open System.IO
open System

let getFiles directory = 
    match Directory.Exists directory with
    | true -> Directory.GetFiles(directory) |> Option.Some
    | false -> None

let countLines (file:string) = 
    use reader = new StreamReader(file)
    let content = reader.ReadToEnd()
    content.ToCharArray() |> Array.fold (fun state item -> if item='\n' then state + 1 else state + 0) 0

let printReport directory =
    match directory |> getFiles with
        | None -> printfn "Couldn't get any files from the directory."
        | Some files -> 
            let lineCounts = files |> Array.map (fun x -> countLines x)
            Array.iter2 (fun x y -> printfn "File: %s - %i lines" x y) files lineCounts
            
// Example usage
printfn "Enter a directory"
Console.ReadLine() |> printReport