Initial implementation of smart-contract

contract.go

@@ -0,0 +1,219 @@
+package smart_contract_bets
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/interop"
+	"github.com/nspcc-dev/neo-go/pkg/interop/iterator"
+	"github.com/nspcc-dev/neo-go/pkg/interop/lib/address"
+	"github.com/nspcc-dev/neo-go/pkg/interop/native/gas"
+	"github.com/nspcc-dev/neo-go/pkg/interop/native/oracle"
+	"github.com/nspcc-dev/neo-go/pkg/interop/native/std"
+	"github.com/nspcc-dev/neo-go/pkg/interop/runtime"
+	"github.com/nspcc-dev/neo-go/pkg/interop/storage"
+)
+
+// url для оракула:
+const dataURLKey = "dataURL"
+
+// контракт, принимает ставки на одно событие:
+const eventIndexValue = 1
+
+// значения, получаемые оракулом: 0 (событие не сыграно), 1 (победа первого игрока), 2 (победа второго игрока):
+const winnerKey = "winner"
+
+// префикс имён ключей для сохранения в storage ставок игроков
+const playerKeyPrefix = "bet_"
+
+type Bet struct {
+	// величина ставки
+	amount int
+	// сторона, на которую сделана ставка (в событии участвует 2 стороны)
+	winner int
+	// флаг, обозначающий что выигрыш получен
+	payed bool
+}
+
+func _deploy(data interface{}, isUpdate bool) {
+	if isUpdate {
+		return
+	}
+
+	ctx := storage.GetContext()
+	dataURL := "https://my-json-server.typicode.com/okonstantinova/smart-contract-bets/events/"
+	storage.Put(ctx, dataURLKey, dataURL)
+}
+
+func PlaceBet(amount int, winner int, player interop.Hash160) {
+	if !runtime.CheckWitness(player) {
+		runtime.Log("Player is not the same as the caller")
+		return
+	}
+
+	if amount <= 0 {
+		runtime.Log("Invalid amount value")
+		return
+	}
+
+	if winner != 1 && winner != 2 {
+		runtime.Log("Invalid winner value")
+		return
+	}
+
+	balance := gas.BalanceOf(player)
+	if balance < amount {
+		runtime.Log("Not enough gas on balance")
+		return
+	}
+
+	ctx := storage.GetContext()
+	if storage.Get(ctx, winnerKey) != nil {
+		runtime.Log("The event has played, cannot place bet")
+		return
+	}
+
+	if storage.Get(ctx, player) != nil {
+		runtime.Log("Player has already placed bet")
+		return
+	}
+
+	contractHash := runtime.GetExecutingScriptHash()
+	result := gas.Transfer(player, contractHash, amount, nil)
+	if !result {
+		runtime.Log("Transfer operation failed")
+		return
+	}
+
+	bet := Bet{
+		amount: amount,
+		winner: winner,
+		payed:  false,
+	}
+
+	playerKey := playerKeyPrefix + address.FromHash160(player)
+	storage.Put(ctx, playerKey, std.Serialize(bet))
+	runtime.Log("Player " + address.FromHash160(player) + " placed " + std.Itoa10(amount) +
+		" gas bet on side " + std.Itoa10(winner))
+}
+
+// OnNEP17Payment вызывается как callback при успешном переводе газа на счёт контракта
+func OnNEP17Payment(from interop.Hash160, amount int, data any) {
+	contractHash := runtime.GetExecutingScriptHash()
+	balance := gas.BalanceOf(contractHash)
+	runtime.Log("Contract's balance changed and has " + std.Itoa10(balance) + " gas")
+}
+
+func CheckEventStatus() {
+	ctx := storage.GetContext()
+
+	if storage.Get(ctx, winnerKey) != nil {
+		runtime.Log("The event has played, no action required anymore")
+		return
+	}
+
+	dataURL := storage.Get(ctx, dataURLKey).(string) + std.Itoa10(eventIndexValue)
+	oracle.Request(dataURL, nil, "oracleCallback", nil, 2*oracle.MinimumResponseGas)
+	runtime.Log("Oracle requested to check " + dataURL)
+}
+
+func OracleCallback(url string, userData any, code int, result []byte) {
+	runtime.Log("Result " + string(result))
+
+	callingHash := runtime.GetCallingScriptHash()
+	if !callingHash.Equals(oracle.Hash) {
+		panic("Not called from the oracle contract")
+	}
+
+	if code != oracle.Success {
+		panic("Request failed for " + url + " with code " + std.Itoa10(code))
+	}
+
+	ctx := storage.GetContext()
+	if storage.Get(ctx, winnerKey) != nil {
+		panic("Event status change is already processed")
+	}
+
+	data := std.JSONDeserialize(result).(map[string]any)
+	winner := data["winner"].(int)
+
+	if winner == 0 {
+		runtime.Log("Oracle reports that the event has not played yet")
+		return
+	}
+
+	if winner != 1 && winner != 2 {
+		panic("Invalid winner value")
+	}
+
+	storage.Put(ctx, winnerKey, winner)
+	runtime.Log("The event winner is set to be " + std.Itoa10(winner))
+}
+
+func ClaimWin(player interop.Hash160) bool {
+	if !runtime.CheckWitness(player) {
+		panic("Player is not the same as the caller")
+	}
+
+	ctx := storage.GetContext()
+	winnerValue := storage.Get(ctx, winnerKey)
+
+	if winnerValue == nil {
+		panic("The event has not played yet")
+	}
+
+	winner := winnerValue.(int)
+
+	playerKey := playerKeyPrefix + address.FromHash160(player)
+	data := storage.Get(ctx, playerKey)
+	if data == nil {
+		panic("Player did not place bet")
+	}
+
+	bet := std.Deserialize(data.([]byte)).(Bet)
+	if bet.payed {
+		runtime.Log("Player has already claimed win")
+		return false
+	}
+
+	if bet.winner != winner {
+		runtime.Log("The bet has not won")
+		return false
+	}
+
+	win := CalculateWin(player, bet)
+	contractHash := runtime.GetExecutingScriptHash()
+	result := gas.Transfer(contractHash, player, win, nil)
+	if !result {
+		panic("Transfer operation failed")
+	}
+
+	bet.payed = true
+	storage.Put(ctx, playerKey, std.Serialize(bet))
+	runtime.Log("Player " + address.FromHash160(player) + " claimed their win and received " +
+		std.Itoa10(win) + " gas")
+
+	return true
+}
+
+// CalculateWin рассчитывает выигрыш для игрока победителя
+func CalculateWin(player interop.Hash160, playerBet Bet) int {
+	ctx := storage.GetContext()
+
+	totalWin := 0  // сумма ставок всех победителей
+	totalLost := 0 // сумма ставок всех проигравших
+
+	it := storage.Find(ctx, playerKeyPrefix, storage.ValuesOnly)
+	for iterator.Next(it) {
+		data := iterator.Value(it)
+		bet := std.Deserialize(data.([]byte)).(Bet)
+
+		if bet.winner == playerBet.winner {
+			totalWin += bet.amount
+		} else {
+			totalLost += bet.amount
+		}
+	}
+	// выигрыш состоит из:
+	// 1) изначальной ставки данного победителя
+	// 2) доли победителя от суммы ставок всех проигравших пропорционально его ставке к сумме ставок всех победителей,
+	// поделенной пополам с владельцем контракта
+	return playerBet.amount + int(float64(totalLost)*float64(playerBet.amount)/float64(totalWin))/2
+}

