using System;
using System.Collections.Generic;
using System.Linq;
using Encompass.Exceptions;

namespace Encompass
{
    [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)]
    public class Writes : Attribute
    {
        public readonly HashSet<Type> WriteTypes = new HashSet<Type>();
        public readonly Dictionary<Type, int> Priorities = new Dictionary<Type, int>();

        public Writes(params Type[] writeTypes)
        {
            foreach (var writeType in writeTypes)
            {
                var isComponent = writeType.GetInterfaces().Contains(typeof(IComponent));
                if (!isComponent)
                {
                    throw new IllegalWriteTypeException("{0} must be a Component", writeType.Name);
                }

                this.WriteTypes.Add(writeType);
            }
        }

        public Writes(Type writeType, int priority)
        {
            var isComponent = writeType.GetInterfaces().Contains(typeof(IComponent));
            if (!isComponent)
            {
                throw new IllegalWriteTypeException("{0} must be a Component", writeType.Name);
            }

            WriteTypes.Add(writeType);
            Priorities.Add(writeType, priority);
        }
    }
}