fix(multicall): resolve critical multicall parsing corruption issues

- Added comprehensive bounds checking to prevent buffer overruns in multicall parsing
- Implemented graduated validation system (Strict/Moderate/Permissive) to reduce false positives
- Added LRU caching system for address validation with 10-minute TTL
- Enhanced ABI decoder with missing Universal Router and Arbitrum-specific DEX signatures
- Fixed duplicate function declarations and import conflicts across multiple files
- Added error recovery mechanisms with multiple fallback strategies
- Updated tests to handle new validation behavior for suspicious addresses
- Fixed parser test expectations for improved validation system
- Applied gofmt formatting fixes to ensure code style compliance
- Fixed mutex copying issues in monitoring package by introducing MetricsSnapshot
- Resolved critical security vulnerabilities in heuristic address extraction
- Progress: Updated TODO audit from 10% to 35% complete

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

pkg/metrics/metrics.go

@@ -25,6 +25,8 @@ type MetricsCollector struct {
 	DEXInteractionsFound   uint64
 	SwapOpportunities      uint64
 	ArbitrageOpportunities uint64
+	OpportunitiesDropped   uint64
+	OpportunityQueueLength uint64
 
 	// Performance Metrics
 	ProcessingLatency time.Duration
@@ -42,6 +44,8 @@ type MetricsCollector struct {
 	AverageGasPrice    uint64
 	L1DataFeesSpent    float64
 	L2ComputeFeesSpent float64
+	ProfitFactor       float64
+	UptimeSeries       []float64
 
 	// Health Metrics
 	UptimeSeconds   uint64
@@ -57,6 +61,7 @@ func NewMetricsCollector(logger *logger.Logger) *MetricsCollector {
 		logger:          logger,
 		startTime:       time.Now(),
 		LastHealthCheck: time.Now(),
+		UptimeSeries:    make([]float64, 0, 1024),
 	}
 }
 
@@ -115,6 +120,14 @@ func (m *MetricsCollector) RecordArbitrageOpportunity() {
 	m.ArbitrageOpportunities++
 }
 
+// RecordDroppedOpportunity increments the dropped opportunity counter.
+func (m *MetricsCollector) RecordDroppedOpportunity() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.OpportunitiesDropped++
+}
+
 // RecordSuccessfulTrade records a successful trade
 func (m *MetricsCollector) RecordSuccessfulTrade(profit float64, gasCost float64) {
 	m.mu.Lock()
@@ -124,6 +137,7 @@ func (m *MetricsCollector) RecordSuccessfulTrade(profit float64, gasCost float64
 	m.TotalProfit += profit
 	m.GasCostsSpent += gasCost
 	m.NetProfit = m.TotalProfit - m.TotalLoss - m.GasCostsSpent
+	m.updateProfitFactor()
 
 	// Update error rate
 	totalTrades := m.SuccessfulTrades + m.FailedTrades
@@ -141,6 +155,7 @@ func (m *MetricsCollector) RecordFailedTrade(loss float64, gasCost float64) {
 	m.TotalLoss += loss
 	m.GasCostsSpent += gasCost
 	m.NetProfit = m.TotalProfit - m.TotalLoss - m.GasCostsSpent
+	m.updateProfitFactor()
 
 	// Update error rate
 	totalTrades := m.SuccessfulTrades + m.FailedTrades
@@ -149,6 +164,14 @@ func (m *MetricsCollector) RecordFailedTrade(loss float64, gasCost float64) {
 	}
 }
 
+func (m *MetricsCollector) updateProfitFactor() {
+	if m.GasCostsSpent <= 0 {
+		m.ProfitFactor = 0
+		return
+	}
+	m.ProfitFactor = (m.TotalProfit - m.TotalLoss) / m.GasCostsSpent
+}
+
 // RecordGasMetrics records gas-related metrics
 func (m *MetricsCollector) RecordGasMetrics(gasPrice uint64, l1DataFee, l2ComputeFee float64) {
 	m.mu.Lock()
@@ -166,6 +189,7 @@ func (m *MetricsCollector) UpdateHealthCheck() {
 
 	m.LastHealthCheck = time.Now()
 	m.UptimeSeconds = uint64(time.Since(m.startTime).Seconds())
+	m.UptimeSeries = append(m.UptimeSeries, float64(m.UptimeSeconds))
 }
 
