signet-backend/endpoints/contribute.go

package endpoints

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	. "github.com/imosed/signet/data"
	"github.com/stellar/go/clients/horizonclient"
	"github.com/stellar/go/keypair"
	"github.com/stellar/go/network"
	"github.com/stellar/go/protocols/horizon"
	"github.com/stellar/go/txnbuild"
)

type ContributeRequest struct {
	PrivateKey string  `json:"privateKey"`
	Amount     float64 `json:"amount"`
	RewardFund uint    `json:"rewardFund"`
}

func Contribute(resp http.ResponseWriter, req *http.Request) {
	var cont ContributeRequest
	err := json.NewDecoder(req.Body).Decode(&cont)
	if err != nil {
		panic("Could not read in contribution")
	}

	var fund RewardFund

	Db.Table("reward_funds").Select("id", "deleted_at", "fund_wallet", "memo", "min_contribution").First(&fund, cont.RewardFund)

	if cont.Amount < fund.MinContribution || !strings.HasPrefix(cont.PrivateKey, "S") || !fund.DeletedAt.Time.IsZero() {
		err = json.NewEncoder(resp).Encode(&SuccessResponse{Success: false})
		if err != nil {
			panic("Could not deliver unsuccessful contribution response")
		}
		return
	}

	source := keypair.MustParseFull(cont.PrivateKey)
	sourceReq := horizonclient.AccountRequest{AccountID: source.Address()}
	var sourceAcct horizon.Account
	sourceAcct, err = client.AccountDetail(sourceReq)
	if err != nil {
		panic("Horizon client: could not get account details")
	}

	tx, err := txnbuild.NewTransaction(
		txnbuild.TransactionParams{
			SourceAccount:        &sourceAcct,
			IncrementSequenceNum: true,
			Operations: []txnbuild.Operation{
				&txnbuild.Payment{
					Destination:   fund.FundWallet,
					Amount:        fmt.Sprintf("%f", cont.Amount),
					Asset:         txnbuild.NativeAsset{},
					SourceAccount: source.Address(),
				},
			},
			BaseFee: txnbuild.MinBaseFee,
			Memo:    txnbuild.Memo(txnbuild.MemoText(fund.Memo)),
			Preconditions: txnbuild.Preconditions{
				TimeBounds: txnbuild.NewTimeout(15),
			},
		})
	if err != nil {
		panic("Could not create contribution transaction")
	}

	tx, err = tx.Sign(network.TestNetworkPassphrase, source)
	if err != nil {
		panic("Could not sign contribution transaction")
	}

	var response horizon.Transaction
	response, err = client.SubmitTransaction(tx)
	if err != nil {
		panic("Could not submit contribution transaction")
	}

	fmt.Println("Successful Transaction:")
	fmt.Println("Ledger:", response.Ledger)
	fmt.Println("Hash:", response.Hash)

	var result SuccessResponse
	result.Success = response.Successful && err == nil

	err = json.NewEncoder(resp).Encode(&result)
	if err != nil {
		panic("Could not create response for new contribution")
	}
}