game_relay.gno

  1package game32
  2
  3// ── Gasless relay: treasury pays gas for BuyTool and TrainSkill ──────────────
  4//
  5// The treasury server calls RelayBuyTool / RelayTrainSkill from the relay
  6// address (set by SetRelayAddress). Effects are recorded against `player`,
  7// not against the relay caller.
  8//
  9// Security model:
 10//   - relayAddress is the ONLY caller that may use these functions.
 11//   - Each call requires an ed25519 signature from the same claimSignerPubKey
 12//     used for claim vouchers. The server signs with MOJI_CLAIM_SIGNER_SEED.
 13//   - Replay protection: relayNonces[player] must increase monotonically.
 14//   - Expiry: relay vouchers expire within relayMaxTTL seconds.
 15//   - The relay cannot grant tools the player cannot normally buy (same
 16//     prerequisite and balance checks as BuyTool/TrainSkill).
 17//
 18// Relay voucher message (signed by the server, verified on-chain):
 19//   gnomoji-relay-v1|<chainId>|<kind>|<player>|<extra>|<nonce>|<expiry>
 20//
 21// Where:
 22//   kind  = "BuyTool" | "TrainSkill"
 23//   extra = toolId   (BuyTool) | skillId (TrainSkill)
 24
 25import (
 26	"crypto/ed25519"
 27	"encoding/hex"
 28	"strconv"
 29	"time"
 30
 31	"chain/runtime"
 32
 33	"chain"
 34)
 35
 36const relayMaxTTL = int64(300) // 5 minutes — relay vouchers are short-lived
 37
 38// relayVoucherMessage builds the canonical message the server signs.
 39func relayVoucherMessage(kind, player, extra string, nonce, expiry int64) string {
 40	return "gnomoji-relay-v1|" + runtime.ChainID() + "|" + kind + "|" + player + "|" +
 41		extra + "|" + strconv.FormatInt(nonce, 10) + "|" + strconv.FormatInt(expiry, 10)
 42}
 43
 44// lastRelayNonce returns the last relay nonce for player (0 if none).
 45func lastRelayNonce(player string) int64 {
 46	if !relayNonces.Has(player) {
 47		return 0
 48	}
 49	n, _ := strconv.ParseInt(relayNonces.Get(player).(string), 10, 64)
 50	return n
 51}
 52
 53// useRelayVoucher verifies and consumes a relay voucher for player.
 54// Panics on any failure so the entire tx is rolled back.
 55func useRelayVoucher(kind, player, extra string, nonce, expiry int64, sigHex string) {
 56	if len(claimSignerPubKey) != 32 {
 57		panic("relay disabled: no claim signer configured")
 58	}
 59	now := time.Now().Unix()
 60	if expiry < now {
 61		panic("relay voucher expired")
 62	}
 63	if expiry > now+relayMaxTTL {
 64		panic("relay voucher expiry too far in the future")
 65	}
 66	lastN := lastRelayNonce(player)
 67	if nonce <= lastN {
 68		panic("relay voucher already used (nonce " + strconv.FormatInt(nonce, 10) + " ≤ last " + strconv.FormatInt(lastN, 10) + ")")
 69	}
 70	sig, err := hex.DecodeString(sigHex)
 71	if err != nil || len(sig) != 64 {
 72		panic("invalid relay voucher signature encoding")
 73	}
 74	msg := relayVoucherMessage(kind, player, extra, nonce, expiry)
 75	if !ed25519.Verify(claimSignerPubKey, []byte(msg), sig) {
 76		panic("invalid relay voucher signature")
 77	}
 78	relayNonces.Set(player, strconv.FormatInt(nonce, 10))
 79}
 80
 81// requireRelay panics unless the caller is the registered relay address.
 82func requireRelay(cur realm) {
 83	if relayAddress == address("") {
 84		panic("relay not configured: SetRelayAddress first")
 85	}
 86	if cur.Previous().Address() != relayAddress {
 87		panic("unauthorized: relay calls must come from the registered relay address")
 88	}
 89}
 90
 91// ── Admin ─────────────────────────────────────────────────────────────────────
 92
 93// SetRelayAddress registers the treasury wallet address as the relay.
 94// Pass "" to disable the relay.
