support better script descriptors in wallet policy

src/main/java/com/sparrowwallet/drongo/policy/Policy.java

@@ -37,19 +37,19 @@ public class Policy {
 
     public static Policy getPolicy(PolicyType policyType, ScriptType scriptType, List<Keystore> keystores, Integer threshold) {
         if(SINGLE.equals(policyType)) {
-            if(P2PK.equals(scriptType)) {
+            return new Policy(new Miniscript(scriptType.getDescriptor() + keystores.get(0).getScriptName() + scriptType.getCloseDescriptor()));
-                return new Policy(new Miniscript("pk(" + keystores.get(0).getScriptName() + ")"));
-            }
-            return new Policy(new Miniscript("pkh(" + keystores.get(0).getScriptName() + ")"));
         }
 
         if(MULTI.equals(policyType)) {
-            StringBuilder builder = new StringBuilder("multi(");
+            StringBuilder builder = new StringBuilder();
+            builder.append(scriptType.getDescriptor());
+            builder.append(MULTISIG.getDescriptor());
             builder.append(threshold);
             for(Keystore keystore : keystores) {
                 builder.append(",").append(keystore.getScriptName());
             }
-            builder.append(")");
+            builder.append(MULTISIG.getCloseDescriptor());
+            builder.append(scriptType.getCloseDescriptor());
             return new Policy(new Miniscript(builder.toString()));
         }
 

src/main/java/com/sparrowwallet/drongo/protocol/ScriptType.java

@@ -58,7 +58,7 @@ public enum ScriptType {
 
         @Override
         public String getOutputDescriptor(ECKey key) {
-            return "pk(" + Utils.bytesToHex(key.getPubKey()) + ")";
+            return getDescriptor() + Utils.bytesToHex(key.getPubKey()) + getCloseDescriptor();
         }
 
         @Override
@@ -66,6 +66,11 @@ public enum ScriptType {
             throw new ProtocolException("No script derived output descriptor for non pay to script type");
         }
 
+        @Override
+        public String getDescriptor() {
+            return "pk(";
+        }
+
         @Override
         public boolean isScriptType(Script script) {
             List<ScriptChunk> chunks = script.chunks;
@@ -165,7 +170,7 @@ public enum ScriptType {
 
         @Override
         public String getOutputDescriptor(ECKey key) {
-            return "pkh(" + Utils.bytesToHex(key.getPubKey()) + ")";
+            return getDescriptor() + Utils.bytesToHex(key.getPubKey()) + getCloseDescriptor();
         }
 
         @Override
@@ -173,6 +178,11 @@ public enum ScriptType {
             throw new ProtocolException("No script derived output descriptor for non pay to script type");
         }
 
+        @Override
+        public String getDescriptor() {
+            return "pkh(";
+        }
+
         @Override
         public boolean isScriptType(Script script) {
             List<ScriptChunk> chunks = script.chunks;
@@ -320,7 +330,12 @@ public enum ScriptType {
                 joiner.add(Utils.bytesToHex(pubKey));
             }
 
-            return "multi(" + threshold + "," + joiner.toString() + ")";
+            return getDescriptor() + threshold + "," + joiner.toString() + getCloseDescriptor();
+        }
+
+        @Override
+        public String getDescriptor() {
+            return "multi(";
         }
 
         @Override
@@ -461,7 +476,12 @@ public enum ScriptType {
                 throw new IllegalArgumentException("Can only create output descriptor from multisig script");
             }
 
-            return "sh(" + MULTISIG.getOutputDescriptor(script) + ")";
+            return getDescriptor() + MULTISIG.getOutputDescriptor(script) + getCloseDescriptor();
+        }
+
+        @Override
+        public String getDescriptor() {
+            return "sh(";
         }
 
         @Override
@@ -577,7 +597,7 @@ public enum ScriptType {
 
         @Override
         public String getOutputDescriptor(ECKey key) {
-            return "sh(wpkh(" + Utils.bytesToHex(key.getPubKey()) + "))";
+            return getDescriptor() + Utils.bytesToHex(key.getPubKey()) + getCloseDescriptor();
         }
 
         @Override
@@ -585,6 +605,11 @@ public enum ScriptType {
             throw new ProtocolException("No script derived output descriptor for non pay to script type");
         }
 
+        @Override
+        public String getDescriptor() {
+            return "sh(wpkh(";
+        }
+
         @Override
         public boolean isScriptType(Script script) {
             return P2SH.isScriptType(script);
@@ -676,7 +701,12 @@ public enum ScriptType {
                 throw new IllegalArgumentException("Can only create output descriptor from multisig script");
             }
 
-            return "sh(wsh(" + MULTISIG.getOutputDescriptor(script) + "))";
+            return getDescriptor() + MULTISIG.getOutputDescriptor(script) + getCloseDescriptor();
+        }
+
+        @Override
+        public String getDescriptor() {
+            return "sh(wsh(";
         }
 