contract.yml

@@ -0,0 +1,5 @@
+name: "Bet contract"
+supported standards: []
+events: []
+permissions:
+  - methods: ["request", "transfer"]

data.json

@@ -0,0 +1,16 @@
+{
+  "events": [
+    {
+      "id": 0,
+      "date": "2023-12-12",
+      "description": "Football: Chelsy & Arsenal",
+      "winner": 1
+    },
+    {
+      "id": 1,
+      "date": "2024-01-07",
+      "description": "Hockey: Avangard Omsk & Ak Bars Kazan",
+      "winner": 0
+    }
+  ]
+}

go.mod

@@ -0,0 +1,8 @@
+module contract
+
+go 1.18
+
+require (
+	github.com/nspcc-dev/neo-go v0.104.0
+	github.com/nspcc-dev/neo-go/pkg/interop v0.0.0-20231121104256-0493ddbd70b2
+)

go.sum

@@ -0,0 +1,9 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/nspcc-dev/neo-go v0.104.0 h1:FGj3Z46yABcFIAI1SCLd1jQSoh+B00h/2VAgEgY1JKQ=
+github.com/nspcc-dev/neo-go v0.104.0/go.mod h1:omsUK5PAtG2/nQ3/evs95QEg3wtkj3LH53e0NKtXVwQ=
+github.com/nspcc-dev/neo-go/pkg/interop v0.0.0-20231121104256-0493ddbd70b2 h1:hPVF8iMmsQ15GSemj1ma6C9BkwfAugEXsUAVTEniK5M=
+github.com/nspcc-dev/neo-go/pkg/interop v0.0.0-20231121104256-0493ddbd70b2/go.mod h1:J/Mk6+nKeKSW4wygkZQFLQ6SkLOSGX5Ga0RuuuktEag=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=