package main

import (
	"fmt"
	"io"
	"os"
)

func CopyFile(dstName, srcName string) (written int64, err error) {
	if dstName == srcName {
		return
	}
	src, err := os.Open(srcName)
	if err != nil {
		fmt.Println("copy file " + srcName + " error")
		return
	}
	defer src.Close()
	os.Remove(dstName)
	dst, err := os.OpenFile(dstName, os.O_WRONLY|os.O_CREATE, 0644)
	if err != nil {
		fmt.Println("open file " + dstName + " error")
		return
	}
	defer dst.Close()
	return io.Copy(dst, src)
}

func copyDir(srcPath string, destPath string) {
	os.MkdirAll(destPath, 0777)
	dir, err := os.ReadDir(srcPath)
	if err != nil {
		return
	}
	for _, fi := range dir {
		if fi.IsDir() { // 忽略目录
			outPath := destPath + PthSep + fi.Name()
			copyDir(srcPath+PthSep+fi.Name(), outPath)
		} else {
			srcFile := srcPath + PthSep + fi.Name()
			destFile := destPath + PthSep + fi.Name()
			CopyFile(destFile, srcFile)
		}
	}
}

func isFileEqual(file1 string, file2 string) bool {
	// 打开文件
	dat1, err1 := os.ReadFile(file1)
	if err1 != nil {
		return false
	}
	dat2, err2 := os.ReadFile(file2)
	if err2 != nil {
		return false
	}
	byteData1 := []byte(dat1)
	dataLen1 := len(byteData1)
	byteData2 := []byte(dat2)
	dataLen2 := len(byteData2)
	if dataLen1 != dataLen2 {
		return false
	}
	//fmt.Println(fmt.Errorf("EncodePicFile %s len = %d", srcFile, dataLen))
	for i := 0; i < dataLen1; i++ {
		if byteData1[i] != byteData2[i] {
			return false
		}
	}
	return true
}

func doCompareFolder(srcPath string, destPath string, outputPath string) int {
	diffCount := 0
	dir, err := os.ReadDir(srcPath)
	if err != nil {
		return diffCount
	}
	for _, fi := range dir {
		if fi.IsDir() { // 忽略目录
			diffCount += doCompareFolder(srcPath+PthSep+fi.Name(), destPath+PthSep+fi.Name(), outputPath+PthSep+fi.Name())
		} else {
			//fmt.Println(dirPth + PthSep + fi.Name())
			srcFile := srcPath + PthSep + fi.Name()
			destFile := destPath + PthSep + fi.Name()
			outFile := outputPath + PthSep + fi.Name()
			//func(src, dest, outName, outPath string) {
			if !isFileEqual(srcFile, destFile) {
				os.MkdirAll(outputPath, 0777)
				CopyFile(outFile, srcFile)
				diffCount++
			}
			//}(srcFile, destFile, outFile, outputPath)
		}
	}
	return diffCount
}

func isDeltaEmpty(srcPath string) bool {
	dir, err := os.ReadDir(srcPath)
	if err != nil {
		return true
	}
	fileCount := 0
	for _, fi := range dir {
		if fi.IsDir() { // 忽略目录
			return false
		} else {
			fileCount++
		}
	}
	return fileCount <= 2
}

func compareFolder(srcPath string, destPath string, outputPath string) {
	fmt.Printf("compareFolder %v:%v to %v\n", srcPath, destPath, outputPath)
	if doCompareFolder(srcPath, destPath, outputPath) <= 2 {
		// 只有版本文件不一样，删除目录
		fmt.Printf("Removing delta folder %v\n", outputPath)
		os.RemoveAll(outputPath)
	}
}