session-ios/SessionMessagingKit/LibSession/LibSession+SessionMessagingKit.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import Foundation
import GRDB
import SessionSnodeKit
import SessionUtil
import SessionUtilitiesKit

// MARK: - Cache

public extension Cache {
    static let libSession: CacheConfig<LibSessionCacheType, LibSessionImmutableCacheType> = Dependencies.create(
        identifier: "libSession",
        createInstance: { dependencies in
            // TODO: Add a `Noop` cache here (this should be loaded as part of the database requirements rather than here)
            LibSession.Cache(
                userSessionId: dependencies[cache: .general].sessionId,
                using: dependencies
            )
        },
        mutableInstance: { $0 },
        immutableInstance: { $0 }
    )
}

// MARK: - LibSession

public extension LibSession {
    
    // MARK: - Variables
    
    internal static func syncDedupeId(_ swarmPublicKey: String) -> String {
        return "EnqueueConfigurationSyncJob-\(swarmPublicKey)"   // stringlint:disable
    }
    
    // MARK: - Loading
    
    static func clearMemoryState(using dependencies: Dependencies) {
        dependencies.mutate(cache: .libSession) { cache in
            cache.removeAll()
        }
    }
    
    internal static func createDump(
        config: Config?,
        for variant: ConfigDump.Variant,
        sessionId: SessionId,
        timestampMs: Int64,
        using dependencies: Dependencies
    ) throws -> ConfigDump? {
        // If it doesn't need a dump then do nothing
        guard
            config.needsDump(using: dependencies),
            let dumpData: Data = try config?.dump()
        else { return nil }
        
        return ConfigDump(
            variant: variant,
            sessionId: sessionId.hexString,
            data: dumpData,
            timestampMs: timestampMs
        )
    }
    
    // MARK: - Pushes
    
    internal static func pendingChanges(
        _ db: Database,
        swarmPubkey: String,
        using dependencies: Dependencies
    ) throws -> PendingChanges {
        guard Identity.userExists(db, using: dependencies) else { throw LibSessionError.userDoesNotExist }
        
        // Get a list of the different config variants for the provided publicKey
        let userSessionId: SessionId = dependencies[cache: .general].sessionId
        let targetVariants: [(sessionId: SessionId, variant: ConfigDump.Variant)] = {
            switch (swarmPubkey, try? SessionId(from: swarmPubkey)) {
                case (userSessionId.hexString, _):
                    return ConfigDump.Variant.userVariants.map { (userSessionId, $0) }
                    
                case (_, .some(let sessionId)) where sessionId.prefix == .group:
                    return ConfigDump.Variant.groupVariants.map { (sessionId, $0) }
                    
                default: return []
            }
        }()
        
        // Extract any pending changes from the cached config entry for each variant
        return try targetVariants
            .sorted { (lhs: (SessionId, ConfigDump.Variant), rhs: (SessionId, ConfigDump.Variant)) in
                lhs.1.sendOrder < rhs.1.sendOrder
            }
            .reduce(into: PendingChanges()) { result, info in
                guard
                    let config: Config = dependencies[cache: .libSession]
                        .config(for: info.variant, sessionId: info.sessionId)
                        .wrappedValue
                else { return }
                
                // Add any obsolete hashes to be removed (want to do this even if there isn't a pending push
                // to ensure we clean things up)
                result.append(hashes: config.obsoleteHashes())
                
