package vm

import (
	"math/big"

	"github.com/ethereum/go-ethereum/ethutil"
	"github.com/ethereum/go-ethereum/logger"
)

var vmlogger = logger.NewLogger("VM")

type Type byte

const (
	StdVmTy Type = iota
	JitVmTy

	MaxVmTy
)

func NewVm(env Environment) VirtualMachine {
	switch env.VmType() {
	case JitVmTy:
		return NewJitVm(env)
	default:
		vmlogger.Infoln("unsupported vm type %d", env.VmType())
		fallthrough
	case StdVmTy:
		return New(env)
	}
}

var (
	GasStep         = big.NewInt(1)
	GasSha          = big.NewInt(10)
	GasSLoad        = big.NewInt(20)
	GasSStore       = big.NewInt(100)
	GasSStoreRefund = big.NewInt(100)
	GasBalance      = big.NewInt(20)
	GasCreate       = big.NewInt(100)
	GasCall         = big.NewInt(20)
	GasCreateByte   = big.NewInt(5)
	GasSha3Byte     = big.NewInt(10)
	GasSha256Byte   = big.NewInt(50)
	GasRipemdByte   = big.NewInt(50)
	GasMemory       = big.NewInt(1)
	GasData         = big.NewInt(5)
	GasTx           = big.NewInt(500)
	GasLog          = big.NewInt(32)
	GasSha256       = big.NewInt(50)
	GasRipemd       = big.NewInt(50)
	GasEcrecover    = big.NewInt(500)
	GasMemCpy       = big.NewInt(1)

	Pow256 = ethutil.BigPow(2, 256)

	LogTyPretty byte = 0x1
	LogTyDiff   byte = 0x2

	U256 = ethutil.U256
	S256 = ethutil.S256
)

const MaxCallDepth = 1025

func calcMemSize(off, l *big.Int) *big.Int {
	if l.Cmp(ethutil.Big0) == 0 {
		return ethutil.Big0
	}

	return new(big.Int).Add(off, l)
}

// Simple helper
func u256(n int64) *big.Int {
	return big.NewInt(n)
}

// Mainly used for print variables and passing to Print*
func toValue(val *big.Int) interface{} {
	// Let's assume a string on right padded zero's
	b := val.Bytes()
	if b[0] != 0 && b[len(b)-1] == 0x0 && b[len(b)-2] == 0x0 {
		return string(b)
	}

	return val
}