// Copyright 2017 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 tracers

import (
	"math/big"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/tests"
)

// callTrace is the result of a callTracer run.
type callTrace struct {
	Type    string          `json:"type"`
	From    common.Address  `json:"from"`
	To      common.Address  `json:"to"`
	Input   hexutil.Bytes   `json:"input"`
	Output  hexutil.Bytes   `json:"output"`
	Gas     *hexutil.Uint64 `json:"gas,omitempty"`
	GasUsed *hexutil.Uint64 `json:"gasUsed,omitempty"`
	Value   *hexutil.Big    `json:"value,omitempty"`
	Error   string          `json:"error,omitempty"`
	Calls   []callTrace     `json:"calls,omitempty"`
}

func BenchmarkTransactionTrace(b *testing.B) {
	key, _ := crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	from := crypto.PubkeyToAddress(key.PublicKey)
	gas := uint64(1000000) // 1M gas
	to := common.HexToAddress("0x00000000000000000000000000000000deadbeef")
	signer := types.LatestSignerForChainID(big.NewInt(1337))
	tx, err := types.SignNewTx(key, signer,
		&types.LegacyTx{
			Nonce:    1,
			GasPrice: big.NewInt(500),
			Gas:      gas,
			To:       &to,
		})
	if err != nil {
		b.Fatal(err)
	}
	txContext := vm.TxContext{
		Origin:   from,
		GasPrice: tx.GasPrice(),
	}
	context := vm.BlockContext{
		CanTransfer: core.CanTransfer,
		Transfer:    core.Transfer,
		Coinbase:    common.Address{},
		BlockNumber: new(big.Int).SetUint64(uint64(5)),
		Time:        new(big.Int).SetUint64(uint64(5)),
		Difficulty:  big.NewInt(0xffffffff),
		GasLimit:    gas,
	}
	alloc := core.GenesisAlloc{}
	// The code pushes 'deadbeef' into memory, then the other params, and calls CREATE2, then returns
	// the address
	loop := []byte{
		byte(vm.JUMPDEST), //  [ count ]
		byte(vm.PUSH1), 0, // jumpdestination
		byte(vm.JUMP),
	}
	alloc[common.HexToAddress("0x00000000000000000000000000000000deadbeef")] = core.GenesisAccount{
		Nonce:   1,
		Code:    loop,
		Balance: big.NewInt(1),
	}
	alloc[from] = core.GenesisAccount{
		Nonce:   1,
		Code:    []byte{},
		Balance: big.NewInt(500000000000000),
	}
	_, statedb := tests.MakePreState(rawdb.NewMemoryDatabase(), alloc, false)
	// Create the tracer, the EVM environment and run it
	tracer := vm.NewStructLogger(&vm.LogConfig{
		Debug: false,
		//DisableStorage: true,
		//EnableMemory: false,
		//EnableReturnData: false,
	})
	evm := vm.NewEVM(context, txContext, statedb, params.AllEthashProtocolChanges, vm.Config{Debug: true, Tracer: tracer})
	msg, err := tx.AsMessage(signer)
	if err != nil {
		b.Fatalf("failed to prepare transaction for tracing: %v", err)
	}
	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		snap := statedb.Snapshot()
		st := core.NewStateTransition(evm, msg, new(core.GasPool).AddGas(tx.Gas()))
		_, err = st.TransitionDb()
		if err != nil {
			b.Fatal(err)
		}
		statedb.RevertToSnapshot(snap)
		if have, want := len(tracer.StructLogs()), 244752; have != want {
			b.Fatalf("trace wrong, want %d steps, have %d", want, have)
		}
		tracer.Reset()
	}
}
