package main

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"errors"
	"flag"
	"fmt"
	"git.nobla.cn/golang/kos/util/env"
	"io"
	"net/http"
	"os"
	"path"
	"runtime"
	"strconv"
	"strings"
	"time"
)

var (
	packageNameFlag = flag.String("package-name", "", "应用程序包名称")
	versionFlag     = flag.String("version", env.Get("MOTO_VERSION", "v0.0.3"), "模板版本号，可以使用环境变量 MOTO_VERSION")
)

var (
	oldPackageName = "git.nobla.cn/golang/moto"
)

func writeFile(dstFile string, r io.Reader) (err error) {
	var (
		fp *os.File
	)
	if fp, err = os.Create(dstFile); err != nil {
		return
	}
	defer fp.Close()
	_, err = io.Copy(fp, r)
	return
}

func extractFile(file string, dirname string) (err error) {
	var (
		prefix     string
		fp         *os.File
		gzipReader *gzip.Reader
	)
	// 清理路径字符串
	dirname = path.Clean(dirname)

	// 打开压缩文件
	if fp, err = os.Open(file); err != nil {
		return
	}
	defer fp.Close()
	// 执行解压操作
	if gzipReader, err = gzip.NewReader(fp); err != nil {
		return
	}
	defer gzipReader.Close()
	tarReader := tar.NewReader(gzipReader)
	for {
		header, errRead := tarReader.Next()
		if errRead != nil {
			if errors.Is(errRead, io.EOF) {
				break
			}
			err = errRead
			break
		}
		if header.Typeflag == tar.TypeXGlobalHeader {
			continue
		}
		if prefix == "" && header.Typeflag == tar.TypeDir {
			prefix = header.Name
			continue
		}
		realname := strings.TrimPrefix(header.Name, prefix)
		if strings.HasPrefix(realname, "generator") {
			continue
		}
		filename := path.Join(dirname, realname)
		if header.Typeflag == tar.TypeDir {
			if err = os.MkdirAll(filename, 0755); err != nil {
				return
			}
		} else {
			if err = writeFile(filename, tarReader); err != nil {
				return err
			}
			if runtime.GOOS != "windows" {
				os.Chmod(filename, 0644)
			}
		}
	}
	return nil
}

func downloadPackage(version string, dirname string) (err error) {
	var (
		uri string
		res *http.Response
	)
	uri = "https://git.nobla.cn/golang/moto/archive/" + version + ".tar.gz"
	if res, err = http.Get(uri); err != nil {
		return
	}
	defer func() {
		res.Body.Close()
	}()
	if res.StatusCode != http.StatusOK {
		err = errors.New(res.Status)
		return
	}
	filename := path.Join(os.TempDir(), strconv.FormatInt(time.Now().UnixMilli(), 10)+".tar.gz")
	if err = writeFile(filename, res.Body); err != nil {
		return
	}
	err = extractFile(filename, dirname)
	return
}

func replaceFiles(dirname string, source, replace string) (err error) {
	var (
		buf   []byte
		files []os.DirEntry
	)
	if files, err = os.ReadDir(dirname); err != nil {
		if errors.Is(err, io.EOF) {
			return nil
		}
		return err
	}
	sb := []byte(source)
	rb := []byte(replace)
	for _, file := range files {
		if file.Name() == "." || file.Name() == ".." {
			continue
		}
		filename := path.Join(dirname, file.Name())
		if file.IsDir() {
			err = replaceFiles(filename, source, replace)
		} else {
			if buf, err = os.ReadFile(filename); err == nil {
				buf = bytes.ReplaceAll(buf, sb, rb)
				os.WriteFile(filename, buf, 064)
			}
		}
	}
	return
}

func main() {
	var (
		pos         int
		err         error
		dirname     string
		appname     string
		packageName string
	)
	flag.Parse()
	packageName = *packageNameFlag
	if packageName == "" {
		if len(os.Args) > 1 {
			packageName = os.Args[1]
		}
	}
	pos = strings.LastIndexByte(packageName, '/')
	if pos == -1 {
		fmt.Println("应用包名称是无效的")
		os.Exit(1)
	}
	appname = packageName[pos:]
	if dirname, err = os.Getwd(); err != nil {
		fmt.Println("获取应用目录失败:" + err.Error())
		os.Exit(1)
	}
	dirname = path.Join(dirname, appname)
	if err = os.MkdirAll(dirname, 0755); err != nil {
		fmt.Println("创建应用目录失败:" + err.Error())
		os.Exit(1)
	}
	if err = downloadPackage(*versionFlag, dirname); err != nil {
		fmt.Println("下载模板文件失败:" + err.Error())
		os.Exit(1)
	}
	if err = replaceFiles(dirname, oldPackageName, packageName); err != nil {
		fmt.Println("生产应用文件失败:" + err.Error())
		os.Exit(1)
	}
	fmt.Println("创建项目成功")
}