// MonoGame - Copyright (C) The MonoGame Team
// This file is subject to the terms and conditions defined in
// file 'LICENSE.txt', which is part of this source code package.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Xml;

namespace Microsoft.Xna.Framework.Content.Pipeline.Serialization.Intermediate
{
    abstract class ElementSerializer<T> : ContentTypeSerializer<T>
    {
        private readonly int _elementCount;

        protected ElementSerializer(string xmlTypeName, int elementCount) :
            base(xmlTypeName)
        {
            _elementCount = elementCount;
        }

        protected void ThrowElementCountException()
        {
            throw new InvalidContentException("Not have enough entries in space-separated list!");
        }

        protected internal abstract T Deserialize(string [] inputs, ref int index);

        protected internal abstract void Serialize(T value, List<string> results);

        

        protected internal void Deserialize(IntermediateReader input, List<T> results)
        {
            var elements = PackedElementsHelper.ReadElements(input);
                            
            for (var index = 0; index < elements.Length;)
            {
                if (elements.Length - index < _elementCount)
                    ThrowElementCountException();

                var elem = Deserialize(elements, ref index);
                results.Add(elem);
            }
        }

        protected internal override T Deserialize(IntermediateReader input, ContentSerializerAttribute format, T existingInstance)
        {
            var elements = PackedElementsHelper.ReadElements(input);

            if (elements.Length < _elementCount)
                ThrowElementCountException();

            var index = 0;
            return Deserialize(elements, ref index);
        }

        protected internal void Serialize(IntermediateWriter output, List<T> values)
        {
            var elements = new List<string>();
            for (var i = 0; i < values.Count; i++)
                Serialize(values[i], elements);
            var str = PackedElementsHelper.JoinElements(elements);
            output.Xml.WriteString(str);
        }

        protected internal override void Serialize(IntermediateWriter output, T value, ContentSerializerAttribute format)
        {
            var elements = new List<string>();
            Serialize(value, elements);
            var str = PackedElementsHelper.JoinElements(elements);
            output.Xml.WriteString(str);
        }
    }
}