using System.Collections.Generic;
using LinFu.IoC.Interfaces;

namespace LinFu.IoC
{
    /// <summary>
    ///     Represents the default base implementation of the <see cref="IFactoryStorage" /> class.
    /// </summary>
    public abstract class BaseFactoryStorage : IFactoryStorage
    {
        private readonly Dictionary<IServiceInfo, IFactory> _entries = new Dictionary<IServiceInfo, IFactory>();
        private readonly object _lock = new object();


        /// <summary>
        ///     Determines which factories should be used
        ///     for a particular service request.
        /// </summary>
        /// <param name="serviceInfo">The <see cref="IServiceInfo" /> object that describes the target factory.</param>
        /// <returns>A factory instance.</returns>
        public virtual IFactory GetFactory(IServiceInfo serviceInfo)
        {
            if (_entries.ContainsKey(serviceInfo))
                return _entries[serviceInfo];

            return null;
        }

        /// <summary>
        ///     Adds a <see cref="IFactory" /> to the current <see cref="IFactoryStorage" /> object.
        /// </summary>
        /// <param name="serviceInfo">The <see cref="IServiceInfo" /> object that describes the target factory.</param>
        /// <param name="factory">The <see cref="IFactory" /> instance that will create the object instance.</param>
        public virtual void AddFactory(IServiceInfo serviceInfo, IFactory factory)
        {
            lock (_lock)
            {
                _entries[serviceInfo] = factory;
            }
        }

        /// <summary>
        ///     Determines whether or not a factory exists in storage.
        /// </summary>
        /// <param name="serviceInfo">The <see cref="IServiceInfo" /> object that describes the target factory.</param>
        /// <returns>Returns <c>true</c> if the factory exists; otherwise, it will return <c>false</c>.</returns>
        public virtual bool ContainsFactory(IServiceInfo serviceInfo)
        {
            return _entries.ContainsKey(serviceInfo);
        }

        /// <summary>
        ///     Gets a value indicating the list of <see cref="IServiceInfo" /> objects
        ///     that describe each available factory in the current <see cref="IFactoryStorage" />
        ///     instance.
        /// </summary>
        public virtual IEnumerable<IServiceInfo> AvailableFactories => _entries.Keys;
    }
}