feat: system transfers (#44)

* Support for subtracting negative numbers

* Add command for listing balances. Calculate system balances

* Scaffold topup-balance command

* Implement system topup feature

* Wire cmd command; fix currency ticker for internal payments

* Fix test cases

* Fix money.String() for negative numbers

cmd/list_balances.go

@@ -0,0 +1,89 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/olekukonko/tablewriter"
+	"github.com/oxygenpay/oxygen/internal/app"
+	"github.com/oxygenpay/oxygen/internal/money"
+	"github.com/oxygenpay/oxygen/internal/service/wallet"
+	"github.com/spf13/cobra"
+)
+
+var listBalancesCommand = &cobra.Command{
+	Use:   "list-balances",
+	Short: "List all balances including system balances",
+	Run:   listBalances,
+}
+
+func listBalances(_ *cobra.Command, _ []string) {
+	var (
+		ctx               = context.Background()
+		cfg               = resolveConfig()
+		service           = app.New(ctx, cfg)
+		walletsService    = service.Locator().WalletService()
+		blockchainService = service.Locator().BlockchainService()
+		logger            = service.Logger()
+	)
+
+	opts := wallet.ListAllBalancesOpts{
+		WithUSD:            true,
+		WithSystemBalances: true,
+		HideEmpty:          true,
+	}
+
+	balances, err := walletsService.ListAllBalances(ctx, opts)
+	if err != nil {
+		logger.Error().Err(err).Msg("Unable to list wallets")
+	}
+
+	t := tablewriter.NewWriter(os.Stdout)
+	defer t.Render()
+
+	t.SetBorder(false)
+	t.SetAutoWrapText(false)
+	t.SetHeaderAlignment(tablewriter.ALIGN_LEFT)
+	t.SetAlignment(tablewriter.ALIGN_LEFT)
+
+	t.SetHeader([]string{"id", "type", "entity Id", "currency", "test", "amount", "usd"})
+
+	add := func(b *wallet.Balance) {
+		currency, err := blockchainService.GetCurrencyByTicker(b.Currency)
+		if err != nil {
+			logger.Error().Err(err)
+			return
+		}
+
+		t.Append(balanceAsRow(currency, b))
+	}
+
+	for _, b := range balances[wallet.EntityTypeMerchant] {
+		add(b)
+	}
+	for _, b := range balances[wallet.EntityTypeWallet] {
+		add(b)
+	}
+	for _, b := range balances[wallet.EntityTypeSystem] {
+		add(b)
+	}
+}
+
+func balanceAsRow(currency money.CryptoCurrency, b *wallet.Balance) []string {
+	isTest := b.NetworkID != currency.NetworkID
+
+	line := fmt.Sprintf(
+		"%d,%s,%d,%s,%t,%s,%s",
+		b.ID,
+		b.EntityType,
+		b.EntityID,
+		b.Currency,
+		isTest,
+		b.Amount.String(),
+		b.UsdAmount.String(),
+	)
+
+	return strings.Split(line, ",")
+}

cmd/root.go

@@ -77,6 +77,10 @@ func init() {
 	createUserCommand.PersistentFlags().BoolVar(&overridePassword, "override-password", false, "overrides password if user already exists")
 
 	rootCmd.AddCommand(listWalletsCommand)
+	rootCmd.AddCommand(listBalancesCommand)
+
+	topupBalanceSetup(topupBalanceCommand)
+	rootCmd.AddCommand(topupBalanceCommand)
 
