package main

import (
	"encoding/hex"
	"fmt"
	"github.com/kaspanet/kaspad/cmd/kaspawallet/keys"
	"github.com/kaspanet/kaspad/cmd/kaspawallet/libkaspawallet"
	utxopkg "github.com/kaspanet/kaspad/domain/consensus/utils/utxo"
	"github.com/kaspanet/kaspad/domain/dagconfig"

	"github.com/kaspanet/kaspad/app/appmessage"
	"github.com/kaspanet/kaspad/domain/consensus/model/externalapi"
	"github.com/kaspanet/kaspad/domain/consensus/utils/transactionid"
	"github.com/kaspanet/kaspad/infrastructure/network/rpcclient"
	"github.com/kaspanet/kaspad/util"
	"github.com/pkg/errors"
)

func send(conf *sendConfig) error {
	keysFile, err := keys.ReadKeysFile(conf.KeysFile)
	if err != nil {
		return err
	}

	toAddress, err := util.DecodeAddress(conf.ToAddress, conf.ActiveNetParams.Prefix)
	if err != nil {
		return err
	}

	fromAddress, err := libkaspawallet.Address(conf.NetParams(), keysFile.PublicKeys, keysFile.MinimumSignatures, keysFile.ECDSA)
	if err != nil {
		return err
	}

	client, err := connectToRPC(conf.NetParams(), conf.RPCServer)
	if err != nil {
		return err
	}
	utxos, err := fetchSpendableUTXOs(conf.NetParams(), client, fromAddress.String())
	if err != nil {
		return err
	}

	sendAmountSompi := uint64(conf.SendAmount * util.SompiPerKaspa)

	const feePerInput = 1000
	selectedUTXOs, changeSompi, err := selectUTXOs(utxos, sendAmountSompi, feePerInput)
	if err != nil {
		return err
	}

	psTx, err := libkaspawallet.CreateUnsignedTransaction(keysFile.PublicKeys,
		keysFile.MinimumSignatures,
		keysFile.ECDSA,
		[]*libkaspawallet.Payment{{
			Address: toAddress,
			Amount:  sendAmountSompi,
		}, {
			Address: fromAddress,
			Amount:  changeSompi,
		}},
		selectedUTXOs)
	if err != nil {
		return err
	}

	privateKeys, err := keysFile.DecryptPrivateKeys()
	if err != nil {
		return err
	}

	updatedPSTx, err := libkaspawallet.Sign(privateKeys, psTx, keysFile.ECDSA)
	if err != nil {
		return err
	}

	tx, err := libkaspawallet.ExtractTransaction(updatedPSTx)
	if err != nil {
		return err
	}

	transactionID, err := sendTransaction(client, tx)
	if err != nil {
		return err
	}

	fmt.Println("Transaction was sent successfully")
	fmt.Printf("Transaction ID: \t%s\n", transactionID)

	return nil
}

func fetchSpendableUTXOs(params *dagconfig.Params, client *rpcclient.RPCClient, address string) ([]*appmessage.UTXOsByAddressesEntry, error) {
	getUTXOsByAddressesResponse, err := client.GetUTXOsByAddresses([]string{address})
	if err != nil {
		return nil, err
	}
	virtualSelectedParentBlueScoreResponse, err := client.GetVirtualSelectedParentBlueScore()
	if err != nil {
		return nil, err
	}
	virtualSelectedParentBlueScore := virtualSelectedParentBlueScoreResponse.BlueScore

	spendableUTXOs := make([]*appmessage.UTXOsByAddressesEntry, 0)
	for _, entry := range getUTXOsByAddressesResponse.Entries {
		if !isUTXOSpendable(entry, virtualSelectedParentBlueScore, params.BlockCoinbaseMaturity) {
			continue
		}
		spendableUTXOs = append(spendableUTXOs, entry)
	}
	return spendableUTXOs, nil
}

func selectUTXOs(utxos []*appmessage.UTXOsByAddressesEntry, spendAmount uint64, feePerInput uint64) (
	selectedUTXOs []*externalapi.OutpointAndUTXOEntryPair, changeSompi uint64, err error) {

	selectedUTXOs = []*externalapi.OutpointAndUTXOEntryPair{}
	totalValue := uint64(0)

	for _, utxo := range utxos {
		txID, err := transactionid.FromString(utxo.Outpoint.TransactionID)
		if err != nil {
			return nil, 0, err
		}

		rpcUTXOEntry := utxo.UTXOEntry
		scriptPublicKeyScript, err := hex.DecodeString(rpcUTXOEntry.ScriptPublicKey.Script)
		if err != nil {
			return nil, 0, err
		}

		scriptPublicKey := &externalapi.ScriptPublicKey{
			Script:  scriptPublicKeyScript,
			Version: rpcUTXOEntry.ScriptPublicKey.Version,
		}

		utxoEntry := utxopkg.NewUTXOEntry(rpcUTXOEntry.Amount, scriptPublicKey, rpcUTXOEntry.IsCoinbase, rpcUTXOEntry.BlockDAAScore)
		selectedUTXOs = append(selectedUTXOs, &externalapi.OutpointAndUTXOEntryPair{
			Outpoint: &externalapi.DomainOutpoint{
				TransactionID: *txID,
				Index:         utxo.Outpoint.Index,
			},
			UTXOEntry: utxoEntry,
		})
		totalValue += utxo.UTXOEntry.Amount

		fee := feePerInput * uint64(len(selectedUTXOs))
		totalSpend := spendAmount + fee
		if totalValue >= totalSpend {
			break
		}
	}

	fee := feePerInput * uint64(len(selectedUTXOs))
	totalSpend := spendAmount + fee
	if totalValue < totalSpend {
		return nil, 0, errors.Errorf("Insufficient funds for send: %f required, while only %f available",
			float64(totalSpend)/util.SompiPerKaspa, float64(totalValue)/util.SompiPerKaspa)
	}

	return selectedUTXOs, totalValue - totalSpend, nil
}

func sendTransaction(client *rpcclient.RPCClient, tx *externalapi.DomainTransaction) (string, error) {
	submitTransactionResponse, err := client.SubmitTransaction(appmessage.DomainTransactionToRPCTransaction(tx))
	if err != nil {
		return "", errors.Wrapf(err, "error submitting transaction")
	}
	return submitTransactionResponse.TransactionID, nil
}