file.go.chunked

package main

import (
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"strconv"
	"syscall"

	"bazil.org/fuse"
	"bazil.org/fuse/fs"
	"golang.org/x/net/context"
)

const BUFSIZE = (4 * 1024) * 10

type File struct {
	fs.NodeRef
	location string
	fuse     *fs.Server
	content  []byte
	count    uint64
	Size     uint64
	Body     *io.ReadCloser
	File     *os.File
}

var _ fs.Node = (*File)(nil)

func (f *File) Attr(ctx context.Context, a *fuse.Attr) error {
	a.Inode = 2
	a.Mode = 0444
	a.Size = f.Size
	return nil
}

var _ fs.NodeOpener = (*File)(nil)

func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fs.Handle, error) {
	// todo: check if exists in cache
	// todo: stream from remote
	dirPath := path.Dir(CACHE + f.location)
	os.MkdirAll(dirPath, 0777)

	// out, err := os.Create(CACHE + f.location + ".tmp")
	// if err != nil {
	// 	panic(err)
	// }

	// defer out.Close()

	client := http.Client{}

	for i := 0; i <= int(f.Size/BUFSIZE); i++ {
		out, _ := os.Create(CACHE + f.location + "." + strconv.Itoa(i))
		rq, err := http.NewRequest("GET", ROOT+f.location, nil)
		if err != nil {
			panic(err)
		}

		rq.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", BUFSIZE*i, BUFSIZE*(i+1)))

		rz, err := client.Do(rq)
		if err != nil {
			panic(err)
		}

		_, err = io.Copy(out, rz.Body)
		if err != nil {
			panic(err)
		}

		rz.Body.Close()
		out.Close()
	}

	// os.Rename(CACHE+f.location+".tmp", CACHE+f.location)

	if !req.Flags.IsReadOnly() {
		return nil, fuse.Errno(syscall.EACCES)
	}
	resp.Flags |= fuse.OpenKeepCache
	return f, nil
}

var _ fs.Handle = (*File)(nil)

var _ fs.HandleReader = (*File)(nil)

func (f *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
	i := int(req.Offset / BUFSIZE)
	fmt.Println(req.Offset, i)
	buf, _ := ioutil.ReadFile(CACHE + f.location + "." + strconv.Itoa(i))

	off := int(req.Offset % BUFSIZE)
	if off+req.Size > BUFSIZE {
		fmt.Println(i, "++")
		buff, _ := ioutil.ReadFile(CACHE + f.location + "." + strconv.Itoa(i+1))
		buf = append(buf, buff[0:(off+req.Size-BUFSIZE)]...)
	}

	resp.Data = buf[off:]
	return nil
}