feat(storage): encrypted wallet file and persistence

src/Core/Storage/WalletDocument.cs

@@ -0,0 +1,102 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace PalladiumWallet.Core.Storage;
+
+/// <summary>
+/// Schema del file wallet (blueprint §8), versionato per consentire migrazioni
+/// automatiche all'apertura. La cifratura (quando c'è una password) avvolge
+/// l'intero documento via <see cref="EncryptedFile"/>.
+/// </summary>
+public sealed class WalletDocument
+{
+    public const int CurrentVersion = 1;
+
+    public int Version { get; set; } = CurrentVersion;
+
+    /// <summary>Nome rete (mainnet/testnet/regtest), come ChainProfile.NetName.</summary>
+    public required string Network { get; set; }
+
+    /// <summary>Tipo di script (nome dell'enum ScriptKind).</summary>
+    public required string ScriptKind { get; set; }
+
+    /// <summary>Mnemonica BIP39 in chiaro nel documento (il documento va cifrato!); null se watch-only.</summary>
+    public string? Mnemonic { get; set; }
+
+    /// <summary>Extension word BIP39 (§4.1); null se assente.</summary>
+    public string? Passphrase { get; set; }
+
+    /// <summary>Path di account (es. "84'/746'/0'").</summary>
+    public required string AccountPath { get; set; }
+
+    /// <summary>Xpub di account in SLIP-132: basta da sola per il watch-only.</summary>
+    public required string AccountXpub { get; set; }
+
+    public string? MasterFingerprint { get; set; }
+
+    /// <summary>Gap limit per la scansione indirizzi (§5), configurabile.</summary>
+    public int GapLimit { get; set; } = 20;
+
+    /// <summary>Etichette per indirizzo/txid (§12).</summary>
+    public Dictionary<string, string> Labels { get; set; } = [];
+
+    /// <summary>Cache dell'ultimo stato sincronizzato (saldo/storico mostrabili offline).</summary>
+    public SyncCache? Cache { get; set; }
+
+    public bool IsWatchOnly => Mnemonic is null;
+
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        WriteIndented = true,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
+    };
+
+    public string ToJson() => JsonSerializer.Serialize(this, JsonOptions);
+
+    public static WalletDocument FromJson(string json)
+    {
+        var doc = JsonSerializer.Deserialize<WalletDocument>(json, JsonOptions)
+            ?? throw new InvalidDataException("File wallet non valido.");
+        return Migrate(doc);
+    }
+
+    /// <summary>Migrazioni di schema all'apertura (§8). Per ora esiste solo la v1.</summary>
+    private static WalletDocument Migrate(WalletDocument doc) => doc.Version switch
+    {
+        CurrentVersion => doc,
+        _ => throw new InvalidDataException(
+            $"Versione file wallet {doc.Version} non supportata (max {CurrentVersion})."),
+    };
+}
+
+/// <summary>Stato sincronizzato persistito: permette di mostrare saldo/storico offline.</summary>
+public sealed class SyncCache
+{
+    public int TipHeight { get; set; }
+    public long ConfirmedSats { get; set; }
+    public long UnconfirmedSats { get; set; }
+    public int NextReceiveIndex { get; set; }
+    public int NextChangeIndex { get; set; }
+    public List<CachedTx> History { get; set; } = [];
+    public List<CachedUtxo> Utxos { get; set; } = [];
+}
+
+public sealed class CachedTx
+{
+    public required string Txid { get; set; }
+    public int Height { get; set; }
+    public long DeltaSats { get; set; }
+    public bool Verified { get; set; }
+}
+
+public sealed class CachedUtxo
+{
+    public required string Txid { get; set; }
+    public int Vout { get; set; }
+    public long ValueSats { get; set; }
+    public required string Address { get; set; }
+    public bool IsChange { get; set; }
+    public int AddressIndex { get; set; }
+    public int Height { get; set; }
+    public bool Frozen { get; set; }
+}