NonEmptyList json serialization.fs

module NonNullListSerialization

open System
open System.IO
open System.Text
open Newtonsoft.Json
open FSharpx.Collections
open System.Collections.Generic
open Newtonsoft.Json.Serialization
open Newtonsoft.Json.Converters
open Microsoft.FSharp.Reflection

type NonEmptyListConverter() =
    inherit JsonConverter()
    
    override x.CanConvert(t:Type) = 
        t.IsGenericType && t.GetGenericTypeDefinition() = typedefof<NonEmptyList<_>>

    override x.WriteJson(writer, value, serializer) =
        let list = value :?> System.Collections.IEnumerable |> Seq.cast
        serializer.Serialize(writer, list)

    override x.ReadJson(reader, t, _, serializer) = 
        let itemType = t.GetGenericArguments().[0]
        let collectionType = typedefof<IEnumerable<_>>.MakeGenericType(itemType)
        let collection = serializer.Deserialize(reader, collectionType) :?> System.Collections.IEnumerable |> Seq.cast        
        match collection |> Seq.toList with
        | [] -> invalidOp "NonEmptyList cannot be empty"
        | h :: t -> NonEmptyList.create h t :> _

let s = new JsonSerializer()    
s.Converters.Add(new NonEmptyListConverter())
    
let serialize o =
    use ms = new MemoryStream()
    (use jsonWriter = new JsonTextWriter(new StreamWriter(ms))
    s.Serialize(jsonWriter, o))
    ms.ToArray()

let deserialize (t, data: byte array) =
    use ms = new MemoryStream(data)
    use jsonReader = new JsonTextReader(new StreamReader(ms))
    s.Deserialize(jsonReader, t)

let twoWay o =
    let bytes = serialize o
    (o.GetType(), bytes) |> deserialize

// OK
let l = twoWay <| NonEmptyList.createParamsArray ("a", [|"b"; "c"|])

type Complex = { List: NonEmptyList<string> }

// System.ArgumentException: Object of type 'FSharpx.Collections.NonEmptyList`1[System.Object]' cannot be converted to type 'FSharpx.Collections.NonEmptyList`1[System.String]'.
let c = twoWay <| { List = NonEmptyList.createParamsArray ("a", [|"b"; "c"|]) }