MEED-3806 Add ERC20 verification token API

gamification-evm-services/src/main/java/io/meeds/gamification/evm/blockchain/BlockchainConfiguration.java

@@ -16,9 +16,11 @@
 package io.meeds.gamification.evm.blockchain;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
+import org.exoplatform.wallet.contract.ERC20;
 import org.web3j.protocol.Web3j;
 import org.web3j.protocol.http.HttpService;
 

gamification-evm-services/src/main/java/io/meeds/gamification/evm/model/ERC20Token.java

@@ -0,0 +1,21 @@
+package io.meeds.gamification.evm.model;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.math.BigInteger;
+
+@Data
+@NoArgsConstructor
+@AllArgsConstructor
+public class ERC20Token {
+
+  private String name;
+
+  private String symbol;
+
+  private BigInteger totalSupply;
+
+  private BigInteger decimals;
+}

gamification-evm-services/src/main/java/io/meeds/gamification/evm/rest/TokensController.java

@@ -0,0 +1,45 @@
+package io.meeds.gamification.evm.rest;
+
+import io.meeds.gamification.evm.model.ERC20Token;
+import io.meeds.gamification.evm.service.BlockchainService;
+import org.exoplatform.commons.exception.ObjectNotFoundException;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.ResponseStatusException;
+
+import java.io.IOException;
+
+@RestController
+@RequestMapping("tokens")
+public class TokensController {
+
+  @Autowired
+  BlockchainService blockchainService;
+
+  @GetMapping
+  @Operation(summary = "Retrieves ERC20 Token details", method = "GET")
+  @ApiResponse(responseCode = "200", description = "Request fulfilled")
+  @ApiResponse(responseCode = "404", description = "Not found")
+  @ApiResponse(responseCode = "503", description = "Service unavailable")
+  public ERC20Token getERC20Token(@Parameter(description = "erc20 contract address", required = true)
+                                  @RequestParam("contractAddress")
+                                  String contractAddress) {
+      if (contractAddress == null) {
+          throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "Contract address is missing");
+      }
+      try {
+        return blockchainService.getERC20TokenDetails(contractAddress);
+      } catch (IOException e) {
+          throw new ResponseStatusException(HttpStatus.NOT_FOUND, "ERC20 doesn't exist");
+      }
+
+  }
+
+}

gamification-evm-services/src/main/java/io/meeds/gamification/evm/service/BlockchainService.java

@@ -16,7 +16,9 @@
 package io.meeds.gamification.evm.service;
 
 import io.meeds.gamification.evm.blockchain.BlockchainConfigurationProperties;
+import io.meeds.gamification.evm.model.ERC20Token;
 import io.meeds.gamification.evm.model.TokenTransferEvent;
+import io.micrometer.common.util.StringUtils;
 import org.apache.commons.collections.CollectionUtils;
 import org.exoplatform.wallet.contract.ERC20;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -48,9 +50,6 @@ public class BlockchainService {
   @Qualifier("polygonNetwork")
   private Web3j polygonWeb3j;
 
-  @Autowired
-  BlockchainConfigurationProperties blockchainProperties;
-
   public static final Event TRANSFER_EVENT = new Event("Transfer",
           Arrays.<TypeReference<?>>asList(new TypeReference<Address>(true) {}, new TypeReference<Address>(true) {}, new TypeReference<Uint256>(false) {}));
 
@@ -89,6 +88,26 @@ public Set<TokenTransferEvent> getTransferredTokensTransactions(long fromBlock,
     }
   }
 
+  public ERC20Token getERC20TokenDetails(String contractAddress) throws IOException {
+    String name = erc20Name(contractAddress);
+    String symbol = erc20Symbol(contractAddress);
+    BigInteger totalSupply = erc20TotalSupply(contractAddress);
+    BigInteger decimals = erc20Decimals(contractAddress);
+    ERC20Token erc20Token = new ERC20Token();
+    if (StringUtils.isNotBlank(name)
+        && StringUtils.isNotBlank(symbol)
+        && !totalSupply.equals(BigInteger.ZERO)
+        && !decimals.equals(BigInteger.ZERO)) {
+      erc20Token.setSymbol(symbol);
+      erc20Token.setDecimals(decimals);
+      erc20Token.setTotalSupply(totalSupply);
+      erc20Token.setName(name);
+      return erc20Token;
+    }
+    return null;
+
+  }
+
   /**
    * @return last block number
    */
@@ -100,6 +119,61 @@ public long getLastBlock() {
     }
   }
 
+  /**
+   * @return ERC20 token name
+   */
+  public String erc20Name(String contractAddress) {
+    try {
+      ERC20 erc20Token = loadPolygonERC20Token(contractAddress);
+      return erc20Token.name().send();
+    } catch (Exception e) {
+      throw new IllegalStateException("Error calling symbol name", e);
+    }
+  }
+
+  /**
+   * @return ERC20 token symbol
+   */
+  public String erc20Symbol(String contractAddress) {
+    try {
+      ERC20 erc20Token = loadPolygonERC20Token(contractAddress);
+      return erc20Token.symbol().send();
+    } catch (Exception e) {
+      throw new IllegalStateException("Error calling symbol method", e);
+    }
+  }
+
+  /**
+   * @return ERC20 token decimals
+   */
+  public BigInteger erc20Decimals(String contractAddress) {
+    try {
+      ERC20 erc20Token = loadPolygonERC20Token(contractAddress);
+      return erc20Token.decimals().send();
+    } catch (Exception e) {
+      throw new IllegalStateException("Error calling decimals method", e);
+    }
+  }
+
+  /**
+   * @return ERC20 token totalSupply
+   */
+  public BigInteger erc20TotalSupply(String contractAddress) {
+    try {
+      ERC20 erc20Token = loadPolygonERC20Token(contractAddress);
+      return erc20Token.totalSupply().send();
+    } catch (Exception e) {
+      throw new IllegalStateException("Error calling totalSupply method", e);
+    }
+  }
+
+  public ERC20 loadPolygonERC20Token(String contractAddress) {
+    return ERC20.load(contractAddress,
+            polygonWeb3j,
+            new ReadonlyTransactionManager(polygonWeb3j, Address.DEFAULT.toString()),
+            new StaticGasProvider(BigInteger.valueOf(20000000000l), BigInteger.valueOf(300000l)));
+  }
+
   private Stream<TokenTransferEvent> getTransferEvents(TransactionReceipt transactionReceipt, String contractAddress) {
     ERC20 erc20Token = ERC20.load(contractAddress,
                                   polygonWeb3j,