// 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 core implements the Ethereum consensus protocol.
package core

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"time"

	"github.com/ledgerwatch/erigon/common"
	"github.com/ledgerwatch/erigon/common/mclock"
	"github.com/ledgerwatch/erigon/consensus"
	"github.com/ledgerwatch/erigon/consensus/misc"
	"github.com/ledgerwatch/erigon/core/state"
	"github.com/ledgerwatch/erigon/core/types"
	"github.com/ledgerwatch/erigon/core/vm"
	"github.com/ledgerwatch/erigon/log"
	"github.com/ledgerwatch/erigon/metrics"
	"github.com/ledgerwatch/erigon/params"
)

var (
	blockExecutionTimer     = metrics.NewRegisteredTimer("chain/execution", nil)
	blockReorgInvalidatedTx = metrics.NewRegisteredMeter("chain/reorg/invalidTx", nil)
)

const (
	TriesInMemory = 128
)

// statsReportLimit is the time limit during import and export after which we
// always print out progress. This avoids the user wondering what's going on.
const statsReportLimit = 8 * time.Second

// report prints statistics if some number of blocks have been processed
// or more than a few seconds have passed since the last message.
func (st *InsertStats) Report(logPrefix string, chain []*types.Block, index int, toCommit bool) {
	// Fetch the timings for the batch
	var (
		now     = mclock.Now()
		elapsed = time.Duration(now) - time.Duration(st.StartTime)
	)
	// If we're at the last block of the batch or report period reached, log
	if index == len(chain)-1 || elapsed >= statsReportLimit || toCommit {
		// Count the number of transactions in this segment
		var txs int
		for _, block := range chain[st.lastIndex : index+1] {
			txs += len(block.Transactions())
		}
		end := chain[index]
		context := []interface{}{
			"blocks", st.Processed, "txs", txs,
			"elapsed", common.PrettyDuration(elapsed),
			"number", end.Number(), "hash", end.Hash(),
		}
		if timestamp := time.Unix(int64(end.Time()), 0); time.Since(timestamp) > time.Minute {
			context = append(context, []interface{}{"age", common.PrettyAge(timestamp)}...)
		}
		if st.queued > 0 {
			context = append(context, []interface{}{"queued", st.queued}...)
		}
		if st.ignored > 0 {
			context = append(context, []interface{}{"ignored", st.ignored}...)
		}
		log.Info(fmt.Sprintf("[%s] Imported new chain segment", logPrefix), context...)
		*st = InsertStats{StartTime: now, lastIndex: index + 1}
	}
}

// ExecuteBlockEphemerally runs a block from provided stateReader and
// writes the result to the provided stateWriter
func ExecuteBlockEphemerally(
	chainConfig *params.ChainConfig,
	vmConfig *vm.Config,
	getHeader func(hash common.Hash, number uint64) *types.Header,
	engine consensus.Engine,
	block *types.Block,
	stateReader state.StateReader,
	stateWriter state.WriterWithChangeSets,
	checkTEVM func(hash common.Hash) (bool, error),
) (types.Receipts, error) {
	defer blockExecutionTimer.UpdateSince(time.Now())
	block.Uncles()
	ibs := state.New(stateReader)
	header := block.Header()
	var receipts types.Receipts
	usedGas := new(uint64)
	gp := new(GasPool)
	gp.AddGas(block.GasLimit())

	if chainConfig.DAOForkSupport && chainConfig.DAOForkBlock != nil && chainConfig.DAOForkBlock.Cmp(block.Number()) == 0 {
		misc.ApplyDAOHardFork(ibs)
	}
	noop := state.NewNoopWriter()
	for i, tx := range block.Transactions() {
		ibs.Prepare(tx.Hash(), block.Hash(), i)
		writeTrace := false
		if vmConfig.Debug && vmConfig.Tracer == nil {
			vmConfig.Tracer = vm.NewStructLogger(&vm.LogConfig{})
			writeTrace = true
		}

		receipt, err := ApplyTransaction(chainConfig, getHeader, engine, nil, gp, ibs, noop, header, tx, usedGas, *vmConfig, checkTEVM)
		if writeTrace {
			w, err1 := os.Create(fmt.Sprintf("txtrace_%x.txt", tx.Hash()))
			if err1 != nil {
				panic(err1)
			}
			encoder := json.NewEncoder(w)
			logs := FormatLogs(vmConfig.Tracer.(*vm.StructLogger).StructLogs())
			if err2 := encoder.Encode(logs); err2 != nil {
				panic(err2)
			}
			if err2 := w.Close(); err2 != nil {
				panic(err2)
			}
			vmConfig.Tracer = nil
		}
		if err != nil {
			return nil, fmt.Errorf("could not apply tx %d from block %d [%v]: %w", i, block.NumberU64(), tx.Hash().Hex(), err)
		}
		if !vmConfig.NoReceipts {
			receipts = append(receipts, receipt)
		}
	}

	if chainConfig.IsByzantium(header.Number.Uint64()) && !vmConfig.NoReceipts {
		receiptSha := types.DeriveSha(receipts)
		if receiptSha != block.Header().ReceiptHash {
			return nil, fmt.Errorf("mismatched receipt headers for block %d", block.NumberU64())
		}
	}

	if !vmConfig.ReadOnly {
		if err := FinalizeBlockExecution(engine, block.Header(), block.Transactions(), block.Uncles(), stateWriter, chainConfig, ibs); err != nil {
			return nil, err
		}
	}
	if *usedGas != header.GasUsed {
		return nil, fmt.Errorf("gas used by execution: %d, in header: %d", *usedGas, header.GasUsed)
	}
	if !vmConfig.NoReceipts {
		bloom := types.CreateBloom(receipts)
		if bloom != header.Bloom {
			return nil, fmt.Errorf("bloom computed by execution: %x, in header: %x", bloom, header.Bloom)
		}
	}

	return receipts, nil
}

func FinalizeBlockExecution(engine consensus.Engine, header *types.Header, txs types.Transactions, uncles []*types.Header, stateWriter state.WriterWithChangeSets, cc *params.ChainConfig, ibs *state.IntraBlockState) error {
	// Finalize the block, applying any consensus engine specific extras (e.g. block rewards)
	engine.Finalize(cc, header, ibs, txs, uncles)

	ctx := cc.WithEIPsFlags(context.Background(), header.Number.Uint64())
	if err := ibs.CommitBlock(ctx, stateWriter); err != nil {
		return fmt.Errorf("committing block %d failed: %v", header.Number.Uint64(), err)
	}
	if err := stateWriter.WriteChangeSets(); err != nil {
		return fmt.Errorf("writing changesets for block %d failed: %v", header.Number.Uint64(), err)
	}
	return nil
}