/*
 * 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.core;

import org.hyperledger.besu.datatypes.Hash;
import org.hyperledger.besu.ethereum.mainnet.TransactionReceiptType;
import org.hyperledger.besu.ethereum.rlp.BytesValueRLPInput;
import org.hyperledger.besu.ethereum.rlp.RLP;
import org.hyperledger.besu.ethereum.rlp.RLPException;
import org.hyperledger.besu.ethereum.rlp.RLPInput;
import org.hyperledger.besu.ethereum.rlp.RLPOutput;
import org.hyperledger.besu.evm.log.Log;
import org.hyperledger.besu.evm.log.LogsBloomFilter;
import org.hyperledger.besu.plugin.data.TransactionType;

import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.stream.Collectors;

import com.google.common.base.MoreObjects;
import org.apache.tuweni.bytes.Bytes;

/**
 * A transaction receipt, containing information pertaining a transaction execution.
 *
 * <p>Transaction receipts have two different formats: state root-encoded and status-encoded. The
 * difference between these two formats is that the state root-encoded transaction receipt contains
 * the state root for world state after the transaction has been processed (e.g. not invalid) and
 * the status-encoded transaction receipt instead has contains the status of the transaction (e.g. 1
 * for success and 0 for failure). The other transaction receipt fields are the same for both
 * formats: logs, logs bloom, and cumulative gas used in the block. The TransactionReceiptType
 * attribute is the best way to check which format has been used.
 */
public class TransactionReceipt implements org.hyperledger.besu.plugin.data.TransactionReceipt {

  private static final int NONEXISTENT = -1;

  private final TransactionType transactionType;
  private final Hash stateRoot;
  private final long cumulativeGasUsed;
  private final List<Log> logs;
  private final LogsBloomFilter bloomFilter;
  private final int status;
  private final TransactionReceiptType transactionReceiptType;
  private final Optional<Bytes> revertReason;

  /**
   * Creates an instance of a state root-encoded transaction receipt.
   *
   * @param stateRoot the state root for the world state after the transaction has been processed
   * @param cumulativeGasUsed the total amount of gas consumed in the block after this transaction
   * @param logs the logs generated within the transaction
   * @param revertReason the revert reason for a failed transaction (if applicable)
   */
  public TransactionReceipt(
      final Hash stateRoot,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final Optional<Bytes> revertReason) {
    this(
        TransactionType.FRONTIER,
        stateRoot,
        NONEXISTENT,
        cumulativeGasUsed,
        logs,
        LogsBloomFilter.builder().insertLogs(logs).build(),
        revertReason);
  }

  private TransactionReceipt(
      final TransactionType transactionType,
      final Hash stateRoot,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final LogsBloomFilter bloomFilter,
      final Optional<Bytes> revertReason) {
    this(
        transactionType,
        stateRoot,
        NONEXISTENT,
        cumulativeGasUsed,
        logs,
        bloomFilter,
        revertReason);
  }

  /**
   * Creates an instance of a status-encoded transaction receipt.
   *
   * @param status the status code for the transaction (1 for success and 0 for failure)
   * @param cumulativeGasUsed the total amount of gas consumed in the block after this transaction
   * @param logs the logs generated within the transaction
   * @param revertReason the revert reason for a failed transaction (if applicable)
   */
  public TransactionReceipt(
      final int status,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final Optional<Bytes> revertReason) {
    this(
        TransactionType.FRONTIER,
        null,
        status,
        cumulativeGasUsed,
        logs,
        LogsBloomFilter.builder().insertLogs(logs).build(),
        revertReason);
  }

  public TransactionReceipt(
      final TransactionType transactionType,
      final int status,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final LogsBloomFilter bloomFilter,
      final Optional<Bytes> revertReason) {
    this(transactionType, null, status, cumulativeGasUsed, logs, bloomFilter, revertReason);
  }

  public TransactionReceipt(
      final TransactionType transactionType,
      final int status,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final Optional<Bytes> maybeRevertReason) {
    this(
        transactionType,
        status,
        cumulativeGasUsed,
        logs,
        LogsBloomFilter.builder().insertLogs(logs).build(),
        maybeRevertReason);
  }

  private TransactionReceipt(
      final TransactionType transactionType,
      final Hash stateRoot,
      final int status,
      final long cumulativeGasUsed,
      final List<Log> logs,
      final LogsBloomFilter bloomFilter,
      final Optional<Bytes> revertReason) {
    this.transactionType = transactionType;
    this.stateRoot = stateRoot;
    this.cumulativeGasUsed = cumulativeGasUsed;
    this.status = status;
    this.logs = logs;
    this.bloomFilter = bloomFilter;
    this.transactionReceiptType =
        stateRoot == null ? TransactionReceiptType.STATUS : TransactionReceiptType.ROOT;
    this.revertReason = revertReason;
  }

  /**
   * Write an RLP representation.
   *
   * @param out The RLP output to write to
   */
  public void writeTo(final RLPOutput out) {
    writeTo(out, false);
  }

  public void writeToWithRevertReason(final RLPOutput out) {
    writeTo(out, true);
  }

  private void writeTo(final RLPOutput rlpOutput, final boolean withRevertReason) {
    if (transactionType.equals(TransactionType.FRONTIER)) {
      writeToForReceiptTrie(rlpOutput, withRevertReason);
    } else {
      rlpOutput.writeBytes(RLP.encode(out -> writeToForReceiptTrie(out, withRevertReason)));
    }
  }

  public void writeToForReceiptTrie(final RLPOutput rlpOutput, final boolean withRevertReason) {
    if (!transactionType.equals(TransactionType.FRONTIER)) {
      rlpOutput.writeIntScalar(transactionType.getSerializedType());
    }

    rlpOutput.startList();

