dex/pkg/lx/x_chain_integration.go

package lx

import (
	"errors"
	"math/big"
	"sync"
	"time"
)

// Settlement status constants
const (
	SettlementPending    = "pending"
	SettlementProcessing = "processing"
	SettlementComplete   = "complete"
	SettlementCompleted  = "completed"
	SettlementFailed     = "failed"
)

// SettlementBatch represents a batch of orders for settlement
type SettlementBatch struct {
	BatchID     uint64
	Timestamp   time.Time
	Orders      []*Order
	Status      string
	TxHash      string
	GasUsed     *big.Int
	CreatedAt   time.Time
	CompletedAt time.Time
	mu          sync.RWMutex
}

// GetStatus returns the batch status (thread-safe)
func (b *SettlementBatch) GetStatus() string {
	b.mu.RLock()
	defer b.mu.RUnlock()
	return b.Status
}

// GetTxHash returns the transaction hash (thread-safe)
func (b *SettlementBatch) GetTxHash() string {
	b.mu.RLock()
	defer b.mu.RUnlock()
	return b.TxHash
}

// GetGasUsed returns the gas used (thread-safe)
func (b *SettlementBatch) GetGasUsed() *big.Int {
	b.mu.RLock()
	defer b.mu.RUnlock()
	return b.GasUsed
}

// XChainIntegration manages cross-chain settlement and clearing
type XChainIntegration struct {
	chainID        uint64
	contractAddr   string
	settledOrders  map[uint64]*SettledOrder
	pendingBatches map[uint64]*SettlementBatch
	mu             sync.RWMutex
}

// SettledOrder represents a successfully settled order
type SettledOrder struct {
	OrderID        uint64
	TxHash         string
	BlockNumber    uint64
	SettlementTime time.Time
	GasUsed        *big.Int
}

// XChainConfig configuration for X-Chain integration
type XChainConfig struct {
	RPC                string
	ChainID            uint64
	SettlementContract string
	BatchSize          int
	BatchTimeout       time.Duration
	MaxGasPrice        *big.Int
}

// XChainStats statistics for X-Chain operations
type XChainStats struct {
	TotalSettled      uint64
	TotalPending      uint64
	TotalFailed       uint64
	AvgGasUsed        *big.Int
	AvgSettlementTime time.Duration
	LastSettlement    time.Time
}

// SettlementEngine manages order settlement
type SettlementEngine struct {
	batches       map[uint64]*SettlementBatch
	pendingOrders []*Order
	batchSize     int
	batchTimeout  time.Duration
	batchCounter  uint64
	mu            sync.RWMutex
}

// ClearingEngine manages position clearing and margin
type ClearingEngine struct {
	positions          map[string]map[string]*Position
	balances           map[string]*Balance
	marginRequirements map[string]*MarginRequirement
	mu                 sync.RWMutex
}

// Position represents a user's position in a market
type Position struct {
	Symbol        string
	User          string
	Size          float64
	EntryPrice    float64
	MarkPrice     float64
	UnrealizedPnL float64
	RealizedPnL   float64
}

// Balance represents a user's balance
type Balance struct {
	User       string
	Available  *big.Int
	Locked     *big.Int
	Total      *big.Int
	LastUpdate time.Time
}

// MarginRequirement represents margin requirements for a user
type MarginRequirement struct {
	User              string
	InitialMargin     *big.Int
	MaintenanceMargin *big.Int
	MarginRatio       float64
	LastCalculation   time.Time
}

// Event structures for X-Chain events
type OrderSettledEvent struct {
	OrderID     uint64
	TxHash      string
	BlockNumber uint64
	Timestamp   time.Time
}

type BatchSettledEvent struct {
	BatchID     uint64
	TxHash      string
	OrderCount  int
	TotalVolume *big.Int
	Timestamp   time.Time
}

type SettlementFailedEvent struct {
	BatchID   uint64
	Reason    string
	Timestamp time.Time
}

// Oracle structures
type OraclePrice struct {
	Symbol    string
	Price     float64
	Timestamp time.Time
	Source    string
}

type OracleUpdate struct {
	Prices    map[string]float64
	Timestamp time.Time
	Signature string
}

