package federation

import (
	"encoding/json"
	"errors"

	log "github.com/sirupsen/logrus"

	"github.com/vapor/blockchain/signers"
	"github.com/vapor/crypto/ed25519"
	"github.com/vapor/crypto/ed25519/chainkd"
	"github.com/vapor/protocol/vm/vmutil"
)

const fedCfgJson = `
{
    "fed_xpubs" : [
    	"7f23aae65ee4307c38d342699e328f21834488e18191ebd66823d220b5a58303496c9d09731784372bade78d5e9a4a6249b2cfe2e3a85464e5a4017aa5611e47",
    	"585e20143db413e45fbc82f03cb61f177e9916ef1df0012daa8cbf6dbb1025ce8f98e51ae319327b63505b64fdbbf6d36ef916d79e6dd67d51b0bfe76fe544c5",
    	"b58170b51ca61604028ba1cb412377dfc2bc6567c0afc84c83aae1c0c297d0227ccf568561df70851f4144bbf069b525129f2434133c145e35949375b22a6c9d",
    	"983705ae71949c1a5d0fcf953658dd9ecc549f02c63e197b4d087ae31148097ece816bbc60d9012c316139fc550fa0f4b00beb0887f6b152f7a69bc8f392b9fa",
    	"d72fb92fa13bf3e0deb39de3a47c8d6eef5584719f7877c82a4c009f78fddf924d9706d48f15b2c782ec80b6bdd621a1f7ba2a0044b0e6f92245de9436885cb9",
    	"6798460919e8dc7095ee8b9f9d65033ef3da8c2334813149da5a1e52e9c6da07ba7d0e7379baaa0c8bdcb21890a54e6b7290bee077c645ee4b74b0c1ae9da59a"
    ],
    "fed_quorum" : 4
}
`

type federation struct {
	XPubs       []chainkd.XPub `json:"fed_xpubs"`
	Quorum      int            `json:"fed_quorum"`
	Path        [][]byte
	PegInScript []byte
}

func parseFedConfig() *federation {
	fed := &federation{}
	if err := json.Unmarshal([]byte(fedCfgJson), fed); err != nil {
		log.Fatalf("invalid federation config json")
	}

	return fed
}

func CheckFedConfig() error {
	fed := parseFedConfig()
	if len(fed.XPubs) <= 1 {
		return errors.New("federation should have more than 1 member")
	}
	if fed.Quorum < 1 {
		return errors.New("federation quorum should be >= 1")
	}

	return nil
}

func GetFederation() *federation {
	fed := parseFedConfig()
	// use 1 for AssetKeyIndex
	assetSigner, err := signers.Create("asset", fed.XPubs, fed.Quorum, 1, signers.BIP0032)
	if err != nil {
		panic("fail to create federation assetSigner")
	}

	fed.Path = signers.GetBip0032Path(assetSigner, signers.AssetKeySpace)
	derivedXPubs := chainkd.DeriveXPubs(assetSigner.XPubs, fed.Path)
	derivedPKs := chainkd.XPubKeys(derivedXPubs)
	if pegInScript, err := buildPegInScript(derivedPKs, assetSigner.Quorum); err == nil {
		fed.PegInScript = pegInScript
	} else {
		panic("fail to build peg-in script")
	}

	return fed
}

func buildPegInScript(pubkeys []ed25519.PublicKey, nrequired int) (program []byte, err error) {
	controlProg, err := vmutil.P2SPMultiSigProgram(pubkeys, nrequired)
	if err != nil {
		return nil, err
	}
	builder := vmutil.NewBuilder()
	builder.AddRawBytes(controlProg)
	prog, err := builder.Build()
	return prog, err
}