// A Go mirror of libfuse's hello.c

package readonly

import (
  "os"
	"bazil.org/fuse"
  "bazil.org/fuse/fs"
  core "github.com/jbenet/go-ipfs/core"
  mdag "github.com/jbenet/go-ipfs/merkledag"
)


type FileSystem struct {
  Ipfs *core.IpfsNode
}

func NewFileSystem(ipfs *core.IpfsNode) *FileSystem {
  return &FileSystem{ Ipfs: ipfs }
}

func (f FileSystem) Root() (fs.Node, fuse.Error) {
  return Root{Ipfs: f.Ipfs }, nil
}


type Root struct {
  Ipfs *core.IpfsNode
}

func (Root) Attr() fuse.Attr {
  return fuse.Attr{Inode: 1, Mode: os.ModeDir | 0111} // -rw+x
}

func (s *Root) Lookup(name string, intr fs.Intr) (fs.Node, fuse.Error) {

  nd, err := s.Ipfs.Resolver.ResolvePath(name)
  if err != nil {
    // todo: make this error more versatile.
    return nil, fuse.ENOENT
  }

  return Node{Ipfs: s.Ipfs, Nd: nd}, nil
}

func (Root) ReadDir(intr fs.Intr) ([]fuse.Dirent, fuse.Error) {
  return nil, fuse.EPERM
}

type Node struct {
  Ipfs *core.IpfsNode
  Nd *mdag.Node
}

func (s Node) Attr() fuse.Attr {

  if len(s.Nd.Links) > 0 {
    return fuse.Attr{Mode: os.ModeDir | 0555}
  }

  size, _ := s.Nd.Size()
  return fuse.Attr{Mode: 0444, Size: uint64(size)}
}

func (s *Node) Lookup(name string, intr fs.Intr) (fs.Node, fuse.Error) {

  nd, err := s.Ipfs.Resolver.ResolveLinks(s.Nd, []string{name})
  if err != nil {
    // todo: make this error more versatile.
    return nil, fuse.ENOENT
  }

  return Node{Ipfs: s.Ipfs, Nd: nd}, nil
}

func (s *Node) ReadDir(intr fs.Intr) ([]fuse.Dirent, fuse.Error) {

  entries := make([]fuse.Dirent, len(s.Nd.Links))
  for i, link := range s.Nd.Links {
    n := link.Name
    if len(n) == 0 {
      n = link.Hash.B58String()
    }
    entries[i] = fuse.Dirent{Name: n, Type: fuse.DT_File}
  }

  if len(entries) > 0 {
    return entries, nil
  }
  return nil, fuse.ENOENT
}

func (s *Node) ReadAll(intr fs.Intr) ([]byte, fuse.Error) {
  return []byte(s.Nd.Data), nil
}



func Mount(ipfs *core.IpfsNode, fpath string) (error) {

  c, err := fuse.Mount(fpath)
  if err != nil {
    return err
  }
  defer c.Close()

  err = fs.Serve(c, FileSystem{Ipfs: ipfs})
  if err != nil {
    return err
  }

  // check if the mount process has an error to report
  <-c.Ready
  if err := c.MountError; err != nil {
    return err
  }
  return nil
}