// Gas optimization structures
type GasEstimator struct {
	baseGas     uint64
	perOrderGas uint64
	maxGasPrice *big.Int
	priorityFee *big.Int
}

type GasOptimizer struct {
	batchSize      int
	maxBatchGas    uint64
	targetGasPrice *big.Int
}

// Security structures
type Signature struct {
	V uint8
	R string
	S string
}

type NonceManager struct {
	currentNonce  uint64
	pendingNonces map[uint64]bool
	mu            sync.RWMutex
}

type AccessControl struct {
	admins    map[string]bool
	operators map[string]bool
	blacklist map[string]bool
	mu        sync.RWMutex
}

// Monitoring structures
type XChainMetrics struct {
	SettlementLatency time.Duration
	GasUsedTotal      *big.Int
	SuccessRate       float64
	FailureCount      uint64
	LastUpdate        time.Time
}

type HealthCheck struct {
	Status      string
	BlockHeight uint64
	PeerCount   int
	Syncing     bool
	LastCheck   time.Time
}

type Alert struct {
	Level     string
	Message   string
	Timestamp time.Time
	Resolved  bool
}

// Recovery structures
type RecoveryManager struct {
	failedBatches map[uint64]*SettlementBatch
	retryAttempts map[uint64]int
	maxRetries    int
	retryDelay    time.Duration
	mu            sync.RWMutex
}

type RetryPolicy struct {
	MaxAttempts   int
	InitialDelay  time.Duration
	MaxDelay      time.Duration
	BackoffFactor float64
}

type DisasterRecovery struct {
	backupEndpoints []string
	currentEndpoint int
	lastSwitch      time.Time
	mu              sync.RWMutex
}

// NewXChainIntegration creates a new X-Chain integration
func NewXChainIntegration(chainID uint64, contractAddr string) *XChainIntegration {
	return &XChainIntegration{
		chainID:        chainID,
		contractAddr:   contractAddr,
		settledOrders:  make(map[uint64]*SettledOrder),
		pendingBatches: make(map[uint64]*SettlementBatch),
	}
}

// SubmitBatch submits a batch for settlement
func (x *XChainIntegration) SubmitBatch(batch *SettlementBatch) error {
	x.mu.Lock()
	defer x.mu.Unlock()

	batch.Status = SettlementPending
	x.pendingBatches[batch.BatchID] = batch

	// In production, this would submit to blockchain
	go x.processBatch(batch)

	return nil
}

// processBatch processes a settlement batch
func (x *XChainIntegration) processBatch(batch *SettlementBatch) {
	// Simulate processing delay
	time.Sleep(100 * time.Millisecond)

	batch.mu.Lock()
	batch.Status = SettlementProcessing
	batch.mu.Unlock()

	// Simulate settlement
	time.Sleep(200 * time.Millisecond)

	batch.mu.Lock()
	batch.Status = SettlementComplete
	batch.TxHash = "0xabcdef123456"
	batch.GasUsed = big.NewInt(210000)
	batch.mu.Unlock()

	// Record settled orders
	x.mu.Lock()
	for _, order := range batch.Orders {
		x.settledOrders[order.ID] = &SettledOrder{
			OrderID:        order.ID,
			TxHash:         batch.TxHash,
			BlockNumber:    1000000,
			SettlementTime: time.Now(),
			GasUsed:        big.NewInt(21000),
		}
	}
	delete(x.pendingBatches, batch.BatchID)
	x.mu.Unlock()
}

// GetStats returns X-Chain statistics
func (x *XChainIntegration) GetStats() *XChainStats {
	x.mu.RLock()
	defer x.mu.RUnlock()

	totalSettled := uint64(len(x.settledOrders))
	totalPending := uint64(len(x.pendingBatches))

	var totalGas int64
	var lastSettlement time.Time

	for _, order := range x.settledOrders {
		if order.GasUsed != nil {
			totalGas += order.GasUsed.Int64()
		}
		if order.SettlementTime.After(lastSettlement) {
			lastSettlement = order.SettlementTime
		}
	}

	avgGas := big.NewInt(0)
	if totalSettled > 0 {
		avgGas = big.NewInt(totalGas / int64(totalSettled))
	}

	return &XChainStats{
		TotalSettled:      totalSettled,
		TotalPending:      totalPending,
		TotalFailed:       0,
		AvgGasUsed:        avgGas,
		AvgSettlementTime: 300 * time.Millisecond,
		LastSettlement:    lastSettlement,
	}
}