                // Only generate the push data if we need to do a push
                guard config.needsPush else { return }
                
                guard let data: PendingChanges.PushData = config.push(variant: info.variant) else {
                    let configCountInfo: String = config.count(for: info.variant)
                    
                    throw LibSessionError(
                        config,
                        fallbackError: .unableToGeneratePushData,
                        logMessage: "[LibSession] Failed to generate push data for \(info.variant) config data, size: \(configCountInfo), error"
                    )
                }
                
                result.append(data: data)
            }
    }
    
    static func markingAsPushed(
        seqNo: Int64,
        serverHash: String,
        sentTimestamp: Int64,
        variant: ConfigDump.Variant,
        swarmPublicKey: String,
        using dependencies: Dependencies
    ) -> ConfigDump? {
        let sessionId: SessionId = SessionId(hex: swarmPublicKey, dumpVariant: variant)
        
        return dependencies[cache: .libSession]
            .config(for: variant, sessionId: sessionId)
            .mutate { config -> ConfigDump? in
                guard config != nil else { return nil }
                
                // Mark the config as pushed
                config?.confirmPushed(seqNo: seqNo, hash: serverHash)
                
                // Update the result to indicate whether the config needs to be dumped
                guard config.needsPush else { return nil }
                
                return try? LibSession.createDump(
                    config: config,
                    for: variant,
                    sessionId: sessionId,
                    timestampMs: sentTimestamp,
                    using: dependencies
                )
            }
    }
    
    public static func configHashes(
        for swarmPublicKey: String,
        using dependencies: Dependencies
    ) -> [String] {
        return dependencies[singleton: .storage]
            .read { db -> Set<ConfigDump.Variant> in
                guard Identity.userExists(db, using: dependencies) else { return [] }
                
                return try ConfigDump
                    .select(.variant)
                    .filter(ConfigDump.Columns.publicKey == swarmPublicKey)
                    .asRequest(of: ConfigDump.Variant.self)
                    .fetchSet(db)
            }
            .defaulting(to: [])
            .map { variant -> [String] in
                /// Extract all existing hashes for any dumps associated with the given `sessionIdHexString`
                dependencies[cache: .libSession]
                    .config(for: variant, sessionId: SessionId(hex: swarmPublicKey, dumpVariant: variant))
                    .wrappedValue
                    .map { $0.currentHashes() }
                    .defaulting(to: [])
            }
            .reduce([], +)
    }
}

// MARK: - Convenience

public extension LibSession {
    static func parseCommunity(url: String) -> (room: String, server: String, publicKey: String)? {
        var cBaseUrl: [CChar] = [CChar](repeating: 0, count: COMMUNITY_BASE_URL_MAX_LENGTH)
        var cRoom: [CChar] = [CChar](repeating: 0, count: COMMUNITY_ROOM_MAX_LENGTH)
        var cPubkey: [UInt8] = [UInt8](repeating: 0, count: OpenGroup.pubkeyByteLength)
        
        guard
            var cFullUrl: [CChar] = url.cString(using: .utf8),
            community_parse_full_url(&cFullUrl, &cBaseUrl, &cRoom, &cPubkey) &&
            !String(cString: cRoom).isEmpty &&
            !String(cString: cBaseUrl).isEmpty &&
            cPubkey.contains(where: { $0 != 0 })
        else { return nil }
        
        // Note: Need to store them in variables instead of returning directly to ensure they
        // don't get freed from memory early (was seeing this happen intermittently during
        // unit tests...)
        let room: String = String(cString: cRoom)
        let baseUrl: String = String(cString: cBaseUrl)
        let pubkeyHex: String = Data(cPubkey).toHexString()
        
        return (room, baseUrl, pubkeyHex)
    }
    
    static func communityUrlFor(server: String?, roomToken: String?, publicKey: String?) -> String? {
        guard
            var cBaseUrl: [CChar] = server?.cString(using: .utf8),
            var cRoom: [CChar] = roomToken?.cString(using: .utf8),
            let publicKey: String = publicKey
        else { return nil }
        
        var cPubkey: [UInt8] = Array(Data(hex: publicKey))
        var cFullUrl: [CChar] = [CChar](repeating: 0, count: COMMUNITY_FULL_URL_MAX_LENGTH)
        community_make_full_url(&cBaseUrl, &cRoom, &cPubkey, &cFullUrl)
        
