package utils

import (
	"archive/tar"
	"compress/gzip"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func addToArchive(tw *tar.Writer, filename string) error {
	file, err := os.Open(filename)
	if err != nil {
		return err
	}
	defer file.Close()

	info, err := file.Stat()
	if err != nil {
		return err
	}

	header, err := tar.FileInfoHeader(info, info.Name())
	if err != nil {
		return err
	}
	header.Name = filepath.Base(file.Name())

	if err := tw.WriteHeader(header); err != nil {
		return err
	}

	_, err = io.Copy(tw, file)
	return err
}

func CreateArchive(destDir, name string, files ...string) (string, error) {
	now := time.Now().UTC()
	archivePath := filepath.Join(destDir, fmt.Sprintf("%s-%s.tar.gz", name, strings.Replace(now.Format(time.RFC3339), ":", "-", -1)))

	file, err := os.Create(archivePath)
	if err != nil {
		return "", fmt.Errorf("unable to create archive=%s, err=%v", archivePath, err)
	}
	defer file.Close()

	gw := gzip.NewWriter(file)
	defer gw.Close()

	tw := tar.NewWriter(gw)
	defer tw.Close()

	for _, f := range files {
		if err := addToArchive(tw, f); err != nil {
			return "", fmt.Errorf("unable to add file=%s to archive=%s, err=%v", f, archivePath, err)
		}
	}

	return archivePath, nil
}