// Learn more about F# at http://fsharp.org
// See the 'F# Tutorial' project for more help.
open LiteDB
module Db=
 let db=new LiteDatabase("data.db")
 type Data={Id:string}
 let find<'a> (predicate:'a->bool) (col:LiteCollection<'a>)= let res=col.Find predicate
                                                             match res|>Seq.isEmpty with
                                                             |true->None
                                                             |false->Some (res|>Seq.head)

 let col=db.GetCollection<Data>("data")
 type Message=Find of (Data->bool)*AsyncReplyChannel<Data option>
 let inbox=MailboxProcessor.Start(fun box->let rec loop()=
                                            async{
                                             let! msg=box.Receive()
                                             match msg with
                                             |Find (p,rc)->find p col|>rc.Reply

                                            }
                                           loop()
                                 )
 type Api={Find:(Data->bool)->Data option}
 let instance={Find=(fun p->inbox.PostAndReply(fun rc->Find(p,rc)))}
 [<EntryPoint>]
 let main argv =
        printfn "%A" argv
        let a=instance.Find(fun d->true)
        0 // return an integer exit code