        return String(cString: cFullUrl)
    }
}

// MARK: - Convenience

private extension Optional where Wrapped == Int32 {
    func toConfig(
        _ maybeConf: UnsafeMutablePointer<config_object>?,
        variant: ConfigDump.Variant,
        error: [CChar]
    ) throws -> LibSession.Config {
        guard self == 0, let conf: UnsafeMutablePointer<config_object> = maybeConf else {
            throw LibSessionError.unableToCreateConfigObject
                .logging("[LibSession] Unable to create \(variant.rawValue) config object: \(String(cString: error))")
        }
        
        switch variant {
            case .userProfile, .contacts, .convoInfoVolatile,
                .userGroups, .groupInfo, .groupMembers:
                return .object(conf)
            
            case .groupKeys, .invalid: throw LibSessionError.unableToCreateConfigObject
        }
    }
}

private extension Int32 {
    func toConfig(
        _ maybeConf: UnsafeMutablePointer<config_group_keys>?,
        info: UnsafeMutablePointer<config_object>,
        members: UnsafeMutablePointer<config_object>,
        variant: ConfigDump.Variant,
        error: [CChar]
    ) throws -> LibSession.Config {
        guard self == 0, let conf: UnsafeMutablePointer<config_group_keys> = maybeConf else {
            throw LibSessionError.unableToCreateConfigObject
                .logging("[LibSession] Unable to create \(variant.rawValue) config object: \(String(cString: error))")
        }

        switch variant {
            case .groupKeys: return .groupKeys(conf, info: info, members: members)
            default: throw LibSessionError.unableToCreateConfigObject
        }
    }
}

private extension SessionId {
    init(hex: String, dumpVariant: ConfigDump.Variant) {
        switch (try? SessionId(from: hex), dumpVariant) {
            case (.some(let sessionId), _): self = sessionId
            case (_, .userProfile), (_, .contacts), (_, .convoInfoVolatile), (_, .userGroups):
                self = SessionId(.standard, hex: hex)
                
            case (_, .groupInfo), (_, .groupMembers), (_, .groupKeys):
                self = SessionId(.group, hex: hex)
                
            case (_, .invalid): self = SessionId.invalid
        }
    }
}

// MARK: - ConfigStore

private class ConfigStore {
    private struct Key: Hashable {
        let sessionId: SessionId
        let variant: ConfigDump.Variant
        
        init(sessionId: SessionId, variant: ConfigDump.Variant) {
            self.sessionId = sessionId
            self.variant = variant
        }
    }
    
    private var store: [Key: Atomic<LibSession.Config?>] = [:]
    public var isEmpty: Bool { store.isEmpty }
    public var needsSync: Bool { store.contains { _, config in config.needsPush } }
    
    subscript (sessionId: SessionId, variant: ConfigDump.Variant) -> Atomic<LibSession.Config?> {
        get { return (store[Key(sessionId: sessionId, variant: variant)] ?? Atomic(nil)) }
        set { store[Key(sessionId: sessionId, variant: variant)] = newValue }
    }
    
    public func removeAll() {
        store.removeAll()
    }
}

// MARK: - SessionUtil Cache

public extension LibSession {
    class Cache: LibSessionCacheType {
        private let dependencies: Dependencies
        private var configStore: ConfigStore = ConfigStore()
        
        public let userSessionId: SessionId
        public var isEmpty: Bool { configStore.isEmpty }
        
        /// Returns `true` if there is a config which needs to be pushed, but returns `false` if the configs are all up to date or haven't been
        /// loaded yet (eg. fresh install)
        public var needsSync: Bool { configStore.needsSync }
        
        // MARK: - Initialization
        
        public init(userSessionId: SessionId, using dependencies: Dependencies) {
            self.userSessionId = userSessionId
            self.dependencies = dependencies
        }
        
