using System;
using System.Collections.Generic;
using System.Web.Script.Serialization;

namespace ISphereWinHelper
{
    internal static class HelperProtocol
    {
        public const string Protocol = "isphere.helper.v1";
        private static readonly JavaScriptSerializer Serializer = new JavaScriptSerializer { MaxJsonLength = 16 * 1024 * 1024, RecursionLimit = 256 };

        public static bool TryParseRequest(string text, out Dictionary<string, object> request, out string requestId, out string op)
        {
            request = null;
            requestId = "";
            op = "";

            if (string.IsNullOrWhiteSpace(text))
            {
                return false;
            }

            try
            {
                object decoded = Serializer.DeserializeObject(text);
                request = decoded as Dictionary<string, object>;
                if (request == null)
                {
                    return false;
                }

                string protocol = GetString(request, "protocol", "");
                requestId = GetString(request, "request_id", "");
                op = GetString(request, "op", "");

                if (protocol != Protocol || string.IsNullOrWhiteSpace(op))
                {
                    return false;
                }

                return true;
            }
            catch
            {
                return false;
            }
        }

        public static Dictionary<string, object> Success(string requestId, string op, object data)
        {
            return Envelope(requestId, op, true, data, null);
        }

        public static Dictionary<string, object> Failure(string requestId, string op, string code, string message)
        {
            var error = new Dictionary<string, object>
            {
                { "code", code },
                { "message", message }
            };
            return Envelope(requestId, op, false, null, error);
        }

        private static Dictionary<string, object> Envelope(string requestId, string op, bool ok, object data, object error)
        {
            return new Dictionary<string, object>
            {
                { "protocol", Protocol },
                { "request_id", requestId ?? "" },
                { "op", op ?? "" },
                { "ok", ok },
                { "data", data },
                { "error", error },
                { "warnings", new object[0] }
            };
        }

        public static string ToJson(object value)
        {
            return Serializer.Serialize(value);
        }

        public static Dictionary<string, object> GetObject(Dictionary<string, object> source, string key)
        {
            if (source == null || !source.ContainsKey(key) || source[key] == null)
            {
                return new Dictionary<string, object>();
            }
            return source[key] as Dictionary<string, object> ?? new Dictionary<string, object>();
        }

        public static string GetString(Dictionary<string, object> source, string key, string defaultValue)
        {
            if (source == null || !source.ContainsKey(key) || source[key] == null)
            {
                return defaultValue;
            }
            return Convert.ToString(source[key]);
        }

        public static bool GetBool(Dictionary<string, object> source, string key, bool defaultValue)
        {
            if (source == null || !source.ContainsKey(key) || source[key] == null)
            {
                return defaultValue;
            }
            try
            {
                return Convert.ToBoolean(source[key]);
            }
            catch
            {
                return defaultValue;
            }
        }

        public static int GetInt(Dictionary<string, object> source, string key, int defaultValue)
        {
            if (source == null || !source.ContainsKey(key) || source[key] == null)
            {
                return defaultValue;
            }
            try
            {
                return Convert.ToInt32(source[key]);
            }
            catch
            {
                return defaultValue;
            }
        }
    }
}