consensus/examples/op_stack_quantum_integration.go

// Copyright (C) 2019-2025, Lux Industries Inc All rights reserved.
// See the file LICENSE for licensing terms.

//go:build skip
// +build skip

// Package main demonstrates integrating Lux Consensus with OP Stack
// for quantum-resistant finality in Layer 2 rollups.
package main

import (
	"context"
	"crypto/rand"
	"encoding/hex"
	"fmt"
	"log"
	"math/big"
	"time"

	"github.com/luxfi/geth/common"
	"github.com/luxfi/geth/core/types"
	"github.com/luxfi/geth/crypto"
	"github.com/luxfi/consensus/engine/core"
	"github.com/luxfi/ids"
)

// QuantumFinalityEngine wraps Lux consensus for OP Stack integration
type QuantumFinalityEngine struct {
	consensus    core.Consensus
	quantumProof *QuantumProof
	opBatcher    *OPBatcher
}

// QuantumProof contains post-quantum cryptographic proofs
type QuantumProof struct {
	// ML-DSA-65 (Dilithium) signature
	DilithiumSig []byte
	// ML-KEM-1024 (Kyber) encapsulated key
	KyberCiphertext []byte
	// Merkle tree root with quantum-resistant hash
	QuantumMerkleRoot [32]byte
	// Finality threshold met
	FinalityHeight uint64
}

// OPBatcher handles OP Stack batch submissions
type OPBatcher struct {
	L1Endpoint     string
	L2Endpoint     string
	BatcherAddress common.Address
	SequencerURL   string
	StateRoot      common.Hash
	BatchIndex     uint64
}

// L2Block represents an OP Stack L2 block
type L2Block struct {
	Number       *big.Int
	Hash         common.Hash
	ParentHash   common.Hash
	StateRoot    common.Hash
	Transactions []*types.Transaction
	Timestamp    uint64

	// Lux consensus fields
	ConsensusID  ids.ID
	VoteCount    int
	IsFinalized  bool
	QuantumProof *QuantumProof
}

// NewQuantumFinalityEngine creates a new quantum-resistant finality engine
func NewQuantumFinalityEngine(opStackConfig *OPStackConfig) (*QuantumFinalityEngine, error) {
	// Initialize Lux consensus with post-quantum parameters
	consensusParams := core.Parameters{
		K:                     30, // Increased for quantum resistance
		AlphaPreference:       22, // 73% threshold
		AlphaConfidence:       22,
		Beta:                  28, // Higher finality threshold
		ConcurrentPolls:       3,
		OptimalProcessing:     2,
		MaxOutstandingItems:   2048,
		MaxItemProcessingTime: 5 * time.Second,
	}

	// Use C implementation for performance
	factory := core.NewConsensusFactory()
	consensus, err := factory.CreateConsensus(consensusParams)
	if err != nil {
		return nil, fmt.Errorf("failed to create consensus: %w", err)
	}

	return &QuantumFinalityEngine{
		consensus:    consensus,
		quantumProof: &QuantumProof{},
		opBatcher: &OPBatcher{
			L1Endpoint:     opStackConfig.L1RPC,
			L2Endpoint:     opStackConfig.L2RPC,
			BatcherAddress: opStackConfig.BatcherAddress,
			SequencerURL:   opStackConfig.SequencerURL,
		},
	}, nil
}

// ProcessL2Block processes an L2 block through quantum-resistant consensus
func (qfe *QuantumFinalityEngine) ProcessL2Block(ctx context.Context, block *L2Block) error {
	// Convert L2 block to Lux consensus block
	luxBlock := &ConsensusBlock{
		id:        generateBlockID(block.Hash),
		parentID:  generateBlockID(block.ParentHash),
		height:    block.Number.Uint64(),
		timestamp: time.Unix(int64(block.Timestamp), 0),
		data:      encodeL2Block(block),
	}

	// Add to consensus engine
	if err := qfe.consensus.Add(luxBlock); err != nil {
		return fmt.Errorf("failed to add block to consensus: %w", err)
	}

