// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package vm

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"math/big"
	"testing"

	"github.com/ethereum/go-ethereum/common"
)

// precompiledTest defines the input/output pairs for precompiled contract tests.
type precompiledTest struct {
	Input, Expected string
	Name            string
	NoBenchmark     bool // Benchmark primarily the worst-cases
}

// precompiledFailureTest defines the input/error pairs for precompiled
// contract failure tests.
type precompiledFailureTest struct {
	Input         string
	ExpectedError string
	Name          string
}

var allPrecompiles = PrecompiledContractsBerlin

// EIP-152 test vectors
var blake2FMalformedInputTests = []precompiledFailureTest{
	{
		Input:         "",
		ExpectedError: errBlake2FInvalidInputLength.Error(),
		Name:          "vector 0: empty input",
	},
	{
		Input:         "00000c48c9bdf267e6096a3ba7ca8485ae67bb2bf894fe72f36e3cf1361d5f3af54fa5d182e6ad7f520e511f6c3e2b8c68059b6bbd41fbabd9831f79217e1319cde05b61626300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000300000000000000000000000000000001",
		ExpectedError: errBlake2FInvalidInputLength.Error(),
		Name:          "vector 1: less than 213 bytes input",
	},
	{
		Input:         "000000000c48c9bdf267e6096a3ba7ca8485ae67bb2bf894fe72f36e3cf1361d5f3af54fa5d182e6ad7f520e511f6c3e2b8c68059b6bbd41fbabd9831f79217e1319cde05b61626300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000300000000000000000000000000000001",
		ExpectedError: errBlake2FInvalidInputLength.Error(),
		Name:          "vector 2: more than 213 bytes input",
	},
	{
		Input:         "0000000c48c9bdf267e6096a3ba7ca8485ae67bb2bf894fe72f36e3cf1361d5f3af54fa5d182e6ad7f520e511f6c3e2b8c68059b6bbd41fbabd9831f79217e1319cde05b61626300000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000300000000000000000000000000000002",
		ExpectedError: errBlake2FInvalidFinalFlag.Error(),
		Name:          "vector 3: malformed final block indicator flag",
	},
}

func testPrecompiled(addr string, test precompiledTest, t *testing.T) {
	p := allPrecompiles[common.HexToAddress(addr)]
	in := common.Hex2Bytes(test.Input)
	contract := NewContract(AccountRef(common.HexToAddress("1337")),
		nil, new(big.Int), p.RequiredGas(in))
	t.Run(fmt.Sprintf("%s-Gas=%d", test.Name, contract.Gas), func(t *testing.T) {
		if res, err := RunPrecompiledContract(p, in, contract); err != nil {
			t.Error(err)
		} else if common.Bytes2Hex(res) != test.Expected {
			t.Errorf("Expected %v, got %v", test.Expected, common.Bytes2Hex(res))
		}
		// Verify that the precompile did not touch the input buffer
		exp := common.Hex2Bytes(test.Input)
		if !bytes.Equal(in, exp) {
			t.Errorf("Precompiled %v modified input data", addr)
		}
	})
}

func testPrecompiledOOG(addr string, test precompiledTest, t *testing.T) {
	p := allPrecompiles[common.HexToAddress(addr)]
	in := common.Hex2Bytes(test.Input)
	contract := NewContract(AccountRef(common.HexToAddress("1337")),
		nil, new(big.Int), p.RequiredGas(in)-1)
	t.Run(fmt.Sprintf("%s-Gas=%d", test.Name, contract.Gas), func(t *testing.T) {
		_, err := RunPrecompiledContract(p, in, contract)
		if err.Error() != "out of gas" {
			t.Errorf("Expected error [out of gas], got [%v]", err)
		}
		// Verify that the precompile did not touch the input buffer
		exp := common.Hex2Bytes(test.Input)
		if !bytes.Equal(in, exp) {
			t.Errorf("Precompiled %v modified input data", addr)
		}
	})
}

func testPrecompiledFailure(addr string, test precompiledFailureTest, t *testing.T) {
	p := allPrecompiles[common.HexToAddress(addr)]
	in := common.Hex2Bytes(test.Input)
	contract := NewContract(AccountRef(common.HexToAddress("31337")),
		nil, new(big.Int), p.RequiredGas(in))

	t.Run(test.Name, func(t *testing.T) {
		_, err := RunPrecompiledContract(p, in, contract)
		if err.Error() != test.ExpectedError {
			t.Errorf("Expected error [%v], got [%v]", test.ExpectedError, err)
		}
		// Verify that the precompile did not touch the input buffer
		exp := common.Hex2Bytes(test.Input)
		if !bytes.Equal(in, exp) {
			t.Errorf("Precompiled %v modified input data", addr)
		}
	})
}

func benchmarkPrecompiled(addr string, test precompiledTest, bench *testing.B) {
	if test.NoBenchmark {
		return
	}
	p := allPrecompiles[common.HexToAddress(addr)]
	in := common.Hex2Bytes(test.Input)
	reqGas := p.RequiredGas(in)
	contract := NewContract(AccountRef(common.HexToAddress("1337")),
		nil, new(big.Int), reqGas)