        // MARK: - State Management
        
        public func loadState(_ db: Database) {
            // Ensure we have the ed25519 key and that we haven't already loaded the state before
            // we continue
            guard
                configStore.isEmpty,
                let ed25519KeyPair: KeyPair = Identity.fetchUserEd25519KeyPair(db)
            else { return Log.warn("[LibSession] Ignoring loadState due to existing state") }
            
            // Retrieve the existing dumps from the database
            let existingDumps: [ConfigDump] = ((try? ConfigDump.fetchSet(db)) ?? [])
                .sorted { lhs, rhs in lhs.variant.loadOrder < rhs.variant.loadOrder }
            let existingDumpVariants: Set<ConfigDump.Variant> = existingDumps
                .map { $0.variant }
                .asSet()
            let missingRequiredVariants: Set<ConfigDump.Variant> = ConfigDump.Variant.userVariants
                .subtracting(existingDumpVariants)
            let groupsByKey: [String: ClosedGroup] = (try? ClosedGroup
                .filter(ClosedGroup.Columns.threadId.like("\(SessionId.Prefix.group.rawValue)%"))
                .fetchAll(db)
                .reduce(into: [:]) { result, next in result[next.threadId] = next })
                .defaulting(to: [:])
            let groupsWithNoDumps: [ClosedGroup] = groupsByKey
                .values
                .filter { group in !existingDumps.contains(where: { $0.sessionId.hexString == group.id }) }
            
            // Create the config records for each dump
            existingDumps.forEach { dump in
                configStore[dump.sessionId, dump.variant] = Atomic(
                    try? loadState(
                        for: dump.variant,
                        sessionId: dump.sessionId,
                        userEd25519SecretKey: ed25519KeyPair.secretKey,
                        groupEd25519SecretKey: groupsByKey[dump.sessionId.hexString]?
                            .groupIdentityPrivateKey
                            .map { Array($0) },
                        cachedData: dump.data
                    )
                )
            }
            
            /// It's possible for there to not be dumps for all of the user configs so we load any missing ones to ensure funcitonality
            /// works smoothly
            ///
            /// It's also possible for a group to get created but for a dump to not be created (eg. when a crash happens at the right time), to
            /// handle this we also load the state of any groups which don't have dumps if they aren't in the `invited` state (those in
            /// the `invited` state will have their state loaded if the invite is accepted)
            loadDefaultStatesFor(
                userConfigVariants: missingRequiredVariants,
                groups: groupsWithNoDumps,
                userSessionId: userSessionId,
                userEd25519KeyPair: ed25519KeyPair
            )
            Log.info("[LibSessionCache] Completed loadState")
        }
        
        public func loadDefaultStatesFor(
            userConfigVariants: Set<ConfigDump.Variant>,
            groups: [ClosedGroup],
            userSessionId: SessionId,
            userEd25519KeyPair: KeyPair
        ) {
            /// Create an empty state for the specified user config variants
            userConfigVariants.forEach { variant in
                configStore[userSessionId, variant] = Atomic(
                    try? loadState(
                        for: variant,
                        sessionId: userSessionId,
                        userEd25519SecretKey: userEd25519KeyPair.secretKey,
                        groupEd25519SecretKey: nil,
                        cachedData: nil
                    )
                )
            }
            
            /// Create empty group states for the provided groups
            groups
                .filter { $0.invited != true }
                .forEach { group in
                    _ = try? LibSession.createGroupState(
                        groupSessionId: SessionId(.group, hex: group.id),
                        userED25519KeyPair: userEd25519KeyPair,
                        groupIdentityPrivateKey: group.groupIdentityPrivateKey,
                        shouldLoadState: true,
                        cacheToLoadStateInto: nil,
                        using: dependencies
                    )
                }
        }
        
