namespace WoofWare.Myriad.Plugins

open Fantomas.FCS.Syntax

type internal SynFieldData<'Ident> =
    {
        Attrs : SynAttribute list
        Ident : 'Ident
        Type : SynType
    }

[<RequireQualifiedAccess>]
module internal SynField =
    /// Get the useful information out of a SynField.
    let extract (SynField (attrs, _, id, fieldType, _, _, _, _, _)) : SynFieldData<Ident option> =
        {
            Attrs = attrs |> List.collect (fun l -> l.Attributes)
            Ident = id
            Type = fieldType
        }

    let mapIdent<'a, 'b> (f : 'a -> 'b) (x : SynFieldData<'a>) : SynFieldData<'b> =
        let ident = f x.Ident

        {
            Attrs = x.Attrs
            Ident = ident
            Type = x.Type
        }

    /// Throws if the field has no identifier.
    let extractWithIdent (f : SynField) : SynFieldData<Ident> =
        f
        |> extract
        |> mapIdent (fun ident ->
            match ident with
            | None -> failwith "expected field identifier to have a value, but it did not"
            | Some i -> i
        )