// Copyright 2014 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 miner

import (
	"crypto/ecdsa"
	"math/big"
	"math/rand"
	"testing"
	"time"

	"github.com/XinFinOrg/XDPoSChain/common"
	"github.com/XinFinOrg/XDPoSChain/core/txpool"
	"github.com/XinFinOrg/XDPoSChain/core/types"
	"github.com/XinFinOrg/XDPoSChain/crypto"
	"github.com/holiman/uint256"
)

func TestTransactionPriceNonceSortLegacy(t *testing.T) {
	testTransactionPriceNonceSort(t, nil)
}

func TestTransactionPriceNonceSort1559(t *testing.T) {
	testTransactionPriceNonceSort(t, big.NewInt(0))
	testTransactionPriceNonceSort(t, big.NewInt(5))
	testTransactionPriceNonceSort(t, big.NewInt(50))
}

// Tests that transactions can be correctly sorted according to their price in
// decreasing order, but at the same time with increasing nonces when issued by
// the same account.
func testTransactionPriceNonceSort(t *testing.T, baseFee *big.Int) {
	// Generate a batch of accounts to start with
	keys := make([]*ecdsa.PrivateKey, 25)
	for i := 0; i < len(keys); i++ {
		keys[i], _ = crypto.GenerateKey()
	}
	signer := types.LatestSignerForChainID(common.Big1)

	// Generate a batch of transactions with overlapping values, but shifted nonces
	groups := map[common.Address][]*txpool.LazyTransaction{}
	expectedCount := 0
	for start, key := range keys {
		addr := crypto.PubkeyToAddress(key.PublicKey)
		count := 25
		for i := 0; i < 25; i++ {
			var tx *types.Transaction
			gasFeeCap := rand.Intn(50)
			if baseFee == nil {
				tx = types.NewTx(&types.LegacyTx{
					Nonce:    uint64(start + i),
					To:       &common.Address{},
					Value:    big.NewInt(100),
					Gas:      100,
					GasPrice: big.NewInt(int64(gasFeeCap)),
					Data:     nil,
				})
			} else {
				tx = types.NewTx(&types.DynamicFeeTx{
					Nonce:     uint64(start + i),
					To:        &common.Address{},
					Value:     big.NewInt(100),
					Gas:       100,
					GasFeeCap: big.NewInt(int64(gasFeeCap)),
					GasTipCap: big.NewInt(int64(rand.Intn(gasFeeCap + 1))),
					Data:      nil,
				})
				if count == 25 && int64(gasFeeCap) < baseFee.Int64() {
					count = i
				}
			}
			tx, err := types.SignTx(tx, signer, key)
			if err != nil {
				t.Fatalf("failed to sign tx: %s", err)
			}
			groups[addr] = append(groups[addr], &txpool.LazyTransaction{
				Hash:      tx.Hash(),
				Tx:        tx,
				Time:      tx.Time(),
				GasFeeCap: uint256.MustFromBig(tx.GasFeeCap()),
				GasTipCap: uint256.MustFromBig(tx.GasTipCap()),
			})
		}
		expectedCount += count
	}
	// Sort the transactions and cross check the nonce ordering
	txset, _ := newTransactionsByPriceAndNonce(signer, groups, map[common.Address]*big.Int{}, baseFee)

	txs := types.Transactions{}
	for tx := txset.Peek(); tx != nil; tx = txset.Peek() {
		txs = append(txs, tx.Tx)
		txset.Shift()
	}
	if len(txs) != expectedCount {
		t.Errorf("expected %d transactions, found %d", expectedCount, len(txs))
	}
	for i, txi := range txs {
		fromi, _ := types.Sender(signer, txi)

		// Make sure the nonce order is valid
		for j, txj := range txs[i+1:] {
			fromj, _ := types.Sender(signer, txj)
			if fromi == fromj && txi.Nonce() > txj.Nonce() {
				t.Errorf("invalid nonce ordering: tx #%d (A=%x N=%v) < tx #%d (A=%x N=%v)", i, fromi[:4], txi.Nonce(), i+j, fromj[:4], txj.Nonce())
			}
		}
		// If the next tx has different from account, the price must be lower than the current one
		if i+1 < len(txs) {
			next := txs[i+1]
			fromNext, _ := types.Sender(signer, next)
			tip, err := txi.EffectiveGasTip(baseFee)
			nextTip, nextErr := next.EffectiveGasTip(baseFee)
			if err != nil || nextErr != nil {
				t.Errorf("error calculating effective tip: %v, %v", err, nextErr)
			}
			if fromi != fromNext && tip.Cmp(nextTip) < 0 {
				t.Errorf("invalid gasprice ordering: tx #%d (A=%x P=%v) < tx #%d (A=%x P=%v)", i, fromi[:4], txi.GasPrice(), i+1, fromNext[:4], next.GasPrice())
			}
		}
	}
}

// Tests that if multiple transactions have the same price, the ones seen earlier
// are prioritized to avoid network spam attacks aiming for a specific ordering.
func TestTransactionTimeSort(t *testing.T) {
	// Generate a batch of accounts to start with
	keys := make([]*ecdsa.PrivateKey, 5)
	for i := 0; i < len(keys); i++ {
		keys[i], _ = crypto.GenerateKey()
	}
	signer := types.HomesteadSigner{}

