// Copyright 2015 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

import (
	"crypto/ecdsa"
	"io/ioutil"
	"math/big"
	"os"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/event"
	"github.com/ethereum/go-ethereum/params"
)

func BenchmarkInsertChain_empty_memdb(b *testing.B) {
	benchInsertChain(b, false, nil)
}
func BenchmarkInsertChain_empty_diskdb(b *testing.B) {
	benchInsertChain(b, true, nil)
}
func BenchmarkInsertChain_valueTx_memdb(b *testing.B) {
	benchInsertChain(b, false, genValueTx(0))
}
func BenchmarkInsertChain_valueTx_diskdb(b *testing.B) {
	benchInsertChain(b, true, genValueTx(0))
}
func BenchmarkInsertChain_valueTx_100kB_memdb(b *testing.B) {
	benchInsertChain(b, false, genValueTx(100*1024))
}
func BenchmarkInsertChain_valueTx_100kB_diskdb(b *testing.B) {
	benchInsertChain(b, true, genValueTx(100*1024))
}
func BenchmarkInsertChain_uncles_memdb(b *testing.B) {
	benchInsertChain(b, false, genUncles)
}
func BenchmarkInsertChain_uncles_diskdb(b *testing.B) {
	benchInsertChain(b, true, genUncles)
}
func BenchmarkInsertChain_ring200_memdb(b *testing.B) {
	benchInsertChain(b, false, genTxRing(200))
}
func BenchmarkInsertChain_ring200_diskdb(b *testing.B) {
	benchInsertChain(b, true, genTxRing(200))
}
func BenchmarkInsertChain_ring1000_memdb(b *testing.B) {
	benchInsertChain(b, false, genTxRing(1000))
}
func BenchmarkInsertChain_ring1000_diskdb(b *testing.B) {
	benchInsertChain(b, true, genTxRing(1000))
}

var (
	// This is the content of the genesis block used by the benchmarks.
	benchRootKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	benchRootAddr   = crypto.PubkeyToAddress(benchRootKey.PublicKey)
	benchRootFunds  = common.BigPow(2, 100)
)

// genValueTx returns a block generator that includes a single
// value-transfer transaction with n bytes of extra data in each
// block.
func genValueTx(nbytes int) func(int, *BlockGen) {
	return func(i int, gen *BlockGen) {
		toaddr := common.Address{}
		data := make([]byte, nbytes)
		gas := IntrinsicGas(data)
		tx, _ := types.NewTransaction(gen.TxNonce(benchRootAddr), toaddr, big.NewInt(1), gas, nil, data).SignECDSA(benchRootKey)
		gen.AddTx(tx)
	}
}

var (
	ringKeys  = make([]*ecdsa.PrivateKey, 1000)
	ringAddrs = make([]common.Address, len(ringKeys))
)

func init() {
	ringKeys[0] = benchRootKey
	ringAddrs[0] = benchRootAddr
	for i := 1; i < len(ringKeys); i++ {
		ringKeys[i], _ = crypto.GenerateKey()
		ringAddrs[i] = crypto.PubkeyToAddress(ringKeys[i].PublicKey)
	}
}

// genTxRing returns a block generator that sends ether in a ring
// among n accounts. This is creates n entries in the state database
// and fills the blocks with many small transactions.
func genTxRing(naccounts int) func(int, *BlockGen) {
	from := 0
	return func(i int, gen *BlockGen) {
		gas := CalcGasLimit(gen.PrevBlock(i - 1))
		for {
			gas.Sub(gas, params.TxGas)
			if gas.Cmp(params.TxGas) < 0 {
				break
			}
			to := (from + 1) % naccounts
			tx := types.NewTransaction(
				gen.TxNonce(ringAddrs[from]),
				ringAddrs[to],
				benchRootFunds,
				params.TxGas,
				nil,
				nil,
			)
			tx, _ = tx.SignECDSA(ringKeys[from])
			gen.AddTx(tx)
			from = to
		}
	}
}

// genUncles generates blocks with two uncle headers.
func genUncles(i int, gen *BlockGen) {
	if i >= 6 {
		b2 := gen.PrevBlock(i - 6).Header()
		b2.Extra = []byte("foo")
		gen.AddUncle(b2)
		b3 := gen.PrevBlock(i - 6).Header()
		b3.Extra = []byte("bar")
		gen.AddUncle(b3)
	}
}

func benchInsertChain(b *testing.B, disk bool, gen func(int, *BlockGen)) {
	// Create the database in memory or in a temporary directory.
	var db ethdb.Database
	if !disk {
		db, _ = ethdb.NewMemDatabase()
	} else {
		dir, err := ioutil.TempDir("", "eth-core-bench")
		if err != nil {
			b.Fatalf("cannot create temporary directory: %v", err)
		}
		defer os.RemoveAll(dir)
		db, err = ethdb.NewLDBDatabase(dir, 0)
		if err != nil {
			b.Fatalf("cannot create temporary database: %v", err)
		}
		defer db.Close()
	}

	// Generate a chain of b.N blocks using the supplied block
	// generator function.
	genesis := WriteGenesisBlockForTesting(db, GenesisAccount{benchRootAddr, benchRootFunds})
	chain, _ := GenerateChain(genesis, db, b.N, gen)

	// Time the insertion of the new chain.
	// State and blocks are stored in the same DB.
	evmux := new(event.TypeMux)
	chainman, _ := NewBlockChain(db, FakePow{}, evmux)
	defer chainman.Stop()
	b.ReportAllocs()
	b.ResetTimer()
	if i, err := chainman.InsertChain(chain); err != nil {
		b.Fatalf("insert error (block %d): %v\n", i, err)
	}
}