// NewSettlementEngine creates a new settlement engine
func NewSettlementEngine(batchSize int, batchTimeout time.Duration) *SettlementEngine {
	return &SettlementEngine{
		batches:       make(map[uint64]*SettlementBatch),
		pendingOrders: make([]*Order, 0),
		batchSize:     batchSize,
		batchTimeout:  batchTimeout,
	}
}

// AddOrder adds an order for settlement
func (s *SettlementEngine) AddOrder(order *Order) {
	s.mu.Lock()
	defer s.mu.Unlock()

	s.pendingOrders = append(s.pendingOrders, order)

	// Create batch if size reached
	if len(s.pendingOrders) >= s.batchSize {
		s.createBatch()
	}
}

// CreateBatch creates a new batch from provided orders (for testing)
func (s *SettlementEngine) CreateBatch(orders []*SettledOrder) *SettlementBatch {
	s.mu.Lock()
	defer s.mu.Unlock()

	s.batchCounter++
	batch := &SettlementBatch{
		BatchID:   s.batchCounter,
		Orders:    make([]*Order, 0, len(orders)),
		Status:    SettlementPending,
		CreatedAt: time.Now(),
	}

	// Convert SettledOrders to Orders for the batch
	for _, settled := range orders {
		order := &Order{
			ID: settled.OrderID,
		}
		batch.Orders = append(batch.Orders, order)
	}

	s.batches[batch.BatchID] = batch
	return batch
}

// ExecuteBatch executes a settlement batch
func (s *SettlementEngine) ExecuteBatch(batchID uint64) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	batch, exists := s.batches[batchID]
	if !exists {
		return errors.New("batch not found")
	}

	batch.Status = SettlementCompleted
	batch.CompletedAt = time.Now()
	return nil
}

// createBatch creates a new settlement batch
func (s *SettlementEngine) createBatch() *SettlementBatch {
	batchID := uint64(time.Now().UnixNano())

	batch := &SettlementBatch{
		BatchID:   batchID,
		Timestamp: time.Now(),
		Orders:    make([]*Order, len(s.pendingOrders)),
		Status:    SettlementPending,
	}

	copy(batch.Orders, s.pendingOrders)
	s.pendingOrders = s.pendingOrders[:0]
	s.batches[batchID] = batch

	return batch
}

// NewClearingEngine creates a new clearing engine
func NewClearingEngine() *ClearingEngine {
	return &ClearingEngine{
		positions:          make(map[string]map[string]*Position),
		balances:           make(map[string]*Balance),
		marginRequirements: make(map[string]*MarginRequirement),
	}
}

// UpdatePosition updates a user's position
func (c *ClearingEngine) UpdatePosition(user, symbol string, size, price float64) {
	c.mu.Lock()
	defer c.mu.Unlock()

	if c.positions[user] == nil {
		c.positions[user] = make(map[string]*Position)
	}

	pos, exists := c.positions[user][symbol]
	if !exists {
		pos = &Position{
			Symbol: symbol,
			User:   user,
		}
		c.positions[user][symbol] = pos
	}

	// Update position
	if pos.Size == 0 {
		pos.EntryPrice = price
	} else {
		// Average entry price
		totalValue := pos.Size*pos.EntryPrice + size*price
		pos.EntryPrice = totalValue / (pos.Size + size)
	}

	pos.Size += size
	pos.MarkPrice = price
	pos.UnrealizedPnL = (price - pos.EntryPrice) * pos.Size
}

// GetPosition returns a user's position
func (c *ClearingEngine) GetPosition(user, symbol string) *Position {
	c.mu.RLock()
	defer c.mu.RUnlock()

	if positions, exists := c.positions[user]; exists {
		return positions[symbol]
	}
	return nil
}

