re-sealed slot192        } else {193            VaultCrypto.zero(newKey)194            adoptSlotA(rawKey, payload) // heal failed — keep using the raw key195        }196    }197198    /** Adopt a derived slot-A [key]/[payload] as the live (real-vault) session. */199    private fun adoptSlotA(key: ByteArray, payload: VaultPayload): UnlockResult {200        return try {201            derivedKey = key202            decoyMode = false203            entryList = payload.entries.toMutableList()204            duressConfigured = payload.duressConfigured205            recoveryWordHash = payload.recoveryWordHash206            recoveryWordsSet = payload.recoveryWordsSet207            _settings.value = store.loadSettings()208            ensureRootKey(payload)209            autoPurgeExpiredTrash()210            publish()211            _isUnlocked.value = true212            UnlockResult.Success213        } catch (e: Exception) {214            UnlockResult.Error(e.message ?: "unlock_failed")215        }216    }217218    // ---- Constant-time unlock (MF-5) --------------------------------------219220    /**221     * A slot-A unlock that has been derived but not yet adopted. Holds the live222     * Argon2id key and decoded payload so the caller can derive several candidates223     * concurrently and commit only the winner. The key is owned by this token until224     * [commitSlotAUnlock] adopts it or [discardSlotAUnlock] zeroes it.225     */226    class SlotAUnlock internal constructor(227        internal val key: ByteArray,228        internal val payload: VaultPayload,229    )230231    /**232     * Derive the slot-A key and decrypt its payload WITHOUT mutating session state.233     * Pure computation (no mutex), so it can run concurrently with other candidate234     * derivations before the caller decides which to commit (MF-5). Returns null on235     * no-vault or wrong password (the derived key is zeroed on a tag mismatch).236     */237    fun tryUnlockSlotA(password: String): SlotAUnlock? {238        val slotA = store.loadSlotA() ?: return null239        val key = VaultCrypto.deriveKey(password, unb64(slotA.salt))240        return try {241            val payload = VaultCodec.decode(VaultCrypto.decrypt(unb64(slotA.blob), key, VaultCrypto.AAD_SLOT_A))242            SlotAUnlock(key, payload)243        } catch (_: Exception) {244            VaultCrypto.zero(key)245            null246        }247    }248249    /** Adopt a previously-derived [SlotAUnlock] as the live session. */250    suspend fun commitSlotAUnlock(unlock: SlotAUnlock): UnlockResult = mutex.withLock {251        adoptSlotA(unlock.key, unlock.payload)252    }253254    /** Zero a derived [SlotAUnlock] that will not be adopted. */255    fun discardSlotAUnlock(unlock: SlotAUnlock) = VaultCrypto.zero(unlock.key)256257    // ---- Duress slot B (MF-6) ---------------------------------------------258259    /**260     * A duress-slot (slot B) unlock derived but not yet adopted. Holds the live key261     * and decoded decoy payload so it can be derived concurrently with slot A and262     * only committed if the duress passphrase was the one entered (MF-5/MF-6).263     */264    class DuressUnlock internal constructor(265        internal val key: ByteArray,266        internal val payload: VaultPayload,267    )268269    /**270     * Try to decrypt the duress slot (slot B) with [password] WITHOUT mutating the271     * session. Success means the entered password is the duress passphrase that keys272     * slot B — indistinguishable from the real slot A at the lock screen. Pure273     * computation (no mutex), safe to run concurrently with [tryUnlockSlotA].274     * Returns null when no duress slot exists or the password is not the duress one.275     */276    fun tryUnlockDuress(password: String): DuressUnlock? {277        val slot = store.loadDecoySlot() ?: return null278        val key = VaultCrypto.deriveKey(password, unb64(slot.salt))279        return try {280            val payload = VaultCodec.decode(VaultCrypto.decrypt(unb64(slot.blob), key, VaultCrypto.AAD_SLOT_A))281            DuressUnlock(key, payload)282        } catch (_: Exception) {283            VaultCrypto.zero(key)284            null285        }286    }287288    /** Adopt a derived [DuressUnlock] as a live decoy session (edits persist to slot B only). */289    suspend fun commitDuressUnlock(unlock: DuressUnlock): UnlockResult = mutex.withLock {290        return try {291            derivedKey = unlock.key292            decoyMode = true293            entryList = unlock.payload.entries.toMutableList()294            duressConfigured = false295            recoveryWordHash = unlock.payload.recoveryWordHash296            recoveryWordsSet = unlock.payload.recoveryWordsSet297            rootKey = if (unlock.payload.rootKeyB64.isNotBlank()) unb64(unlock.payload.rootKeyB64)298                      else VaultCrypto.generateRootKey()299            _settings.value = store.loadSettings()300            publish()301            _isUnlocked.value = true302            UnlockResult.Success303        } catch (e: Exception) {304            UnlockResult.Error(e.message ?: "decoy_unlock_failed")305        }306    }307308    /** Zero a derived [DuressUnlock] that will not be adopted. */309    fun discardDuressUnlock(unlock: DuressUnlock) = VaultCrypto.zero(unlock.key)310311    /**312     * Configure the duress vault (MF-6): seal a fresh, empty decoy payload under an313     * Argon2id key derived from [duressPassphrase] (fresh salt) into slot B. The314     * passphrase is never stored — only its ability to decrypt slot B proves it.315     * Requires the real vault to be unlocked and not itself a decoy session.316     */317    suspend fun setDuressPassphrase(duressPassphrase: String): Boolean = mutex.withLock {318        if (derivedKey == null || decoyMode) return false319        // Reject a duress passphrase that also opens the real vault: it would make the320        // lock screen ambiguous (both slots would decrypt for the same input).321        tryUnlockSlotA(duressPassphrase)?.let { discardSlotAUnlock(it); return false }322        return try {323            val salt = VaultCrypto.generateSalt()324            val key = VaultCrypto.deriveKey(duressPassphrase, salt)325            // An empty decoy vault with its own fresh sync root key — nothing real leaks.326            val decoyPayload = VaultPayload(entries = emptyList(), rootKeyB64 = b64(VaultCrypto.generateRootKey()))327            val plaintext = VaultCodec.encode(decoyPayload)328            val blob = b64(VaultCrypto.encrypt(plaintext, key, VaultCrypto.AAD_SLOT_A))329            VaultCrypto.zero(key)330            VaultCrypto.zero(plaintext)331            val ok = store.writeDecoySlot(StoredVault(version = 1, salt = b64(salt), blob = blob))332            if (ok) {333                duressConfigured = true334                runCatching { persistSlotA(bumpVersion = false) }335            }336            ok337        } catch (_: Exception) {338            false339        }340    }341342    /** Tear down the duress vault: drop slot B and the duress flag on the real payload. */343    suspend fun clearDuress(): Boolean = mutex.withLock {344        store.clearDecoySlot()345        if (derivedKey != null && !decoyMode) {346            duressConfigured = false347            runCatching { persistSlotA(bumpVersion = false) }348        }349        true350    }351352    /** Unlock with an already-derived AES-256 key (biometric path). */353    suspend fun unlockWithKey(key: ByteArray): UnlockResult = mutex.withLock {354        val slotA = store.loadSlotA() ?: return UnlockResult.Error("no_vault")355        return try {356            val payload = VaultCodec.decode(357                VaultCrypto.decrypt(unb64(slotA.blob), key, VaultCrypto.AAD_SLOT_A),358            )359            derivedKey = key.copyOf()360            decoyMode = false361            entryList = payload.entries.toMutableList()362            duressConfigured = payload.duressConfigured363            recoveryWordHash = payload.recoveryWordHash364            recoveryWordsSet = payload.recoveryWordsSet365            _settings.value = store.loadSettings()366            ensureRootKey(payload)367            autoPurgeExpiredTrash()368            publish()369            _isUnlocked.value = true370            UnlockResult.Success371        } catch (_: Exception) {372            UnlockResult.WrongPassword373        }374    }375376    fun lock() {377        derivedKey?.let(VaultCrypto::zero)378        rootKey?.let(VaultCrypto::zero)379        derivedKey = null380        rootKey = null381        entryList = mutableListOf()382        duressConfigured = false383        recoveryWordHash = null384        recoveryWordsSet = false385        decoyMode = false386        _entries.value = emptyList()387        _isUnlocked.value = false388    }389390    // ---- Sync identity ----------------------------------------------------391392    /**393     * The vault's stable sync master key (a copy). Caller must zero it. Backs394     * vault_id, the Noise static key, the Ed25519 manifest key, and per-entry395     * envelope keys. Null when locked. See [VaultPayload.rootKeyB64].396     */397    fun syncMasterKey(): ByteArray? = rootKey?.copyOf()398399    /** Stable per-vault id two paired devices must share to sync. Null when locked. */400    fun syncVaultId(): String? = rootKey?.let { com.peachpasswords.sync.computeVaultId(it) }401402    /**403     * A copy of the live Argon2id-derived vault key, for biometric escrow only404     * (wrapped under a hardware KeyStore key on biometric enable). Null when405     * locked. Caller must [VaultCrypto.zero] it after use.406     */407    fun currentVaultKey(): ByteArray? = derivedKey?.copyOf()408409    suspend fun changePassword(oldPassword: String, newPassword: