using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Microsoft.EntityFrameworkCore;

namespace Hncore.Infrastructure.EF
{
    public static class AutoMapExtensions
    {
        private static object syncRoot = new object();
        private static ConcurrentDictionary<IEntityMap, object> maps;

        public static void AutoMap(this ModelBuilder modelBuilder, Type assType)
        {
            if (maps == null)
            {
                lock (syncRoot)
                {
                    if (maps == null)
                    {
                        maps = new ConcurrentDictionary<IEntityMap, object>();

                        Type mappingInterface = typeof(IEntityMap<>);

                        var mappingTypes = assType.GetTypeInfo().Assembly.GetTypes()
                            .Where(x => !x.IsAbstract
                                        && x.GetInterfaces().Any(y => y.GetTypeInfo().IsGenericType
                                                                      && y.GetGenericTypeDefinition() ==
                                                                      mappingInterface));

                        foreach (var map in mappingTypes.Select(Activator.CreateInstance).Cast<IEntityMap>())
                        {
                            maps.TryAdd(map, null);
                        }
                    }
                }
            }

            foreach (var map in maps.Keys)
            {
                map.Map(modelBuilder);
            }
        }
    }
}