wallet_api: expose signed message verification details

diff --git a/src/wallet/api/wallet.cpp b/src/wallet/api/wallet.cpp
index 07e09dd..2c31920 100644
--- a/src/wallet/api/wallet.cpp
+++ b/src/wallet/api/wallet.cpp
@@ -2262,13 +2262,26 @@ std::string WalletImpl::signMessage(const std::string &message, const std::strin
 }
 
 bool WalletImpl::verifySignedMessage(const std::string &message, const std::string &address, const std::string &signature) const
+{
+  return verifySignedMessageWithDetails(message, address, signature).valid;
+}
+
+Wallet::MessageSignatureResult WalletImpl::verifySignedMessageWithDetails(const std::string &message, const std::string &address, const std::string &signature) const
 {
   cryptonote::address_parse_info info;
 
   if (!cryptonote::get_account_address_from_str(info, m_wallet->nettype(), address))
-    return false;
+    return {};
 
-  return m_wallet->verify(message, info.address, signature).valid;
+  const tools::wallet2::message_signature_result_t result = m_wallet->verify(message, info.address, signature);
+  MessageSignatureType type = MessageSignatureType_Invalid;
+  switch (result.type)
+  {
+    case tools::wallet2::sign_with_spend_key: type = MessageSignatureType_Spend; break;
+    case tools::wallet2::sign_with_view_key: type = MessageSignatureType_View; break;
+    default: break;
+  }
+  return {result.valid, result.version, result.old, type};
 }
 
 std::string WalletImpl::signMultisigParticipant(const std::string &message) const
diff --git a/src/wallet/api/wallet.h b/src/wallet/api/wallet.h
index 931f31d..30659cd 100644
--- a/src/wallet/api/wallet.h
+++ b/src/wallet/api/wallet.h
@@ -211,6 +211,7 @@ public:
     virtual bool checkReserveProof(const std::string &address, const std::string &message, const std::string &signature, bool &good, uint64_t &total, uint64_t &spent) const override;
     virtual std::string signMessage(const std::string &message, const std::string &address) override;
     virtual bool verifySignedMessage(const std::string &message, const std::string &address, const std::string &signature) const override;
+    virtual MessageSignatureResult verifySignedMessageWithDetails(const std::string &message, const std::string &address, const std::string &signature) const override;
     virtual std::string signMultisigParticipant(const std::string &message) const override;
     virtual bool verifyMessageWithPublicKey(const std::string &message, const std::string &publicKey, const std::string &signature) const override;
     virtual void startRefresh() override;
diff --git a/src/wallet/api/wallet2_api.h b/src/wallet/api/wallet2_api.h
index a8c1e8d..de13e55 100644
--- a/src/wallet/api/wallet2_api.h
+++ b/src/wallet/api/wallet2_api.h
@@ -445,6 +445,19 @@ struct Wallet
         BackgroundSync_CustomPassword = 2
     };
 
+    enum MessageSignatureType {
+        MessageSignatureType_Invalid = 0,
+        MessageSignatureType_Spend,
+        MessageSignatureType_View
+    };
+
+    struct MessageSignatureResult {
+        bool valid = false;
+        unsigned version = 0;
+        bool old = false;
+        MessageSignatureType type = MessageSignatureType_Invalid;
+    };
+
     virtual ~Wallet() = 0;
     virtual std::string seed(const std::string& seed_offset = "") const = 0;
     virtual std::string getSeedLanguage() const = 0;
@@ -1052,6 +1065,14 @@ struct Wallet
      * \return true if the signature verified, false otherwise
      */
     virtual bool verifySignedMessage(const std::string &message, const std::string &addres, const std::string &signature) const = 0;
+    /*!
+     * \brief verifySignedMessageWithDetails - verify a signature and identify the signing key and algorithm
+     * \param message - the message (arbitrary byte data)
+     * \param address - the address the signature claims to be made with
+     * \param signature - the signature
+     * \return the verification result, including the signature version and key type
+     */
+    virtual MessageSignatureResult verifySignedMessageWithDetails(const std::string &message, const std::string &address, const std::string &signature) const = 0;
 
     /*!
      * \brief signMultisigParticipant   signs given message with the multisig public signer key
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 5c4b414..e0a778b 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -1304,9 +1304,9 @@ private:
      */
     void set_account_tag_description(const std::string& tag, const std::string& description);
 
-    enum message_signature_type_t { sign_with_spend_key, sign_with_view_key };
+    enum message_signature_type_t { sign_with_spend_key, sign_with_view_key, sign_with_invalid_key };
     std::string sign(const std::string &data, message_signature_type_t signature_type, cryptonote::subaddress_index index = {0, 0}) const;
-    struct message_signature_result_t { bool valid; unsigned version; bool old; message_signature_type_t type; };
+    struct message_signature_result_t { bool valid = false; unsigned version = 0; bool old = false; message_signature_type_t type = sign_with_invalid_key; };
     message_signature_result_t verify(const std::string &data, const cryptonote::account_public_address &address, const std::string &signature) const;
 
     /*!