// UpdateBalanceWithLocked updates a user's balance with available and locked amounts
func (c *ClearingEngine) UpdateBalanceWithLocked(user string, available, locked *big.Int) {
	c.mu.Lock()
	defer c.mu.Unlock()

	balance, exists := c.balances[user]
	if !exists {
		balance = &Balance{
			User:      user,
			Available: big.NewInt(0),
			Locked:    big.NewInt(0),
			Total:     big.NewInt(0),
		}
		c.balances[user] = balance
	}

	if available != nil {
		balance.Available = new(big.Int).Set(available)
	}
	if locked != nil {
		balance.Locked = new(big.Int).Set(locked)
	}

	balance.Total = new(big.Int).Add(balance.Available, balance.Locked)
	balance.LastUpdate = time.Now()
}

// GetBalance returns a user's balance
func (c *ClearingEngine) GetBalance(user string) *Balance {
	c.mu.RLock()
	defer c.mu.RUnlock()

	return c.balances[user]
}

// UpdateBalance updates a user's balance with a single amount
func (c *ClearingEngine) UpdateBalance(user string, amount *big.Int) {
	c.mu.Lock()
	defer c.mu.Unlock()

	if c.balances[user] == nil {
		c.balances[user] = &Balance{
			User:       user,
			Available:  new(big.Int).Set(amount),
			Locked:     big.NewInt(0),
			Total:      new(big.Int).Set(amount),
			LastUpdate: time.Now(),
		}
	} else {
		c.balances[user].Available.Add(c.balances[user].Available, amount)
		c.balances[user].Total.Add(c.balances[user].Total, amount)
		c.balances[user].LastUpdate = time.Now()
	}
}

// CalculateMarginRequirement calculates margin requirements for a user
func (c *ClearingEngine) CalculateMarginRequirement(user string) *MarginRequirement {
	c.mu.Lock()
	defer c.mu.Unlock()

	req := &MarginRequirement{
		User:              user,
		InitialMargin:     big.NewInt(0),
		MaintenanceMargin: big.NewInt(0),
		LastCalculation:   time.Now(),
	}

	// Calculate based on positions
	if positions, exists := c.positions[user]; exists {
		for _, pos := range positions {
			positionValue := int64(pos.Size * pos.EntryPrice)
			initial := big.NewInt(positionValue / 10)     // 10% initial margin
			maintenance := big.NewInt(positionValue / 20) // 5% maintenance margin

			req.InitialMargin.Add(req.InitialMargin, initial)
			req.MaintenanceMargin.Add(req.MaintenanceMargin, maintenance)
		}
	}

	// Calculate margin ratio
	if balance := c.balances[user]; balance != nil && req.InitialMargin.Sign() > 0 {
		balanceFloat := new(big.Float).SetInt(balance.Available)
		marginFloat := new(big.Float).SetInt(req.InitialMargin)
		ratio, _ := new(big.Float).Quo(balanceFloat, marginFloat).Float64()
		req.MarginRatio = ratio
	}

	c.marginRequirements[user] = req
	return req
}

// CheckMargin checks if a user has sufficient margin
func (c *ClearingEngine) CheckMargin(user string) bool {
	req := c.CalculateMarginRequirement(user)
	balance := c.GetBalance(user)

	if balance == nil || req == nil {
		return false
	}

	return balance.Available.Cmp(req.InitialMargin) >= 0
}

// CheckLiquidation checks if a user needs liquidation
func (c *ClearingEngine) CheckLiquidation(user string) bool {
	c.mu.RLock()
	defer c.mu.RUnlock()

	req := c.marginRequirements[user]
	balance := c.balances[user]

	if req == nil || balance == nil {
		return false
	}

	// Check if account value is below maintenance margin
	return balance.Available.Cmp(req.MaintenanceMargin) < 0
}

// Liquidate liquidates a user's positions
func (c *ClearingEngine) Liquidate(user string) bool {
	c.mu.Lock()
	defer c.mu.Unlock()

	// Check if liquidation is needed
	if c.balances[user] == nil || c.marginRequirements[user] == nil {
		return false
	}

	if c.balances[user].Available.Cmp(c.marginRequirements[user].MaintenanceMargin) >= 0 {
		return false // No liquidation needed
	}

	// Close all positions
	delete(c.positions, user)

	// Reset margin requirements
	c.marginRequirements[user] = &MarginRequirement{
		User:              user,
		InitialMargin:     big.NewInt(0),
		MaintenanceMargin: big.NewInt(0),
		MarginRatio:       0,
		LastCalculation:   time.Now(),
	}

	return true
}

// NewGasEstimator creates a new gas estimator
func NewGasEstimator() *GasEstimator {
	return &GasEstimator{
		baseGas:     21000,
		perOrderGas: 50000,
		maxGasPrice: big.NewInt(100000000000), // 100 gwei
		priorityFee: big.NewInt(2000000000),   // 2 gwei
	}
}

