using System;
using System.Data.Entity;
using System.Data.Entity.Migrations;
using System.Linq;
using System.Linq.Expressions;
using EntityFramework.Extensions;
using OpenAuth.Domain.Interface;
using Infrastructure;
using OpenAuth.Domain;
using OpenAuth.Repository.Models;

namespace OpenAuth.Repository
{
 public class UnitWork: IUnitWork
 {
 protected OpenAuthDBContext Context = new OpenAuthDBContext();


 /// <summary>
 /// 根据过滤条件,获取记录
 /// </summary>
 /// <param name="exp">The exp.</param>
 public IQueryable<T> Find<T>(Expression<Func<T, bool>> exp = null) where T : class 
 {
 return Filter(exp);
 }

 public bool IsExist<T>(Expression<Func<T, bool>> exp) where T : class
 {
 return Context.Set<T>().Any(exp);
 }

 /// <summary>
 /// 查找单个
 /// </summary>
 public T FindSingle<T>(Expression<Func<T, bool>> exp) where T:class 
 {
 return Context.Set<T>().AsNoTracking().FirstOrDefault(exp);
 }

 /// <summary>
 /// 得到分页记录
 /// </summary>
 /// <param name="pageindex">The pageindex.</param>
 /// <param name="pagesize">The pagesize.</param>
 /// <param name="orderby">排序,格式如:"Id"/"Id descending"</param>
 public IQueryable<T> Find<T>(int pageindex, int pagesize, string orderby = "", Expression<Func<T, bool>> exp = null) where T : class
 {
 if (pageindex < 1) pageindex = 1;
 if (string.IsNullOrEmpty(orderby))
 orderby = "Id descending";

 return Filter(exp).OrderBy(orderby).Skip(pagesize * (pageindex - 1)).Take(pagesize);
 }

 /// <summary>
 /// 根据过滤条件获取记录数
 /// </summary>
 public int GetCount<T>(Expression<Func<T, bool>> exp = null) where T : class
 {
 return Filter(exp).Count();
 }

 public void Add<T>(T entity) where T : Domain.Entity
 {
 entity.Id = Guid.NewGuid();
 Context.Set<T>().Add(entity);
 }

 /// <summary>
 /// 批量添加
 /// </summary>
 /// <param name="entities">The entities.</param>
 public void BatchAdd<T>(T[] entities) where T : Domain.Entity
 {
 foreach (var entity in entities)
 {
 entity.Id = Guid.NewGuid();
 }
 Context.Set<T>().AddRange(entities);
 }

 public void Update<T>(T entity) where T:class
 {
 var entry = this.Context.Entry(entity);
 //todo:如果状态没有任何更改,会报错
 entry.State = EntityState.Modified;

 }

 public void Delete<T>(T entity) where T:class
 {
 Context.Set<T>().Remove(entity);
 }

 /// <summary>
 /// 按指定id更新实体,会更新整个实体
 /// </summary>
 /// <param name="identityExp">The identity exp.</param>
 /// <param name="entity">The entity.</param>
 public void Update<T>(Expression<Func<T, object>> identityExp, T entity) where T:class
 {
 Context.Set<T>().AddOrUpdate(identityExp, entity);
 }

 /// <summary>
 /// 实现按需要只更新部分更新
 /// <para>如:Update(u =>u.Id==1,u =>new User{Name="ok"});</para>
 /// </summary>
 /// <param name="where">The where.</param>
 /// <param name="entity">The entity.</param>
 public void Update<T>(Expression<Func<T, bool>> where, Expression<Func<T, T>> entity) where T:class
 {
 Context.Set<T>().Where(where).Update(entity);
 }

 public virtual void Delete<T>(Expression<Func<T, bool>> exp) where T : class
 {
 Context.Set<T>().Where(exp).Delete();
 }

 public void Save()
 {
 Context.SaveChanges();
 }

 private IQueryable<T> Filter<T>(Expression<Func<T, bool>> exp) where T : class
 {
 var dbSet = Context.Set<T>().AsQueryable();
 if (exp != null)
 dbSet = dbSet.Where(exp);
 return dbSet;
 }

 }
}