feat: add token transfer and approve builders

src/main/java/org/arkecosystem/crypto/enums/AbiFunction.java

@@ -4,7 +4,9 @@ public enum AbiFunction {
     VOTE("vote"),
     UNVOTE("unvote"),
     VALIDATOR_REGISTRATION("registerValidator"),
-    VALIDATOR_RESIGNATION("resignValidator");
+    VALIDATOR_RESIGNATION("resignValidator"),
+    TRANSFER("transfer"),
+    APPROVE("approve");
 
     private final String functionName;
 

src/main/java/org/arkecosystem/crypto/transactions/builder/TokenApproveBuilder.java

@@ -0,0 +1,44 @@
+package org.arkecosystem.crypto.transactions.builder;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.List;
+import org.arkecosystem.crypto.enums.AbiFunction;
+import org.arkecosystem.crypto.transactions.types.AbstractTransaction;
+import org.arkecosystem.crypto.transactions.types.EvmCall;
+import org.arkecosystem.crypto.utils.AbiEncoder;
+
+public class TokenApproveBuilder extends AbstractTransactionBuilder<TokenApproveBuilder> {
+    public TokenApproveBuilder contractAddress(String address) {
+        this.transaction.recipientAddress = address;
+        return this.instance();
+    }
+
+    public TokenApproveBuilder spender(String address, BigInteger amount) {
+        List<Object> args = new ArrayList<>();
+        args.add(address);
+        args.add(amount);
+
+        try {
+            String payload =
+                    new AbiEncoder("Abi.Token.json")
+                            .encodeFunctionCall(AbiFunction.APPROVE.toString(), args);
+
+            this.transaction.data = payload.replaceFirst("^0x", "");
+        } catch (Exception e) {
+            throw new RuntimeException("Error encoding token approve", e);
+        }
+
+        return this.instance();
+    }
+
+    @Override
+    protected AbstractTransaction getTransactionInstance() {
+        return new EvmCall();
+    }
+
+    @Override
+    protected TokenApproveBuilder instance() {
+        return this;
+    }
+}

src/main/java/org/arkecosystem/crypto/transactions/builder/TokenTransferBuilder.java

@@ -0,0 +1,44 @@
+package org.arkecosystem.crypto.transactions.builder;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.List;
+import org.arkecosystem.crypto.enums.AbiFunction;
+import org.arkecosystem.crypto.transactions.types.AbstractTransaction;
+import org.arkecosystem.crypto.transactions.types.EvmCall;
+import org.arkecosystem.crypto.utils.AbiEncoder;
+
+public class TokenTransferBuilder extends AbstractTransactionBuilder<TokenTransferBuilder> {
+    public TokenTransferBuilder contractAddress(String address) {
+        this.transaction.recipientAddress = address;
+        return this.instance();
+    }
+
+    public TokenTransferBuilder recipient(String address, BigInteger amount) {
+        List<Object> args = new ArrayList<>();
+        args.add(address);
+        args.add(amount);
+
+        try {
+            String payload =
+                    new AbiEncoder("Abi.Token.json")
+                            .encodeFunctionCall(AbiFunction.TRANSFER.toString(), args);
+
+            this.transaction.data = payload.replaceFirst("^0x", "");
+        } catch (Exception e) {
+            throw new RuntimeException("Error encoding token transfer", e);
+        }
+
+        return this.instance();
+    }
+
+    @Override
+    protected AbstractTransaction getTransactionInstance() {
+        return new EvmCall();
+    }
+
+    @Override
+    protected TokenTransferBuilder instance() {
+        return this;
+    }
+}

src/main/java/org/arkecosystem/crypto/utils/AbiBase.java

@@ -14,8 +14,10 @@ public abstract class AbiBase {
     protected List<Map<String, Object>> abi;
 
     public AbiBase() throws IOException {
-        String abiFilePath = "Abi.Consensus.json";
+        this("Abi.Consensus.json");
+    }
 
+    public AbiBase(String abiFilePath) throws IOException {
         InputStream abiInputStream = getClass().getClassLoader().getResourceAsStream(abiFilePath);
 
         ObjectMapper mapper = new ObjectMapper();

src/main/java/org/arkecosystem/crypto/utils/AbiEncoder.java

@@ -11,6 +11,10 @@ public AbiEncoder() throws IOException {
         super();
     }
 
+    public AbiEncoder(String abiFilePath) throws IOException {
+        super(abiFilePath);
+    }
+
     public String encodeFunctionCall(String functionName) throws Exception {
         return encodeFunctionCall(functionName, Collections.emptyList());
     }
@@ -266,7 +270,7 @@ private Map<String, Object> encodeNumber(Object value, boolean signed) throws Ex
             }
         }
         String hex = bigValue.toString(16);
-        String encoded = String.format("%064s", hex);
+        String encoded = "0".repeat(Math.max(0, 64 - hex.length())) + hex;
 
         return Map.of("dynamic", false, "encoded", "0x" + encoded);
     }