using System.Collections.Generic;
using System.Security;

namespace SimpleFirebaseUnity
{
	using MiniJSON;

    public class DataSnapshot
    {
        protected object val_obj;
        protected Dictionary<string, object> val_dict;
        protected List<string> keys;
        protected string json;

        protected DataSnapshot()
        {
            val_dict = null;
            val_obj = null;
            keys = null;
            json = null;
        }

        /// <summary>
        /// Creates snapshot from Json string 
        /// </summary>
        /// <param name="json">Json string</param>
        public DataSnapshot(string _json = "")
        {
			object obj = (_json != null && _json.Length > 0)?Json.Deserialize(_json):null;

            if (obj is Dictionary<string, object>)
                val_dict = obj as Dictionary<string, object>;
            else
                val_obj = obj;

            keys = null;
            json = _json;
        }

        /// <summary>
        /// If snapshot is a Dictionary, returns keys of the snapshot , else null
        /// </summary>
        public List<string> Keys
        {
            get
            {
                if (keys == null && val_dict != null)
                    keys = new List<string>(val_dict.Keys);

                return keys;
            }
        }

        /// <summary>
        /// If snapshot is a Dictionary, gives the first key founded on snapshot, else null
        /// </summary>
        public string FirstKey
        {
            get
            {
                return (val_dict == null) ? null : Keys[0];
            }
        }

        /// <summary>
        /// Raw json of snapshot
        /// </summary>
        public string RawJson
        {
            get
            {
                return json;
            }

        }

        /// <summary>
        /// Raw value of snapshot
        /// </summary>
        public object RawValue
        {
            get
            {
                return (val_dict == null) ? val_obj : val_dict;
            }
        }

        /// <summary>
        /// Gets value from snapshot
        /// </summary>
        /// <typeparam name="T">Desired type</typeparam>
        /// <returns>Value of snapshot as the defined type, null if typecasting failed</returns>
        [SecuritySafeCritical]
        public T Value<T>()
        {
			try
			{
				if (val_obj != null)
					return (T)val_obj;
				object obj = val_dict;
				return (T)obj;
			}
			catch {
				return default(T);
			}
        }
    }
}