using Microsoft.EntityFrameworkCore;
using System.Collections.Generic;
using System.Transactions;
using System;
using Church.Net.DAL.EF;
using System.Linq;
using Church.Net.Utility;
using System.Threading.Tasks;
using Church.Net.Entity.Interface;
using System.ComponentModel.DataAnnotations;
using System.Reflection;
using static Microsoft.EntityFrameworkCore.DbLoggerCategory;
using System.ComponentModel.DataAnnotations.Schema;
using Microsoft.EntityFrameworkCore.Metadata.Internal;

namespace Church.Net.DAL.EFCoreDBF
{
    public class CombinedKeyCrudDALCBase<T> : ICombinedKeyCrudDAL<T> where T : class, Church.Net.Entity.Interface.ICombinedKeyEntity, new()
    {
        private readonly DatabaseOptions databaseOptions;

        public CombinedKeyCrudDALCBase(DatabaseOptions databaseOptions)
        {  
            this.databaseOptions = databaseOptions;
            InitKeyProperty();
        }
        public IQueryable<T> GetDbSet()
        {
            //var result = (DbSet<T>)typeof(ChurchNetContext).GetMethod("Set").MakeGenericMethod(typeof(T)).Invoke(dbContext, null);

            return databaseOptions.GetDbContext().Set<T>().AsNoTracking();
            //return result;
        }

        public ChurchNetContext GetDbContext()
        {
            //var result = (DbSet<T>)typeof(ChurchNetContext).GetMethod("Set").MakeGenericMethod(typeof(T)).Invoke(dbContext, null);

            return databaseOptions.GetDbContext();//.Set<T>().AsNoTracking();
            //return result;
        }
        public virtual T First(Func<T, bool> filter = null)
        {
            using (var dbContext = GetDbContext())
            {
                return dbContext.Set<T>().Where(filter ?? (s => true)).FirstOrDefault();
            }
        }

        public virtual T GetById(IEnumerable<string> Ids)
        {
            return this.GetQuery(Ids).FirstOrDefault();
        }

        //public virtual T GetByRefndx(string refndx)
        //{
        //    return MapDBModelToEntity(GetFirstDBModelByRefndx<ST>(refndx, this.actionScreen));
        //}

        public virtual IEnumerable<T> GetAll(Func<T, bool> filter = null)
        {
            //var dbObjs = GetDbSet().ToArray();

            //IEnumerable<T> list = GetDbSet().Where(filter ?? (s => true)).ToList();

            return GetDbSet().AsNoTracking().Where(filter ?? (s => true)).ToList();
        }

        public virtual int Create(T entity)
        {
            this.CheckCombinedKeyIsEmpty(entity);
            this.ConvertUTCTime(entity);

            using (var dbContext = GetDbContext())
            {
                dbContext.Add(entity);

                return dbContext.SaveChanges();
            }
        }
        public virtual Task<int> CreateAsync(T entity)
        {
            this.CheckCombinedKeyIsEmpty(entity);
            this.ConvertUTCTime(entity);
            using (var dbContext = GetDbContext())
            {
                dbContext.Add(entity);

                //CreateDone(entity, newDbObj);
                return dbContext.SaveChangesAsync();
            }
        }


        public int CreateOrUpdate(T entity)
        {
            int result = 0;
            this.ConvertUTCTime(entity);
            if (CheckExist(entity))
            {
                result = this.Update(entity);
            }
            else
            {
                result = this.Create(entity);
            }
            return result;
        }

        public virtual int Update(T entity)
        {

            //if (!this.CheckExist(entity))
            //{
            //    throw new ArgumentNullException("the Id is not exist.");
            //}
            this.ConvertUTCTime(entity);

            using (var dbContext = GetDbContext())
            {
                dbContext.Update(entity);

                return dbContext.SaveChanges();
            }


        }
        public virtual void CreateDone(T entity)
        {

        }
        public virtual void UpdateDone(T entity)
        {

        }

        public virtual int UpdateRange(IEnumerable<T> entities)
        {
            using (var dbContext = GetDbContext())
            {
                dbContext.UpdateRange(entities);

                return dbContext.SaveChanges();
            }
        }

        public virtual int Delete(T obj)
        {
            using (var dbContext = GetDbContext())
            {
                dbContext.Remove(obj);
                return dbContext.SaveChanges();
            }
        }

        public virtual int Delete(IEnumerable<string> combinedKeyIds)
        {
            var obj = this.GetById(combinedKeyIds);
            return obj == null ? this.Delete(obj) : 0;
        }

        public int Delete(Func<T, bool> filter)
        {
            var list = GetDbSet().Where(filter).ToList();
            using (var dbContext = GetDbContext())
            {
                foreach (var item in list)
                {
                    dbContext.Remove(item);
                }
                return dbContext.SaveChanges();
            }
        }

        public virtual bool CheckExist(T obj)
        {
            //var query = GetDbSet().AsQueryable();
            var query = GetAll();
            List<PropertyInfo> props = new List<PropertyInfo>();
            for (int i = 0; i < keyProps.Count; i++)
            {
                var prop = keyProps[i];
                props.Add(prop);
                var value = prop.GetValue(obj)?.ToString();
                query = query.Where(e => prop.GetValue(e)?.ToString() == value).ToList();
            }

            return query.Any();
        }

        private void ConvertUTCTime(T entity)
        {

            var props = typeof(T).GetProperties();
            foreach (var prop in props)
            {
                if (prop.PropertyType == typeof(DateTime))
                {
                    //do stuff like prop.SetValue(t, DateTime.Now, null);
                    DateTime utcTime = ((DateTime)prop.GetValue(entity)).ToUniversalTime();
                    prop.SetValue(entity, utcTime, null);

                }
            }
        }

        private List<PropertyInfo> keyProps;

        private void InitKeyProperty()
        {
            keyProps = typeof(T).GetProperties().Where(
                prop => Attribute.IsDefined(prop, typeof(KeyAttribute))).OrderBy(prop =>
                prop.GetCustomAttribute<ColumnAttribute>().Order
                )
                .ToList();

        }

        private IQueryable<T> GetQuery(IEnumerable<string> Ids)
        {
            using (var dbContext = GetDbContext())
            {
                var query = dbContext.Set<T>().AsQueryable();

                for (int i = 0; i < keyProps.Count; i++)
                {
                    query = query.Where(e => keyProps[i].GetValue(e).ToString() == Ids.ElementAt(i));
                }
                return query;
            }
        }
        private void CheckCombinedKeyIsEmpty(T entity)
        {
            for (int i = 0; i < keyProps.Count; i++)
            {
                if (string.IsNullOrEmpty(keyProps[i].GetValue(entity)?.ToString()))
                {
                    throw new Exception($"Combined Key [{keyProps[i].Name}] not defined!");
                }
            }
        }
    }


}