package planr

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


func Exists(filePath string) bool {
    if _, err := os.Stat(filePath); os.IsNotExist(err) {
        return false
    }

    return true
}

func CreateIfNotExists(dir string, perm os.FileMode) error {
    if Exists(dir) {
        return nil
    }

    if err := os.MkdirAll(dir, perm); err != nil {
        return fmt.Errorf("failed to create directory: '%s', error: '%s'", dir, err.Error())
    }

    return nil
}

func CopySymlink(src, dst string, perm os.FileMode) error {
    link, err := os.Readlink(src)
    if err != nil {
        return err
    }

    if err := os.Chmod(src, perm); err != nil {
      return err
    }

    return os.Symlink(link, dst)
}

func Copy(srcFile, dstFile string, perm os.FileMode) error {
    src, err := os.Open(srcFile)
    if err != nil {
      return err
    }

    defer src.Close()

    dst, err := os.OpenFile(dstFile, os.O_CREATE | os.O_WRONLY | os.O_TRUNC, perm)
    if err != nil {
        return err
    }

    defer dst.Close()

    _, err = io.Copy(dst, src)
    if err != nil {
        return err
    }

    return nil
}


func RecursiveCopyDir(source, destination string) error {
    err := filepath.Walk(source, func(path string, info os.FileInfo, err error) error {
        relPath, err := filepath.Rel(source, path)

        if err != nil {
          return err
        }

	dst := filepath.Join(destination, relPath)
        src  := filepath.Join(source, relPath)

        mode := info.Mode()

        if relPath == "" {
            return nil
        }

        switch info.Mode() & os.ModeType {
          case os.ModeDir:
            return CreateIfNotExists(dst, mode)
          case os.ModeSymlink:
            return CopySymlink(src, dst, mode)
          default:
            return Copy(src, dst, mode)
        }
    });

    return err
}