String): Boolean = mutex.withLock {410        val slotA = store.loadSlotA() ?: return false411        return try {412            val oldKey = VaultCrypto.deriveKey(oldPassword, unb64(slotA.salt))413            val payload = VaultCodec.decode(414                VaultCrypto.decrypt(unb64(slotA.blob), oldKey, VaultCrypto.AAD_SLOT_A),415            )416            val newSalt = VaultCrypto.generateSalt()417            val newKey = VaultCrypto.deriveKey(newPassword, newSalt)418            // Re-seal the existing payload under the new key/salt.419            val plaintext = VaultCodec.encode(payload)420            val blob = b64(VaultCrypto.encrypt(plaintext, newKey, VaultCrypto.AAD_SLOT_A))421            // The escrow seals the slot-A PLAINTEXT, which a password change does not422            // alter — only the wrapping changes — so carry it forward; rebuilding the423            // StoredVault from scratch would silently drop it.424            // Carry BOTH escrows forward unchanged: each seals plaintext/root-key425            // content that a password change does not alter — only the slot-A426            // wrapping rotates. The root-key escrow staying stable across password427            // changes matches the browser (`vault.ts:363-364`).428            val next = StoredVault(429                version = slotA.version,430                salt = b64(newSalt),431                blob = blob,432                recoveryEscrow = slotA.recoveryEscrow,433                rootKeyEscrow = slotA.rootKeyEscrow,434            )435            if (!store.writeSlotA(next)) return false436            writeMatchingNoiseSlotB(next)437            store.stampLocalMutation()438            VaultCrypto.zero(oldKey)439            derivedKey?.let(VaultCrypto::zero)440            derivedKey = newKey441            true442        } catch (_: Exception) {443            false444        }445    }446447    /**448     * Irreversible wipe. Locks the session and clears every vault key. The Pro449     * license is in a separate store and is preserved by construction.450     */451    suspend fun destroyVault() = mutex.withLock {452        lock()453        store.clearVault()454        store.clearDecoySlot()455    }456457    // ---- Entry CRUD -------------------------------------------------------458459    suspend fun addEntry(draft: VaultEntry): VaultEntry = mutex.withLock {460        requireUnlocked()461        val stamp = VaultCrypto.monotonicEntryTimestamp()462        val now = System.currentTimeMillis()463        val entry = withDerivedLast4(draft.copy(464            id = draft.id.ifBlank { UUID.randomUUID().toString() },465            createdAt = if (draft.createdAt > 0) draft.createdAt else now,466            modifiedAt = stamp,467            passwordChangedAt = if (!draft.password.isNullOrEmpty()) stamp else draft.passwordChangedAt,468        ))469        val rollback = entryList.toMutableList()470        entryList.add(entry)471        persistOrRollback(rollback)472        entry473    }474475    suspend fun updateEntry(patch: VaultEntry): VaultEntry = mutex.withLock {476        requireUnlocked()477        val idx = entryList.indexOfFirst { it.id == patch.id }478        if (idx == -1 || entryList[idx].deletedAt != null) throw IllegalStateException("entry_not_found")479        val current = entryList[idx]480        val stamp = VaultCrypto.monotonicEntryTimestamp(current.modifiedAt)481        // Only refresh passwordChangedAt when the password value actually changes.482        val passwordChanged = patch.password != null && patch.password != current.password483        // Capture the outgoing password (newest first) so the user can reveal/copy/484        // restore it later. History is computed authoritatively from `current`, not485        // the patch — updateEntry is a full-entry replace, so trusting patch's value486        // would let a stale form clobber the real history. Record the age the old487        // password carried, skip an empty prior, and skip an immediate exact dupe488        // (e.g. restore-then-restore). Capped at PASSWORD_HISTORY_MAX.489        val priorPassword = current.password490        val shouldCapture = passwordChanged &&491            !priorPassword.isNullOrEmpty() &&492            current.passwordHistory?.firstOrNull()?.password != priorPassword493        val nextHistory = if (shouldCapture) {494            (listOf(PasswordHistoryItem(priorPassword!!, current.passwordChangedAt ?: current.createdAt)) +495                (current.passwordHistory ?: emptyList())).take(PASSWORD_HISTORY_MAX)496        } else {497            current.passwordHistory498        }499        val updated = withDerivedLast4(patch.copy(500            createdAt = current.createdAt,501            modifiedAt = stamp,502            passwordChangedAt = if (passwordChanged) stamp else current.passwordChangedAt,503            passwordHistory = nextHistory,504        ))505        val