package file

import (
	"fmt"
	"io"
	"os"

	"linkfog.com/public/lib/common"
)

func CopyFile(dstFile, srcFile string, perm os.FileMode) error {
	srcStat, err := os.Stat(srcFile)
	if err != nil {
		return err
	}

	if !srcStat.Mode().IsRegular() {
		return fmt.Errorf("src file is not a regular file")
	}

	srcf, err := os.Open(srcFile)
	if err != nil {
		return err
	}
	defer srcf.Close()
	defer FadviseSwitch(srcf)
	dstf, err := os.OpenFile(dstFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, perm)
	if err != nil {
		return err
	}
	defer dstf.Close()
	defer FadviseSwitch(dstf)
	_, err = io.Copy(dstf, srcf)
	return err
}

func CopyFileWithCmd(dstFile, srcFile string) error {
	srcStat, err := os.Stat(srcFile)
	if err != nil {
		return err
	}

	if !srcStat.Mode().IsRegular() {
		return fmt.Errorf("src file is not a regular file")
	}

	out, err := common.ExecCmd(fmt.Sprintf("cp -f %s %s", srcFile, dstFile))
	if err != nil {
		return fmt.Errorf("exec cp err: %s %s", err, out)
	}

	return nil
}

// CopyFileRateLimit 限速拷贝文件
func CopyFileRateLimit(dstFile, srcFile string) error {
	src, err := os.Open(srcFile)
	if err != nil {
		return err
	}
	defer src.Close()
	defer FadviseSwitch(src)
	dst, err := os.Create(dstFile)
	if err != nil {
		return err
	}
	defer dst.Close()
	defer FadviseSwitch(dst)
	_, err = CopyRateLimit(dst, src)
	if err != nil {
		return err
	}
	return nil
}