package shellcode

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

// CopyFile - copies a file
func CopyFile(src, dst string) (int64, error) {
	sourceFileStat, err := os.Stat(src)
	if err != nil {
		return 0, err
	}

	if !sourceFileStat.Mode().IsRegular() {
		return 0, fmt.Errorf("%s is not a regular file", src)
	}

	source, err := os.Open(src)
	if err != nil {
		return 0, err
	}
	defer source.Close()

	destination, err := os.Create(dst)
	if err != nil {
		return 0, err
	}
	defer destination.Close()
	nBytes, err := io.Copy(destination, source)
	return nBytes, err
}

// DirExists - returns true iff a directory exists
func DirExists(dirname string) bool {
	info, err := os.Stat(dirname)
	if os.IsNotExist(err) {
		return false
	}
	return info.IsDir()
}

// WalkMatch - returns all files matching a pattern recursively
func WalkMatch(root, pattern string) ([]string, error) {
	var matches []string
	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			return nil
		}
		if matched, err := filepath.Match(pattern, filepath.Base(path)); err != nil {
			return err
		} else if matched {
			matches = append(matches, path)
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	return matches, nil
}