package main

import (
  "labix.org/v2/mgo/bson"
  "math/rand"
)

/* gfs is a *mgo.GridFS defined in imgsrv.go */

func GetFileByFilename(filename string) (this_file File, err error) {
  err = gfs.Find(bson.M{"filename":filename}).One(&this_file)
  if (err != nil) {
    return this_file, err
  }
  return this_file, nil
}

func GetFileRandom() (this_file File, err error) {
  r := rand.Int63()
  err = gfs.Find(bson.M{"random": bson.M{"$gt" : r } }).One(&this_file)
  if (err != nil) {
    return this_file, err
  }
  if (len(this_file.Md5) == 0) {
    err = gfs.Find(bson.M{"random": bson.M{"$lt" : r } }).One(&this_file)
  }
  if (err != nil) {
    return this_file, err
  }
  return this_file, nil
}

/* Check whether this File filename is on Mongo */
func HasFileByFilename(filename string) (exists bool, err error) {
  c, err := gfs.Find(bson.M{"filename": filename}).Count()
  if (err != nil) {
    return false, err
  }
  exists = (c > 0)
  return exists, nil
}

func HasFileByMd5(md5 string) (exists bool, err error) {
  c, err := gfs.Find(bson.M{"md5": md5 }).Count()
  if (err != nil) {
    return false, err
  }
  exists = (c > 0)
  return exists, nil
}

func HasFileByKeyword(keyword string) (exists bool, err error) {
  c, err := gfs.Find(bson.M{"metadata": bson.M{"keywords": keyword} }).Count()
  if (err != nil) {
    return false, err
  }
  exists = (c > 0)
  return exists, nil
}