rollback = entryList.toMutableList()506        entryList[idx] = updated507        persistOrRollback(rollback)508        updated509    }510511    /** Soft-delete: writes a tombstone whose timestamp beats any in-flight edit. */512    suspend fun deleteEntry(id: String) = mutex.withLock {513        requireUnlocked()514        val idx = entryList.indexOfFirst { it.id == id }515        if (idx == -1 || entryList[idx].deletedAt != null) throw IllegalStateException("entry_not_found")516        val current = entryList[idx]517        val stamp = VaultCrypto.monotonicEntryTimestamp(current.modifiedAt)518        val rollback = entryList.toMutableList()519        entryList[idx] = current.copy(deletedAt = stamp, modifiedAt = stamp)520        persistOrRollback(rollback)521    }522523    suspend fun restoreEntry(id: String) = mutex.withLock {524        requireUnlocked()525        val idx = entryList.indexOfFirst { it.id == id && it.deletedAt != null }526        if (idx == -1) throw IllegalStateException("deleted entry not found")527        val current = entryList[idx]528        val rollback = entryList.toMutableList()529        entryList[idx] = current.copy(deletedAt = null, modifiedAt = VaultCrypto.monotonicEntryTimestamp(current.modifiedAt))530        persistOrRollback(rollback)531    }532533    /** Permanent delete — no tombstone, no recovery. */534    suspend fun purgeEntry(id: String) = mutex.withLock {535        requireUnlocked()536        val idx = entryList.indexOfFirst { it.id == id && it.deletedAt != null }537        if (idx == -1) throw IllegalStateException("deleted entry not found")538        val rollback = entryList.toMutableList()539        entryList.removeAt(idx)540        persistOrRollback(rollback)541    }542543    /** Permanently empty the trash — hard-deletes every soft-deleted entry. */544    suspend fun purgeDeletedEntries(): Int = mutex.withLock {545        requireUnlocked()546        val rollback = entryList.toMutableList()547        val before = entryList.size548        entryList.removeAll { it.deletedAt != null }549        val removed = before - entryList.size550        if (removed > 0) persistOrRollback(rollback)551        removed552    }553554    fun getEntries(): List<VaultEntry> = entryList.filter { it.deletedAt == null }555    fun getEntry(id: String): VaultEntry? = entryList.firstOrNull { it.id == id && it.deletedAt == null }556    fun getDeletedEntries(): List<VaultEntry> =557        entryList.filter { it.deletedAt != null }.sortedByDescending { it.deletedAt }558559    /** Active entries, optionally narrowed to those carrying [tagFilter]. */560    fun getActiveEntries(tagFilter: String? = null): List<VaultEntry> {561        val active = entryList.filter { it.deletedAt == null }562        if (tagFilter == null) return active563        val needle = tagFilter.trim().lowercase()564        return active.filter { e -> e.tags?.any { it.equals(needle, ignoreCase = true) } == true }565    }566567    /** Sorted, de-duplicated tags across all active entries. */568    fun getDistinctTags(): List<String> =569        entryList.asSequence()570            .filter { it.deletedAt == null }571            .flatMap { it.tags?.asSequence() ?: emptySequence() }572            .map { it.trim().lowercase() }573            .filter { it.isNotEmpty() }574            .distinct()575            .sorted()576            .toList()577578    /**579     * Distinct non-blank values for an identity field across active entries,580     * most-frequently-used first. Supports "username" and "email"; unknown field581     * names return an empty list. Values keep original casing (deduped582     * case-insensitively) so a suggestion matches what the user typed.583     */584    fun getDistinctFieldValues(field: String): List<String> {585        val select: (VaultEntry) -> String? = when (field) {586            "username" -> { e -> e.username }587            "email" -> { e -> e.email }588            else -> return emptyList()589        }590        return entryList.asSequence()591            .filter { it.deletedAt == null }592            .mapNotNull { select(it)?.trim() }593            .filter { it.isNotEmpty() }594            .groupingBy { it.lowercase() }595            .aggregate { _, acc: Pair<String, Int>?, value, _ ->596                Pair(acc?.first ?: value, (acc?.second ?: 0) + 1)597            }598            .values599            .sortedWith(compareByDescending<Pair<String, Int>> { it.second }.thenBy { it.first.lowercase() })600            .map { it.first }601    }602603    fun getTombstones(): List<Tombstone> =604        entryList.filter { it.deletedAt != null }.map { Tombstone(it.id, it.deletedAt!!) }605    fun getVaultVersion(): Long = store.version()606607    // ---- Sync apply (does NOT advance the version) ------------------------608609    /**610     * Apply remote entryList + tombstones with per-entry last-write-wins. Persists611     * WITHOUT