add importdescriptors RPC and tests for native descriptor wallets

Co-authored-by: Andrew Chow <achow101-github@achow101.com>

src/wallet/wallet.cpp

@@ -4399,6 +4399,7 @@ void CWallet::SetupDescriptorScriptPubKeyMans()
 
 void CWallet::SetActiveScriptPubKeyMan(uint256 id, OutputType type, bool internal, bool memonly)
 {
+    WalletLogPrintf("Setting spkMan to active: id = %s, type = %d, internal = %d\n", id.ToString(), static_cast<int>(type), static_cast<int>(internal));
     auto& spk_mans = internal ? m_internal_spk_managers : m_external_spk_managers;
     auto spk_man = m_spk_managers.at(id).get();
     spk_man->SetType(type, internal);
@@ -4421,3 +4422,88 @@ bool CWallet::IsLegacy() const
     auto spk_man = dynamic_cast<LegacyScriptPubKeyMan*>(m_internal_spk_managers.at(OutputType::LEGACY));
     return spk_man != nullptr;
 }
+
+DescriptorScriptPubKeyMan* CWallet::GetDescriptorScriptPubKeyMan(const WalletDescriptor& desc) const
+{
+    for (auto& spk_man_pair : m_spk_managers) {
+        // Try to downcast to DescriptorScriptPubKeyMan then check if the descriptors match
+        DescriptorScriptPubKeyMan* spk_manager = dynamic_cast<DescriptorScriptPubKeyMan*>(spk_man_pair.second.get());
+        if (spk_manager != nullptr && spk_manager->HasWalletDescriptor(desc)) {
+            return spk_manager;
+        }
+    }
+
+    return nullptr;
+}
+
+ScriptPubKeyMan* CWallet::AddWalletDescriptor(WalletDescriptor& desc, const FlatSigningProvider& signing_provider, const std::string& label)
+{
+    if (!IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
+        WalletLogPrintf("Cannot add WalletDescriptor to a non-descriptor wallet\n");
+        return nullptr;
+    }
+
+    LOCK(cs_wallet);
+    auto new_spk_man = std::unique_ptr<DescriptorScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this, desc));
+
+    // If we already have this descriptor, remove it from the maps but add the existing cache to desc
+    auto old_spk_man = GetDescriptorScriptPubKeyMan(desc);
+    if (old_spk_man) {
+        WalletLogPrintf("Update existing descriptor: %s\n", desc.descriptor->ToString());
+
+        {
+            LOCK(old_spk_man->cs_desc_man);
+            new_spk_man->SetCache(old_spk_man->GetWalletDescriptor().cache);
+        }
+
+        // Remove from maps of active spkMans
+        auto old_spk_man_id = old_spk_man->GetID();
+        for (bool internal : {false, true}) {
+            for (OutputType t : OUTPUT_TYPES) {
+                auto active_spk_man = GetScriptPubKeyMan(t, internal);
+                if (active_spk_man && active_spk_man->GetID() == old_spk_man_id) {
+                    if (internal) {
+                        m_internal_spk_managers.erase(t);
+                    } else {
+                        m_external_spk_managers.erase(t);
+                    }
+                    break;
+                }
+            }
+        }
+        m_spk_managers.erase(old_spk_man_id);
+    }
+
+    // Add the private keys to the descriptor
+    for (const auto& entry : signing_provider.keys) {
+        const CKey& key = entry.second;
+        new_spk_man->AddDescriptorKey(key, key.GetPubKey());
+    }
+
+    // Top up key pool, the manager will generate new scriptPubKeys internally
+    new_spk_man->TopUp();
+
+    // Apply the label if necessary
+    // Note: we disable labels for ranged descriptors
+    if (!desc.descriptor->IsRange()) {
+        auto script_pub_keys = new_spk_man->GetScriptPubKeys();
+        if (script_pub_keys.empty()) {
+            WalletLogPrintf("Could not generate scriptPubKeys (cache is empty)\n");
+            return nullptr;
+        }
+
+        CTxDestination dest;
+        if (ExtractDestination(script_pub_keys.at(0), dest)) {
+            SetAddressBook(dest, label, "receive");
+        }
+    }
+
+    // Save the descriptor to memory
+    auto ret = new_spk_man.get();
+    m_spk_managers[new_spk_man->GetID()] = std::move(new_spk_man);
+
+    // Save the descriptor to DB
+    ret->WriteDescriptor();
+
+    return ret;
+}