using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using NewLife.Cube.Extensions;
using NewLife.Log;
using NewLife.Reflection;
using XCode;
using HttpContext = NewLife.Web.HttpContext;

namespace NewLife.Cube
{
    /// <summary>实体模型绑定器</summary>
    public class EntityModelBinder : ComplexTypeModelBinder
    {
        /// <summary>实例化实体模型绑定器</summary>
        /// <param name="propertyBinders"></param>
        /// <param name="loggerFactory"></param>
        public EntityModelBinder(IDictionary<ModelMetadata, IModelBinder> propertyBinders, ILoggerFactory loggerFactory)
            : base(propertyBinders, loggerFactory) { }

        /// <summary>创建模型。对于有Key的请求，使用FindByKeyForEdit方法先查出来数据，而不是直接反射实例化实体对象</summary>
        /// <param name="bindingContext"></param>
        /// <returns></returns>
        protected override Object CreateModel(ModelBindingContext bindingContext)
        {
            var modelType = bindingContext.ModelType;
            if (modelType.As<IEntity>())
            {
                var fact = EntityFactory.CreateOperate(modelType);
                if (fact != null)
                {
                    var rvs = bindingContext.ActionContext.RouteData.Values;
                    var pks = fact.Table.PrimaryKeys;
                    var uk = fact.Unique;

                    IEntity entity = null;
                    if (uk != null)
                    {
                        // 查询实体对象用于编辑
                        var id = rvs[uk.Name];
                        //if (id != null) entity = GetEntity(fact.EntityType, id) ?? fact.FindByKeyForEdit(id);
                        if (id != null) entity = fact.FindByKeyForEdit(id);
                        if (entity == null) entity = fact.Create();
                    }
                    else if (pks.Length > 0)
                    {
                        // 查询实体对象用于编辑
                        var req = bindingContext.HttpContext.Request.Query;
                        var exp = new WhereExpression();
                        foreach (var item in pks)
                        {
                            var v = req[item.Name].FirstOrDefault();
                            exp &= item.Equal(v.ChangeType(item.Type));
                        }

                        entity = fact.Find(exp);

                        if (entity == null) entity = fact.Create();
                    }

                    if (entity != null)
                    {
                        var fs = bindingContext.HttpContext.Request.Form;
                        // 提前填充动态字段的扩展属性
                        foreach (var item in fact.Fields)
                        {
                            if (item.IsDynamic && fs.ContainsKey(item.Name)) entity.SetItem(item.Name, fs[item.Name]);
                        }

                        return entity;
                    }

                    return fact.Create();
                }
            }

            return base.CreateModel(bindingContext);
        }
    }

    /// <summary>实体模型绑定器提供者，为所有XCode实体类提供实体模型绑定器</summary>
    public class EntityModelBinderProvider : IModelBinderProvider
    {
        /// <summary>获取绑定器</summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public IModelBinder GetBinder(ModelBinderProviderContext context)
        {
            if (context == null) throw new ArgumentNullException(nameof(context));

            if (!context.Metadata.ModelType.As<IEntity>()) return null;

            var propertyBinders = new Dictionary<ModelMetadata, IModelBinder>();
            foreach (var property in context.Metadata.Properties)
            {
                propertyBinders.Add(property, context.CreateBinder(property));
            }

            var loggerFactory = context.Services.GetRequiredService<ILoggerFactory>();
            return new EntityModelBinder(propertyBinders, loggerFactory);
        }

        /// <summary>实例化</summary>
        public EntityModelBinderProvider()
        {
            XTrace.WriteLine("注册实体模型绑定器：{0}", typeof(EntityModelBinderProvider).FullName);
            //ModelBinderProviders.BinderProviders.Add(new EntityModelBinderProvider());
        }
    }
}