buy.gno

  1package nsskin
  2
  3import (
  4	"chain"
  5	"strings"
  6	"chain/banker"
  7	"chain/runtime/unsafe"
  8
  9	"gno.land/p/nt/ufmt/v0"
 10	"gno.land/r/nym-mnsrehearsal001/nsdata/v1"
 11)
 12
 13const ugnot = "ugnot"
 14
 15/*
 16BUYING ONE, AND WEARING IT, IN A SINGLE TRANSACTION.
 17
 18Splitting these would mean a buyer signs twice and can stop between —
 19leaving a skin they paid for sitting unworn in a wallet, which is the
 20state nobody wants and the one a two-step flow produces most often. So
 21the name is an argument: pass it and the skin is minted and attached
 22together; pass "" and it is minted loose, which is what somebody buying
 23ahead of registering a name needs.
 24
 25NOTHING IS EVER HELD. Payment, treasury and refund all settle inside the
 26buyer's own transaction, exactly as nslogic does it — and for the same
 27reason, which is worth restating because it is a legal position rather
 28than a style: a realm you can have a BALANCE in is a different kind of
 29thing to operate, subject to different rules, run by people with
 30licences. Every ugnot that arrives leaves again in the same call.
 31
 32THE 70/30 SPLIT IS NOT HERE, and that is deliberate rather than
 33forgotten. Every skin in this collection is ours, so the artist and the
 34treasury are the same address and a split would move money from a
 35pocket to itself while costing gas to do it. The artist is recorded on
 36every definition so the day it stops being us, this is where the split
 37goes — see SKINS.md.
 38*/
 39func Buy(cur realm, id, label, domain string) string {
 40	if !cur.Previous().IsUserCall() {
 41		panic("nsskin: only direct wallet calls may attach payment")
 42	}
 43	buyer := cur.Previous().Address()
 44	// Same normalization as Mint, for the same reason: the token id is
 45	// built from this string, and an un-lowercased one mints a token
 46	// that can never render. See the note in write.gno.
 47	id = strings.ToLower(strings.TrimSpace(id))
 48	s := mustSkin(id)
 49	if s.withdrawn {
 50		panic("nsskin: " + id + " has been withdrawn and is not for sale")
 51	}
 52	// Refuse the sale rather than the attach. Minting a locked skin to
 53	// somebody who wanted it for a name it will never go on is a refund
 54	// request wearing the clothes of a successful purchase.
 55	if label != "" && s.lock != "" && s.lock != domain {
 56		panic(ufmt.Sprintf("nsskin: %s only goes on *%s names, not *%s", id, s.lock, domain))
 57	}
 58
 59	sent := unsafe.OriginSend()
 60	for _, c := range sent {
 61		if c.Denom != ugnot {
 62			panic("nsskin: only ugnot is accepted, got: " + c.Denom)
 63		}
 64	}
 65	// PER DESIGN, not one figure for the collection. A third of the
 66	// definitions are free by the rule in price.gno, and an admin may
 67	// have priced any of them by hand — see PriceOf, which is the only
 68	// place that decides.
 69	due := PriceOf(id)
 70	paid := sent.AmountOf(ugnot)
 71	if paid < due {
 72		panic(ufmt.Sprintf("nsskin: insufficient payment: need %d ugnot, got %d", due, paid))
 73	}
 74
 75	// A FREE SKIN TAKES NO PAYMENT AND MOVES NO COINS, and the refund
 76	// below is what makes that safe: somebody whose page quoted the old
 77	// price, or who simply attached coins to a free mint, gets every
 78	// ugnot back in the same transaction rather than donating it.
 79	b := banker.NewBanker(banker.BankerTypeRealmSend, cur)
 80	me := cur.Address()
 81	if due > 0 {
 82		b.SendCoins(me, nsdata.GetTreasury(), chain.Coins{chain.NewCoin(ugnot, due)})
 83	}
 84	if excess := paid - due; excess > 0 {
 85		b.SendCoins(me, buyer, chain.Coins{chain.NewCoin(ugnot, excess)})
 86	}
 87
 88	s.minted++
 89	tid := ufmt.Sprintf("%s#%d", id, s.minted)
 90	if err := ledger.Mint(buyer, grcID(tid)); err != nil {
 91		panic("nsskin: mint failed: " + err.Error())
 92	}
 93	tokenSkin.Set(tid, id)
 94
 95	if label != "" {
 96		wear(cur, tid, label, domain, buyer)
 97	}
 98	return tid
 99}
100
101// SetPrice sets the BASE price, in ugnot — what a design costs when the
102// rule has not made it free and no admin has priced it by hand. ugnot
103// because that is what the chain moves: what it is worth in anything
104// else is a question for the page that quotes it, and pinning a dollar
105// figure into a contract that cannot see an exchange rate would be a lie
106// with a number in it.
107func SetPrice(cur realm, p int64) {
108	assertIsAdmin(cur)
109	if p < 0 {
110		panic("nsskin: a negative price is not a discount")
111	}
112	price = p
113}
114
115func GetPrice() int64 { return price }
116
117// Free calls must not be able to strand coins here. This realm has no
118// withdrawal path, so anything attached to one would sit in its address
119// permanently.
120func assertNoSend(cur realm) {
121	if !cur.Previous().IsUserCall() {
122		return
123	}
124	if len(unsafe.OriginSend()) > 0 {
125		panic("nsskin: this call takes no payment")
126	}
127}