	var (
		res  []byte
		err  error
		data = make([]byte, len(in))
	)

	bench.Run(fmt.Sprintf("%s-Gas=%d", test.Name, contract.Gas), func(bench *testing.B) {
		bench.ReportAllocs()
		bench.ResetTimer()
		for i := 0; i < bench.N; i++ {
			contract.Gas = reqGas
			copy(data, in)
			res, err = RunPrecompiledContract(p, data, contract)
		}
		bench.StopTimer()
		bench.ReportMetric(float64(reqGas), "gas/op")
		//Check if it is correct
		if err != nil {
			bench.Error(err)
			return
		}
		if common.Bytes2Hex(res) != test.Expected {
			bench.Error(fmt.Sprintf("Expected %v, got %v", test.Expected, common.Bytes2Hex(res)))
			return
		}
	})
}

// Benchmarks the sample inputs from the ECRECOVER precompile.
func BenchmarkPrecompiledEcrecover(bench *testing.B) {
	t := precompiledTest{
		Input:    "38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e000000000000000000000000000000000000000000000000000000000000001b38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e789d1dd423d25f0772d2748d60f7e4b81bb14d086eba8e8e8efb6dcff8a4ae02",
		Expected: "000000000000000000000000ceaccac640adf55b2028469bd36ba501f28b699d",
		Name:     "",
	}
	benchmarkPrecompiled("01", t, bench)
}

// Benchmarks the sample inputs from the SHA256 precompile.
func BenchmarkPrecompiledSha256(bench *testing.B) {
	t := precompiledTest{
		Input:    "38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e000000000000000000000000000000000000000000000000000000000000001b38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e789d1dd423d25f0772d2748d60f7e4b81bb14d086eba8e8e8efb6dcff8a4ae02",
		Expected: "811c7003375852fabd0d362e40e68607a12bdabae61a7d068fe5fdd1dbbf2a5d",
		Name:     "128",
	}
	benchmarkPrecompiled("02", t, bench)
}

// Benchmarks the sample inputs from the RIPEMD precompile.
func BenchmarkPrecompiledRipeMD(bench *testing.B) {
	t := precompiledTest{
		Input:    "38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e000000000000000000000000000000000000000000000000000000000000001b38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e789d1dd423d25f0772d2748d60f7e4b81bb14d086eba8e8e8efb6dcff8a4ae02",
		Expected: "0000000000000000000000009215b8d9882ff46f0dfde6684d78e831467f65e6",
		Name:     "128",
	}
	benchmarkPrecompiled("03", t, bench)
}

// Benchmarks the sample inputs from the identiy precompile.
func BenchmarkPrecompiledIdentity(bench *testing.B) {
	t := precompiledTest{
		Input:    "38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e000000000000000000000000000000000000000000000000000000000000001b38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e789d1dd423d25f0772d2748d60f7e4b81bb14d086eba8e8e8efb6dcff8a4ae02",
		Expected: "38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e000000000000000000000000000000000000000000000000000000000000001b38d18acb67d25c8bb9942764b62f18e17054f66a817bd4295423adf9ed98873e789d1dd423d25f0772d2748d60f7e4b81bb14d086eba8e8e8efb6dcff8a4ae02",
		Name:     "128",
	}
	benchmarkPrecompiled("04", t, bench)
}

// Tests the sample inputs from the ModExp EIP 198.
func TestPrecompiledModExp(t *testing.T)      { testJson("modexp", "05", t) }
func BenchmarkPrecompiledModExp(b *testing.B) { benchJson("modexp", "05", b) }

// Tests the sample inputs from the elliptic curve addition EIP 213.
func TestPrecompiledBn256Add(t *testing.T)      { testJson("bn256Add", "06", t) }
func BenchmarkPrecompiledBn256Add(b *testing.B) { benchJson("bn256Add", "06", b) }

// Tests OOG
func TestPrecompiledModExpOOG(t *testing.T) {
	modexpTests, err := loadJson("modexp")
	if err != nil {
		t.Fatal(err)
	}
	for _, test := range modexpTests {
		testPrecompiledOOG("05", test, t)
	}
}

// Tests the sample inputs from the elliptic curve scalar multiplication EIP 213.
func TestPrecompiledBn256ScalarMul(t *testing.T)      { testJson("bn256ScalarMul", "07", t) }
func BenchmarkPrecompiledBn256ScalarMul(b *testing.B) { benchJson("bn256ScalarMul", "07", b) }