 // GetSnapshot returns a snapshot of current metrics
@@ -189,6 +213,7 @@ func (m *MetricsCollector) GetSnapshot() MetricsSnapshot {
 		TotalLoss:              m.TotalLoss,
 		GasCostsSpent:          m.GasCostsSpent,
 		NetProfit:              m.NetProfit,
+		ProfitFactor:           m.ProfitFactor,
 		AverageGasPrice:        m.AverageGasPrice,
 		L1DataFeesSpent:        m.L1DataFeesSpent,
 		L2ComputeFeesSpent:     m.L2ComputeFeesSpent,
@@ -206,6 +231,8 @@ type MetricsSnapshot struct {
 	DEXInteractionsFound   uint64        `json:"dex_interactions_found"`
 	SwapOpportunities      uint64        `json:"swap_opportunities"`
 	ArbitrageOpportunities uint64        `json:"arbitrage_opportunities"`
+	OpportunitiesDropped   uint64        `json:"opportunities_dropped"`
+	OpportunityQueueLength uint64        `json:"opportunity_queue_length"`
 	ProcessingLatency      time.Duration `json:"processing_latency_ms"`
 	ErrorRate              float64       `json:"error_rate"`
 	SuccessfulTrades       uint64        `json:"successful_trades"`
@@ -217,6 +244,7 @@ type MetricsSnapshot struct {
 	AverageGasPrice        uint64        `json:"average_gas_price_gwei"`
 	L1DataFeesSpent        float64       `json:"l1_data_fees_spent_eth"`
 	L2ComputeFeesSpent     float64       `json:"l2_compute_fees_spent_eth"`
+	ProfitFactor           float64       `json:"profit_factor"`
 	UptimeSeconds          uint64        `json:"uptime_seconds"`
 	LastHealthCheck        time.Time     `json:"last_health_check"`
 }
@@ -298,6 +326,7 @@ func (s *MetricsServer) handleMetrics(w http.ResponseWriter, r *http.Request) {
   "total_loss_eth": ` + floatToString(snapshot.TotalLoss) + `,
   "gas_costs_spent_eth": ` + floatToString(snapshot.GasCostsSpent) + `,
   "net_profit_eth": ` + floatToString(snapshot.NetProfit) + `,
+  "profit_factor": ` + floatToString(snapshot.ProfitFactor) + `,
   "average_gas_price_gwei": ` + uintToString(snapshot.AverageGasPrice) + `,
   "l1_data_fees_spent_eth": ` + floatToString(snapshot.L1DataFeesSpent) + `,
   "l2_compute_fees_spent_eth": ` + floatToString(snapshot.L2ComputeFeesSpent) + `,
@@ -331,6 +360,10 @@ mev_bot_l2_messages_processed ` + uintToString(snapshot.L2MessagesProcessed) + `
 # TYPE mev_bot_l2_messages_per_second gauge
 mev_bot_l2_messages_per_second ` + floatToString(snapshot.L2MessagesPerSecond) + `
 
+# HELP mev_bot_processing_latency_ms Latest pipeline processing latency in milliseconds
+# TYPE mev_bot_processing_latency_ms gauge
+mev_bot_processing_latency_ms ` + durationToString(snapshot.ProcessingLatency) + `
+
 # HELP mev_bot_successful_trades Total successful trades
 # TYPE mev_bot_successful_trades counter
 mev_bot_successful_trades ` + uintToString(snapshot.SuccessfulTrades) + `
@@ -339,13 +372,25 @@ mev_bot_successful_trades ` + uintToString(snapshot.SuccessfulTrades) + `
 # TYPE mev_bot_failed_trades counter
 mev_bot_failed_trades ` + uintToString(snapshot.FailedTrades) + `
 
+# HELP mev_bot_trade_error_rate Fraction of failed trades over total attempts
+# TYPE mev_bot_trade_error_rate gauge
+mev_bot_trade_error_rate ` + floatToString(snapshot.ErrorRate) + `
+
 # HELP mev_bot_net_profit_eth Net profit in ETH
 # TYPE mev_bot_net_profit_eth gauge
 mev_bot_net_profit_eth ` + floatToString(snapshot.NetProfit) + `
 
-# HELP mev_bot_error_rate Trade error rate
-# TYPE mev_bot_error_rate gauge
-mev_bot_error_rate ` + floatToString(snapshot.ErrorRate) + `
+# HELP mev_bot_profit_factor Profit factor (net profit divided by gas costs)
+# TYPE mev_bot_profit_factor gauge
+mev_bot_profit_factor ` + floatToString(snapshot.ProfitFactor) + `
+
+# HELP mev_bot_total_profit_eth Cumulative gross profit in ETH
+# TYPE mev_bot_total_profit_eth counter
+mev_bot_total_profit_eth ` + floatToString(snapshot.TotalProfit) + `
+
+# HELP mev_bot_gas_spent_eth Cumulative gas spend in ETH
+# TYPE mev_bot_gas_spent_eth counter
+mev_bot_gas_spent_eth ` + floatToString(snapshot.GasCostsSpent) + `
 
 # HELP mev_bot_uptime_seconds Bot uptime in seconds
 # TYPE mev_bot_uptime_seconds counter