open System.Threading
let mkThread f = Thread (ThreadStart f)
let startThread f = (mkThread f).Start()
let waitFor obj = ignore(Monitor.Wait obj)
let wakeWaiters obj = Monitor.PulseAll obj
let numClients = 5

let blahblah = ref false

type Client(clientID:int) =
    let clients:Client[] ref = ref Array.empty
    let inCharge = ref (if clientID=0 then true else false)
    let usingNow = ref false
    member this.ClientID = clientID



    member this.init(theClients) = clients:=theClients
                                   startThread <| fun () ->
                                        for i in 1..10 do
                                            this.NewRequest i
                                        printfn "Client %d: DONE WITH EVERYTHING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" clientID


    member this.NewRequest exp = // Makes the client do a new request
        lock this <| fun()->
            while(not (!inCharge)) do
                inCharge := !clients |> Array.exists (fun cl -> cl.CanIHaveIt this.ClientID)

            usingNow:=true
            printfn "Client %d: took charge" clientID
            Thread.Sleep 100 // Only one client should do this at a time.
            usingNow:=false
            printfn "Client %d: Finished exp %d" clientID exp
            lock blahblah <| fun()-> wakeWaiters blahblah


    member this.CanIHaveIt clID = // Returns true when giving to the caller
        lock blahblah <| fun()-> // printfn "Client %d: Request from client %d" clientID clID
                                while (!usingNow) do waitFor blahblah
                                let wasInCharge = !inCharge
                                inCharge:=false
                                wasInCharge
let clients = Array.map (fun clID -> Client(clID)) [|0..numClients-1|]
clients |> Array.iter (fun cl -> cl.init clients)