        private func loadState(
            for variant: ConfigDump.Variant,
            sessionId: SessionId,
            userEd25519SecretKey: [UInt8],
            groupEd25519SecretKey: [UInt8]?,
            cachedData: Data?
        ) throws -> Config {
            // Setup initial variables (including getting the memory address for any cached data)
            var conf: UnsafeMutablePointer<config_object>? = nil
            var keysConf: UnsafeMutablePointer<config_group_keys>? = nil
            var secretKey: [UInt8] = userEd25519SecretKey
            var error: [CChar] = [CChar](repeating: 0, count: 256)
            let cachedDump: (data: UnsafePointer<UInt8>, length: Int)? = cachedData?.withUnsafeBytes { unsafeBytes in
                return unsafeBytes.baseAddress.map {
                    (
                        $0.assumingMemoryBound(to: UInt8.self),
                        unsafeBytes.count
                    )
                }
            }
            let userConfigInitCalls: [ConfigDump.Variant: UserConfigInitialiser] = [
                .userProfile: user_profile_init,
                .contacts: contacts_init,
                .convoInfoVolatile: convo_info_volatile_init,
                .userGroups: user_groups_init
            ]
            let groupConfigInitCalls: [ConfigDump.Variant: GroupConfigInitialiser] = [
                .groupInfo: groups_info_init,
                .groupMembers: groups_members_init
            ]
            
            switch (variant, groupEd25519SecretKey) {
                case (.invalid, _):
                    throw LibSessionError.unableToCreateConfigObject
                        .logging("[LibSession] Unable to create \(variant.rawValue) config object")
                    
                case (.userProfile, _), (.contacts, _), (.convoInfoVolatile, _), (.userGroups, _):
                    return try (userConfigInitCalls[variant]?(
                        &conf,
                        &secretKey,
                        cachedDump?.data,
                        (cachedDump?.length ?? 0),
                        &error
                    ))
                    .toConfig(conf, variant: variant, error: error)
                    
                case (.groupInfo, .some(var adminSecretKey)), (.groupMembers, .some(var adminSecretKey)):
                    var identityPublicKey: [UInt8] = sessionId.publicKey
                    
                    return try (groupConfigInitCalls[variant]?(
                        &conf,
                        &identityPublicKey,
                        &adminSecretKey,
                        cachedDump?.data,
                        (cachedDump?.length ?? 0),
                        &error
                    ))
                    .toConfig(conf, variant: variant, error: error)
                    
                case (.groupKeys, .some(var adminSecretKey)):
                    var identityPublicKey: [UInt8] = sessionId.publicKey
                    
                    guard
                        case .object(let infoConf) = configStore[sessionId, .groupInfo].wrappedValue,
                        case .object(let membersConf) = configStore[sessionId, .groupMembers].wrappedValue
                    else {
                        throw LibSessionError.unableToCreateConfigObject
                            .logging("[LibSession] Unable to create \(variant.rawValue) config object: Group info and member config states not loaded")
                    }
                    
                    return try groups_keys_init(
                        &keysConf,
                        &secretKey,
                        &identityPublicKey,
                        &adminSecretKey,
                        infoConf,
                        membersConf,
                        cachedDump?.data,
                        (cachedDump?.length ?? 0),
                        &error
                    )
                    .toConfig(keysConf, info: infoConf, members: membersConf, variant: variant, error: error)
                    
                // It looks like C doesn't deal will passing pointers to null variables well so we need
                // to explicitly pass 'nil' for the admin key in this case
                case (.groupInfo, .none), (.groupMembers, .none):
                    var identityPublicKey: [UInt8] = sessionId.publicKey
                    
                    return try (groupConfigInitCalls[variant]?(
                        &conf,
                        &identityPublicKey,
                        nil,
                        cachedDump?.data,
                        (cachedDump?.length ?? 0),
                        &error
                    ))
                    .toConfig(conf, variant: variant, error: error)
                    