	// Generate a batch of transactions with overlapping prices, but different creation times
	groups := map[common.Address][]*txpool.LazyTransaction{}
	for start, key := range keys {
		addr := crypto.PubkeyToAddress(key.PublicKey)

		tx, _ := types.SignTx(types.NewTransaction(0, common.Address{}, big.NewInt(100), 100, big.NewInt(1), nil), signer, key)
		tx.SetTime(time.Unix(0, int64(len(keys)-start)))

		groups[addr] = append(groups[addr], &txpool.LazyTransaction{
			Hash:      tx.Hash(),
			Tx:        tx,
			Time:      tx.Time(),
			GasFeeCap: uint256.MustFromBig(tx.GasFeeCap()),
			GasTipCap: uint256.MustFromBig(tx.GasTipCap()),
		})
	}
	// Sort the transactions and cross check the nonce ordering
	txset, _ := newTransactionsByPriceAndNonce(signer, groups, map[common.Address]*big.Int{}, nil)

	txs := types.Transactions{}
	for tx := txset.Peek(); tx != nil; tx = txset.Peek() {
		txs = append(txs, tx.Tx)
		txset.Shift()
	}
	if len(txs) != len(keys) {
		t.Errorf("expected %d transactions, found %d", len(keys), len(txs))
	}
	for i, txi := range txs {
		fromi, _ := types.Sender(signer, txi)
		if i+1 < len(txs) {
			next := txs[i+1]
			fromNext, _ := types.Sender(signer, next)

			if txi.GasPrice().Cmp(next.GasPrice()) < 0 {
				t.Errorf("invalid gasprice ordering: tx #%d (A=%x P=%v) < tx #%d (A=%x P=%v)", i, fromi[:4], txi.GasPrice(), i+1, fromNext[:4], next.GasPrice())
			}
			// Make sure time order is ascending if the txs have the same gas price
			if txi.GasPrice().Cmp(next.GasPrice()) == 0 && txi.Time().After(next.Time()) {
				t.Errorf("invalid received time ordering: tx #%d (A=%x T=%v) > tx #%d (A=%x T=%v)", i, fromi[:4], txi.Time(), i+1, fromNext[:4], next.Time())
			}
		}
	}
}

// TestNewTransactionsByPriceAndNonce_SpecialSeparation uses table-driven tests to verify separation of special and normal transactions.
func TestNewTransactionsByPriceAndNonce_SpecialSeparation(t *testing.T) {
	signer := types.HomesteadSigner{}

	genNormalTx := func(nonce uint64, key *ecdsa.PrivateKey) *txpool.LazyTransaction {
		tx, _ := types.SignTx(types.NewTransaction(nonce, common.HexToAddress("0x1234567890123456789012345678901234567890"), big.NewInt(1), 21000, big.NewInt(1), nil), signer, key)
		return &txpool.LazyTransaction{Tx: tx, Hash: tx.Hash(), Time: tx.Time(), GasFeeCap: uint256.MustFromBig(tx.GasFeeCap()), GasTipCap: uint256.MustFromBig(tx.GasTipCap())}
	}
	genSpecialTx := func(nonce uint64, key *ecdsa.PrivateKey) *txpool.LazyTransaction {
		tx, _ := types.SignTx(types.NewTransaction(nonce, common.BlockSignersBinary, big.NewInt(1), 21000, big.NewInt(1), nil), signer, key)
		return &txpool.LazyTransaction{Tx: tx, Hash: tx.Hash(), Time: tx.Time(), GasFeeCap: uint256.MustFromBig(tx.GasFeeCap()), GasTipCap: uint256.MustFromBig(tx.GasTipCap())}
	}

	testCases := []struct {
		name          string
		normalCount   int
		specialCount  int
		expectNormal  int
		expectSpecial int
	}{
		{"no transactions", 0, 0, 0, 0},
		{"only 1 normal", 1, 0, 1, 0},
		{"only 2 normal", 2, 0, 2, 0},
		{"only 3 normal", 3, 0, 3, 0},
		{"only 1 special", 0, 1, 0, 1},
		{"only 2 special", 0, 2, 0, 2},
		{"only 3 special", 0, 3, 0, 3},
		{"1 normal, 1 special", 1, 1, 1, 1},
		{"2 normal, 2 special", 2, 2, 2, 2},
		{"3 normal, 3 special", 3, 3, 3, 3},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			key, _ := crypto.GenerateKey()
			addr := crypto.PubkeyToAddress(key.PublicKey)
			txs := make([]*txpool.LazyTransaction, 0, tc.normalCount+tc.specialCount)
			for i := 0; i < tc.normalCount; i++ {
				txs = append(txs, genNormalTx(uint64(i), key))
			}
			for i := 0; i < tc.specialCount; i++ {
				txs = append(txs, genSpecialTx(uint64(tc.normalCount+i), key))
			}
			group := map[common.Address][]*txpool.LazyTransaction{}
			if len(txs) > 0 {
				group[addr] = txs
			}
			txset, specialTxs := newTransactionsByPriceAndNonce(signer, group, map[common.Address]*big.Int{}, nil)

			// Check special transactions
			if len(specialTxs) != tc.expectSpecial {
				t.Errorf("expected %d special txs, got %d", tc.expectSpecial, len(specialTxs))
			}
			for _, tx := range specialTxs {
				if tx.To() == nil || *tx.To() != common.BlockSignersBinary {
					t.Errorf("specialTxs contains non-special tx: %v", tx)
				}
			}

			// Check normal transactions
			normalCount := 0
			for tx := txset.Peek(); tx != nil; tx = txset.Peek() {
				resolved := tx.Resolve()
				if resolved == nil || resolved.To() == nil || *resolved.To() == common.BlockSignersBinary {
					t.Errorf("txset contains special or nil-to tx: %v", resolved)
				}
				normalCount++
				txset.Shift()
			}
			if normalCount != tc.expectNormal {
				t.Errorf("expected %d normal txs, got %d", tc.expectNormal, normalCount)
			}
		})
	}
}