bumping the version counter, so a sync round cannot cascade into612     * another outbound sync. Returns the number of locally-applied changes.613     */614    suspend fun applyMergedRemoteEntries(615        remoteEntries: List<VaultEntry>,616        remoteTombstones: List<Tombstone>,617    ): Int = mutex.withLock {618        requireUnlocked()619        val tombMap = remoteTombstones.associate { it.id to it.deletedAt }620        var applied = 0621        val byId = entryList.associateBy { it.id }.toMutableMap()622623        for (remote in remoteEntries) {624            val tomb = tombMap[remote.id]625            if (tomb != null && tomb >= remote.modifiedAt) continue626            val local = byId[remote.id]627            if (local == null) {628                entryList.add(remote); byId[remote.id] = remote; applied++629            } else if (remote.modifiedAt > local.modifiedAt) {630                val i = entryList.indexOfFirst { it.id == local.id }631                if (i != -1) { entryList[i] = remote; byId[remote.id] = remote; applied++ }632            }633        }634635        for ((id, deletedAt) in tombMap) {636            val local = byId[id] ?: continue637            if (local.deletedAt != null && local.deletedAt >= deletedAt) continue638            if (deletedAt < local.modifiedAt) continue639            val i = entryList.indexOfFirst { it.id == id }640            if (i != -1) { entryList[i] = local.copy(deletedAt = deletedAt, modifiedAt = deletedAt); applied++ }641        }642643        if (applied > 0) {644            persistSlotA(bumpVersion = false)645            publish()646        }647        applied648    }649650    suspend fun updateSettings(settings: VaultSettings) = mutex.withLock {651        _settings.value = settings652        store.writeSettings(settings)653    }654655    // ---- Recovery words (vault metadata) ----------------------------------656657    /** True once the user has confirmed their recovery words for this vault. */658    fun isRecoveryWordsSet(): Boolean = recoveryWordsSet659660    /**661     * Record the BLAKE3 hash of the confirmed recovery words and mark them set.662     * Persisted without bumping the version — recovery metadata is local-only and663     * is not an entry mutation paired devices should sync against.664     */665    suspend fun setRecoveryWords(words: List<String>): Boolean = mutex.withLock {666        requireUnlocked()667        recoveryWordHash = recoveryWordsHash(words)668        recoveryWordsSet = true669        // Seal TWO escrows (MF-1): the browser-byte-compatible root-key escrow670        // (cross-platform recovery of the sync root key) and Android's whole-payload671        // escrow (offline forgot-password restore of entries). Both derive their key672        // from the same `wordsToRootKeyMaterial` IKM but use distinct AADs.673        runCatching {674            persistSlotAWithEscrows(buildRecoveryEscrow(words), buildRootKeyEscrow(words))675        }.getOrDefault(false)676    }677678    /** Verify entered words against the stored recovery hash. */679    fun verifyRecoveryWords(words: List<String>): Boolean {680        val stored = recoveryWordHash ?: return false681        return stored == recoveryWordsHash(words)682    }683684    // ---- Recovery escrow (forgot-password) --------------------------------685686    /** True at rest if this vault has any recovery escrow the recovery flow can use. */687    fun hasRecoveryEscrow(): Boolean =688        store.loadSlotA()?.let { it.recoveryEscrow != null || it.rootKeyEscrow != null } ?: false689690    /**691     * Attempt to unlock the vault using the 12 BIP39 recovery [words] instead of692     * the master password. On success the slot-A plaintext sealed in the escrow is693     * adopted as the live session (entries, rootKey, settings), but no Argon2id694     * password key exists yet — call [resetPasswordWithRecoveryWords] next to set a695     * new password and finish unlocking. Returns false when there is no escrow, the696     * words fail the BIP39 checksum, or the words are wrong (GCM tag mismatch).697     *698     * Unlike the brief's `unlockWithRecoveryWords(): ByteArray?`, there is no699     * detached vault key to return here — slot A is wrapped under the rotating700     * Argon2id key — so this opens the escrowed payload directly.701     */702    suspend fun unlockWithRecoveryWords(words: List<String>): Boolean = mutex.withLock {703        val slotA = store.loadSlotA() ?: return false704        if (words.size != 12 || findInvalidWords(words).isNotEmpty()) return false705706        // Prefer Android's whole-payload escrow: a full offline restore of entries,707        // root key, and settings. Present for Android-created vaults.708        slotA.recoveryEscrow?.let { escrow ->709            val material = runCatching { wordsToRootKeyMaterial(words) }.getOrNull() ?: return@let710            val recoveryKey = deriveRecoveryKey(material, unb64(escrow.salt))711            val keyBytes = recoveryKey.encoded712            try {713                val plaintext = VaultCrypto.decrypt(unb64(escrow.blob), keyBytes, VaultCrypto.AAD_RECOVERY)714                val payload = VaultCodec.decode(plaintext)715                decoyMode = false716                entryList = payload.entries.toMutableList()717                duressConfigured = payload.duressConfigured718                recoveryWordHash = payload.recoveryWordHash719                recoveryWordsSet = payload.recoveryWordsSet720                rootKey = if (payload.rootKeyB64.isNotBlank()) unb64(payload.rootKeyB64)721                          else generateRecoverableRootKey()722                _settings.value = store.loadSettings()723                VaultCrypto.zero(plaintext)724                return true725            } catch (_: Exception) {726                // Wrong words against this escrow — fall through to the root-key escrow.727            } finally {728                VaultCrypto.zero(material)729                VaultCrypto.zero(keyBytes)730            }731        }732733        // Browser-format vault (only the root-key escrow): recover the 32-byte root734        // key (sync identity) and reset the password; entries return via sync. This735        // is exactly the browser's recovery semantics (`messages.ts:312-347`).736        slotA.rootKeyEscrow?.let { escrow ->737            val rk = unsealRootKeyEscrow(words, escrow) ?: return false738            decoyMode = false739            entryList = mutableListOf()740            duressConfigured = false741            recoveryWordHash = recoveryWordsHash(words)742            recoveryWordsSet = true743            rootKey = rk744            _settings.value = store.loadSettings()745            return true746        }747        return false748    }749750    /**751     * After [unlockWithRecoveryWords] succeeds, set a brand-new master password:752     * re-seal slot A under a fresh Argon2id key, rotate the escrow under the same753     * words, mark the session fully unlocked, and publish. Returns false if called754     * without a prior successful recovery unlock (no in-memory root key).755     *756     * Folds the brief's `resetPasswordWithRecoveryKey(vaultKey, …)` + `unlock(…)`757     * into one step, since there is no detached vault key here.758     */759    suspend fun resetPasswordWithRecoveryWords(760        words: List<String>,761        newPassword: String,762    ): Boolean = mutex.withLock {763        if (rootKey == null) return false // must have recovered first764        return try {765            val newSalt = VaultCrypto.generateSalt()766            val newKey = VaultCrypto.deriveKey(newPassword, newSalt)767            val plaintext = VaultCodec.encode(currentPayload())768            val blob = b64(VaultCrypto.encrypt(plaintext, newKey, VaultCrypto.AAD_SLOT_A))769            val prior = store.loadSlotA()770            // Rebuild both escrows against the recovered session so their salts rotate771            // with the password reset; fall back to the prior escrows if rebuild fails772            // (e.g. a checksum-invalid phrase). The same 12 words keep working.773            val valid = words.size == 12 && findInvalidWords(words).isEmpty()774            val freshRecovery = if (valid) buildRecoveryEscrow(words) ?: prior?.recoveryEscrow else prior?.recoveryEscrow775            val freshRootKey = if (valid) buildRootKeyEscrow(words) ?: prior?.rootKeyEscrow else prior?.rootKeyEscrow776            val next = StoredVault(777                version = prior?.version ?: 1,778                salt = b64(newSalt),779                blob = blob,780                recoveryEscrow = freshRecovery,781                rootKeyEscrow = freshRootKey,782            )783            if (!store.writeSlotA(next)) return false784            writeMatchingNoiseSlotB(next)785            store.stampLocalMutation()786            derivedKey?.let(VaultCrypto::zero)787            derivedKey = newKey788            VaultCrypto.zero(plaintext)789            publish()790            _isUnlocked.value = true791            true792        } catch (_: Exception) {793            false794        }795    }796797    /**798     * Seal the current slot-A plaintext under a key derived from the 12 BIP39799     * recovery [words] (Android offline-restore escrow). IKM is the browser's800     * `wordsToRootKeyMaterial` (MF-1), AAD is the string [VaultCrypto.AAD_RECOVERY].801     * Returns null for a checksum-invalid phrase.802     */803    private fun buildRecoveryEscrow(words: List<String>): RecoveryEscrow? {804        if (words.size != 12 || findInvalidWords(words).isNotEmpty()) return null805        val material = runCatching { wordsToRootKeyMaterial(words) }.getOrNull() ?: return null806        val salt = VaultCrypto.generateSalt()807        val recoveryKey = deriveRecoveryKey(material, salt)808        