/*
 * Copyright ConsenSys AG.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */

package org.hyperledger.besu.ethereum.mainnet;

import static org.assertj.core.api.Assertions.assertThat;

import org.hyperledger.besu.config.GenesisConfigFile;
import org.hyperledger.besu.config.JsonUtil;
import org.hyperledger.besu.config.StubGenesisConfigOptions;
import org.hyperledger.besu.datatypes.Address;
import org.hyperledger.besu.datatypes.Hash;
import org.hyperledger.besu.ethereum.core.BlockHeader;
import org.hyperledger.besu.ethereum.core.BlockHeaderBuilder;
import org.hyperledger.besu.ethereum.core.Difficulty;
import org.hyperledger.besu.evm.internal.EvmConfiguration;
import org.hyperledger.besu.evm.log.LogsBloomFilter;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.stream.Stream;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.io.Resources;
import org.apache.tuweni.bytes.Bytes;
import org.apache.tuweni.units.bigints.UInt256;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

public class DifficultyCalculatorTests {

  public static Stream<Arguments> getTestParametersForConfig() throws IOException {
    return Stream.of(
        Arguments.of(
            "/BasicTests/difficultyMainNetwork.json",
            MainnetProtocolSchedule.fromConfig(
                GenesisConfigFile.mainnet()
                    .getConfigOptions(Map.of("shanghaiTime", "999999999999")),
                EvmConfiguration.DEFAULT)),
        Arguments.of(
          "/DifficultyTests/dfGrayGlacier/difficultyGrayGlacierForkBlock.json",
          MainnetProtocolSchedule.fromConfig(
              new StubGenesisConfigOptions().grayGlacierBlock(15050000))
        ),
        Arguments.of(
                "/DifficultyTests/dfGrayGlacier/difficultyGrayGlacierTimeDiff1.json",
                MainnetProtocolSchedule.fromConfig(
                        new StubGenesisConfigOptions().grayGlacierBlock(15050000))
        ),
        Arguments.of(
                "/DifficultyTests/dfGrayGlacier/difficultyGrayGlacierTimeDiff2.json",
                MainnetProtocolSchedule.fromConfig(
                        new StubGenesisConfigOptions().grayGlacierBlock(15050000))
        ),
        Arguments.of(
          "/DifficultyTests/dfArrowGlacier/difficultyArrowGlacierForkBlock.json",
          MainnetProtocolSchedule.fromConfig(
              new StubGenesisConfigOptions().arrowGlacierBlock(13773000))
        ),
        Arguments.of(
          "/DifficultyTests/dfArrowGlacier/difficultyArrowGlacierTimeDiff1.json",
          MainnetProtocolSchedule.fromConfig(
              new StubGenesisConfigOptions().arrowGlacierBlock(13773000))
        ),
        Arguments.of(
          "/DifficultyTests/dfArrowGlacier/difficultyArrowGlacierTimeDiff2.json",
          MainnetProtocolSchedule.fromConfig(
              new StubGenesisConfigOptions().arrowGlacierBlock(13773000))
        ),
        Arguments.of(
          "/DifficultyTests/dfByzantium/difficultyByzantium.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().byzantiumBlock(0))
        ),
        Arguments.of(
          "/DifficultyTests/dfConstantinople/difficultyConstantinople.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().constantinopleBlock(0))
        ),
        Arguments.of(
          "/DifficultyTests/dfEIP2384/difficultyEIP2384.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().muirGlacierBlock(0))
        ),
        Arguments.of(
          "/DifficultyTests/dfEIP2384/difficultyEIP2384_random.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().muirGlacierBlock(0))
        ),
        Arguments.of(
          "/DifficultyTests/dfEIP2384/difficultyEIP2384_random_to20M.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().muirGlacierBlock(0))
        ),
        Arguments.of(
          "/DifficultyTests/dfFrontier/difficultyFrontier.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions())
        ),
        Arguments.of(
          "/DifficultyTests/dfHomestead/difficultyHomestead.json",
          MainnetProtocolSchedule.fromConfig(new StubGenesisConfigOptions().homesteadBlock(0))
        ));
  }

  @ParameterizedTest(name = "TestFile: {0}")
  @MethodSource("getTestParametersForConfig")
  public void testDifficultyCalculation(final String testFile, final ProtocolSchedule protocolSchedule) throws IOException {
    final MainnetBlockHeaderFunctions blockHeaderFunctions = new MainnetBlockHeaderFunctions();
    final ObjectNode testObject =
        JsonUtil.objectNodeFromString(
            Resources.toString(
                DifficultyCalculatorTests.class.getResource(testFile), StandardCharsets.UTF_8));

    if (testObject.size() == 1) {
      final var topObjectIterator = testObject.fields();
      while (topObjectIterator.hasNext()) {
        final Map.Entry<String, JsonNode> testNameIterator = topObjectIterator.next();
        final var testHolderIter = testNameIterator.getValue().fields();
        while (testHolderIter.hasNext()) {
          final var testList = testHolderIter.next();
          if (!testList.getKey().equals("_info")) {
            testDifficulty(testFile, protocolSchedule, blockHeaderFunctions, (ObjectNode) testList.getValue());
          }
        }
      }
    } else {
      testDifficulty(testFile, protocolSchedule, blockHeaderFunctions, testObject);
    }
  }

  private void testDifficulty(
      final String testFile, final ProtocolSchedule protocolSchedule, final MainnetBlockHeaderFunctions blockHeaderFunctions, final ObjectNode testObject) {
    final var fields = testObject.fields();
    while (fields.hasNext()) {
      final var entry = fields.next();
      final JsonNode value = entry.getValue();
      final long currentBlockNumber = extractLong(value, "currentBlockNumber");
      String parentUncles = value.get("parentUncles").asText();
      final BlockHeader testHeader =
          BlockHeaderBuilder.create()
              .parentHash(Hash.EMPTY)
              .coinbase(Address.ZERO)
              .gasLimit(Long.MAX_VALUE)
              .stateRoot(Hash.EMPTY)
              .transactionsRoot(Hash.EMPTY)
              .receiptsRoot(Hash.EMPTY)
              .logsBloom(new LogsBloomFilter())
              .gasUsed(0)
              .extraData(Bytes.of())
              .mixHash(Hash.EMPTY)
              .nonce(0)
              .blockHeaderFunctions(blockHeaderFunctions)
              .timestamp(extractLong(value, "parentTimestamp"))
              .difficulty(Difficulty.fromHexString(value.get("parentDifficulty").asText()))
              .ommersHash(
                  parentUncles.equals("0x00")
                      ? Hash.EMPTY_LIST_HASH
                      : Hash.fromHexStringLenient(parentUncles))
              .number(currentBlockNumber)
              .buildBlockHeader();
      final long currentTime = extractLong(value, "currentTimestamp");
      final UInt256 currentDifficulty =
          UInt256.fromHexString(value.get("currentDifficulty").asText());
      final var spec = protocolSchedule.getByBlockHeader(testHeader);
      final var calculator = spec.getDifficultyCalculator();
      assertThat(UInt256.valueOf(calculator.nextDifficulty(currentTime, testHeader, null)))
          .describedAs("File %s Test %s", testFile, entry.getKey())
          .isEqualTo(currentDifficulty);
    }
  }

  private long extractLong(final JsonNode node, final String name) {
    return Long.decode(node.get(name).asText());
  }
}