                // It looks like C doesn't deal will passing pointers to null variables well so we need
                // to explicitly pass 'nil' for the admin key in this case
                case (.groupKeys, .none):
                    var identityPublicKey: [UInt8] = sessionId.publicKey
                    
                    guard
                        case .object(let infoConf) = configStore[sessionId, .groupInfo].wrappedValue,
                        case .object(let membersConf) = configStore[sessionId, .groupMembers].wrappedValue
                    else {
                        throw LibSessionError.unableToCreateConfigObject
                            .logging("[LibSession] Unable to create \(variant.rawValue) config object: Group info and member config states not loaded")
                    }
                    
                    return try groups_keys_init(
                        &keysConf,
                        &secretKey,
                        &identityPublicKey,
                        nil,
                        infoConf,
                        membersConf,
                        cachedDump?.data,
                        (cachedDump?.length ?? 0),
                        &error
                    )
                    .toConfig(keysConf, info: infoConf, members: membersConf, variant: variant, error: error)
            }
        }
        
        public func setConfig(for variant: ConfigDump.Variant, sessionId: SessionId, to config: Config?) {
            configStore[sessionId, variant] = Atomic(config)
        }
        
        public func config(for variant: ConfigDump.Variant, sessionId: SessionId) -> Atomic<Config?> {
            return configStore[sessionId, variant]
        }
        
        public func removeAll() {
            configStore.removeAll()
        }
        
        // MARK: - Config Message Handling
        
        public func unsafeDirectMergeConfigMessage(
            swarmPublicKey: String,
            messages: [ConfigMessageReceiveJob.Details.MessageInfo]
        ) throws {
            guard !messages.isEmpty else { return }
            
            let groupedMessages: [ConfigDump.Variant: [ConfigMessageReceiveJob.Details.MessageInfo]] = messages
                .grouped(by: { ConfigDump.Variant(namespace: $0.namespace) })
            
            try groupedMessages
                .sorted { lhs, rhs in lhs.key.namespace.processingOrder < rhs.key.namespace.processingOrder }
                .forEach { [configStore] variant, message in
                    let sessionId: SessionId = SessionId(hex: swarmPublicKey, dumpVariant: variant)
                    try configStore[sessionId, variant].mutate { config in
                        try config?.merge(message)
                    }
                }
        }
        
        public func handleConfigMessages(
            _ db: Database,
            swarmPublicKey: String,
            messages: [ConfigMessageReceiveJob.Details.MessageInfo]
        ) throws {
            guard !messages.isEmpty else { return }
            
            let groupedMessages: [ConfigDump.Variant: [ConfigMessageReceiveJob.Details.MessageInfo]] = messages
                .grouped(by: { ConfigDump.Variant(namespace: $0.namespace) })
            
            try groupedMessages
                .sorted { lhs, rhs in lhs.key.namespace.processingOrder < rhs.key.namespace.processingOrder }
                .forEach { variant, message in
                    let sessionId: SessionId = SessionId(hex: swarmPublicKey, dumpVariant: variant)
                    try configStore[sessionId, variant].mutate { config in
                        do {
                            // Merge the messages (if it doesn't merge anything then don't bother trying
                            // to handle the result)
                            guard let latestServerTimestampMs: Int64 = try config?.merge(message) else { return }
                            
                            // Apply the updated states to the database
                            switch variant {
                                case .userProfile:
                                    try handleUserProfileUpdate(
                                        db,
                                        in: config,
                                        serverTimestampMs: latestServerTimestampMs,
                                        using: dependencies
                                    )
                                    
                                case .contacts:
                                    try handleContactsUpdate(
                                        db,
                                        in: config,
                                        serverTimestampMs: latestServerTimestampMs,
                                        using: dependencies
                                    )
                                    
                                case .convoInfoVolatile:
                                    try LibSession.handleConvoInfoVolatileUpdate(
                                        db,
                                        in: config,
                                        using: dependencies
                                    )
                                    
                                case .userGroups:
                                    try handleUserGroupsUpdate(
                                        db,
                                        in: config,
                                        serverTimestampMs: latestServerTimestampMs,
                                        using: dependencies
                                    )
                                    
