feature: create log if write log error true

.gitignore

@@ -8,3 +8,4 @@ go.work
 *.dylib
 *.test
 *.out
+*.log

types.go

@@ -1,15 +1,22 @@
 package welog
 
-import "io"
+import (
+	"io"
+	"os"
+)
 
 type LogLevel int
 
 type LogMode string
 
+type LogWrite bool
+
 type Logger struct {
 	level     LogLevel
 	mode      LogMode
 	writer    io.Writer
+	writeFile LogWrite
+	logFile   *os.File
 	formatter func(LogLevel, string) string
 }
 

welog.go

@@ -2,14 +2,38 @@ package welog
 
 import (
 	"fmt"
+	"io"
+	"os"
 	"time"
 )
 
-func GenerateLogger(level LogLevel, mode LogMode) *Logger {
-	return &Logger{
-		level: level,
-		mode:  mode,
+func GenerateLogger(level LogLevel, mode LogMode, writeFile LogWrite) *Logger {
+	var writer io.Writer
+	var file *os.File
+	var err error
+
+	if writeFile {
+		file, err = os.OpenFile("welog-errors.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to create log file: %v\n", err)
+			writer = os.Stderr
+		} else {
+			writer = io.MultiWriter(os.Stderr, file)
+		}
+	} else {
+		writer = os.Stderr
+	}
+
+	logger := &Logger{
+		level:     level,
+		mode:      mode,
+		writer:    writer,
+		writeFile: writeFile,
+		logFile:   file,
 	}
+
+	return logger
 }
 
 func (l *Logger) Log(level LogLevel, message string) {
@@ -20,6 +44,10 @@ func (l *Logger) Log(level LogLevel, message string) {
 		logMessage := fmt.Sprintf("[%s] [%s] %s\n", timestamp, levelString, message)
 
 		fmt.Fprint(l.writer, logMessage)
+
+		if l.logFile != nil && level == Error {
+			fmt.Fprint(l.logFile, logMessage)
+		}
 	}
 }
 

welog_test.go

@@ -12,7 +12,7 @@ import (
 func TestBasicMode(t *testing.T) {
 	var buf bytes.Buffer
 
-	logger := GenerateLogger(Info, Basic)
+	logger := GenerateLogger(Info, Basic, false)
 
 	logger.SetOutput(&buf)
 
@@ -43,7 +43,7 @@ func TestBasicMode(t *testing.T) {
 func TestColorfulMode(t *testing.T) {
 	var buf bytes.Buffer
 
-	logger := GenerateLogger(Info, Colorful)
+	logger := GenerateLogger(Info, Colorful, false)
 
 	logger.SetOutput(&buf)