using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;

namespace Svg.Transforms
{
    [TypeConverter(typeof(SvgTransformConverter))]
    public class SvgTransformCollection : List<SvgTransform>, ICloneable
    {
    	private void AddItem(SvgTransform item)
    	{
    		base.Add(item);
    	}
    	
    	public new void Add(SvgTransform item)
    	{
    		AddItem(item);
    		OnTransformChanged();
    	}
    	
    	public new void AddRange(IEnumerable<SvgTransform> collection)
    	{
    		base.AddRange(collection);
    		OnTransformChanged();
    	}
    	
    	public new void Remove(SvgTransform item)
    	{
    		base.Remove(item);
    		OnTransformChanged();
    	}
    	
    	public new void RemoveAt(int index)
    	{
    		base.RemoveAt(index);
    		OnTransformChanged();
    	}
    	
    	/// <summary>
    	/// Multiplies all matrices
    	/// </summary>
    	/// <returns>The result of all transforms</returns>
    	public Matrix GetMatrix()
    	{
    		var transformMatrix =  new Matrix();
    		
    		// Return if there are no transforms
            if (this.Count == 0)
            {
            	return transformMatrix;
            }

            foreach (SvgTransform transformation in this)
            {
                transformMatrix.Multiply(transformation.Matrix);
            }

            return transformMatrix;
    	}

		public override bool Equals(object obj)
		{
			if (this.Count == 0 && this.Count == base.Count) //default will be an empty list 
				return true;
			return base.Equals(obj);
		}

        public override int GetHashCode()
        {
            return base.GetHashCode();
        }

		public new SvgTransform this[int i]
        {
			get { return base[i]; }
			set
			{
				var oldVal = base[i];
				base[i] = value;
				if(oldVal != value)
					OnTransformChanged();
			}
		}
		
		/// <summary>
        /// Fired when an SvgTransform has changed
        /// </summary>
        public event EventHandler<AttributeEventArgs> TransformChanged;
        
        protected void OnTransformChanged()
        {
        	var handler = TransformChanged;
        	if(handler != null)
        	{
        		//make a copy of the current value to avoid collection changed exceptions
        		handler(this, new AttributeEventArgs { Attribute = "transform", Value = this.Clone() });
        	}
        }	
    	
		public object Clone()
		{
			var result = new SvgTransformCollection();
			foreach (var trans in this) 
			{
				result.AddItem(trans.Clone() as SvgTransform);
			}
			return result;
		}

        public override string ToString()
        {
            if (this.Count < 1) return string.Empty;
            return (from t in this select t.ToString()).Aggregate((p,c) => p + " " + c);
        }
    }
}