open System.Collections.Generic

open System.Text.Json.Serialization

open FsToolkit.ErrorHandling

open FSharp.Data.GraphQL

open FSharp.Data.GraphQL.Extensions

type ValidationResult<'Err> =

| Success

| ValidationError of 'Err list

member this.AsResult : Result<unit, 'Err list> =

match this with

| Success -> Ok ()

| ValidationError errors -> Error errors

type ResultBuilder with

member inline _.Source (result : ValidationResult<'error>) = result.AsResult

let (@@) (res1 : ValidationResult<'Err>) (res2 : ValidationResult<'Err>) : ValidationResult<'Err> =

match res1, res2 with

| Success, Success -> Success

| Success, _ -> res2

| _, Success -> res1

| ValidationError e1, ValidationError e2 -> ValidationError (e1 @ e2)

/// Call the given sequence of validations, accumulating any errors, and return one ValidationResult.

let collect (f : 'T -> ValidationResult<'Err>) (xs : 'T seq) : ValidationResult<'Err> =

// TODO: Use PSeq

Seq.fold (fun acc t -> acc @@ (f t)) Success xs

let mapErrors (f : 'Err1 -> 'Err2) (res : ValidationResult<'Err1>) : ValidationResult<'Err2> =

match res with

| Success -> Success

| ValidationError errors -> ValidationError (List.map f errors)

type internal GQLValidator<'Val> = 'Val -> ValidationResult<IGQLError>

let empty = fun _ -> Success

type AstError =

static member AsResult (message : string, ?path : FieldPath) =

[

{

Message = message

Exception = ValueNone

Path = path |> Skippable.ofOption |> Skippable.map List.rev

Locations = Skip

Extensions =

Include (

Dictionary<string, obj> ()

|> GQLProblemDetails.SetErrorKind ErrorKind.Validation

)

}

]

|> ValidationResult.ValidationError