first commit

internal/logger/logger.go

@@ -0,0 +1,73 @@
+package logger
+
+import (
+	"fmt"
+	"log"
+	"strings"
+)
+
+// Level represents the logging verbosity level.
+type Level int
+
+const (
+	LevelDebug Level = iota
+	LevelInfo
+	LevelWarn
+)
+
+var currentLevel = LevelInfo
+
+// SetLevel sets the global log level from a string: "debug", "info", or "warn".
+func SetLevel(s string) {
+	switch strings.ToLower(s) {
+	case "debug":
+		currentLevel = LevelDebug
+	case "info":
+		currentLevel = LevelInfo
+	case "warn":
+		currentLevel = LevelWarn
+	default:
+		currentLevel = LevelInfo
+	}
+}
+
+// Debug logs a message only when LOG_LEVEL=debug.
+func Debug(format string, args ...interface{}) {
+	if currentLevel <= LevelDebug {
+		log.Printf(format, args...)
+	}
+}
+
+// Info logs a message when LOG_LEVEL is debug or info.
+func Info(format string, args ...interface{}) {
+	if currentLevel <= LevelInfo {
+		log.Printf(format, args...)
+	}
+}
+
+// Warn logs a message at any log level (always visible).
+func Warn(format string, args ...interface{}) {
+	if currentLevel <= LevelWarn {
+		log.Printf(format, args...)
+	}
+}
+
+// Fatal logs and exits. Always visible regardless of level.
+func Fatal(format string, args ...interface{}) {
+	log.Fatalf(format, args...)
+}
+
+// formatKV formats key=value pairs for structured console output.
+func formatKV(pairs ...interface{}) string {
+	if len(pairs)%2 != 0 {
+		return fmt.Sprint(pairs...)
+	}
+	var b strings.Builder
+	for i := 0; i < len(pairs); i += 2 {
+		if i > 0 {
+			b.WriteString(" | ")
+		}
+		b.WriteString(fmt.Sprintf("%v=%v", pairs[i], pairs[i+1]))
+	}
+	return b.String()
+}