	// Generate quantum-resistant proof
	if err := qfe.generateQuantumProof(block); err != nil {
		return fmt.Errorf("failed to generate quantum proof: %w", err)
	}

	return nil
}

// generateQuantumProof creates post-quantum cryptographic proofs
func (qfe *QuantumFinalityEngine) generateQuantumProof(block *L2Block) error {
	// 1. Generate Dilithium signature (ML-DSA-65)
	dilithiumSig := qfe.signWithDilithium(block.Hash.Bytes())
	qfe.quantumProof.DilithiumSig = dilithiumSig

	// 2. Generate Kyber key encapsulation (ML-KEM-1024)
	kyberCiphertext := qfe.encapsulateWithKyber(block.StateRoot.Bytes())
	qfe.quantumProof.KyberCiphertext = kyberCiphertext

	// 3. Build quantum-resistant Merkle tree
	merkleRoot := qfe.buildQuantumMerkleTree(block.Transactions)
	qfe.quantumProof.QuantumMerkleRoot = merkleRoot

	// 4. Set finality height
	qfe.quantumProof.FinalityHeight = block.Number.Uint64()

	block.QuantumProof = qfe.quantumProof

	return nil
}

// signWithDilithium signs data using ML-DSA-65 (Dilithium3)
func (qfe *QuantumFinalityEngine) signWithDilithium(data []byte) []byte {
	// In production, this would use actual Dilithium implementation
	// from github.com/luxfi/crypto/dilithium

	// Placeholder for demonstration
	sig := make([]byte, 3293) // Dilithium3 signature size
	rand.Read(sig)

	fmt.Printf("Generated Dilithium signature (ML-DSA-65): %d bytes\n", len(sig))
	return sig
}

// encapsulateWithKyber performs key encapsulation using ML-KEM-1024
func (qfe *QuantumFinalityEngine) encapsulateWithKyber(data []byte) []byte {
	// In production, this would use actual Kyber implementation
	// from github.com/luxfi/crypto/kyber

	// Placeholder for demonstration
	ciphertext := make([]byte, 1568) // Kyber1024 ciphertext size
	rand.Read(ciphertext)

	fmt.Printf("Generated Kyber ciphertext (ML-KEM-1024): %d bytes\n", len(ciphertext))
	return ciphertext
}

// buildQuantumMerkleTree builds a Merkle tree with quantum-resistant hash
func (qfe *QuantumFinalityEngine) buildQuantumMerkleTree(txs []*types.Transaction) [32]byte {
	// Use SHA3-256 as quantum-resistant hash function
	// In production, could use SHAKE256 or other quantum-resistant hash

	var root [32]byte
	if len(txs) == 0 {
		return root
	}

	// Build tree (simplified)
	hashes := make([][]byte, len(txs))
	for i, tx := range txs {
		hashes[i] = crypto.Keccak256(tx.Hash().Bytes())
	}

	// Compute root
	rootHash := crypto.Keccak256(hashes...)
	copy(root[:], rootHash)

	fmt.Printf("Built quantum-resistant Merkle tree with %d transactions\n", len(txs))
	return root
}

// SubmitBatchWithQuantumFinality submits a batch to L1 with quantum-resistant finality proof
func (qfe *QuantumFinalityEngine) SubmitBatchWithQuantumFinality(
	ctx context.Context,
	blocks []*L2Block,
) error {
	// 1. Check consensus finality for all blocks
	for _, block := range blocks {
		if !qfe.consensus.IsAccepted(block.ConsensusID) {
			return fmt.Errorf("block %s not finalized by consensus", block.Hash.Hex())
		}
	}

	// 2. Create batch with quantum proofs
	batch := &QuantumBatch{
		Blocks:        blocks,
		BatchIndex:    qfe.opBatcher.BatchIndex,
		Timestamp:     time.Now().Unix(),
		QuantumProofs: make([]*QuantumProof, len(blocks)),
	}

	for i, block := range blocks {
		batch.QuantumProofs[i] = block.QuantumProof
	}

	// 3. Submit to L1 with quantum finality proof
	txData := qfe.encodeBatchWithQuantumProof(batch)

	fmt.Printf("Submitting batch %d with %d blocks to L1\n", batch.BatchIndex, len(blocks))
	fmt.Printf("Batch data size: %d bytes\n", len(txData))
	fmt.Printf("Quantum proofs included: %d\n", len(batch.QuantumProofs))

