// Copyright 2018 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 rawdb

import (
	"github.com/XinFinOrg/XDPoSChain/common"
	"github.com/XinFinOrg/XDPoSChain/core/types"
	"github.com/XinFinOrg/XDPoSChain/ethdb"
	"github.com/XinFinOrg/XDPoSChain/log"
	"github.com/XinFinOrg/XDPoSChain/rlp"
)

type TxLookupEntry struct {
	BlockHash  common.Hash
	BlockIndex uint64
	Index      uint64
}

// WriteTxLookupEntriesByBlock stores a positional metadata for every transaction from
// a block, enabling hash based transaction and receipt lookups.
func WriteTxLookupEntriesByBlock(db ethdb.KeyValueWriter, block *types.Block) {
	// Iterate over each transaction and encode its metadata
	for i, tx := range block.Transactions() {
		entry := TxLookupEntry{
			BlockHash:  block.Hash(),
			BlockIndex: block.NumberU64(),
			Index:      uint64(i),
		}
		data, err := rlp.EncodeToBytes(entry)
		if err != nil {
			log.Crit("Failed to RLP encode TxLookupEntry", "err", err)
		}
		if err := db.Put(txLookupKey(tx.Hash()), data); err != nil {
			log.Crit("Failed to store tx lookup entry", "err", err)
		}
	}
}

// DeleteTxLookupEntry removes all transaction data associated with a hash.
func DeleteTxLookupEntry(db ethdb.KeyValueWriter, hash common.Hash) {
	db.Delete(txLookupKey(hash))
}