added multi accounting #4

Sources/Shared/Persistence/AccountPreferences.swift

@@ -3,6 +3,7 @@ import Foundation
 final class AccountPreferences {
     private let defaults: UserDefaults
     private let accountKey = "luma.active-account.v1"
+    private let accountsKey = "luma.accounts.v1"
     private let encryptionSettingsKey = "luma.encryption-settings.v1"
     private let chatStateSettingsKey = "luma.chat-state-settings.v1"
 
@@ -15,6 +16,39 @@ final class AccountPreferences {
         return try? JSONDecoder().decode(AccountConfiguration.self, from: data)
     }
 
+    /// Returns every configured account. The original single-account key is
+    /// migrated lazily so existing installations keep working.
+    func loadAccounts() -> [AccountConfiguration] {
+        if let data = defaults.data(forKey: accountsKey),
+           let accounts = try? JSONDecoder().decode([AccountConfiguration].self, from: data) {
+            return accounts
+        }
+        guard let account = load() else { return [] }
+        return [account]
+    }
+
+    func saveAccounts(_ accounts: [AccountConfiguration]) throws {
+        let normalized = accounts.reduce(into: [String: AccountConfiguration]()) { result, account in
+            result[account.normalizedJID] = account
+        }.values.sorted { $0.normalizedJID < $1.normalizedJID }
+        defaults.set(try JSONEncoder().encode(normalized), forKey: accountsKey)
+        if let active = load(), normalized.contains(where: { $0.normalizedJID == active.normalizedJID }) {
+            try save(active)
+        } else if let first = normalized.first {
+            try save(first)
+        } else {
+            clear()
+        }
+    }
+
+    func add(_ account: AccountConfiguration) throws {
+        try saveAccounts(loadAccounts() + [account])
+    }
+
+    func remove(jid: String) throws {
+        try saveAccounts(loadAccounts().filter { $0.normalizedJID != jid.lowercased() })
+    }
+
     func save(_ account: AccountConfiguration) throws {
         let data = try JSONEncoder().encode(account)
         defaults.set(data, forKey: accountKey)