refactor: make plugin more easier to maintain

.github/workflows/ci.yml

@@ -24,5 +24,7 @@ jobs:
         run: |
           go build .
       - name: Test with the Go CLI
+        # we cannot use `go test ./...` currently, because many test cases are failed
         run: |
           go test ./internal
+          go test ./internal/luai

cmd/cmd.go

@@ -18,10 +18,12 @@ package cmd
 
 import (
 	"fmt"
+	"os"
+
 	"github.com/urfave/cli/v2"
 	"github.com/version-fox/vfox/cmd/commands"
 	"github.com/version-fox/vfox/internal"
-	"os"
+	"github.com/version-fox/vfox/internal/logger"
 )
 
 func Execute(args []string) {
@@ -66,6 +68,19 @@ func newCmd() *cmd {
 			_, _ = fmt.Fprintln(ctx.App.Writer, command.Name)
 		}
 	}
+
+	debugFlags := &cli.BoolFlag{
+		Name:  "debug",
+		Usage: "show debug information",
+		Action: func(ctx *cli.Context, b bool) error {
+			logger.SetLevel(logger.DebugLevel)
+			return nil
+		},
+	}
+
+	app.Flags = []cli.Flag{
+		debugFlags,
+	}
 	app.Commands = []*cli.Command{
 		commands.Info,
 		commands.Install,

internal/logger/logger.go

@@ -0,0 +1,69 @@
+/*
+ *    Copyright 2024 Han Li and contributors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+package logger
+
+import "fmt"
+
+type LoggerLevel int
+
+const (
+	ErrorLevel LoggerLevel = iota
+	InfoLevel
+	DebugLevel
+)
+
+var globalLevel = InfoLevel
+
+func SetLevel(_level LoggerLevel) {
+	globalLevel = _level
+}
+
+func Log(level LoggerLevel, args ...interface{}) {
+	if globalLevel >= level {
+		fmt.Println(args...)
+	}
+}
+
+func Logf(level LoggerLevel, message string, args ...interface{}) {
+	if globalLevel >= level {
+		fmt.Printf(message, args...)
+	}
+}
+
+func Error(message string) {
+	Log(ErrorLevel, message)
+}
+
+func Errorf(message string, args ...interface{}) {
+	Logf(ErrorLevel, message, args...)
+}
+
+func Info(message string) {
+	Log(InfoLevel, message)
+}
+
+func Infof(message string, args ...interface{}) {
+	Logf(InfoLevel, message, args...)
+}
+
+func Debug(args ...interface{}) {
+	Log(DebugLevel, args...)
+}
+
+func Debugf(message string, args ...interface{}) {
+	Logf(DebugLevel, message, args...)
+}