using Prism.Ioc;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http.Controllers;
using System.Web.Http.Dependencies;

namespace LocalhostMES.Infrastructure
{
    /// <summary>
    /// Web API 与 Prism 容器桥接（需要时可在此扩展从容器解析的类型）。
    /// </summary>
    public class PrismDependencyResolver : IDependencyResolver
    {
        private readonly IContainerProvider _containerProvider;

        public PrismDependencyResolver(IContainerProvider containerProvider)
        {
            _containerProvider = containerProvider;
        }

        public IDependencyScope BeginScope()
        {
            return this;
        }

        public object GetService(Type serviceType)
        {
            try
            {
                if (typeof(IHttpController).IsAssignableFrom(serviceType))
                {
                    return _containerProvider.Resolve(serviceType);
                }

                if (IsRegisteredCustomType(serviceType))
                {
                    return _containerProvider.Resolve(serviceType);
                }

                return null;
            }
            catch (ContainerResolutionException)
            {
                return null;
            }
            catch
            {
                return null;
            }
        }

        private static bool IsRegisteredCustomType(Type serviceType)
        {
            // 当前控制器均使用无参构造；若后续有需注入单例，在此按类型或命名空间登记。
            return false;
        }

        public IEnumerable<object> GetServices(Type serviceType)
        {
            try
            {
                var enumerableType = typeof(IEnumerable<>).MakeGenericType(serviceType);
                var services = _containerProvider.Resolve(enumerableType);
                return (IEnumerable<object>)services;
            }
            catch
            {
                return Enumerable.Empty<object>();
            }
        }

        public void Dispose()
        {
        }
    }
}