/*
 * 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.api.jsonrpc.internal.methods;

import org.hyperledger.besu.ethereum.api.jsonrpc.RpcMethod;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.JsonRpcRequestContext;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.exception.InvalidJsonRpcParameters;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.parameters.JsonRpcParameter.JsonRpcParameterException;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.parameters.TransactionTraceParams;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.processor.BlockTrace;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.processor.BlockTracer;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.processor.Tracer;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcErrorResponse;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcResponse;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.JsonRpcSuccessResponse;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.response.RpcErrorType;
import org.hyperledger.besu.ethereum.api.jsonrpc.internal.results.DebugTraceTransactionResult;
import org.hyperledger.besu.ethereum.api.query.BlockchainQueries;
import org.hyperledger.besu.ethereum.core.Block;
import org.hyperledger.besu.ethereum.core.BlockHeaderFunctions;
import org.hyperledger.besu.ethereum.debug.TraceOptions;
import org.hyperledger.besu.ethereum.rlp.RLP;
import org.hyperledger.besu.ethereum.rlp.RLPException;
import org.hyperledger.besu.ethereum.vm.DebugOperationTracer;

import java.util.Collection;
import java.util.Optional;
import java.util.function.Supplier;

import org.apache.tuweni.bytes.Bytes;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DebugTraceBlock implements JsonRpcMethod {

  private static final Logger LOG = LoggerFactory.getLogger(DebugTraceBlock.class);
  private final Supplier<BlockTracer> blockTracerSupplier;
  private final BlockHeaderFunctions blockHeaderFunctions;
  private final BlockchainQueries blockchainQueries;

  public DebugTraceBlock(
      final Supplier<BlockTracer> blockTracerSupplier,
      final BlockHeaderFunctions blockHeaderFunctions,
      final BlockchainQueries blockchainQueries) {
    this.blockTracerSupplier = blockTracerSupplier;
    this.blockHeaderFunctions = blockHeaderFunctions;
    this.blockchainQueries = blockchainQueries;
  }

  @Override
  public String getName() {
    return RpcMethod.DEBUG_TRACE_BLOCK.getMethodName();
  }

  @Override
  public JsonRpcResponse response(final JsonRpcRequestContext requestContext) {
    final Block block;
    try {
      final String input = requestContext.getRequiredParameter(0, String.class);
      block = Block.readFrom(RLP.input(Bytes.fromHexString(input)), this.blockHeaderFunctions);
    } catch (final RLPException e) {
      LOG.debug("Failed to parse block RLP (index 0)", e);
      return new JsonRpcErrorResponse(
          requestContext.getRequest().getId(), RpcErrorType.INVALID_BLOCK_PARAMS);
    } catch (JsonRpcParameterException e) {
      throw new InvalidJsonRpcParameters(
          "Invalid block params (index 0)", RpcErrorType.INVALID_BLOCK_PARAMS, e);
    }
    final TraceOptions traceOptions;
    try {
      traceOptions =
          requestContext
              .getOptionalParameter(1, TransactionTraceParams.class)
              .map(TransactionTraceParams::traceOptions)
              .orElse(TraceOptions.DEFAULT);
    } catch (JsonRpcParameterException e) {
      throw new InvalidJsonRpcParameters(
          "Invalid transaction trace parameter (index 1)",
          RpcErrorType.INVALID_TRANSACTION_TRACE_PARAMS,
          e);
    }

    if (this.blockchainQueries.blockByHash(block.getHeader().getParentHash()).isPresent()) {
      final Collection<DebugTraceTransactionResult> results =
          Tracer.processTracing(
                  blockchainQueries,
                  Optional.of(block.getHeader()),
                  mutableWorldState ->
                      blockTracerSupplier
                          .get()
                          .trace(
                              mutableWorldState,
                              block,
                              new DebugOperationTracer(traceOptions, true))
                          .map(BlockTrace::getTransactionTraces)
                          .map(DebugTraceTransactionResult::of))
              .orElse(null);
      return new JsonRpcSuccessResponse(requestContext.getRequest().getId(), results);
    } else {
      return new JsonRpcErrorResponse(
          requestContext.getRequest().getId(), RpcErrorType.PARENT_BLOCK_NOT_FOUND);
    }
  }
}