	// In production, this would submit to actual L1
	// tx := qfe.submitToL1(ctx, txData)

	qfe.opBatcher.BatchIndex++

	return nil
}

// ProcessValidatorVotes processes validator votes for L2 blocks
func (qfe *QuantumFinalityEngine) ProcessValidatorVotes(
	ctx context.Context,
	blockHash common.Hash,
	votes []*ValidatorVote,
) error {
	blockID := generateBlockID(blockHash)

	for _, vote := range votes {
		voterID := ids.NodeID(vote.ValidatorID)

		// Process vote in consensus engine
		err := qfe.consensus.ProcessVote(voterID, blockID, vote.IsSupport)
		if err != nil {
			return fmt.Errorf("failed to process vote: %w", err)
		}

		// Verify quantum-resistant signature
		if !qfe.verifyQuantumSignature(vote.QuantumSig, vote.Data) {
			return fmt.Errorf("invalid quantum signature from validator %s", vote.ValidatorID)
		}
	}

	// Check if finality reached
	if qfe.consensus.IsAccepted(blockID) {
		fmt.Printf("Block %s achieved quantum-resistant finality with %d votes\n",
			blockHash.Hex(), len(votes))
	}

	return nil
}

// verifyQuantumSignature verifies a post-quantum signature
func (qfe *QuantumFinalityEngine) verifyQuantumSignature(sig, data []byte) bool {
	// In production, verify using actual post-quantum crypto
	// This would use Dilithium or Falcon signature verification
	return len(sig) > 0 && len(data) > 0
}

// GetFinalityStatus returns the finality status of a block
func (qfe *QuantumFinalityEngine) GetFinalityStatus(blockHash common.Hash) *FinalityStatus {
	blockID := generateBlockID(blockHash)

	isFinalized := qfe.consensus.IsAccepted(blockID)
	preference := qfe.consensus.GetPreference()

	stats, _ := qfe.consensus.GetStats()

	return &FinalityStatus{
		BlockHash:        blockHash,
		IsFinalized:      isFinalized,
		VotesReceived:    int(stats.VotesProcessed),
		PreferredBlock:   hex.EncodeToString(preference[:]),
		QuantumSecure:    qfe.quantumProof != nil,
		FinalityHeight:   qfe.quantumProof.FinalityHeight,
		ConsensusMetrics: stats,
	}
}

// MonitorAndFinalize monitors L2 blocks and finalizes them
func (qfe *QuantumFinalityEngine) MonitorAndFinalize(ctx context.Context) {
	ticker := time.NewTicker(12 * time.Second) // L1 block time
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			// Get pending L2 blocks
			blocks := qfe.getPendingL2Blocks()

			if len(blocks) > 0 {
				fmt.Printf("Processing %d pending L2 blocks for finalization\n", len(blocks))

				// Process each block
				for _, block := range blocks {
					if err := qfe.ProcessL2Block(ctx, block); err != nil {
						log.Printf("Error processing block: %v", err)
						continue
					}
				}

				// Submit batch if ready
				if qfe.shouldSubmitBatch(blocks) {
					if err := qfe.SubmitBatchWithQuantumFinality(ctx, blocks); err != nil {
						log.Printf("Error submitting batch: %v", err)
					}
				}
			}
		}
	}
}

// Helper functions

func generateBlockID(hash common.Hash) ids.ID {
	var id ids.ID
	copy(id[:], hash[:32])
	return id
}

func encodeL2Block(block *L2Block) []byte {
	// Encode block data for consensus
	data := append(block.Hash.Bytes(), block.StateRoot.Bytes()...)
	return data
}

func (qfe *QuantumFinalityEngine) getPendingL2Blocks() []*L2Block {
	// In production, fetch from L2 node
	return []*L2Block{}
}

func (qfe *QuantumFinalityEngine) shouldSubmitBatch(blocks []*L2Block) bool {
	// Submit when we have enough finalized blocks or timeout
	finalizedCount := 0
	for _, block := range blocks {
		if qfe.consensus.IsAccepted(block.ConsensusID) {
			finalizedCount++
		}
	}
	return finalizedCount >= 10 || len(blocks) >= 100
}

func (qfe *QuantumFinalityEngine) encodeBatchWithQuantumProof(batch *QuantumBatch) []byte {
	// Encode batch data with quantum proofs
	// In production, this would follow OP Stack batch format
	return []byte{}
}