val keyBytes = recoveryKey.encoded809        val plaintext = VaultCodec.encode(currentPayload())810        return try {811            val sealed = VaultCrypto.encrypt(plaintext, keyBytes, VaultCrypto.AAD_RECOVERY)812            RecoveryEscrow(salt = b64(salt), blob = b64(sealed))813        } finally {814            VaultCrypto.zero(material)815            VaultCrypto.zero(keyBytes)816            VaultCrypto.zero(plaintext)817        }818    }819820    /**821     * Seal ONLY the 32-byte root key under a key the recovery [words] derive,822     * byte-for-byte the browser algorithm (MF-1): plaintext = lowercase ASCII hex823     * of the root key, IKM = `wordsToRootKeyMaterial`, HKDF salt random-16,824     * info `peach-recovery-v1`, AES-256-GCM AAD = 0x01. The same 12 words unwrap825     * the same root key on the browser. Returns null with no in-memory root key or826     * a checksum-invalid phrase.827     */828    private fun buildRootKeyEscrow(words: List<String>): RootKeyEscrow? {829        if (words.size != 12 || findInvalidWords(words).isNotEmpty()) return null830        val rk = rootKey ?: return null831        val material = runCatching { wordsToRootKeyMaterial(words) }.getOrNull() ?: return null832        val salt = VaultCrypto.generateSalt()833        val recoveryKey = deriveRecoveryKey(material, salt)834        val keyBytes = recoveryKey.encoded835        val plaintext = rootKeyToHex(rk).toByteArray(Charsets.US_ASCII)836        return try {837            // combined = nonce(12) || ciphertext || tag(16)838            val combined = VaultCrypto.encrypt(plaintext, keyBytes, VaultCrypto.AAD_RECOVERY_ROOTKEY)839            val nonce = combined.copyOfRange(0, VaultCrypto.NONCE_SIZE)840            val ctTag = combined.copyOfRange(VaultCrypto.NONCE_SIZE, combined.size)841            val tag = ctTag.copyOfRange(ctTag.size - 16, ctTag.size)842            val ct = ctTag.copyOfRange(0, ctTag.size - 16)843            RootKeyEscrow(salt = b64(salt), wrappedRootKey = b64(ct), nonce = b64(nonce), tag = b64(tag))844        } finally {845            VaultCrypto.zero(material)846            VaultCrypto.zero(keyBytes)847            VaultCrypto.zero(plaintext)848        }849    }850851    /** Unwrap the 32-byte root key from a browser-compatible [escrow]; null on wrong words. */852    private fun unsealRootKeyEscrow(words: List<String>, escrow: RootKeyEscrow): ByteArray? {853        val material = runCatching { wordsToRootKeyMaterial(words) }.getOrNull() ?: return null854        val recoveryKey = deriveRecoveryKey(material, unb64(escrow.salt))855        val keyBytes = recoveryKey.encoded856        return try {857            val combined = unb64(escrow.nonce) + unb64(escrow.wrappedRootKey) + unb64(escrow.tag)858            val pt = VaultCrypto.decrypt(combined, keyBytes, VaultCrypto.AAD_RECOVERY_ROOTKEY)859            hexToRootKey(String(pt, Charsets.US_ASCII))860        } catch (_: Exception) {861            null862        } finally {863            VaultCrypto.zero(material)864            VaultCrypto.zero(keyBytes)865        }866    }867868    /**869     * Re-seal slot A from the current in-memory state under the live key, carrying870     * both [recoveryEscrow] and [rootKeyEscrow] onto the written record. Never runs871     * in decoy mode (recovery is never offered for the decoy) and persists without872     * a version bump, like the recovery-words metadata write it replaces.873     */874    private fun persistSlotAWithEscrows(875        recoveryEscrow: RecoveryEscrow?,876        rootKeyEscrow: RootKeyEscrow?,877    ): Boolean {878        val key = derivedKey ?: throw IllegalStateException("vault_locked")879        if (decoyMode) return false880        val prior = store.loadSlotA() ?: throw IllegalStateException("missing slot A")881        val plaintext = VaultCodec.encode(currentPayload())882        val blob = b64(VaultCrypto.encrypt(plaintext, key, VaultCrypto.AAD_SLOT_A))883        val next = prior.copy(884            blob = blob,885            recoveryEscrow = recoveryEscrow ?: prior.recoveryEscrow,886            rootKeyEscrow = rootKeyEscrow ?: prior.rootKeyEscrow,887        )888        if (!store.writeSlotA(next)) return false889        try {890            writeMatchingNoiseSlotB(next)891        } catch (e: Exception) {892            store.writeSlotA(prior)893            throw e894        }895        return true896    }897898    // ---- Internals --------------------------------------------------------899900    private fun requireUnlocked() {901        if (derivedKey == null) throw IllegalStateException("vault_locked")902    }903904    /**905     * Keep [VaultEntry.last4] in sync with the card number for card entries (MF-3),906     * so it is stored explicitly and survives the sync wire format rather than being907     * re-derived at render time. Non-card entries pass through unchanged.908     */909    private fun