package node

import (
	"crypto/ecdsa"
	"math/big"
	"os"

	"github.com/harmony-one/harmony/core"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/harmony-one/harmony/internal/utils"

	"github.com/ethereum/go-ethereum/common/hexutil"
)

//constants related to staking
//The first four bytes of the call data for a function call specifies the function to be called.
//It is the first (left, high-order in big-endian) four bytes of the Keccak-256 (SHA-3)
//Refer: https://solidity.readthedocs.io/en/develop/abi-spec.html

const (
	funcSingatureBytes = 4
	lockPeriodInEpochs = 3 // This should be in sync with contracts/StakeLockContract.sol
)

// StakeInfoReturnValue is the struct for the return value of listLockedAddresses func in stake contract.
type StakeInfoReturnValue struct {
	LockedAddresses  []common.Address
	BlsAddresses     [][20]byte
	BlockNums        []*big.Int
	LockPeriodCounts []*big.Int // The number of locking period the token will be locked.
	Amounts          []*big.Int
}

// StakeInfo stores the staking information for a staker.
type StakeInfo struct {
	BlsAddress      [20]byte
	BlockNum        *big.Int
	LockPeriodCount *big.Int // The number of locking period the token will be locked.
	Amount          *big.Int
}

// UpdateStakingList updates staking information by querying the staking smart contract.
func (node *Node) UpdateStakingList(stakeInfoReturnValue *StakeInfoReturnValue) {
	node.CurrentStakes = make(map[common.Address]*StakeInfo)
	if stakeInfoReturnValue != nil {
		for i, addr := range stakeInfoReturnValue.LockedAddresses {
			blockNum := stakeInfoReturnValue.BlockNums[i]
			lockPeriodCount := stakeInfoReturnValue.LockPeriodCounts[i]

			startEpoch := core.GetEpochFromBlockNumber(blockNum.Uint64())
			curEpoch := core.GetEpochFromBlockNumber(node.blockchain.CurrentBlock().NumberU64())

			if startEpoch == curEpoch {
				continue // The token are counted into stakes at the beginning of next epoch.
			}
			if curEpoch-startEpoch <= lockPeriodCount.Uint64()*lockPeriodInEpochs {
				node.CurrentStakes[addr] = &StakeInfo{
					stakeInfoReturnValue.BlsAddresses[i],
					blockNum,
					lockPeriodCount,
					stakeInfoReturnValue.Amounts[i],
				}
			}
		}
	}
}

func (node *Node) printStakingList() {
	utils.GetLogInstance().Info("\n")
	utils.GetLogInstance().Info("CURRENT STAKING INFO [START] ------------------------------------")
	for addr, stakeInfo := range node.CurrentStakes {
		utils.GetLogInstance().Info("", "Address", addr, "StakeInfo", stakeInfo)
	}
	utils.GetLogInstance().Info("CURRENT STAKING INFO [END}   ------------------------------------")
	utils.GetLogInstance().Info("\n")
}

//The first four bytes of the call data for a function call specifies the function to be called.
//It is the first (left, high-order in big-endian) four bytes of the Keccak-256 (SHA-3)
//Refer: https://solidity.readthedocs.io/en/develop/abi-spec.html
func decodeStakeCall(getData []byte) int64 {
	value := new(big.Int)
	value.SetBytes(getData[funcSingatureBytes:]) //Escape the method call.
	return value.Int64()
}

//The first four bytes of the call data for a function call specifies the function to be called.
//It is the first (left, high-order in big-endian) four bytes of the Keccak-256 (SHA-3)
//Refer: https://solidity.readthedocs.io/en/develop/abi-spec.html
//gets the function signature from data.
func decodeFuncSign(data []byte) string {
	funcSign := hexutil.Encode(data[:funcSingatureBytes]) //The function signature is first 4 bytes of data in ethereum
	return funcSign
}

// StoreStakingKeyFromFile load the staking private key and store it in local keyfile
func StoreStakingKeyFromFile(keyfile string, priKey string) *ecdsa.PrivateKey {
	// contract.FakeAccounts[0] gets minted tokens in genesis block of beacon chain.
	key, err := crypto.HexToECDSA(priKey)
	if err != nil {
		utils.GetLogInstance().Error("Unable to get staking key")
		os.Exit(1)
	}
	if err := crypto.SaveECDSA(keyfile, key); err != nil {
		utils.GetLogInstance().Error("Unable to save the private key", "error", err)
		os.Exit(1)
	}
	// TODO(minhdoan): Enable this back.
	// key, err := crypto.LoadECDSA(keyfile)
	// if err != nil {
	// 	GetLogInstance().Error("no key file. Let's create a staking private key")
	// 	key, err = crypto.GenerateKey()
	// 	if err != nil {
	// 		GetLogInstance().Error("Unable to generate the private key")
	// 		os.Exit(1)
	// 	}
	// 	if err = crypto.SaveECDSA(keyfile, key); err != nil {
	// 		GetLogInstance().Error("Unable to save the private key", "error", err)
	// 		os.Exit(1)
	// 	}
	// }
	return key
}