// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package types

import (
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/params"
	"github.com/holiman/uint256"
)

//go:generate go run ../../rlp/rlpgen -type Log -out gen_log_rlp.go
//go:generate go run github.com/fjl/gencodec -type Log -field-override logMarshaling -out gen_log_json.go

// Log represents a contract log event. These events are generated by the LOG opcode and
// stored/indexed by the node.
type Log struct {
	// Consensus fields:
	// address of the contract that generated the event
	Address common.Address `json:"address" gencodec:"required"`
	// list of topics provided by the contract.
	Topics []common.Hash `json:"topics" gencodec:"required"`
	// supplied by the contract, usually ABI-encoded
	Data []byte `json:"data" gencodec:"required"`

	// Derived fields. These fields are filled in by the node
	// but not secured by consensus.
	// block in which the transaction was included
	BlockNumber uint64 `json:"blockNumber" rlp:"-"`
	// hash of the transaction
	TxHash common.Hash `json:"transactionHash" gencodec:"required" rlp:"-"`
	// index of the transaction in the block
	TxIndex uint `json:"transactionIndex" rlp:"-"`
	// hash of the block in which the transaction was included
	BlockHash common.Hash `json:"blockHash" rlp:"-"`
	// timestamp of the block in which the transaction was included
	BlockTimestamp uint64 `json:"blockTimestamp" rlp:"-"`
	// index of the log in the block
	Index uint `json:"logIndex" rlp:"-"`

	// The Removed field is true if this log was reverted due to a chain reorganisation.
	// You must pay attention to this field if you receive logs through a filter query.
	Removed bool `json:"removed" rlp:"-"`
}

type logMarshaling struct {
	Data           hexutil.Bytes
	BlockNumber    hexutil.Uint64
	TxIndex        hexutil.Uint
	BlockTimestamp hexutil.Uint64
	Index          hexutil.Uint
}

// EthTransferLog creates and ETH transfer log according to EIP-7708.
// Specification: https://eips.ethereum.org/EIPS/eip-7708
func EthTransferLog(from, to common.Address, amount *uint256.Int) *Log {
	amount32 := amount.Bytes32()
	return &Log{
		Address: params.SystemAddress,
		Topics: []common.Hash{
			params.EthTransferLogEvent,
			common.BytesToHash(from.Bytes()),
			common.BytesToHash(to.Bytes()),
		},
		Data: amount32[:],
	}
}

// EthBurnLog creates an ETH burn log according to EIP-7708.
// Specification: https://eips.ethereum.org/EIPS/eip-7708
func EthBurnLog(from common.Address, amount *uint256.Int) *Log {
	amount32 := amount.Bytes32()
	return &Log{
		Address: params.SystemAddress,
		Topics: []common.Hash{
			params.EthBurnLogEvent,
			common.BytesToHash(from.Bytes()),
		},
		Data: amount32[:],
	}
}
