package main

import (
	"fmt"
	"io"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"time"

	ccfg "git.wecise.com/wecise/common/matrix/cfg"
	clog "git.wecise.com/wecise/common/matrix/logger"
	"git.wecise.com/wecise/util/filewalker"
)

var config = ccfg.MConfig()
var logger = clog.New()

// 同步指定文件夹中的内容

func PrintUsage() {
	println(`Usage:
sync <frompath> <topath> 
`)
}

var option = struct {
	Debug bool
}{
	Debug: false,
}

func main() {
	var frompath string = ""
	var topath string = ""
	for _, arg := range os.Args[1:] {
		if strings.HasPrefix(arg, "-") {
			switch arg {
			case "-debug":
				option.Debug = true
			}
		} else if arg != "" {
			if frompath == "" {
				frompath = arg
			} else if topath == "" {
				topath = arg
			}
		}
	}
	switch {
	case frompath != "" && topath != "":
		fmt.Println("sync from", frompath, "to", topath)
		for {
			err := sync(frompath, topath)
			if err != nil {
				println(err.Error())
				os.Exit(1)
			}
			time.Sleep(5 * time.Second)
		}
	default:
		PrintUsage()
		os.Exit(1)
	}
}

func sync(frompath, topath string) (err error) {
	fw, e := filewalker.NewFileWalker([]string{frompath}, `^[^\.].*`) // orderby: dirfirst, filefirst, fullpath
	if e != nil {
		return e
	}
	count := 0
	e = fw.List(func(basedir, fpath string) bool {
		if option.Debug {
			fmt.Println("basedir=", basedir, ", fpath=", fpath)
		}
		absbasedir, e := filepath.Abs(basedir)
		if e != nil {
			err = e
			return false
		}
		abstopath, e := filepath.Abs(topath)
		if e != nil {
			err = e
			return false
		}
		hiddenpath := fmt.Sprintf(`.*\%c\..*`, os.PathSeparator)
		if regexp.MustCompile(`^[^\.].*`).MatchString(fpath) && !regexp.MustCompile(hiddenpath).MatchString(fpath) {
			fromfile := filepath.Join(absbasedir, fpath)
			tofile := filepath.Join(abstopath, fpath)
			if option.Debug {
				fmt.Println(time.Now().Format("2006-01-02 15:04:05"), fromfile, " ==> ", tofile)
			}
			todir := filepath.Dir(tofile)
			e = os.MkdirAll(todir, os.ModePerm)
			if e != nil {
				err = fmt.Errorf("to dir %v", e)
				return false
			}
			fromfi, e := os.Stat(fromfile)
			if e != nil {
				err = fmt.Errorf("from file %v", e)
				return false
			}
			tofi, e := os.Stat(tofile)
			if e != nil && !os.IsNotExist(e) {
				err = fmt.Errorf("to file %v", e)
				return false
			}
			if tofi != nil && fromfi.Size() == tofi.Size() && fromfi.ModTime() == tofi.ModTime() {
				return true
			}
			fmt.Println(fromfile, " ==> ", tofile)
			frombs, e := ReadFile(fromfile)
			if e != nil {
				err = fmt.Errorf("from file %v", e)
				return false
			}
			e = os.WriteFile(tofile, frombs, os.ModePerm)
			if e != nil {
				err = fmt.Errorf("to file %v", e)
				return false
			}
			e = os.Chtimes(tofile, fromfi.ModTime(), fromfi.ModTime())
			if e != nil {
				err = fmt.Errorf("to file %v", e)
				return false
			}
			count++
		}
		return true
	})
	if e != nil {
		return e
	}
	if err != nil {
		return
	}
	if count > 0 || option.Debug {
		fmt.Println(time.Now().Format("2006-01-02 15:04:05"), count, "files copied")
	}
	return
}

func ReadFile(name string) (data []byte, err error) {
	data = make([]byte, 0, 512)
	for {
		data, err = ReadFileContinue(name, data)
		if err == io.EOF {
			err = nil
			return
		}
	}
}

func ReadFileContinue(name string, data []byte) ([]byte, error) {
	f, err := os.Open(name)
	if err != nil {
		return data, err
	}
	defer f.Close()

	var size int
	if info, err := f.Stat(); err == nil {
		size64 := info.Size()
		if int64(int(size64)) == size64 {
			size = int(size64)
		}
	}
	size++ // one byte for final read at EOF

	// If a file claims a small size, read at least 512 bytes.
	// In particular, files in Linux's /proc claim size 0 but
	// then do not work right if read in small pieces,
	// so an initial read of 1 byte would not work correctly.
	offset := len(data)
	if size > cap(data) {
		ndata := make([]byte, len(data), size)
		copy(ndata, data)
		data = ndata
	}

	for {
		n, err := f.ReadAt(data[offset:cap(data)], int64(offset))
		offset += n
		if err != nil {
			return data[:offset], err
		}
		if offset >= cap(data) {
			d := append(data[:cap(data)], 0)
			data = d[:offset]
		}
	}
}