/*
Copyright 2021 The Karmada Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package utils

import (
	"archive/tar"
	"compress/gzip"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"time"
)

// Downloader Download progress
type Downloader struct {
	io.Reader
	Total   int64
	Current int64
}

// Read Implementation of Downloader
func (d *Downloader) Read(p []byte) (n int, err error) {
	n, err = d.Reader.Read(p)
	if err != nil {
		if err != io.EOF {
			return
		}
		fmt.Println("\nDownload complete.")
		return
	}

	d.Current += int64(n)
	fmt.Printf("\rDownloading...[ %.2f%% ]", float64(d.Current*10000/d.Total)/100)
	return
}

// DownloadFile Download files via URL
func DownloadFile(url, filePath string) error {
	httpClient := http.Client{
		Timeout: 60 * time.Second,
	}
	resp, err := httpClient.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("failed download file. url: %s code: %v", url, resp.StatusCode)
	}

	file, err := os.Create(filePath)
	if err != nil {
		return err
	}
	defer file.Close()

	downloader := &Downloader{
		Reader: resp.Body,
		Total:  resp.ContentLength,
	}

	if _, err := io.Copy(file, downloader); err != nil {
		return err
	}

	return nil
}

// DeCompress decompress tar.gz
func DeCompress(file, targetPath string) error {
	r, err := os.Open(file)
	if err != nil {
		return err
	}
	defer r.Close()

	gr, err := gzip.NewReader(r)
	if err != nil {
		return fmt.Errorf("new reader failed. %v", err)
	}
	defer gr.Close()

	tr := tar.NewReader(gr)
	for {
		header, err := tr.Next()
		if errors.Is(err, io.EOF) {
			break
		}
		if err != nil {
			return err
		}

		switch header.Typeflag {
		case tar.TypeDir:
			if err := os.Mkdir(targetPath+"/"+header.Name, 0700); err != nil {
				return err
			}
		case tar.TypeReg:
			outFile, err := os.Create(targetPath + "/" + header.Name)
			if err != nil {
				return err
			}
			if err := ioCopyN(outFile, tr); err != nil {
				return err
			}
			outFile.Close()
		default:
			fmt.Printf("unknown type: %v in %s\n", header.Typeflag, header.Name)
		}
	}
	return nil
}

// ioCopyN fix Potential DoS vulnerability via decompression bomb.
func ioCopyN(outFile *os.File, tr *tar.Reader) error {
	for {
		if _, err := io.CopyN(outFile, tr, 1024); err != nil {
			if errors.Is(err, io.EOF) {
				break
			}
			return err
		}
	}
	return nil
}

// ListFiles traverse directory files
func ListFiles(path string) []string {
	var files []string
	if err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
		if !info.IsDir() {
			files = append(files, path)
		}
		return nil
	}); err != nil {
		fmt.Println(err)
	}
	return files
}