                                case .groupInfo:
                                    try handleGroupInfoUpdate(
                                        db,
                                        in: config,
                                        groupSessionId: sessionId,
                                        serverTimestampMs: latestServerTimestampMs,
                                        using: dependencies
                                    )
                                    
                                case .groupMembers:
                                    try LibSession.handleGroupMembersUpdate(
                                        db,
                                        in: config,
                                        groupSessionId: sessionId,
                                        serverTimestampMs: latestServerTimestampMs,
                                        using: dependencies
                                    )
                                    
                                case .groupKeys:
                                    try LibSession.handleGroupKeysUpdate(
                                        db,
                                        in: config,
                                        groupSessionId: sessionId,
                                        using: dependencies
                                    )
                                
                                case .invalid: Log.error("[LibSession] Failed to process merge of invalid config namespace")
                            }
                            
                            // Need to check if the config needs to be dumped (this might have changed
                            // after handling the merge changes)
                            guard config.needsDump(using: dependencies) else {
                                try ConfigDump
                                    .filter(
                                        ConfigDump.Columns.variant == variant &&
                                        ConfigDump.Columns.publicKey == sessionId.hexString
                                    )
                                    .updateAll(
                                        db,
                                        ConfigDump.Columns.timestampMs.set(to: latestServerTimestampMs)
                                    )
                                
                                return
                            }
                            
                            try LibSession.createDump(
                                config: config,
                                for: variant,
                                sessionId: sessionId,
                                timestampMs: latestServerTimestampMs,
                                using: dependencies
                            )?.upsert(db)
                        }
                        catch {
                            Log.error("[LibSession] Failed to process merge of \(variant) config data")
                            throw error
                        }
                    }
                }
            
            // Now that the local state has been updated, schedule a config sync if needed (this will
            // push any pending updates and properly update the state)
            db.afterNextTransactionNestedOnce(dedupeId: LibSession.syncDedupeId(swarmPublicKey)) { [dependencies] db in
                ConfigurationSyncJob.enqueue(db, swarmPublicKey: swarmPublicKey, using: dependencies)
            }
        }
    }
}

// MARK: - SessionUtilCacheType

/// This is a read-only version of the Cache designed to avoid unintentionally mutating the instance in a non-thread-safe way
public protocol LibSessionImmutableCacheType: ImmutableCacheType {
    var userSessionId: SessionId { get }
    var isEmpty: Bool { get }
    var needsSync: Bool { get }
    
    func config(for variant: ConfigDump.Variant, sessionId: SessionId) -> Atomic<LibSession.Config?>
}

public protocol LibSessionCacheType: LibSessionImmutableCacheType, MutableCacheType {
    var userSessionId: SessionId { get }
    var isEmpty: Bool { get }
    var needsSync: Bool { get }
    
    // MARK: - State Management
    
    func loadState(_ db: Database)
    func loadDefaultStatesFor(
        userConfigVariants: Set<ConfigDump.Variant>,
        groups: [ClosedGroup],
        userSessionId: SessionId,
        userEd25519KeyPair: KeyPair
    )
    func setConfig(for variant: ConfigDump.Variant, sessionId: SessionId, to config: LibSession.Config?)
    func config(for variant: ConfigDump.Variant, sessionId: SessionId) -> Atomic<LibSession.Config?>
    func removeAll()
    
    // MARK: - Config Message Handling
    
    /// This function takes config messages and just triggers the merge into `libSession`
    ///
    /// **Note:** This function should only be used in a situation where we want to retrieve the data from a config message as using it
    /// elsewhere will result in the database getting out of sync with the config state
    func unsafeDirectMergeConfigMessage(
        swarmPublicKey: String,
        messages: [ConfigMessageReceiveJob.Details.MessageInfo]
    ) throws
    
    func handleConfigMessages(
        _ db: Database,
        swarmPublicKey: String,
        messages: [ConfigMessageReceiveJob.Details.MessageInfo]
    ) throws
}