         @Override
@@ -765,7 +795,7 @@ public enum ScriptType {
 
         @Override
         public String getOutputDescriptor(ECKey key) {
-            return "wpkh(" + Utils.bytesToHex(key.getPubKey()) + ")";
+            return getDescriptor() + Utils.bytesToHex(key.getPubKey()) + getCloseDescriptor();
         }
 
         @Override
@@ -773,6 +803,11 @@ public enum ScriptType {
             throw new ProtocolException("No script derived output descriptor for non pay to script type");
         }
 
+        @Override
+        public String getDescriptor() {
+            return "wpkh(";
+        }
+
         @Override
         public boolean isScriptType(Script script) {
             List<ScriptChunk> chunks = script.chunks;
@@ -874,7 +909,12 @@ public enum ScriptType {
                 throw new IllegalArgumentException("Can only create output descriptor from multisig script");
             }
 
-            return "wsh(" + MULTISIG.getOutputDescriptor(script) + ")";
+            return getDescriptor() + MULTISIG.getOutputDescriptor(script) + getCloseDescriptor();
+        }
+
+        @Override
+        public String getDescriptor() {
+            return "wsh(";
         }
 
         @Override
@@ -1003,6 +1043,12 @@ public enum ScriptType {
 
     public abstract String getOutputDescriptor(Script script);
 
+    public abstract String getDescriptor();
+
+    public String getCloseDescriptor() {
+        return getDescriptor().chars().filter(ch -> ch == '(').boxed().map(n -> ")").collect(Collectors.joining());
+    }
+
     public abstract boolean isScriptType(Script script);
 
     public abstract byte[] getHashFromScript(Script script);
@@ -1055,6 +1101,16 @@ public enum ScriptType {
         return null;
     }
 
+    public static ScriptType fromDescriptor(String descriptor) {
+        for(ScriptType type : values()) {
+            if(type.getDescriptor().equals(descriptor.toLowerCase())) {
+                return type;
+            }
+        }
+
+        return null;
+    }
+
     /**
      * Determines the dust threshold for the given output for this script type.
      *

src/test/java/com/sparrowwallet/drongo/wallet/PolicyTest.java

@@ -0,0 +1,42 @@
+package com.sparrowwallet.drongo.wallet;
+
+import com.sparrowwallet.drongo.policy.Policy;
+import com.sparrowwallet.drongo.policy.PolicyType;
+import com.sparrowwallet.drongo.protocol.ScriptType;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.List;
+
+public class PolicyTest {
+    @Test
+    public void testMiniscriptParsing() {
+        Keystore keystore1 = new Keystore("Keystore 1");
+        Keystore keystore2 = new Keystore("Keystore 2");
+        Keystore keystore3 = new Keystore("Keystore 3");
+
+        Policy policy = Policy.getPolicy(PolicyType.SINGLE, ScriptType.P2PKH, List.of(keystore1), 1);
+        Assert.assertEquals("pkh(keystore1)", policy.getMiniscript().toString());
+        Assert.assertEquals(1, policy.getNumSignaturesRequired());
+
+        Policy policy2 = Policy.getPolicy(PolicyType.SINGLE, ScriptType.P2SH_P2WPKH, List.of(keystore1), 1);
+        Assert.assertEquals("sh(wpkh(keystore1))", policy2.getMiniscript().toString());
+        Assert.assertEquals(1, policy2.getNumSignaturesRequired());
+
+        Policy policy3 = Policy.getPolicy(PolicyType.SINGLE, ScriptType.P2WPKH, List.of(keystore1), 1);
+        Assert.assertEquals("wpkh(keystore1)", policy3.getMiniscript().toString());
+        Assert.assertEquals(1, policy3.getNumSignaturesRequired());
+
+        Policy policy4 = Policy.getPolicy(PolicyType.MULTI, ScriptType.P2SH, List.of(keystore1, keystore2, keystore3), 2);
+        Assert.assertEquals("sh(multi(2,keystore1,keystore2,keystore3))", policy4.getMiniscript().toString());
+        Assert.assertEquals(2, policy4.getNumSignaturesRequired());
+
+        Policy policy5 = Policy.getPolicy(PolicyType.MULTI, ScriptType.P2SH_P2WSH, List.of(keystore1, keystore2, keystore3), 2);
+        Assert.assertEquals("sh(wsh(multi(2,keystore1,keystore2,keystore3)))", policy5.getMiniscript().toString());
+        Assert.assertEquals(2, policy5.getNumSignaturesRequired());
+
+        Policy policy6 = Policy.getPolicy(PolicyType.MULTI, ScriptType.P2WSH, List.of(keystore1, keystore2, keystore3), 2);
+        Assert.assertEquals("wsh(multi(2,keystore1,keystore2,keystore3))", policy6.getMiniscript().toString());
+        Assert.assertEquals(2, policy6.getNumSignaturesRequired());
+    }
+}