func (c Config) PreferredPaymentType() string {
	switch {
	case c.BTC != "":
		return PaymentTypeBTC
	case c.USDC != "":
		return PaymentTypeUSDC
	case c.PayPal != "":
		return PaymentTypePayPal
	}
	return PaymentTypeNone
}
PreferredPaymentType returns the payment type that should be used, in the case that multiple
are specified.
package conf
import (
	"encoding/json"
	"fmt"
	"os"
	"path"
	"regexp"
	"github.com/pkg/errors"
)
type PaymentType string
const (
	DonateFile string = ".donate"
	PaymentTypeBTC string = "BTC"
	PaymentTypePayPal string = "PayPal"
	PaymentTypeUSDC string = "USDC"
	PaymentTypeNone string = ""
)
var (
	ErrNoSupportedPaymentType error = errors.New("No supported payment type")
	usdcAddressPattern = regexp.MustCompile("^0x[0-9a-fA-F]{40}$")
)
type Config struct {
	BTC    string `json:"BTC,omitempty"`
	PayPal string `json:"PayPal,omitempty"`
	USDC   string `json:"USDC,omitempty"`
}