From 6e866b622a8731ecc1787039607db3c93ef1166b Mon Sep 17 00:00:00 2001
From: Evgeniy Stratonikov <evgeniy@nspcc.ru>
Date: Mon, 8 Feb 2021 11:06:01 +0300
Subject: [PATCH] compiler: implement NEO contract wrapper

---
 pkg/compiler/analysis.go      |  8 +++-
 pkg/compiler/codegen.go       |  3 +-
 pkg/interop/native/neo/neo.go | 80 +++++++++++++++++++++++++++++++++++
 3 files changed, 89 insertions(+), 2 deletions(-)
 create mode 100644 pkg/interop/native/neo/neo.go

diff --git a/pkg/compiler/analysis.go b/pkg/compiler/analysis.go
index fa3fa5501..bc55364d5 100644
--- a/pkg/compiler/analysis.go
+++ b/pkg/compiler/analysis.go
@@ -275,6 +275,12 @@ func isSyscall(fun *funcScope) bool {
 	return ok
 }
 
+const interopPrefix = "github.com/nspcc-dev/neo-go/pkg/interop"
+
 func isInteropPath(s string) bool {
-	return strings.HasPrefix(s, "github.com/nspcc-dev/neo-go/pkg/interop")
+	return strings.HasPrefix(s, interopPrefix)
+}
+
+func isNativeHelpersPath(s string) bool {
+	return strings.HasPrefix(s, interopPrefix+"/native")
 }
diff --git a/pkg/compiler/codegen.go b/pkg/compiler/codegen.go
index 4d9c7dc4d..57652b405 100644
--- a/pkg/compiler/codegen.go
+++ b/pkg/compiler/codegen.go
@@ -1915,7 +1915,8 @@ func (c *codegen) compile(info *buildInfo, pkg *loader.PackageInfo) error {
 				// Don't convert the function if it's not used. This will save a lot
 				// of bytecode space.
 				name := c.getFuncNameFromDecl(pkg.Path(), n)
-				if !isInitFunc(n) && !isDeployFunc(n) && funUsage.funcUsed(name) && !isInteropPath(pkg.Path()) {
+				if !isInitFunc(n) && !isDeployFunc(n) && funUsage.funcUsed(name) &&
+					(!isInteropPath(pkg.Path()) || isNativeHelpersPath(pkg.Path())) {
 					c.convertFuncDecl(f, n, pkg)
 				}
 			}
diff --git a/pkg/interop/native/neo/neo.go b/pkg/interop/native/neo/neo.go
new file mode 100644
index 000000000..b0ff66f78
--- /dev/null
+++ b/pkg/interop/native/neo/neo.go
@@ -0,0 +1,80 @@
+package neo
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/interop"
+	"github.com/nspcc-dev/neo-go/pkg/interop/contract"
+)
+
+// Hash represents NEO contract hash.
+const Hash = "\x83\xab\x06\x79\xad\x55\xc0\x50\xa1\x3a\xd4\x3f\x59\x36\xea\x73\xf5\xeb\x1e\xf6"
+
+// Symbol represents `symbol` method of NEO native contract.
+func Symbol() string {
+	return contract.Call(interop.Hash160(Hash), "symbol", contract.NoneFlag).(string)
+}
+
+// Decimals represents `decimals` method of NEO native contract.
+func Decimals() int {
+	return contract.Call(interop.Hash160(Hash), "decimals", contract.NoneFlag).(int)
+}
+
+// TotalSupply represents `totalSupply` method of NEO native contract.
+func TotalSupply() int {
+	return contract.Call(interop.Hash160(Hash), "totalSupply", contract.ReadStates).(int)
+}
+
+// BalanceOf represents `balanceOf` method of NEO native contract.
+func BalanceOf(addr interop.Hash160) int {
+	return contract.Call(interop.Hash160(Hash), "balanceOf", contract.ReadStates, addr).(int)
+}
+
+// Transfer represents `transfer` method of NEO native contract.
+func Transfer(from, to interop.Hash160, amount int, data interface{}) bool {
+	return contract.Call(interop.Hash160(Hash), "transfer",
+		contract.WriteStates|contract.AllowCall|contract.AllowNotify, from, to, amount, data).(bool)
+}
+
+// GetCommittee represents `getCommittee` method of NEO native contract.
+func GetCommittee() []interop.PublicKey {
+	return contract.Call(interop.Hash160(Hash), "getCommittee", contract.ReadStates).([]interop.PublicKey)
+}
+
+// GetCandidates represents `getCandidates` method of NEO native contract.
+func GetCandidates() []interop.PublicKey {
+	return contract.Call(interop.Hash160(Hash), "getCandidates", contract.ReadStates).([]interop.PublicKey)
+}
+
+// GetNextBlockValidators represents `getNextBlockValidators` method of NEO native contract.
+func GetNextBlockValidators() []interop.PublicKey {
+	return contract.Call(interop.Hash160(Hash), "getNextBlockValidators", contract.ReadStates).([]interop.PublicKey)
+}
+
+// GetGASPerBlock represents `getGasPerBlock` method of NEO native contract.
+func GetGASPerBlock() int {
+	return contract.Call(interop.Hash160(Hash), "getGasPerBlock", contract.ReadStates).(int)
+}
+
+// SetGASPerBlock represents `setGasPerBlock` method of NEO native contract.
+func SetGASPerBlock(amount int) {
+	contract.Call(interop.Hash160(Hash), "setGasPerBlock", contract.WriteStates, amount)
+}
+
+// RegisterCandidate represents `registerCandidate` method of NEO native contract.
+func RegisterCandidate(pub interop.PublicKey) bool {
+	return contract.Call(interop.Hash160(Hash), "registerCandidate", contract.WriteStates, pub).(bool)
+}
+
+// UnregisterCandidate represents `unregisterCandidate` method of NEO native contract.
+func UnregisterCandidate(pub interop.PublicKey) bool {
+	return contract.Call(interop.Hash160(Hash), "unregisterCandidate", contract.WriteStates, pub).(bool)
+}
+
+// Vote represents `vote` method of NEO native contract.
+func Vote(addr interop.Hash160, pub interop.PublicKey) bool {
+	return contract.Call(interop.Hash160(Hash), "vote", contract.WriteStates, addr, pub).(bool)
+}
+
+// UnclaimedGAS represents `unclaimedGas` method of NEO native contract.
+func UnclaimedGAS(addr interop.Hash160, end int) int {
+	return contract.Call(interop.Hash160(Hash), "unclaimedGas", contract.ReadStates, addr, end).(int)
+}