// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using Microsoft.Extensions.Caching.Distributed;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.DependencyInjection.Extensions;
 
namespace Microsoft.Extensions.DependencyInjection
{
    /// <summary>
    /// Extension methods for setting up memory cache related services in an <see cref="IServiceCollection" />.
    /// </summary>
    public static class MemoryCacheServiceCollectionExtensions
    {
        /// <summary>
        /// Adds a non distributed in-memory implementation of <see cref="IMemoryCache"/> to the
        /// <see cref="IServiceCollection" />.
        /// </summary>
        /// <param name="services">The <see cref="IServiceCollection" /> to add services to.</param>
        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
        public static IServiceCollection AddMemoryCache(this IServiceCollection services)
        {
            ThrowHelper.ThrowIfNull(services);
 
            services.AddOptions();
            services.TryAdd(ServiceDescriptor.Singleton<IMemoryCache, MemoryCache>());
 
            return services;
        }
 
        /// <summary>
        /// Adds a non distributed in-memory implementation of <see cref="IMemoryCache"/> to the
        /// <see cref="IServiceCollection" />.
        /// </summary>
        /// <param name="services">The <see cref="IServiceCollection" /> to add services to.</param>
        /// <param name="setupAction">
        /// The <see cref="Action{MemoryCacheOptions}"/> to configure the provided <see cref="MemoryCacheOptions"/>.
        /// </param>
        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
        public static IServiceCollection AddMemoryCache(this IServiceCollection services, Action<MemoryCacheOptions> setupAction)
        {
            ThrowHelper.ThrowIfNull(services);
            ThrowHelper.ThrowIfNull(setupAction);
 
            services.AddMemoryCache();
            services.Configure(setupAction);
 
            return services;
        }
 
        /// <summary>
        /// Adds a default implementation of <see cref="IDistributedCache"/> that stores items in memory
        /// to the <see cref="IServiceCollection" />. Frameworks that require a distributed cache to work
        /// can safely add this dependency as part of their dependency list to ensure that there is at least
        /// one implementation available.
        /// </summary>
        /// <remarks>
        /// <see cref="AddDistributedMemoryCache(IServiceCollection)"/> should only be used in single
        /// server scenarios as this cache stores items in memory and doesn't expand across multiple machines.
        /// For those scenarios it is recommended to use a proper distributed cache that can expand across
        /// multiple machines.
        /// </remarks>
        /// <param name="services">The <see cref="IServiceCollection" /> to add services to.</param>
        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
        public static IServiceCollection AddDistributedMemoryCache(this IServiceCollection services)
        {
            ThrowHelper.ThrowIfNull(services);
 
            services.AddOptions();
            services.TryAdd(ServiceDescriptor.Singleton<IDistributedCache, MemoryDistributedCache>());
 
            return services;
        }
 
        /// <summary>
        /// Adds a default implementation of <see cref="IDistributedCache"/> that stores items in memory
        /// to the <see cref="IServiceCollection" />. Frameworks that require a distributed cache to work
        /// can safely add this dependency as part of their dependency list to ensure that there is at least
        /// one implementation available.
        /// </summary>
        /// <remarks>
        /// <see cref="AddDistributedMemoryCache(IServiceCollection)"/> should only be used in single
        /// server scenarios as this cache stores items in memory and doesn't expand across multiple machines.
        /// For those scenarios it is recommended to use a proper distributed cache that can expand across
        /// multiple machines.
        /// </remarks>
        /// <param name="services">The <see cref="IServiceCollection" /> to add services to.</param>
        /// <param name="setupAction">
        /// The <see cref="Action{MemoryDistributedCacheOptions}"/> to configure the provided <see cref="MemoryDistributedCacheOptions"/>.
        /// </param>
        /// <returns>The <see cref="IServiceCollection"/> so that additional calls can be chained.</returns>
        public static IServiceCollection AddDistributedMemoryCache(this IServiceCollection services, Action<MemoryDistributedCacheOptions> setupAction)
        {
            ThrowHelper.ThrowIfNull(services);
            ThrowHelper.ThrowIfNull(setupAction);
 
            services.AddDistributedMemoryCache();
            services.Configure(setupAction);
 
            return services;
        }
    }
}