// The MIT License (MIT)

// Copyright (c) 2016 Bazinga Technologies Inc

[<AutoOpen>]

module FSharp.Data.GraphQL.Types.ResolveFieldContextExtensions

open FSharp.Data.GraphQL

open FSharp.Data.GraphQL.Extensions

type ResolveFieldContext with

/// Returns an argument by provided name. If argument was not found a GraphQL exception will be thrown.

/// <exception cref="GraphQLException">When argument with the name not found in the Args.</exception>

member x.Arg(name : string) : 't =

match Map.tryFind name x.Args with

| Some found -> downcast found

| None -> raise (GQLMessageException $"Argument '%s{name}' was not provided within context of a field '%s{x.ExecutionInfo.Identifier}'. Check if it was supplied within GraphQL query.")