open System

open System.IO

open System.Reflection

type Reference = Cdn of string | Full | NoReference | Require

type Snapshot = {

Json: string

Reference: Reference

PlotlySource: string option

HeadTags: string

Description: string

Title: string

Charset: string

DocumentDescription: string

Favicon: string

}

let private flags = BindingFlags.Public ||| BindingFlags.Static

let rec private chartType (candidate: Type) =

if isNull candidate then None

elif candidate.FullName = "Plotly.NET.GenericChart"

&& candidate.Assembly.GetName().Name = "Plotly.NET" then Some candidate

else chartType candidate.BaseType

let private methodWithArgument (owner: Type) name (argumentType: Type) =

owner.GetMethod(name, flags, null, [| argumentType |], null)

let tryGetChartType (value: obj) =

if isNull value then None

else

chartType (value.GetType())

|> Option.filter (fun sourceType ->

let serialize = methodWithArgument sourceType "toJson" sourceType

let display = methodWithArgument sourceType "getDisplayOptions" sourceType

not (isNull serialize) && serialize.ReturnType = typeof<string> && not (isNull display))

let private invoke (owner: Type) name (argumentType: Type) argument =

let methodInfo = methodWithArgument owner name argumentType

if isNull methodInfo then invalidOp $"The originating Plotly.NET assembly does not provide {owner.Name}.{name}."

methodInfo.Invoke(null, [| argument |])

let private property name (value: obj) =

let info = value.GetType().GetProperty(name)

if isNull info then invalidOp $"The originating Plotly.NET value does not provide {name}."

info.GetValue(value)

let private renderNodes (methodInfo: MethodInfo) options =

let nodes = methodInfo.Invoke(null, [| options |])

let nodeType = methodInfo.ReturnType.GetGenericArguments()[0]

let renderer = nodeType.Assembly.GetType("Giraffe.ViewEngine.RenderView+AsString", true)

invoke renderer "htmlNodes" methodInfo.ReturnType nodes :?> string

let capture forceOffline (value: obj) =

let sourceType = tryGetChartType value |> Option.defaultWith (fun () -> invalidArg "value" "Expected a Plotly.NET GenericChart.")

let options = invoke sourceType "getDisplayOptions" sourceType value

// Static getters belong to the declared base type, even for custom options subclasses.

let optionsType = (methodWithArgument sourceType "getDisplayOptions" sourceType).ReturnType

let get name = invoke optionsType name optionsType options

let getString name = get name :?> string

let htmlList name =

let getter = methodWithArgument optionsType name optionsType

if isNull getter then invalidOp $"The originating Plotly.NET assembly does not provide {name}."

renderNodes getter options

let resourceName =

sourceType.Assembly.GetManifestResourceNames()

|> Array.filter (fun name -> name.StartsWith("Plotly.NET.plotly-", StringComparison.Ordinal) && name.EndsWith(".min.js", StringComparison.Ordinal))

|> function

| [| name |] -> name

| _ -> invalidOp "Cannot identify the originating Plotly.NET JavaScript resource."

let version = resourceName.Substring("Plotly.NET.plotly-".Length).Replace(".min.js", "")

let reference =

if forceOffline then Full

else

match get "tryGetPlotlyReference" with

| null -> Cdn $"https://cdn.plot.ly/plotly-{version}.min.js"

| some ->

let reference = property "Value" some

let isCase name = property name reference :?> bool

if isCase "IsFull" then Full

elif isCase "IsCDN" then Cdn (property "Item" reference :?> string)

elif isCase "IsNoReference" then NoReference

elif isCase "IsRequire" then Require

else invalidOp "Unsupported originating Plotly.NET JavaScript reference."

let source =

match reference with

| Full ->

use stream = sourceType.Assembly.GetManifestResourceStream(resourceName)

use reader = new StreamReader(stream)

Some (reader.ReadToEnd())

| _ -> None

let favicon = get "getDocumentFavicon"

let faviconType = (methodWithArgument optionsType "getDocumentFavicon" optionsType).ReturnType

let renderer = faviconType.Assembly.GetType("Giraffe.ViewEngine.RenderView+AsString", true)

{

Json = invoke sourceType "toJson" sourceType value :?> string

Reference = reference

PlotlySource = source

HeadTags = htmlList "getAdditionalHeadTags"

Description = htmlList "getChartDescription"

Title = getString "getDocumentTitle"

Charset = getString "getDocumentCharset"

DocumentDescription = getString "getDocumentDescription"

Favicon = invoke renderer "htmlNode" faviconType favicon :?> string

}