package os

import "os"
import "io"
import "time"
import "io/fs"
import "html/template"
import "git.tebibyte.media/sashakoshka/step"

var _ step.FuncProvider = new(Provider)

// FileInfo is like the fs.FileInfo interface, but it directly contains the
// values instead of having getters for them.
type FileInfo struct {
	Name    string
	Size    int64
	Mode    fs.FileMode
	ModTime time.Time
	IsDir   bool
}

// Provider provides OS functions.
type Provider struct {
	
}

// FuncMap fulfills the step.FuncProvider interface.
func (this *Provider) FuncMap () template.FuncMap {
	return template.FuncMap {
		"env":        funcEnv,
		"fileExists": funcFileExists,
		"statFile":   funcStatFile,
		"readFile":   funcReadFile,
		"readDir":    funcReadDir,
		"writeFile":  funcWriteFile,
		"renameFile": funcRenameFile,
		"removeFile": funcRemoveFile,
	}
}

func funcEnv (name string) string {
	return os.Getenv(name)
}

func funcFileExists (name string) (bool) {
	_, err := os.Stat(name)
	return err == nil
}

func funcStatFile (name string) (FileInfo, error) {
	info, err := os.Stat(name)
	if err != nil { return FileInfo { }, err }
	return FileInfo {
		Name:    info.Name(),
		Size:    info.Size(),
		Mode:    info.Mode(),
		ModTime: info.ModTime(),
		IsDir:   info.IsDir(),
	}, nil
}

func funcReadFile (name string) (string, error) {
	file, err := os.Open(name)
	if err != nil { return "", err  }
	defer file.Close()
	buffer, err := io.ReadAll(file)
	if err != nil { return "", err  }
	return string(buffer), nil
}

func funcReadDir (name string) ([]string, error) {
	entries, err := os.ReadDir(name)
	if err != nil { return nil, err }
	names := make([]string, len(entries))
	for index, entry := range entries {
		names[index] = entry.Name()
	}
	return names, nil
}

func funcWriteFile (name, content string) error {
	file, err := os.Create(name)
	if err != nil { return err }
	_, err = io.WriteString(file, content)
	return err
}

func funcRenameFile (name, newName string) error {
	return os.Rename(name, newName)
}

func funcRemoveFile (name string) error {
	return os.Remove(name)
}