package storage

import (
    "io"
	"io/ioutil"
	"http"
	"log"
	"strconv"
	"strings"
)

type Needle struct{
  Cookie uint8 "random number to mitigate brute force lookups"
  Key uint64 "file id"
  AlternateKey uint32 "supplemental id"
  Size uint32 "Data size"
  Data []byte "The actual file data"
  Checksum int32 "CRC32 to check integrity"
  Padding []byte "Aligned to 8 bytes"
}
func NewNeedle(r *http.Request)(n *Needle){
  n = new(Needle)
  form,fe:=r.MultipartReader()
  if fe!=nil {
    log.Fatalf("MultipartReader [ERROR] %s\n", fe)
  }
  part,_:=form.NextPart()
  data,_:=ioutil.ReadAll(part)
  n.Data = data

  n.ParsePath(r.URL.Path[1:strings.LastIndex(r.URL.Path,".")])

  return
}
func (n *Needle) ParsePath(path string){
  a := strings.Split(path,"_")
  log.Println("cookie",a[0],"key",a[1],"altKey",a[2])
  cookie,_ := strconv.Atoi(a[0])
  n.Cookie = uint8(cookie)
  n.Key,_ = strconv.Atoui64(a[1])
  altKey,_ := strconv.Atoui64(a[2])
  n.AlternateKey = uint32(altKey)
}
func (n *Needle) Append(w io.Writer){
  header := make([]byte,17)
  header[0] = n.Cookie
  uint64toBytes(header[1:9],n.Key)
  uint32toBytes(header[9:13],n.AlternateKey)
  n.Size = uint32(len(n.Data))
  uint32toBytes(header[13:17],n.Size)
  w.Write(header)
  w.Write(n.Data)
  rest := 8-((n.Size+17+4)%8)
  uint32toBytes(header[0:4],uint32(n.Checksum))
  w.Write(header[0:rest+4])
}
func (n *Needle) Read(r io.Reader, size uint32){
  bytes := make([]byte,size+17+4)
  r.Read(bytes)
  n.Cookie = bytes[0]
  n.Key = bytesToUint64(bytes[1:9])
  n.AlternateKey = bytesToUint32(bytes[9:13])
  n.Size = bytesToUint32(bytes[13:17])
  n.Data = bytes[17:17+size]
  n.Checksum = int32(bytesToUint32(bytes[17+size:17+size+4]))
}