mev-beta/internal/logger/logger.go

package logger

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"time"

	pkgerrors "github.com/fraktal/mev-beta/pkg/errors"
)

// LogLevel represents different log levels
type LogLevel int

const (
	DEBUG LogLevel = iota
	INFO
	WARN
	ERROR
	OPPORTUNITY // Special level for opportunities
)

var logLevelNames = map[LogLevel]string{
	DEBUG:       "DEBUG",
	INFO:        "INFO",
	WARN:        "WARN",
	ERROR:       "ERROR",
	OPPORTUNITY: "OPPORTUNITY",
}

var suppressedWarningSubstrings = []string{
	"extractTokensGeneric",
	"extractTokensFromMulticall",
}

// Logger represents a multi-file logger with separation of concerns
type Logger struct {
	// Main application logger
	logger *log.Logger
	level  LogLevel

	// Specialized loggers for different concerns
	opportunityLogger *log.Logger // MEV opportunities and arbitrage attempts
	errorLogger       *log.Logger // Errors and warnings only
	performanceLogger *log.Logger // Performance metrics and RPC calls
	transactionLogger *log.Logger // Detailed transaction analysis

	// Security filtering
	secureFilter *SecureFilter

	levelName string
}

// parseLogLevel converts string log level to LogLevel enum
func parseLogLevel(level string) LogLevel {
	switch strings.ToLower(level) {
	case "debug":
		return DEBUG
	case "info":
		return INFO
	case "warn", "warning":
		return WARN
	case "error":
		return ERROR
	default:
		return INFO // Default to INFO level
	}
}

// createLogFile creates a log file or returns stdout if it fails
func createLogFile(filename string) *os.File {
	if filename == "" {
		return os.Stdout
	}

	if err := os.MkdirAll(filepath.Dir(filename), 0o755); err != nil {
		log.Printf("Failed to create log directory for %s: %v, falling back to stdout", filename, err)
		return os.Stdout
	}

	// Check and rotate log file if needed (100MB max size)
	maxSize := int64(100 * 1024 * 1024) // 100 MB
	if err := rotateLogFile(filename, maxSize); err != nil {
		log.Printf("Failed to rotate log file %s: %v", filename, err)
		// Continue anyway, rotation failure shouldn't stop logging
	}

	f, err := os.OpenFile(filename, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
	if err != nil {
		log.Printf("Failed to create log file %s: %v, falling back to stdout", filename, err)
		return os.Stdout
	}
	return f
}

// New creates a new multi-file logger with separation of concerns
func New(level string, format string, file string) *Logger {
	// Parse base filename for specialized logs
	baseDir := "logs"
	baseName := "mev_bot"
	if file != "" {
		// Extract directory and base filename
		parts := strings.Split(file, "/")
		if len(parts) > 1 {
			baseDir = strings.Join(parts[:len(parts)-1], "/")
		}
		filename := parts[len(parts)-1]
		if strings.Contains(filename, ".") {
			baseName = strings.Split(filename, ".")[0]
		}
	}

	// Create specialized log files
	mainFile := createLogFile(file)
	opportunityFile := createLogFile(fmt.Sprintf("%s/%s_opportunities.log", baseDir, baseName))
	errorFile := createLogFile(fmt.Sprintf("%s/%s_errors.log", baseDir, baseName))
	performanceFile := createLogFile(fmt.Sprintf("%s/%s_performance.log", baseDir, baseName))
	transactionFile := createLogFile(fmt.Sprintf("%s/%s_transactions.log", baseDir, baseName))

	// Create loggers with no prefixes (we format ourselves)
	logLevel := parseLogLevel(level)

	// Determine security level based on environment and log level
	var securityLevel SecurityLevel
	env := os.Getenv("GO_ENV")
	switch {
	case env == "production":
		securityLevel = SecurityLevelProduction
	case logLevel >= WARN:
		securityLevel = SecurityLevelInfo
	default:
		securityLevel = SecurityLevelDebug
	}

	return &Logger{
		logger:            log.New(mainFile, "", 0),
		opportunityLogger: log.New(opportunityFile, "", 0),
		errorLogger:       log.New(errorFile, "", 0),
		performanceLogger: log.New(performanceFile, "", 0),
		transactionLogger: log.New(transactionFile, "", 0),
		level:             logLevel,
		secureFilter:      NewSecureFilter(securityLevel),
		levelName:         level,
	}
}