    // Determine whether it's a state root-encoded transaction receipt
    // or is a status code-encoded transaction receipt.
    if (stateRoot != null) {
      rlpOutput.writeBytes(stateRoot);
    } else {
      rlpOutput.writeLongScalar(status);
    }
    rlpOutput.writeLongScalar(cumulativeGasUsed);
    rlpOutput.writeBytes(bloomFilter);
    rlpOutput.writeList(logs, Log::writeTo);
    if (withRevertReason && revertReason.isPresent()) {
      rlpOutput.writeBytes(revertReason.get());
    }
    rlpOutput.endList();
  }

  /**
   * Creates a transaction receipt for the given RLP
   *
   * @param input the RLP-encoded transaction receipt
   * @return the transaction receipt
   */
  public static TransactionReceipt readFrom(final RLPInput input) {
    return readFrom(input, true);
  }

  /**
   * Creates a transaction receipt for the given RLP
   *
   * @param rlpInput the RLP-encoded transaction receipt
   * @param revertReasonAllowed whether the rlp input is allowed to have a revert reason
   * @return the transaction receipt
   */
  public static TransactionReceipt readFrom(
      final RLPInput rlpInput, final boolean revertReasonAllowed) {
    RLPInput input = rlpInput;
    TransactionType transactionType = TransactionType.FRONTIER;
    if (!rlpInput.nextIsList()) {
      final Bytes typedTransactionReceiptBytes = input.readBytes();
      transactionType = TransactionType.of(typedTransactionReceiptBytes.get(0));
      input = new BytesValueRLPInput(typedTransactionReceiptBytes.slice(1), false);
    }

    input.enterList();
    // Get the first element to check later to determine the
    // correct transaction receipt encoding to use.
    final RLPInput firstElement = input.readAsRlp();
    final long cumulativeGas = input.readLongScalar();
    // The logs below will populate the bloom filter upon construction.
    // TODO consider validating that the logs and bloom filter match.
    final LogsBloomFilter bloomFilter = LogsBloomFilter.readFrom(input);
    final List<Log> logs = input.readList(Log::readFrom);
    final Optional<Bytes> revertReason;
    if (input.isEndOfCurrentList()) {
      revertReason = Optional.empty();
    } else {
      if (!revertReasonAllowed) {
        throw new RLPException("Unexpected value at end of TransactionReceipt");
      }
      revertReason = Optional.of(input.readBytes());
    }

    // Status code-encoded transaction receipts have a single
    // byte for success (0x01) or failure (0x80).
    if (firstElement.raw().size() == 1) {
      final int status = firstElement.readIntScalar();
      input.leaveList();
      return new TransactionReceipt(
          transactionType, status, cumulativeGas, logs, bloomFilter, revertReason);
    } else {
      final Hash stateRoot = Hash.wrap(firstElement.readBytes32());
      input.leaveList();
      return new TransactionReceipt(
          transactionType, stateRoot, cumulativeGas, logs, bloomFilter, revertReason);
    }
  }

  /**
   * Returns the state root for a state root-encoded transaction receipt
   *
   * @return the state root if the transaction receipt is state root-encoded; otherwise {@code null}
   */
  public Hash getStateRoot() {
    return stateRoot;
  }

  /**
   * Returns the total amount of gas consumed in the block after the transaction has been processed.
   *
   * @return the total amount of gas consumed in the block after the transaction has been processed
   */
  @Override
  public long getCumulativeGasUsed() {
    return cumulativeGasUsed;
  }

  /**
   * Returns the logs generated by the transaction.
   *
   * @return the logs generated by the transaction
   */
  @Override
  public List<? extends org.hyperledger.besu.plugin.data.Log> getLogs() {
    return logs.stream().map(LogsWrapper::new).collect(Collectors.toList());
  }

  /**
   * Returns the logs generated by the transaction.
   *
   * @return the logs generated by the transaction
   */
  public List<Log> getLogsList() {
    return logs;
  }

  /**
   * Returns the logs bloom filter for the logs generated by the transaction
   *
   * @return the logs bloom filter for the logs generated by the transaction
   */
  @Override
  public LogsBloomFilter getBloomFilter() {
    return bloomFilter;
  }

  /**
   * Returns the status code for the status-encoded transaction receipt
   *
   * @return the status code if the transaction receipt is status-encoded; otherwise {@code -1}
   */
  @Override
  public int getStatus() {
    return status;
  }

  public TransactionReceiptType getTransactionReceiptType() {
    return transactionReceiptType;
  }

  @Override
  public Optional<Bytes> getRevertReason() {
    return revertReason;
  }

  @Override
  public boolean equals(final Object obj) {
    if (obj == this) {
      return true;
    }
    if (!(obj instanceof TransactionReceipt)) {
      return false;
    }
    final TransactionReceipt other = (TransactionReceipt) obj;
    return logs.equals(other.getLogsList())
        && Objects.equals(stateRoot, other.stateRoot)
        && cumulativeGasUsed == other.getCumulativeGasUsed()
        && status == other.status;
  }

  @Override
  public int hashCode() {
    return Objects.hash(logs, stateRoot, cumulativeGasUsed);
  }

  @Override
  public String toString() {
    return MoreObjects.toStringHelper(this)
        .add("stateRoot", stateRoot)
        .add("cumulativeGasUsed", cumulativeGasUsed)
        .add("logs", logs)
        .add("bloomFilter", bloomFilter)
        .add("status", status)
        .add("transactionReceiptType", transactionReceiptType)
        .toString();
  }
}
