package viacoin

import (
	"bytes"

	"github.com/martinboehm/btcd/wire"
	"github.com/martinboehm/btcutil/chaincfg"
	"github.com/trezor/blockbook/bchain"
	"github.com/trezor/blockbook/bchain/coins/btc"
	"github.com/trezor/blockbook/bchain/coins/utils"
)

// magic numbers
const (
	MainnetMagic wire.BitcoinNet = 0xcbc6680f
	RegtestMagic wire.BitcoinNet = 0x377b972d
)

// chain parameters
var (
	MainNetParams chaincfg.Params
	RegtestParams chaincfg.Params
)

func init() {
	MainNetParams = chaincfg.MainNetParams
	MainNetParams.Net = MainnetMagic

	// Mainnet address encoding magics
	MainNetParams.PubKeyHashAddrID = []byte{71} // base58 prefix: v
	MainNetParams.ScriptHashAddrID = []byte{33} // base68 prefix: E
	MainNetParams.Bech32HRPSegwit = "via"

	RegtestParams = chaincfg.RegressionNetParams
	RegtestParams.Net = RegtestMagic

	// Regtest address encoding magics
	RegtestParams.PubKeyHashAddrID = []byte{111} // base58 prefix: m or n
	RegtestParams.ScriptHashAddrID = []byte{196} // base58 prefix: 2
	RegtestParams.Bech32HRPSegwit = "tvia"
}

// ViacoinParser handle
type ViacoinParser struct {
	*btc.BitcoinParser
}

// NewViacoinParser returns new VertcoinParser instance
func NewViacoinParser(params *chaincfg.Params, c *btc.Configuration) *ViacoinParser {
	return &ViacoinParser{BitcoinParser: btc.NewBitcoinParser(params, c)}
}

// GetChainParams returns network parameters
func GetChainParams(chain string) *chaincfg.Params {
	if !chaincfg.IsRegistered(&MainNetParams) {
		err := chaincfg.Register(&MainNetParams)
		if err == nil {
			err = chaincfg.Register(&RegtestParams)
		}
		if err != nil {
			panic(err)
		}
	}

	switch chain {
	case "regtest":
		return &RegtestParams
	default:
		return &MainNetParams
	}
}

// ParseBlock parses raw block to our Block struct
// it has special handling for Auxpow blocks that cannot be parsed by standard btc wire parse
func (p *ViacoinParser) ParseBlock(b []byte) (*bchain.Block, error) {
	r := bytes.NewReader(b)
	w := wire.MsgBlock{}
	h := wire.BlockHeader{}
	err := h.Deserialize(r)
	if err != nil {
		return nil, err
	}

	if (h.Version & utils.VersionAuxpow) != 0 {
		if err = utils.SkipAuxpow(r); err != nil {
			return nil, err
		}
	}

	err = utils.DecodeTransactions(r, 0, wire.WitnessEncoding, &w)
	if err != nil {
		return nil, err
	}

	txs := make([]bchain.Tx, len(w.Transactions))
	for ti, t := range w.Transactions {
		txs[ti] = p.TxFromMsgTx(t, false)
	}

	return &bchain.Block{
		BlockHeader: bchain.BlockHeader{
			Size: len(b),
			Time: h.Timestamp.Unix(),
		},
		Txs: txs,
	}, nil
}