package main

import (
	"bufio"
	"flag"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"
	"strings"
)

var (
	dir            = flag.String("d", "./attaches", "目录")
	mode           = flag.String("m", "scan", "模式:scan扫描目录 rename更名")
	sourceDatafile = flag.String("sdf", "./source.txt", "原始数据文件（不能换顺序）")
	targetDatafile = flag.String("tdf", "./target.txt", "目标数据文件（不能换顺序）")
)

// init
func init() {
	flag.Parse()
}

// scan
func scan() {
	fo1, err := os.Create(*sourceDatafile)
	if err != nil {
		log.Fatal(err)
	}
	fo2, err := os.Create(*targetDatafile)
	if err != nil {
		log.Fatal(err)
	}
	defer fo1.Close()
	defer fo2.Close()

	fs, err := ioutil.ReadDir(*dir)
	if err != nil {
		log.Fatal(err)
	}

	for _, f := range fs {
		if strings.HasPrefix(f.Name(), ".") {
			continue
		}
		fo1.WriteString(f.Name() + "\n")
		fo2.WriteString(f.Name() + "\n")
	}
}

// rename
func rename() {
	fi1, err := os.Open(*sourceDatafile)
	if err != nil {
		log.Fatal(err)
	}
	fi2, err := os.Open(*targetDatafile)
	if err != nil {
		log.Fatal(err)
	}
	defer fi1.Close()
	defer fi2.Close()
	source, target := make([]string, 0, 0), make([]string, 0, 0)
	br1 := bufio.NewReader(fi1)
	for {
		bytes, _, err := br1.ReadLine()
		if err != nil {
			break
		}
		source = append(source, string(bytes))
	}
	br2 := bufio.NewReader(fi2)
	for {
		bytes, _, err := br2.ReadLine()
		if err != nil {
			break
		}
		target = append(target, string(bytes))
	}
	if len(source) != len(target) {
		log.Println("数据文件，源 目标 长度不一致")
		return
	}
	for index, s := range source {
		oldName, newName := s, target[index]
		log.Println(oldName, ">>", newName)
		os.Rename(filepath.Join(*dir, oldName), filepath.Join(*dir, newName))
	}
}

// main
func main() {
	switch *mode {
	case "scan":
		scan()
	case "rename":
		rename()
	}
}