// Read about this and other fiddles on .NET Fiddle Newsletter https://dotnetfiddle.substack.com/

//

// This fiddle demonstrates how to return three latest posts from WallStreetBets subreddit, to be voiced out by a google speaker/assistant

​

using System;

using System.Collections.Generic;

​

using System.Threading.Tasks;

using System.Net.Http;

​

using System.Dynamic;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

​

public class Program

{

    public static async Task Main()

    {

        //emulate google action which requests top posts

        var request = new GoogleActionWebhookRequest

        {

            handler = new GoogleActionWebhookRequest.Handler

            {

                name = "top_posts",  //This is the handler id specified in Google Action config

            },

            intent = new GoogleActionWebhookRequest.Intent

            {

                name = "top_posts",

                query = "Top posts"

            },

            session = new GoogleActionWebhookRequest.Session

            {

                id = "TestSessionId"

            },

        };

        var response = await ProcessGoogleAction(request);

        var serializerOptions = new JsonSerializerOptions

        {

            WriteIndented = true

        };

        Console.WriteLine("Request from Google Aciton is:\n");

        Console.WriteLine(JsonSerializer.Serialize(request, serializerOptions));

        Console.WriteLine("\n===================================\n");

        Console.WriteLine("Webhook Response to Google Aciton is:\n");

        Console.WriteLine(JsonSerializer.Serialize(response, serializerOptions));

    }

​

    public static async Task<GoogleActionWebhookResponse> ProcessGoogleAction(GoogleActionWebhookRequest request)

    {

​

        var speech = await GetSpeechText(request.handler.name);

        var response = new GoogleActionWebhookResponse()

        {

            prompt = new GoogleActionWebhookResponse.Prompt

            {

                firstSimple = new GoogleActionWebhookResponse.Prompt.Simple

                {

                    speech = speech

                }

            },

            scene = new GoogleActionWebhookResponse.Scene

            {

                next = new GoogleActionWebhookResponse.Scene.Next

                {

                    name = "waiting"

                }

            },

            session = new GoogleActionWebhookResponse.Session

            {

                id = request.session.id

            }

        };

        return response;

    }

​

    private static async Task<string> GetSpeechText(string handler)

    {

        switch (handler)

        {

            case "top_posts":

                return await GetTopPostsText();

​

            // put other handlers here

        }

​

        return "No comprende";

    }

​

    public const string RedditPostsUrl = "https://www.reddit.com/r/{0}/.json?limit={1}";

    private static async Task<string> GetTopPostsText()

    {

        var url = String.Format(RedditPostsUrl, "wallstreetbets", 3);

        string text = null;

        using (var client = new HttpClient())

        {

            var httpResponse = await client.GetAsync(url);

            string json = await httpResponse.Content.ReadAsStringAsync();

​

            var serializerOptions = new JsonSerializerOptions

            {

                Converters = { new DynamicJsonConverter() }   //this is needed to get dynamic json structure instead of jsonElement

            };

​

            var jsonData = JsonSerializer.Deserialize<dynamic>(json, serializerOptions);

            //json data looks like https://www.reddit.com/r/wallstreetbets/.json?limit=3

            var children = jsonData.data.children;

            var postNumber = 1;

            foreach (var child in children)

            {

                //skip stickied posts   

                if (child.data.stickied)

                    continue;

​

                 string title = child.data.title;

                 text += "\nPost " + postNumber + ": '" + title + "'.";

                 postNumber++;

             }

        }

​

        return text;

    }

    //Partial request from google action and response

    //Full documenttion is here req/res here https://developers.google.com/assistant/conversational/webhooks#example-response

