using System;
using System.Collections.Generic;

namespace Mist
{
    /// <summary>
    /// Container class implements the IServiceProvider interface. This is used
    /// to pass shared services between different components, for instance the
    /// ContentManager uses it to locate the IGraphicsDeviceService implementation.
    /// </summary>
    public class ServiceContainer : IServiceProvider
    {
        /// <summary>
        /// A container that maps the type of service to an actual instance of the service.
        /// </summary>
        public Dictionary<Type, Object> Services = new Dictionary<Type, Object>();

        /// <summary>
        /// Adds a new service to the collection.
        /// </summary>
        /// <typeparam name="T">The type of parameter to be added.</typeparam>
        /// <param name="service">The service instance to be added.</param>
        public void AddService<T>(T service)
        {
            // Add the service to the container by type
            this.Services.Add(typeof(T), service);
        }

        /// <summary>
        /// Looks up the specified service.
        /// </summary>
        /// <param name="serviceType">A type that represents the service type.</param>
        /// <returns>Returns the service (or null if it was not found).</returns>
        public Object GetService(Type serviceType)
        {
            // This will store the service
            Object service;

            // Attempt to get the service by type out of the services map
            this.Services.TryGetValue(serviceType, out service);

            // Return the service
            return service;
        }
    }
}