Add debug package for logging with adjustable levels

- Introduced a new debug package that allows for logging at various levels (1-7).
- Implemented initialization, logger retrieval, and logging functions.
- Added functionality to set and get the current debug level.

pkg/debug/debug.go

@@ -0,0 +1,112 @@
+package debug
+
+import (
+	"flag"
+	"fmt"
+	"log/slog"
+	"os"
+)
+
+const (
+	DEBUG_CRITICAL = 1
+	DEBUG_ERROR    = 2
+	DEBUG_INFO     = 3
+	DEBUG_VERBOSE  = 4
+	DEBUG_TRACE    = 5
+	DEBUG_PACKETS  = 6
+	DEBUG_ALL      = 7
+)
+
+var (
+	debugLevel = flag.Int("debug", 3, "debug level (1-7)")
+	logger     *slog.Logger
+	initialized bool
+)
+
+func Init() {
+	if initialized {
+		return
+	}
+	initialized = true
+
+	var level slog.Level
+	switch {
+	case *debugLevel >= DEBUG_ALL:
+		level = slog.LevelDebug
+	case *debugLevel >= DEBUG_PACKETS:
+		level = slog.LevelDebug
+	case *debugLevel >= DEBUG_TRACE:
+		level = slog.LevelDebug
+	case *debugLevel >= DEBUG_VERBOSE:
+		level = slog.LevelDebug
+	case *debugLevel >= DEBUG_INFO:
+		level = slog.LevelInfo
+	case *debugLevel >= DEBUG_ERROR:
+		level = slog.LevelWarn
+	case *debugLevel >= DEBUG_CRITICAL:
+		level = slog.LevelError
+	default:
+		level = slog.LevelError
+	}
+
+	opts := &slog.HandlerOptions{
+		Level: level,
+	}
+	logger = slog.New(slog.NewTextHandler(os.Stderr, opts))
+	slog.SetDefault(logger)
+}
+
+func GetLogger() *slog.Logger {
+	if !initialized {
+		Init()
+	}
+	return logger
+}
+
+func Log(level int, msg string, args ...interface{}) {
+	if !initialized {
+		Init()
+	}
+
+	if *debugLevel < level {
+		return
+	}
+
+	var slogLevel slog.Level
+	switch {
+	case level >= DEBUG_ALL:
+		slogLevel = slog.LevelDebug
+	case level >= DEBUG_PACKETS:
+		slogLevel = slog.LevelDebug
+	case level >= DEBUG_TRACE:
+		slogLevel = slog.LevelDebug
+	case level >= DEBUG_VERBOSE:
+		slogLevel = slog.LevelDebug
+	case level >= DEBUG_INFO:
+		slogLevel = slog.LevelInfo
+	case level >= DEBUG_ERROR:
+		slogLevel = slog.LevelWarn
+	case level >= DEBUG_CRITICAL:
+		slogLevel = slog.LevelError
+	default:
+		slogLevel = slog.LevelError
+	}
+
+	if !logger.Enabled(nil, slogLevel) {
+		return
+	}
+
+	logger.Log(nil, slogLevel, fmt.Sprintf(msg, args...), "debug_level", level)
+}
+
+func SetDebugLevel(level int) {
+	*debugLevel = level
+	if initialized {
+		Init()
+	}
+}
+
+func GetDebugLevel() int {
+	return *debugLevel
+}
+