// Types for OP Stack integration

type OPStackConfig struct {
	L1RPC          string
	L2RPC          string
	BatcherAddress common.Address
	SequencerURL   string
}

type ConsensusBlock struct {
	id        ids.ID
	parentID  ids.ID
	height    uint64
	timestamp time.Time
	data      []byte
}

func (b *ConsensusBlock) ID() ids.ID           { return b.id }
func (b *ConsensusBlock) Parent() ids.ID       { return b.parentID }
func (b *ConsensusBlock) Height() uint64       { return b.height }
func (b *ConsensusBlock) Timestamp() time.Time { return b.timestamp }
func (b *ConsensusBlock) Bytes() []byte        { return b.data }

type ValidatorVote struct {
	ValidatorID [32]byte
	BlockHash   common.Hash
	IsSupport   bool
	QuantumSig  []byte // Post-quantum signature
	Data        []byte
}

type QuantumBatch struct {
	Blocks        []*L2Block
	BatchIndex    uint64
	Timestamp     int64
	QuantumProofs []*QuantumProof
}

type FinalityStatus struct {
	BlockHash        common.Hash
	IsFinalized      bool
	VotesReceived    int
	PreferredBlock   string
	QuantumSecure    bool
	FinalityHeight   uint64
	ConsensusMetrics core.Stats
}

// Example usage
func main() {
	fmt.Println("=== Lux Consensus + OP Stack Quantum Integration ===")
	fmt.Println()

	// Configure OP Stack connection
	config := &OPStackConfig{
		L1RPC:          "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY",
		L2RPC:          "https://mainnet.optimism.io",
		BatcherAddress: common.HexToAddress("0x6887246668a3b87F54DeB3b94Ba47a6f63F32985"),
		SequencerURL:   "https://sequencer.optimism.io",
	}

	// Create quantum finality engine
	engine, err := NewQuantumFinalityEngine(config)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("✅ Quantum Finality Engine initialized")
	fmt.Println()

	// Example: Process an L2 block
	exampleBlock := &L2Block{
		Number:      big.NewInt(100000),
		Hash:        common.HexToHash("0x123..."),
		ParentHash:  common.HexToHash("0x122..."),
		StateRoot:   common.HexToHash("0x456..."),
		Timestamp:   uint64(time.Now().Unix()),
		ConsensusID: ids.GenerateTestID(),
	}

	ctx := context.Background()

	// Process block through consensus
	if err := engine.ProcessL2Block(ctx, exampleBlock); err != nil {
		log.Printf("Error processing block: %v", err)
	}

	// Simulate validator votes
	votes := []*ValidatorVote{
		{
			ValidatorID: [32]byte{1},
			BlockHash:   exampleBlock.Hash,
			IsSupport:   true,
			QuantumSig:  make([]byte, 3293), // Dilithium signature
		},
		// Add more votes...
	}

	if err := engine.ProcessValidatorVotes(ctx, exampleBlock.Hash, votes); err != nil {
		log.Printf("Error processing votes: %v", err)
	}

	// Check finality status
	status := engine.GetFinalityStatus(exampleBlock.Hash)
	fmt.Printf("Block Finality Status:\n")
	fmt.Printf("  Finalized: %v\n", status.IsFinalized)
	fmt.Printf("  Quantum Secure: %v\n", status.QuantumSecure)
	fmt.Printf("  Votes: %d\n", status.VotesReceived)
	fmt.Printf("  Finality Height: %d\n", status.FinalityHeight)
	fmt.Println()

	// Start monitoring (in production)
	// go engine.MonitorAndFinalize(ctx)

	fmt.Println("🔐 Quantum-resistant finality for OP Stack enabled!")
	fmt.Println()
	fmt.Println("Key Features:")
	fmt.Println("  ✅ ML-DSA-65 (Dilithium) signatures")
	fmt.Println("  ✅ ML-KEM-1024 (Kyber) key encapsulation")
	fmt.Println("  ✅ Quantum-resistant Merkle trees")
	fmt.Println("  ✅ Lux consensus for fast finality")
	fmt.Println("  ✅ OP Stack batch submission integration")
}