​

    public class GoogleActionWebhookRequest

    {

        public Handler handler { get; set; }

​

        public Intent intent { get; set; }

​

        public Session session { get; set; }

​

        public class Handler

        {

            public string name { get; set; }

        }

​

​

        public class Intent

        {

            public string name { get; set; }

​

            public string query { get; set; }

        }

​

​

        public class Session

        {

            public string id { get; set; }

        }

    }

    public class GoogleActionWebhookResponse

    {

        public Session session { get; set; }

​

        public Prompt prompt { get; set; }

​

        public Scene scene { get; set; }

​

        public class Session

        {

            public string id { get; set; }

​

        }

​

        public class Prompt

        {

            public Simple firstSimple { get; set; }

​

            public class Simple

            {

                public string speech { get; set; }

                public string text { get; set; }

​

            }

​

        }

​

​

        public class Scene

        {

            public string name { get; set; }

            public Next next { get; set; }

​

            public class Next

            {

                public string name { get; set; }

            }

        }

    }

    //Class that converts jsonElement to dynamic, to make it much easier to traverse

    public class DynamicJsonConverter : JsonConverter<dynamic>

    {

        public override dynamic Read(ref Utf8JsonReader reader,

            Type typeToConvert,

            JsonSerializerOptions options)

        {

            if (reader.TokenType == JsonTokenType.True)

                return true;

​

            if (reader.TokenType == JsonTokenType.False)

                return false;

​

            if (reader.TokenType == JsonTokenType.Number)

            {

                if (reader.TryGetInt64(out long l))

                    return l;

​

                return reader.GetDouble();

            }

​

            if (reader.TokenType == JsonTokenType.String)

            {

                if (reader.TryGetDateTime(out DateTime datetime))

                    return datetime;

​

                return reader.GetString();

            }

​

            if (reader.TokenType == JsonTokenType.StartObject)

            {

                using JsonDocument documentV = JsonDocument.ParseValue(ref reader);

                return ReadObject(documentV.RootElement);

            }

​

            if (reader.TokenType == JsonTokenType.StartArray)

            {

                using JsonDocument documentV = JsonDocument.ParseValue(ref reader);

                return ReadList(documentV.RootElement); 

            }

​

            // Use JsonElement as fallback.

            JsonDocument document = JsonDocument.ParseValue(ref reader);

            return document.RootElement.Clone();

        }

​

        private object ReadObject(JsonElement jsonElement)

        {

            IDictionary<string, object> expandoObject = new ExpandoObject();

            foreach (var obj in jsonElement.EnumerateObject())

            {

                var k = obj.Name;

                var value = ReadValue(obj.Value);

                expandoObject[k] = value;

            }

            return expandoObject;

        }

​

        private object ReadValue(JsonElement jsonElement)

        {

            object result = null;

            switch (jsonElement.ValueKind)

            {

                case JsonValueKind.Object:

                    result = ReadObject(jsonElement);

                    break;

                case JsonValueKind.Array:

                    result = ReadList(jsonElement);

                    break;

                case JsonValueKind.String:

                    //TODO: Missing Datetime&Bytes Convert

                    result = jsonElement.GetString();

                    break;

                case JsonValueKind.Number:

                    //TODO: more num type

                    result = 0;

                    if (jsonElement.TryGetInt64(out long l))

                    {

                        result = l;

                    }

                    else

                    {

                        if (jsonElement.TryGetDouble(out double d))

                        {

                            result = d;

                        }

                    }

                    break;

                case JsonValueKind.True:

                    result = true;

                    break;

                case JsonValueKind.False:

                    result = false;

                    break;

                case JsonValueKind.Undefined:

                case JsonValueKind.Null:

                    result = null;

                    break;

                default:

                    throw new ArgumentOutOfRangeException();

            }

            return result;

        }

​

        private object ReadList(JsonElement jsonElement)

        {

            IList<object> list = new List<object>();

            foreach (var item in jsonElement.EnumerateArray())

            {

                list.Add(ReadValue(item));

            }

            return list.Count == 0 ? null : list;

        }

​

        public override void Write(Utf8JsonWriter writer,

            object value,

            JsonSerializerOptions options)

        {

            throw new NotImplementedException();

        }

    }

}