module OBJLoader =

    type Vertex = {
        x: float
        y: float
        z: float
    }

    type TexCoord = {
        u: float
        v: float
    }

    type FaceDef = {
        v: int option
        n: int option
        t: int option
    }

    let space = pchar ' '

    let load name =

        let vertices = new List<Vertex>()
        let pvertex = pchar 'v' >>. spaces >>. tuple3 (pfloat .>> space) (pfloat .>> space) pfloat .>> newline
                      |>> fun (x, y, z) -> vertices.Add({ x=x; y=y; z=z })

        let normals = new List<Vertex>()
        let pnormal = pstring "vn" >>. spaces >>. tuple3 (pfloat .>> space) (pfloat .>> space) pfloat .>> newline
                      |>> fun (x, y, z) -> normals.Add({ x=x; y=y; z=z })

        let texcoords = new List<TexCoord>()
        let ptex = pstring "vt" >>. spaces >>. tuple2 (pfloat .>> space) pfloat .>> newline
                   |>> fun (u, v) -> texcoords.Add({ u=u; v=v })

        let pfacevert = sepBy (opt pint32) (pchar '/')
                        |>> function
                            | [v; t; n] -> { v=v; n=n; t=t }
                            | _ -> { v=None; n=None; t=None }

        let faces = new List<FaceDef>()
        let pface = pchar 'f' >>. spaces >>. sepBy pfacevert space .>> newline
                    |>> faces.AddRange

        // These are basically comments...
        let mtllib = (choice [pstring "mtllib"; pstring "usemtl"]) >>. skipRestOfLine true
        let pgroup = pchar 'g' >>. skipRestOfLine true

        let comment = pchar '#' >>. skipRestOfLine true

        let toplevel = many (choice [pface; ptex; pnormal; pvertex; pgroup; mtllib; comment])

        let foo = System.DateTime.Now
        match runParserOnFile toplevel () name System.Text.Encoding.ASCII with
            | Success(v,_,_) ->
                let diff = System.DateTime.Now - foo
                ()
            | Failure(str,_,_) -> ()