using System;
using System.Collections.Generic;
using System.Dynamic;

namespace Microsoft.AspNet.Mvc
{
    public class ViewDataDictionary : DynamicObject
    {
        private Dictionary<object, dynamic> _data;

        public ViewDataDictionary()
        {
            _data = new Dictionary<object, dynamic>();
        }

        public ViewDataDictionary(ViewDataDictionary source)
        {
            _data = new Dictionary<object, dynamic>(source._data);
        }

        public object Model { get; set; }

        public override bool TryGetMember(GetMemberBinder binder, out object result)
        {
            result = _data[binder.Name];
            // We return true here because ViewDataDictionary returns null if the key is not
            // in the dictionary, so we simply pass on the returned value.
            return true;
        }

        public override bool TrySetMember(SetMemberBinder binder, object value)
        {
            // This cast should always succeed assuming TValue is dynamic.
            dynamic v = value;
            _data[binder.Name] = v;
            return true;
        }

        public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
        {
            if (indexes == null || indexes.Length != 1)
            {
                throw new ArgumentException("Invalid number of indexes");
            }

            object index = indexes[0];

            if (_data.TryGetValue(index, out result))
            {
                result = _data[index];
            }
            else
            {
                result = null;
            }
            return true;
        }

        public override bool TrySetIndex(SetIndexBinder binder, object[] indexes, object value)
        {
            if (indexes == null || indexes.Length != 1)
            {
                throw new ArgumentException("Invalid number of indexes");
            }

            object index = indexes[0];
            // This cast should always succeed assuming TValue is dynamic.
            _data[index] = (dynamic)value;
            return true;
        }
    }
}