package log

import (
	"fmt"
	"os"
	"path/filepath"
)

// getExeFilename
func getExeFilename() string {
	_, logfilename := filepath.Split(os.Args[0])
	if logfilename == "" {
		panic("get exe filename failed")
	}
	return logfilename
}

// tryOptLogDirs
func tryOptLogDirs(optLogDirs []string) (string, error) {
	optionDirsStr := ""
	for i, d := range optLogDirs {
		dir := fmt.Sprintf("%s/", d)
		optionDirsStr += fmt.Sprintf("%d.[%s];", i, dir)
		if ok := canWriteByTest(dir); ok {
			return dir, nil
		}
	}
	return "", fmt.Errorf("all optional dir are not exist or writeable: %s", optionDirsStr)
}

// canWriteByTest
func canWriteByTest(dir string) bool {
	testFile := filepath.Join(dir, ".write_test.log.tmp")
	if err := os.WriteFile(testFile, []byte("test"), 0644); err != nil {
		return false
	}
	os.Remove(testFile)
	return true
}