// Tests the sample inputs from the elliptic curve pairing check EIP 197.
func TestPrecompiledBn256Pairing(t *testing.T)      { testJson("bn256Pairing", "08", t) }
func BenchmarkPrecompiledBn256Pairing(b *testing.B) { benchJson("bn256Pairing", "08", b) }

func TestPrecompiledBlake2F(t *testing.T)      { testJson("blake2F", "09", t) }
func BenchmarkPrecompiledBlake2F(b *testing.B) { benchJson("blake2F", "09", b) }

func TestPrecompileBlake2FMalformedInput(t *testing.T) {
	for _, test := range blake2FMalformedInputTests {
		testPrecompiledFailure("09", test, t)
	}
}

func TestPrecompiledEcrecover(t *testing.T) { testJson("ecRecover", "01", t) }

func testJson(name, addr string, t *testing.T) {
	tests, err := loadJson(name)
	if err != nil {
		t.Fatal(err)
	}
	for _, test := range tests {
		testPrecompiled(addr, test, t)
	}
}

func testJsonFail(name, addr string, t *testing.T) {
	tests, err := loadJsonFail(name)
	if err != nil {
		t.Fatal(err)
	}
	for _, test := range tests {
		testPrecompiledFailure(addr, test, t)
	}
}

func benchJson(name, addr string, b *testing.B) {
	tests, err := loadJson(name)
	if err != nil {
		b.Fatal(err)
	}
	for _, test := range tests {
		benchmarkPrecompiled(addr, test, b)
	}
}

func TestPrecompiledBLS12381G1Add(t *testing.T)      { testJson("blsG1Add", "0a", t) }
func TestPrecompiledBLS12381G1Mul(t *testing.T)      { testJson("blsG1Mul", "0b", t) }
func TestPrecompiledBLS12381G1MultiExp(t *testing.T) { testJson("blsG1MultiExp", "0c", t) }
func TestPrecompiledBLS12381G2Add(t *testing.T)      { testJson("blsG2Add", "0d", t) }
func TestPrecompiledBLS12381G2Mul(t *testing.T)      { testJson("blsG2Mul", "0e", t) }
func TestPrecompiledBLS12381G2MultiExp(t *testing.T) { testJson("blsG2MultiExp", "0f", t) }
func TestPrecompiledBLS12381Pairing(t *testing.T)    { testJson("blsPairing", "10", t) }
func TestPrecompiledBLS12381MapG1(t *testing.T)      { testJson("blsMapG1", "11", t) }
func TestPrecompiledBLS12381MapG2(t *testing.T)      { testJson("blsMapG2", "12", t) }

func BenchmarkPrecompiledBLS12381G1Add(b *testing.B)      { benchJson("blsG1Add", "0a", b) }
func BenchmarkPrecompiledBLS12381G1Mul(b *testing.B)      { benchJson("blsG1Mul", "0b", b) }
func BenchmarkPrecompiledBLS12381G1MultiExp(b *testing.B) { benchJson("blsG1MultiExp", "0c", b) }
func BenchmarkPrecompiledBLS12381G2Add(b *testing.B)      { benchJson("blsG2Add", "0d", b) }
func BenchmarkPrecompiledBLS12381G2Mul(b *testing.B)      { benchJson("blsG2Mul", "0e", b) }
func BenchmarkPrecompiledBLS12381G2MultiExp(b *testing.B) { benchJson("blsG2MultiExp", "0f", b) }
func BenchmarkPrecompiledBLS12381Pairing(b *testing.B)    { benchJson("blsPairing", "10", b) }
func BenchmarkPrecompiledBLS12381MapG1(b *testing.B)      { benchJson("blsMapG1", "11", b) }
func BenchmarkPrecompiledBLS12381MapG2(b *testing.B)      { benchJson("blsMapG2", "12", b) }

// Failure tests
func TestPrecompiledBLS12381G1AddFail(t *testing.T)      { testJsonFail("blsG1Add", "0a", t) }
func TestPrecompiledBLS12381G1MulFail(t *testing.T)      { testJsonFail("blsG1Mul", "0b", t) }
func TestPrecompiledBLS12381G1MultiExpFail(t *testing.T) { testJsonFail("blsG1MultiExp", "0c", t) }
func TestPrecompiledBLS12381G2AddFail(t *testing.T)      { testJsonFail("blsG2Add", "0d", t) }
func TestPrecompiledBLS12381G2MulFail(t *testing.T)      { testJsonFail("blsG2Mul", "0e", t) }
func TestPrecompiledBLS12381G2MultiExpFail(t *testing.T) { testJsonFail("blsG2MultiExp", "0f", t) }
func TestPrecompiledBLS12381PairingFail(t *testing.T)    { testJsonFail("blsPairing", "10", t) }
func TestPrecompiledBLS12381MapG1Fail(t *testing.T)      { testJsonFail("blsMapG1", "11", t) }
func TestPrecompiledBLS12381MapG2Fail(t *testing.T)      { testJsonFail("blsMapG2", "12", t) }

func loadJson(name string) ([]precompiledTest, error) {
	data, err := ioutil.ReadFile(fmt.Sprintf("testdata/precompiles/%v.json", name))
	if err != nil {
		return nil, err
	}
	var testcases []precompiledTest
	err = json.Unmarshal(data, &testcases)
	return testcases, err
}

func loadJsonFail(name string) ([]precompiledFailureTest, error) {
	data, err := ioutil.ReadFile(fmt.Sprintf("testdata/precompiles/fail-%v.json", name))
	if err != nil {
		return nil, err
	}
	var testcases []precompiledFailureTest
	err = json.Unmarshal(data, &testcases)
	return testcases, err
}