using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Reflection;
using IgniteEngine.Content.Items;

namespace IgniteEngine.IO
{
    /// <summary>
    /// Class that contains objects from a file that was processed.
    /// </summary>
    /// <typeparam name="T">The type of object.</typeparam>
    public class ObjectCollection<T>
    {
        /// <summary>
        /// The contained objects.
        /// </summary>
        private readonly Dictionary<dynamic, T> Objects;

        /// <summary>
        /// Creates a new instance of the <see cref="ObjectCollection{T}"/> class.
        /// </summary>
        public ObjectCollection()
        {
            Objects = new Dictionary<dynamic, T>();
        }

	    /// <summary>
	    /// Returns the object with the identity.
	    /// </summary>
	    /// <param name="identity">The identity of the object.</param>
	    /// <returns>The object.</returns>
	    public T this[byte identity] => !Objects.ContainsKey(identity) ? default(T) : Objects[identity];

		/// <summary>
		/// Returns the object with the identity.
		/// </summary>
		/// <param name="identity">The identity of the object.</param>
		/// <returns>The object.</returns>
		public T this[ushort identity] => !Objects.ContainsKey(identity) ? default(T) : Objects[identity];

		/// <summary>
		/// Returns the object with the identity.
		/// </summary>
		/// <param name="identity">The identity of the object.</param>
		/// <returns>The object.</returns>
		public T this[string identity] => !Objects.ContainsKey(identity) ? default(T) : Objects[identity];

        /// <summary>
        /// Adds an item to the collection if it's not already there.
        /// </summary>
        /// <param name="reader">The object to read data from.</param>
        public void Add(DataTableReader reader)
        {
            var instance = (T)Activator.CreateInstance(typeof(T));
            var properties = instance.GetType().GetProperties();

            PropertyInfo identityProperty = null;

            for (var i = 0; i < properties.Length; i++)
            {
                var property = properties[i];
                var propertyType = properties[i].PropertyType;
                var value = reader.GetValue(reader.GetOrdinal(property.Name));

                if (propertyType == typeof(byte))
                {
                    property.SetValue(instance, (byte) value, null);
                }

                if (propertyType == typeof(ushort))
                {
                    property.SetValue(instance, (ushort) value, null);
                }

                if (propertyType == typeof(uint))
                {
                    property.SetValue(instance, (uint) value, null);
                }

                if (propertyType == typeof(string))
                {
                    property.SetValue(instance, (string) value, null);
                }

                if (propertyType == typeof(ItemEquip))
                {
                    property.SetValue(instance, (ItemEquip) (uint) value, null);
                }

                // Get the identity's value.
                if (property.GetCustomAttributes<Identity>().Any())
                {
                    identityProperty = property;
                }
            }

            if (identityProperty == null)
            {
                Debug.LogAssert("Definition identity property did not exist.");
                return;
            }

            Objects.Add(identityProperty.GetValue(instance), instance);
        }
    }
}