10 PRINT "ERIK" 20 GOTO 10

#light
open System
open Array

let width, height = 100, 100

let tick game =
   let number index =
      let X, Y = index % width, index / width
      [|(-1, -1); (0, -1); (1, -1); (1, 0); (1, 1); (0, 1); (-1, 1); (-1, 0)|]
         |> map (fun (x, y) -> X + x, Y + y)
         |> filter (fun (x, y) -> x > 0 && x < width && y > 0 && y < height)
         |> map (fun (x, y) -> y * width + x)
         |> map (fun i -> if game.[i] then 1 else 0)
         |> sum

   game |> mapi (fun i alive ->
      match (alive, number i) with
      | (true, n) when n < 2 -> false
      | (true, n) when n > 3 -> false
      | (true, _) -> true
      | (false, 3) -> true
      | (false, _) -> false
      | _ -> failwith "no."
   )

let random = Random()
let mutable life = [|0..width * height - 1|] |> map (fun _ -> random.Next() % 2 = 0)

open SdlSimple
SdlSimpleSetup (width * 2) (height * 2 + 10) 16 false

draw {
   let yellow = colour 255 255 0
   life |> zip [|0..width * height - 1|] |> filter (fun (_, a) -> a)
        |> iter (fun (i, _) -> pixel yellow (i % width * 2, i / width * 2 + 10))
   life <- tick life
}

//press 'enter' to restart game.
onevent (KeyDown 13) { life <- [|0..width * height - 1|] |> map (fun _ -> random.Next() % 2 = 0) }

Console.ReadLine() |> ignore