wugnot.gno

  1package wugnot
  2
  3import (
  4	"chain"
  5	"chain/banker"
  6	"chain/runtime"
  7	"strings"
  8
  9	"gno.land/p/demo/tokens/grc20"
 10	"gno.land/p/nt/ufmt/v0"
 11	"gno.land/r/demo/defi/grc20reg"
 12)
 13
 14var Token, adm = grc20.NewToken("wrapped GNOT", "wugnot", 0)
 15
 16const (
 17	ugnotMinDeposit  int64 = 1000
 18	wugnotMinDeposit int64 = 1
 19)
 20
 21func init() {
 22	grc20reg.Register(cross, Token, "")
 23}
 24
 25func Deposit(cur realm) {
 26	// Prevent cross-realm MITM: without this, an intermediary could
 27	// deposit on behalf of the caller and mint wugnot to itself
 28	// instead of the actual sender.
 29	runtime.AssertOriginCall()
 30	caller := runtime.PreviousRealm().Address()
 31	sent := banker.OriginSend()
 32	amount := sent.AmountOf("ugnot")
 33
 34	require(int64(amount) >= ugnotMinDeposit, ufmt.Sprintf("Deposit below minimum: %d/%d ugnot.", amount, ugnotMinDeposit))
 35
 36	checkErr(adm.Mint(caller, int64(amount)))
 37}
 38
 39func Withdraw(cur realm, amount int64) {
 40	runtime.AssertOriginCall()
 41	require(amount >= wugnotMinDeposit, ufmt.Sprintf("Deposit below minimum: %d/%d wugnot.", amount, wugnotMinDeposit))
 42
 43	caller := runtime.PreviousRealm().Address()
 44	pkgaddr := runtime.CurrentRealm().Address()
 45	callerBal := Token.BalanceOf(caller)
 46	require(amount <= callerBal, ufmt.Sprintf("Insufficient balance: %d available, %d needed.", callerBal, amount))
 47
 48	// send swapped ugnots to qcaller
 49	stdBanker := banker.NewBanker(banker.BankerTypeRealmSend)
 50	send := chain.Coins{{"ugnot", int64(amount)}}
 51	stdBanker.SendCoins(pkgaddr, caller, send)
 52	checkErr(adm.Burn(caller, amount))
 53}
 54
 55func Render(path string) string {
 56	parts := strings.Split(path, "/")
 57	c := len(parts)
 58
 59	switch {
 60	case path == "":
 61		return Token.RenderHome()
 62	case c == 2 && parts[0] == "balance":
 63		owner := address(parts[1])
 64		balance := Token.BalanceOf(owner)
 65		return ufmt.Sprintf("%d", balance)
 66	default:
 67		return "404"
 68	}
 69}
 70
 71func TotalSupply() int64 {
 72	return Token.TotalSupply()
 73}
 74
 75func BalanceOf(owner address) int64 {
 76	return Token.BalanceOf(owner)
 77}
 78
 79func Allowance(owner, spender address) int64 {
 80	return Token.Allowance(owner, spender)
 81}
 82
 83func Transfer(cur realm, to address, amount int64) {
 84	userTeller := Token.CallerTeller()
 85	checkErr(userTeller.Transfer(to, amount))
 86}
 87
 88func Approve(cur realm, spender address, amount int64) {
 89	userTeller := Token.CallerTeller()
 90	checkErr(userTeller.Approve(spender, amount))
 91}
 92
 93func TransferFrom(cur realm, from, to address, amount int64) {
 94	userTeller := Token.CallerTeller()
 95	checkErr(userTeller.TransferFrom(from, to, amount))
 96}
 97
 98func require(condition bool, msg string) {
 99	if !condition {
100		panic(msg)
101	}
102}
103
104func checkErr(err error) {
105	if err != nil {
106		panic(err)
107	}
108}