// shouldLog determines if a message should be logged based on level
func (l *Logger) shouldLog(level LogLevel) bool {
	return level >= l.level
}

// formatMessage formats a log message with timestamp and level
func (l *Logger) formatMessage(level LogLevel, v ...interface{}) string {
	timestamp := time.Now().Format("2006/01/02 15:04:05")
	levelName := logLevelNames[level]
	message := formatKVMessage(v...)
	return fmt.Sprintf("%s [%s] %s", timestamp, levelName, message)
}

// formatKVMessage converts a variadic list of arguments into a structured log string.
// It treats consecutive key/value pairs (string key followed by any value) specially
// so that existing logger calls like logger.Error("msg", "key", value) render as
// `msg key=value`.
func formatKVMessage(args ...interface{}) string {
	if len(args) == 0 {
		return ""
	}

	var b strings.Builder

	// Always print the first argument verbatim to preserve legacy formatting.
	fmt.Fprintf(&b, "%v", args[0])

	// Process subsequent arguments as key/value pairs where possible.
	for i := 1; i < len(args); i++ {
		key, ok := args[i].(string)
		if !ok || i == len(args)-1 {
			// Not a key/value pair, fall back to simple spacing.
			fmt.Fprintf(&b, " %v", args[i])
			continue
		}

		value := args[i+1]
		fmt.Fprintf(&b, " %s=%v", key, value)
		i++
	}

	return b.String()
}

// Debug logs a debug message
func (l *Logger) Debug(v ...interface{}) {
	if l.shouldLog(DEBUG) {
		l.logger.Println(l.formatMessage(DEBUG, v...))
	}
}

// Info logs an info message
func (l *Logger) Info(v ...interface{}) {
	if l.shouldLog(INFO) {
		l.logger.Println(l.formatMessage(INFO, v...))
	}
}

// Warn logs a warning message
func (l *Logger) Warn(v ...interface{}) {
	if l.shouldLog(WARN) {
		message := l.formatMessage(WARN, v...)
		for _, substr := range suppressedWarningSubstrings {
			if strings.Contains(message, substr) {
				return
			}
		}
		l.logger.Println(message)
		l.errorLogger.Println(message) // Also log to error file
	}
}

// Error logs an error message
func (l *Logger) Error(v ...interface{}) {
	if l.shouldLog(ERROR) {
		message := l.formatMessage(ERROR, v...)
		l.logger.Println(message)
		l.errorLogger.Println(message) // Also log to error file
	}
}

// ErrorStructured logs a structured error with full context
func (l *Logger) ErrorStructured(err *pkgerrors.StructuredError) {
	if !l.shouldLog(ERROR) {
		return
	}

	// Log compact format to main log
	compactMsg := fmt.Sprintf("%s [%s] %s",
		time.Now().Format("2006/01/02 15:04:05"),
		"ERROR",
		err.FormatCompact())
	l.logger.Println(compactMsg)

	// Log full detailed format to error log
	fullMsg := fmt.Sprintf("%s [%s] %s",
		time.Now().Format("2006/01/02 15:04:05"),
		"ERROR",
		err.FormatForLogging())
	l.errorLogger.Println(fullMsg)
}

// WarnStructured logs a structured warning with full context
func (l *Logger) WarnStructured(err *pkgerrors.StructuredError) {
	if !l.shouldLog(WARN) {
		return
	}

	// Log compact format to main log
	compactMsg := fmt.Sprintf("%s [%s] %s",
		time.Now().Format("2006/01/02 15:04:05"),
		"WARN",
		err.FormatCompact())