// EstimateGas estimates gas for a batch
func (g *GasEstimator) EstimateGas(orderCount int) uint64 {
	return g.baseGas + uint64(orderCount)*g.perOrderGas
}

// NewNonceManager creates a new nonce manager
func NewNonceManager(startNonce uint64) *NonceManager {
	return &NonceManager{
		currentNonce:  startNonce,
		pendingNonces: make(map[uint64]bool),
	}
}

// GetNextNonce returns the next available nonce
func (n *NonceManager) GetNextNonce() uint64 {
	n.mu.Lock()
	defer n.mu.Unlock()

	nonce := n.currentNonce
	n.pendingNonces[nonce] = true
	n.currentNonce++

	return nonce
}

// ConfirmNonce confirms a nonce has been used
func (n *NonceManager) ConfirmNonce(nonce uint64) {
	n.mu.Lock()
	defer n.mu.Unlock()

	delete(n.pendingNonces, nonce)
}

// NewAccessControl creates a new access control manager
func NewAccessControl() *AccessControl {
	return &AccessControl{
		admins:    make(map[string]bool),
		operators: make(map[string]bool),
		blacklist: make(map[string]bool),
	}
}

// IsAdmin checks if an address is an admin
func (a *AccessControl) IsAdmin(address string) bool {
	a.mu.RLock()
	defer a.mu.RUnlock()

	return a.admins[address]
}

// IsOperator checks if an address is an operator
func (a *AccessControl) IsOperator(address string) bool {
	a.mu.RLock()
	defer a.mu.RUnlock()

	return a.operators[address]
}

// IsBlacklisted checks if an address is blacklisted
func (a *AccessControl) IsBlacklisted(address string) bool {
	a.mu.RLock()
	defer a.mu.RUnlock()

	return a.blacklist[address]
}

// NewRecoveryManager creates a new recovery manager
func NewRecoveryManager(maxRetries int, retryDelay time.Duration) *RecoveryManager {
	return &RecoveryManager{
		failedBatches: make(map[uint64]*SettlementBatch),
		retryAttempts: make(map[uint64]int),
		maxRetries:    maxRetries,
		retryDelay:    retryDelay,
	}
}

// AddFailedBatch adds a failed batch for retry
func (r *RecoveryManager) AddFailedBatch(batch *SettlementBatch) bool {
	r.mu.Lock()
	defer r.mu.Unlock()

	// Capture batch ID while holding the lock to avoid race conditions
	batchID := batch.BatchID

	attempts := r.retryAttempts[batchID]
	if attempts >= r.maxRetries {
		return false
	}

	r.failedBatches[batchID] = batch
	r.retryAttempts[batchID] = attempts + 1

	// Schedule retry using captured batchID
	go r.scheduleRetry(batchID)

	return true
}

// scheduleRetry schedules a batch retry
func (r *RecoveryManager) scheduleRetry(batchID uint64) {
	time.Sleep(r.retryDelay)

	r.mu.Lock()
	batch, exists := r.failedBatches[batchID]
	if !exists {
		r.mu.Unlock()
		return
	}
	delete(r.failedBatches, batchID)
	r.mu.Unlock()

	// Retry the batch (would call settlement logic in production)
	_ = batch
}

// FailedBatchCount returns the number of failed batches (thread-safe)
func (r *RecoveryManager) FailedBatchCount() int {
	r.mu.Lock()
	defer r.mu.Unlock()
	return len(r.failedBatches)
}

// GetRetryAttempts returns the retry attempts for a batch (thread-safe)
func (r *RecoveryManager) GetRetryAttempts(batchID uint64) int {
	r.mu.Lock()
	defer r.mu.Unlock()
	return r.retryAttempts[batchID]
}

// AddFailedBatchForTest adds a batch directly to failed batches (thread-safe, for testing)
func (r *RecoveryManager) AddFailedBatchForTest(batch *SettlementBatch) {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.failedBatches[batch.BatchID] = batch
}