withDerivedLast4(entry: VaultEntry): VaultEntry {910        if (!entry.isCard()) return entry911        val digits = entry.cardNumber?.filter { it.isDigit() } ?: ""912        return entry.copy(last4 = if (digits.length >= 4) digits.takeLast(4) else null)913    }914915    /**916     * On unlock, hard-delete trashed entries older than the retention window.917     * A null or non-positive [VaultSettings.trashRetentionDays] means "never"918     * (the app's "Never" option), so nothing is purged. Persists without a919     * version bump and without touching the publish state (caller publishes).920     */921    private fun autoPurgeExpiredTrash() {922        val days = _settings.value.trashRetentionDays ?: return923        if (days <= 0) return924        val cutoff = System.currentTimeMillis() - days.toLong() * 24L * 60L * 60L * 1000L925        val before = entryList.size926        entryList.removeAll { it.deletedAt != null && it.deletedAt < cutoff }927        if (entryList.size != before) runCatching { persistSlotA(bumpVersion = false) }928    }929930    /** The slot-A plaintext envelope for the current in-memory session. */931    private fun currentPayload(): VaultPayload =932        VaultPayload(933            entries = entryList.toList(),934            duressConfigured = duressConfigured,935            rootKeyB64 = rootKey?.let(::b64) ?: "",936            recoveryWordHash = recoveryWordHash,937            recoveryWordsSet = recoveryWordsSet,938        )939940    /**941     * Adopt the payload's root key, lazily minting one for legacy payloads.942     * A freshly-minted key is persisted WITHOUT bumping the version — adopting943     * a root key is not a mutation paired devices should sync against.944     */945    private fun ensureRootKey(payload: VaultPayload) {946        if (payload.rootKeyB64.isNotBlank()) {947            rootKey = unb64(payload.rootKeyB64)948            return949        }950        rootKey = generateRecoverableRootKey()951        runCatching { persistSlotA(bumpVersion = false) }952    }953954    private fun publish() {955        _entries.value = entryList.filter { it.deletedAt == null }956    }957958    private fun sealSlotA(key: ByteArray, salt: ByteArray): StoredVault {959        val plaintext = VaultCodec.encode(currentPayload())960        val blob = b64(VaultCrypto.encrypt(plaintext, key, VaultCrypto.AAD_SLOT_A))961        return StoredVault(version = 1, salt = b64(salt), blob = blob)962    }963964    private fun writeMatchingNoiseSlotB(slotA: StoredVault) {965        // Size the noise so its base64 length matches slot A's blob (MN-1): with the966        // plaintext now bucket-padded, an at-rest observer sees two equal-length slots967        // and cannot pick the real one by size. b64(N bytes) ≈ N*4/3 chars.968        val approxBytes = (slotA.blob.length * 3 / 4).coerceAtLeast(VaultCrypto.NONCE_SIZE + 16)969        val noise = ByteArray(approxBytes).also(rng::nextBytes)970        store.writeSlotB(b64(noise))971    }972973    /** Re-seal slot A from the current in-memory state under the live key. */974    private fun persistSlotA(bumpVersion: Boolean): Boolean {975        val key = derivedKey ?: throw IllegalStateException("vault_locked")976        // Decoy sessions persist to the decoy slot only — never touch the real slot A.977        if (decoyMode) {978            val prior = store.loadDecoySlot() ?: throw IllegalStateException("missing decoy slot")979            val plaintext = VaultCodec.encode(currentPayload())980            val blob = b64(VaultCrypto.encrypt(plaintext, key, VaultCrypto.AAD_SLOT_A))981            return store.writeDecoySlot(prior.copy(blob = blob))982        }983        val prior = store.loadSlotA() ?: throw IllegalStateException("missing slot A")984        val plaintext = VaultCodec.encode(currentPayload())985        val blob = b64(VaultCrypto.encrypt(plaintext, key, VaultCrypto.AAD_SLOT_A))986        val next = prior.copy(blob = blob)987        if (!store.writeSlotA(next)) return false988        // Slot A committed — keep slot B size-matched, then advance the version989        // for local writes only. Restore slot A if a later step fails.990        try {991            writeMatchingNoiseSlotB(next)992            if (bumpVersion) store.stampLocalMutation()993        } catch (e: Exception) {994            store.writeSlotA(prior)995            throw e996        }997        return true998    }9991000    /** Persist a local mutation, rolling the in-memory list back on failure. */1001    private fun persistOrRollback(rollback: MutableList<VaultEntry>) {1002        try {1003            if (!persistSlotA(bumpVersion = true)) {1004                entryList = rollback1005                throw IllegalStateException("storage_write_failed")1006            }1007        } catch (e: Exception) {1008            entryList = rollback1009            throw e1010        }1011        publish()1012    }1013}