 95func SetRelayAddress(cur realm, addr string) {
 96	requireAdmin(cur)
 97	if addr == "" {
 98		relayAddress = address("")
 99		return
100	}
101	a := address(addr)
102	if !a.IsValid() {
103		panic("invalid relay address")
104	}
105	relayAddress = a
106	chain.Emit("RelayAddressSet", "relay", addr)
107}
108
109func RelayAddress() string { return relayAddress.String() }
110
111// ── RelayBuyTool ──────────────────────────────────────────────────────────────
112
113// RelayBuyTool executes BuyTool logic on behalf of `player` (the relay pays
114// gas). The server must sign a relay voucher with MOJI_CLAIM_SIGNER_SEED:
115//
116//	gnomoji-relay-v1|<chainId>|BuyTool|<player>|<toolId>|<nonce>|<expiry>
117//
118// All prerequisites (coin balance, tool chain, existing ownership) are checked
119// the same as BuyTool — the relay cannot bypass them.
120func RelayBuyTool(cur realm, player string, toolId string, nonce int64, expiry int64, sigHex string) {
121	requireRelay(cur)
122	requireNotPaused()
123	if isBlacklisted(player) {
124		panic("player address is banned")
125	}
126	if !address(player).IsValid() {
127		panic("invalid player address")
128	}
129	useRelayVoucher("BuyTool", player, toolId, nonce, expiry, sigHex)
130
131	// ── BuyTool logic (identical to BuyTool but acts on `player`, not caller) ──
132	costs, hasCost := toolCosts[toolId]
133	if !hasCost {
134		panic("unknown tool: " + toolId)
135	}
136	if ownsTool(player, toolId) {
137		panic("already own " + toolId + " — use RepairTool to restore durability")
138	}
139	if prereq, ok := toolRequires[toolId]; ok && !ownsTool(player, prereq) {
140		panic("must own " + prereq + " before buying " + toolId)
141	}
142	deductBalances(player, costs)
143
144	if !ownedTools.Has(player) || ownedTools.Get(player).(string) == "" {
145		ownedTools.Set(player, toolId)
146	} else {
147		ownedTools.Set(player, ownedTools.Get(player).(string)+","+toolId)
148	}
149	if mx, ok := toolMaxLife[toolId]; ok && mx > 0 {
150		setU(&toolLife, player+":"+toolId, effectiveMaxLife(player, toolId))
151	}
152	chain.Emit("RelayedBuyTool", "player", player, "tool", toolId, "relay", cur.Previous().Address().String())
153}
154
155// ── RelayTrainSkill ───────────────────────────────────────────────────────────
156
157// RelayTrainSkill executes TrainSkill logic on behalf of `player`.
158// Relay voucher message:
159//
160//	gnomoji-relay-v1|<chainId>|TrainSkill|<player>|<skillId>|<nonce>|<expiry>
161//
162// Same checks as TrainSkill; max rank and coin deduction apply normally.
163func RelayTrainSkill(cur realm, player string, skillId string, nonce int64, expiry int64, sigHex string) {
164	requireRelay(cur)
165	requireNotPaused()
166	if isBlacklisted(player) {
167		panic("player address is banned")
168	}
169	if !address(player).IsValid() {
170		panic("invalid player address")
171	}
172	useRelayVoucher("TrainSkill", player, skillId, nonce, expiry, sigHex)
173
174	// ── TrainSkill logic (identical to TrainSkill but acts on `player`) ──────
175	key := player + ":" + skillId
176	rank := getU(&skillRanks, key)
177	maxRank, ok := skillMaxRanks[skillId]
178	if !ok {
179		panic("unknown skill: " + skillId)
180	}
181	if rank >= maxRank {
182		panic("skill already at maximum rank")
183	}
184	baseCosts, ok := skillBaseCosts[skillId]
185	if !ok {
186		panic("unknown skill: " + skillId)
187	}
188	mult := uint64(1) << rank
189	var scaled [][2]string
190	for _, pair := range baseCosts {
191		baseAmt, _ := strconv.ParseUint(pair[1], 10, 64)
192		if s := baseAmt * mult; s > 0 {
193			scaled = append(scaled, [2]string{pair[0], strconv.FormatUint(s, 10)})
194		}
195	}
196	deductBalances(player, scaled)
197	setU(&skillRanks, key, rank+1)
198	chain.Emit("RelayedTrainSkill", "player", player, "skill", skillId, "relay", cur.Previous().Address().String())
199}
200
201// LastRelayNonce returns the last relay nonce used by addr (0 if none).
202// Used by the server to compute the next nonce.
203func LastRelayNonce(addr string) int64 { return lastRelayNonce(addr) }