 	rand.Seed(time.Now().Unix())
 }

cmd/topup_balance.go

@@ -0,0 +1,159 @@
+package cmd
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/oxygenpay/oxygen/internal/app"
+	"github.com/oxygenpay/oxygen/internal/money"
+	"github.com/oxygenpay/oxygen/internal/service/processing"
+	"github.com/oxygenpay/oxygen/internal/service/wallet"
+	"github.com/oxygenpay/oxygen/internal/util"
+	"github.com/samber/lo"
+	"github.com/spf13/cobra"
+)
+
+var topupBalanceCommand = &cobra.Command{
+	Use:   "topup-balance",
+	Short: "Topup Merchant's balance using 'system' funds",
+	Run:   topupBalance,
+}
+
+var topupBalanceArgs = struct {
+	MerchantID *int64
+	Ticker     *string
+	Amount     *string
+	Comment    *string
+	IsTest     *bool
+}{
+	MerchantID: util.Ptr(int64(0)),
+	Ticker:     util.Ptr(""),
+	Amount:     util.Ptr(""),
+	Comment:    util.Ptr(""),
+	IsTest:     util.Ptr(false),
+}
+
+func topupBalance(_ *cobra.Command, _ []string) {
+	var (
+		ctx               = context.Background()
+		cfg               = resolveConfig()
+		service           = app.New(ctx, cfg)
+		blockchainService = service.Locator().BlockchainService()
+		merchantService   = service.Locator().MerchantService()
+		walletService     = service.Locator().WalletService()
+		processingService = service.Locator().ProcessingService()
+		logger            = service.Logger()
+		exit              = func(err error, message string) { logger.Fatal().Err(err).Msg(message) }
+	)
+
+	// 1. Get input
+	currency, err := blockchainService.GetCurrencyByTicker(*topupBalanceArgs.Ticker)
+	if err != nil {
+		exit(err, "invalid ticker")
+	}
+
+	amount, err := money.CryptoFromStringFloat(currency.Ticker, *topupBalanceArgs.Amount, currency.Decimals)
+	if err != nil {
+		exit(err, "invalid amount")
+	}
+
+	merchant, err := merchantService.GetByID(ctx, *topupBalanceArgs.MerchantID, false)
+	if err != nil {
+		exit(err, "invalid merchant id")
+	}
+
+	if *topupBalanceArgs.Comment == "" {
+		exit(nil, "comment should not be empty")
+	}
+
+	isTest := *topupBalanceArgs.IsTest
+	comment := *topupBalanceArgs.Comment
+
+	// 2. Locate system balance
+	balances, err := walletService.ListAllBalances(ctx, wallet.ListAllBalancesOpts{WithSystemBalances: true})
+	if err != nil {
+		exit(err, "unable to list balances")
+	}
+
+	systemBalance, found := lo.Find(balances[wallet.EntityTypeSystem], func(b *wallet.Balance) bool {
+		tickerMatches := b.Currency == currency.Ticker
+		networkMatches := b.NetworkID == currency.ChooseNetwork(isTest)
+
+		return tickerMatches && networkMatches
+	})
+
+	if !found {
+		exit(err, "unable to locate system balance")
+	}
+
+	logger.Info().
+		Str("amount", amount.String()).
+		Str("currency", currency.Ticker).
+		Str("merchant.name", merchant.Name).
+		Int64("merchant.id", merchant.ID).
+		Str("merchant.uuid", merchant.UUID.String()).
+		Str("system_balance", systemBalance.Amount.String()).
+		Msg("Performing internal topup from the system balance")
+
+	// 3. Confirm
+	if !confirm("Are you sure you want to continue?") {
+		logger.Info().Msg("Aborting.")
+		return
+	}
+
+	// 4. Perform topup
+	logger.Info().Msg("Sending...")
+
+	input := processing.TopupInput{
+		Currency: currency,
+		Amount:   amount,
+		Comment:  comment,
+		IsTest:   isTest,
+	}
+
+	out, err := processingService.TopupMerchantFromSystem(ctx, merchant.ID, input)
+	if err != nil {
+		exit(err, "unable to topup the balance")
+	}
+
+	logger.
+		Info().
+		Int64("payment.id", out.Payment.ID).
+		Int64("tx.id", out.Transaction.ID).
+		Str("tx.usd_amount", out.Transaction.USDAmount.String()).
+		Str("merchant.balance", out.MerchantBalance.Amount.String()).
+		Msg("Done")
+}
+
+func topupBalanceSetup(cmd *cobra.Command) {
+	f := cmd.Flags()
+
+	f.Int64Var(topupBalanceArgs.MerchantID, "merchant-id", 0, "Merchant ID")
+	f.StringVar(topupBalanceArgs.Ticker, "ticker", "", "Ticker")
+	f.StringVar(topupBalanceArgs.Amount, "amount", "0", "Amount")
+	f.StringVar(topupBalanceArgs.Comment, "comment", "", "Comment")
+	f.BoolVar(topupBalanceArgs.IsTest, "is-test", false, "Test balance")
+
+	for _, name := range []string{"merchant-id", "ticker", "amount", "comment"} {
+		if err := cmd.MarkFlagRequired(name); err != nil {
+			panic(name + ": " + err.Error())
+		}
+	}
+}
+
+func confirm(message string) bool {
+	reader := bufio.NewReader(os.Stdin)
+	fmt.Printf("%s (y/n): ", message)
+
+	response, err := reader.ReadString('\n')
+	if err != nil {
+		return false
+	}
+
+	response = strings.ToLower(strings.TrimSpace(response))
+
+	return response == "y" || response == "yes"
+}

internal/db/repository/helpers.go

@@ -112,6 +112,5 @@ func MoneyToNumeric(m money.Money) pgtype.Numeric {
 
 func MoneyToNegNumeric(m money.Money) pgtype.Numeric {
 	bigInt, _ := m.BigInt()
-
 	return BigIntToNumeric(big.NewInt(0).Neg(bigInt))
 }

internal/money/money.go

@@ -144,6 +144,12 @@ func (m Money) Decimals() int64 {
 
 func (m Money) String() string {
 	stringRaw := m.StringRaw()
+
+	isNegative := m.IsNegative()
+	if isNegative {
+		stringRaw = stringRaw[1:]
+	}
+
 	l, d := len(stringRaw), int(m.decimals)
 
 	var result string
@@ -159,10 +165,16 @@ func (m Money) String() string {
 	}
 
 	if m.moneyType == Fiat {
-		return strings.TrimSuffix(result, ".00")
+		result = strings.TrimSuffix(result, ".00")
+	} else {
+		result = strings.TrimRight(strings.TrimRight(result, "0"), ".")
 	}
 
-	return strings.TrimRight(strings.TrimRight(result, "0"), ".")
+	if isNegative {
+		result = "-" + result
+	}
+
+	return result
 }
 
 func (m Money) StringRaw() string {
@@ -202,8 +214,22 @@ func (m Money) Add(amount Money) (Money, error) {
 	return NewFromBigInt(m.moneyType, m.ticker, a.Add(a, b), m.decimals)
 }
 
-// Sub subtracts money of the same type.
+// Sub subtracts money of the same type. Restricts having negative values.
 func (m Money) Sub(amount Money) (Money, error) {
+	out, err := m.SubNegative(amount)
+	if err != nil {
+		return Money{}, err
+	}
+
+	if out.IsNegative() {
+		return Money{}, ErrNegative
+	}
+
+	return out, nil
+}
+
+// SubNegative subtracts money allowing negative outcome
+func (m Money) SubNegative(amount Money) (Money, error) {
 	if !m.CompatibleTo(amount) {
 		return Money{}, errors.Wrapf(
 			ErrIncompatibleMoney,
@@ -220,10 +246,6 @@ func (m Money) Sub(amount Money) (Money, error) {
 		return Money{}, nil
 	}
 
-	if m.IsNegative() {
-		return Money{}, ErrNegative
-	}
-
 	return m, nil
 }