Refactor wallet file parsing (Fix: #5690) (#5692)

BTCPayServer/Services/WalletFileParsing/ElectrumWalletFileParser.cs

@@ -1,88 +1,61 @@
 #nullable enable
 using System;
+using System.Diagnostics.CodeAnalysis;
 using BTCPayServer;
 using NBitcoin;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 namespace BTCPayServer.Services.WalletFileParsing;
 public class ElectrumWalletFileParser : IWalletFileParser
 {
-    public (BTCPayServer.DerivationSchemeSettings? DerivationSchemeSettings, string? Error) TryParse(BTCPayNetwork network,
-        string data)
+    class ElectrumFormat
     {
-        try
+        internal class KeyStoreFormat
         {
-            var derivationSchemeParser = network.GetDerivationSchemeParser();
-            var jobj = JObject.Parse(data);
-            var result = new BTCPayServer.DerivationSchemeSettings() {Network = network};
-
-            if (jobj["keystore"] is JObject keyStore)
-            {
-                result.Source = "ElectrumFile";
-                jobj = keyStore;
-
-                if (!jobj.TryGetValue("xpub", StringComparison.InvariantCultureIgnoreCase, out var xpubToken))
-                {
-                    return (null, "no xpub");
-                }
-                var strategy = derivationSchemeParser.Parse(xpubToken.Value<string>(), false, false, true);
-                result.AccountDerivation = strategy;
-                result.AccountOriginal = xpubToken.Value<string>();
-                result.GetSigningAccountKeySettings();
-                
-                if (jobj["label"]?.Value<string>() is string label)
-                {
-                    try
-                    {
-                        result.Label = label;
-                    }
-                    catch
-                    {
-                        return (null, "Label was not a string");
-                    }
-                }
-
-                if (jobj["ckcc_xfp"]?.Value<uint>() is uint xfp)
-                {
-                    try
-                    {
-                        result.AccountKeySettings[0].RootFingerprint =
-                            new HDFingerprint(xfp);
-                    }
-                    catch
-                    {
-                        return (null, "fingerprint was not a uint");
-                    }
-                }
-
-                if (jobj["derivation"]?.Value<string>() is string derivation)
-                {
-                    try
-                    {
-                        result.AccountKeySettings[0].AccountKeyPath = new KeyPath(derivation);
-                    }
-                    catch
-                    {
-                        return (null, "derivation keypath was not valid");
-                    }
-                }
-                
-                
-                if (jobj.ContainsKey("ColdCardFirmwareVersion"))
-                {
-                    result.Source = "ColdCard";
-                }
-                else if (jobj.ContainsKey("CoboVaultFirmwareVersion"))
-                {
-                    result.Source = "CoboVault";
-                }
-                return (result, null);
-            }
-
+            public string? xpub { get; set; }
+            public string? label { get; set; }
+            public uint? ckcc_xfp { get; set; }
+            public string? derivation { get; set; }
+            public string? ColdCardFirmwareVersion { get; set; }
+            public string? CoboVaultFirmwareVersion { get; set; }
         }
-        catch (FormatException)
+        public KeyStoreFormat? keystore { get; set; }
+    }
+    public bool TryParse(BTCPayNetwork network, string data, [MaybeNullWhen(false)] out DerivationSchemeSettings derivationSchemeSettings)
+    {
+        derivationSchemeSettings = null;
+        var jobj = JsonConvert.DeserializeObject<ElectrumFormat>(data);
+        if (jobj?.keystore is null)
+            return false;
+
+        var result = new BTCPayServer.DerivationSchemeSettings() { Network = network };
+        var derivationSchemeParser = network.GetDerivationSchemeParser();
+        result.Source = "ElectrumFile";
+
+        if (jobj.keystore.xpub is null || jobj.keystore.ckcc_xfp is null || jobj.keystore.derivation is null)
+            return false;
+
+        var strategy = derivationSchemeParser.Parse(jobj.keystore.xpub, false, false, true);
+        result.AccountDerivation = strategy;
+        result.AccountOriginal = jobj.keystore.xpub;
+        result.GetSigningAccountKeySettings();
+
+        if (jobj.keystore.label is not null)
+            result.Label = jobj.keystore.label;
+
+        result.AccountKeySettings[0].RootFingerprint = new HDFingerprint(jobj.keystore.ckcc_xfp.Value);
+        result.AccountKeySettings[0].AccountKeyPath = new KeyPath(jobj.keystore.derivation);
+
+
+        if (jobj.keystore.ColdCardFirmwareVersion is not null)
         {
-            return (null, "invalid xpub");
+            result.Source = "ColdCard";
         }
-        return (null, null);
+        else if (jobj.keystore.CoboVaultFirmwareVersion is not null)
+        {
+            result.Source = "CoboVault";
+        }
+        derivationSchemeSettings = result;
+        return true;
     }
 }