	// Check if warning should be suppressed
	for _, substr := range suppressedWarningSubstrings {
		if strings.Contains(compactMsg, substr) {
			return
		}
	}

	l.logger.Println(compactMsg)
	l.errorLogger.Println(compactMsg)
}

// Opportunity logs a found opportunity with detailed information
// This always logs regardless of level since opportunities are critical
func (l *Logger) Opportunity(txHash, from, to, method, protocol string, amountIn, amountOut, minOut, profitUSD float64, additionalData map[string]interface{}) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	// Create sanitized additional data for production
	sanitizedData := l.secureFilter.SanitizeForProduction(additionalData)

	message := fmt.Sprintf(`%s [OPPORTUNITY] 🎯 ARBITRAGE OPPORTUNITY DETECTED
├── Transaction: %s
├── From: %s → To: %s
├── Method: %s (%s)
├── Amount In: %.6f tokens
├── Amount Out: %.6f tokens  
├── Min Out: %.6f tokens
├── Estimated Profit: $%.2f USD
└── Additional Data: %v`,
		timestamp, txHash, from, to, method, protocol,
		amountIn, amountOut, minOut, profitUSD, sanitizedData)

	// Apply security filtering to the entire message
	filteredMessage := l.secureFilter.FilterMessage(message)

	l.logger.Println(filteredMessage)
	l.opportunityLogger.Println(filteredMessage) // Dedicated opportunity log
}

// OpportunitySimple logs a simple opportunity message (for backwards compatibility)
func (l *Logger) OpportunitySimple(v ...interface{}) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")
	message := fmt.Sprintf("%s [OPPORTUNITY] %s", timestamp, fmt.Sprint(v...))
	l.logger.Println(message)
	l.opportunityLogger.Println(message) // Dedicated opportunity log
}

// Performance logs performance metrics for optimization analysis
func (l *Logger) Performance(component, operation string, duration time.Duration, metadata map[string]interface{}) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	// Add standard performance fields
	data := map[string]interface{}{
		"component":   component,
		"operation":   operation,
		"duration_ms": duration.Milliseconds(),
		"duration_ns": duration.Nanoseconds(),
		"timestamp":   timestamp,
	}

	// Merge with provided metadata
	for k, v := range metadata {
		data[k] = v
	}

	message := fmt.Sprintf(`%s [PERFORMANCE] 📊 %s.%s completed in %v - %v`,
		timestamp, component, operation, duration, data)

	l.performanceLogger.Println(message) // Dedicated performance log only
}

// Metrics logs business metrics for analysis
func (l *Logger) Metrics(name string, value float64, unit string, tags map[string]string) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	message := fmt.Sprintf(`%s [METRICS] 📈 %s: %.6f %s %v`,
		timestamp, name, value, unit, tags)

	l.performanceLogger.Println(message) // Metrics go to performance log
}

// Transaction logs detailed transaction information for MEV analysis
func (l *Logger) Transaction(txHash, from, to, method, protocol string, gasUsed, gasPrice uint64, value float64, success bool, metadata map[string]interface{}) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	status := "FAILED"
	if success {
		status = "SUCCESS"
	}

	// Sanitize metadata for production
	sanitizedMetadata := l.secureFilter.SanitizeForProduction(metadata)

	message := fmt.Sprintf(`%s [TRANSACTION] 💳 %s
├── Hash: %s
├── From: %s → To: %s  
├── Method: %s (%s)
├── Gas Used: %d (Price: %d wei)
├── Value: %.6f ETH
├── Status: %s
└── Metadata: %v`,
		timestamp, status, txHash, from, to, method, protocol,
		gasUsed, gasPrice, value, status, sanitizedMetadata)

	// Apply security filtering to the entire message
	filteredMessage := l.secureFilter.FilterMessage(message)

	l.transactionLogger.Println(filteredMessage) // Dedicated transaction log only
}

// BlockProcessing logs block processing metrics for sequencer monitoring
func (l *Logger) BlockProcessing(blockNumber uint64, txCount, dexTxCount int, processingTime time.Duration) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	message := fmt.Sprintf(`%s [BLOCK_PROCESSING] 🧱 Block %d: %d txs (%d DEX) processed in %v`,
		timestamp, blockNumber, txCount, dexTxCount, processingTime)

	l.performanceLogger.Println(message) // Block processing metrics go to performance log
}

// ArbitrageAnalysis logs arbitrage opportunity analysis results
func (l *Logger) ArbitrageAnalysis(poolA, poolB, tokenPair string, priceA, priceB, priceDiff, estimatedProfit float64, feasible bool) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	status := "REJECTED"
	if feasible {
		status = "VIABLE"
	}

	message := fmt.Sprintf(`%s [ARBITRAGE_ANALYSIS] 🔍 %s %s
├── Pool A: %s (Price: %.6f)
├── Pool B: %s (Price: %.6f)
├── Price Difference: %.4f%%
├── Estimated Profit: $%.2f
└── Status: %s`,
		timestamp, status, tokenPair, poolA, priceA, poolB, priceB,
		priceDiff*100, estimatedProfit, status)

	// Apply security filtering to protect sensitive pricing data
	filteredMessage := l.secureFilter.FilterMessage(message)

	l.opportunityLogger.Println(filteredMessage) // Arbitrage analysis goes to opportunity log
}

// RPC logs RPC call metrics for endpoint optimization
func (l *Logger) RPC(endpoint, method string, duration time.Duration, success bool, errorMsg string) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	status := "SUCCESS"
	if !success {
		status = "FAILED"
	}

	message := fmt.Sprintf(`%s [RPC] 🌐 %s %s.%s in %v`,
		timestamp, status, endpoint, method, duration)

	if !success && errorMsg != "" {
		message += fmt.Sprintf(" - Error: %s", errorMsg)
	}

	l.performanceLogger.Println(message) // RPC metrics go to performance log
}

// SwapAnalysis logs swap event analysis with security filtering
func (l *Logger) SwapAnalysis(tokenIn, tokenOut string, amountIn, amountOut float64, protocol, poolAddr string, metadata map[string]interface{}) {
	timestamp := time.Now().Format("2006/01/02 15:04:05")

	// Sanitize metadata for production
	sanitizedMetadata := l.secureFilter.SanitizeForProduction(metadata)

	message := fmt.Sprintf(`%s [SWAP_ANALYSIS] 🔄 %s → %s
├── Amount In: %.6f %s
├── Amount Out: %.6f %s
├── Protocol: %s
├── Pool: %s
└── Metadata: %v`,
		timestamp, tokenIn, tokenOut, amountIn, tokenIn, amountOut, tokenOut,
		protocol, poolAddr, sanitizedMetadata)

	// Apply security filtering to the entire message
	filteredMessage := l.secureFilter.FilterMessage(message)

	l.transactionLogger.Println(filteredMessage) // Dedicated transaction log
}

// rotateLogFile rotates a log file when it exceeds the maximum size
func rotateLogFile(filename string, maxSize int64) error {
	// Check if file exists
	if _, err := os.Stat(filename); os.IsNotExist(err) {
		return nil // File doesn't exist, nothing to rotate
	}

	// Get file info
	fileInfo, err := os.Stat(filename)
	if err != nil {
		return fmt.Errorf("failed to get file info: %w", err)
	}

	// Check if file exceeds max size
	if fileInfo.Size() < maxSize {
		return nil // File is within size limits
	}

	// Create archive directory if it doesn't exist
	archiveDir := "logs/archived"
	if err := os.MkdirAll(archiveDir, 0755); err != nil {
		return fmt.Errorf("failed to create archive directory: %w", err)
	}

	// Generate archive filename with timestamp
	timestamp := time.Now().Format("20060102_150405")
	baseName := filepath.Base(filename)
	ext := filepath.Ext(baseName)
	name := strings.TrimSuffix(baseName, ext)
	archiveFilename := filepath.Join(archiveDir, fmt.Sprintf("%s_%s%s", name, timestamp, ext))

	// Close current file handle and rename
	if err := os.Rename(filename, archiveFilename); err != nil {
		return fmt.Errorf("failed to rotate log file: %w", err)
	}

	return nil
}