using DW5S.Entity;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;

namespace DW5S.Repostory
{
    public interface IRepository<T> where T : BaseEntity
    {
        IQueryable<T> AsQueryable();
        Task<T> GetByIdAsync(object id);
        Task<IEnumerable<T>> GetAllAsync();
        Task<IEnumerable<T>> GetAllAsync<TKey>(Expression<Func<T, TKey>> keySelector = null, bool asc = true);
        Task<IEnumerable<T>> FindAsync(Expression<Func<T, bool>> predicate);
        Task<IEnumerable<T>> FindAsync<TKey>(Expression<Func<T, bool>> predicate, Expression<Func<T, TKey>> keySelector = null, bool asc = true);
        Task<IEnumerable<Res>> GetDistinctAsync<Res>(Expression<Func<T, Res>> selector);

        Task<T> FirstOrDefaultAsync(Expression<Func<T, bool>> predicate = null);
        Task<T> AddOrUpdateAsync(T entity);
        Task AddOrUpdateAsync(IEnumerable<T> entitis);

        /// <summary>
        /// 修改某些字段
        /// </summary>
        /// <typeparam name="TProperty"></typeparam>
        /// <param name="predicate"></param>
        /// <param name="propertyExpression"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        Task<int> UpdatePropAsync<TProperty>(Expression<Func<T, bool>> predicate, Func<T, TProperty> propertyExpression, TProperty value);


        Task<int> DeleteAsync(T entity);
        Task<int> DeleteAsync(IEnumerable<T> entitis);

        Task<int> DeleteAsync(Expression<Func<T, bool>> predicate = null);

        Task<bool> AnyAsync(Expression<Func<T, bool>> predicate = null);

        T MaxBy<TResult>(Expression<Func<T, TResult>> selector, Expression<Func<T, bool>> predicate = null);
    }

    public class Repository<T> : IRepository<T> where T : BaseEntity
    {
        protected readonly OracleContext ctx;
        protected readonly DbSet<T> dbSet;

        public Repository(OracleContext ctx)
        {
            this.ctx = ctx;
            this.dbSet = ctx.Set<T>();
        }
        public IQueryable<T> AsQueryable()
        {
            return dbSet.AsQueryable();
        }
        public async Task<T> GetByIdAsync(object id)
        {
            return await dbSet.FindAsync(id);
        }
        public async Task<IEnumerable<T>> GetAllAsync()
        {
            return await dbSet.ToListAsync();
        }

        public async Task<IEnumerable<T>> GetAllAsync<TKey>(Expression<Func<T, TKey>> keySelector = null, bool asc = true)
        {
            if (keySelector == null)
            {
                return await dbSet.ToListAsync();
            }
            else
            {
                if (asc)
                    return await dbSet.OrderBy(keySelector).ToListAsync();
                else
                    return await dbSet.OrderByDescending(keySelector).ToListAsync();

            }
        }

        public async Task<IEnumerable<T>> FindAsync(Expression<Func<T, bool>> predicate)
        {
            return await dbSet.Where(predicate).ToListAsync();
        }
        public async Task<IEnumerable<T>> FindAsync<TKey>(Expression<Func<T, bool>> predicate, Expression<Func<T, TKey>> keySelector = null, bool asc = true)
        {
            if (keySelector == null)
            {
                return await dbSet.Where(predicate).ToListAsync();
            }
            else
            {
                if (asc)
                    return await dbSet.Where(predicate).OrderBy(keySelector).ToListAsync();
                else
                    return await dbSet.Where(predicate).OrderByDescending(keySelector).ToListAsync();

            }
        }
        public async Task<T> FirstOrDefaultAsync(Expression<Func<T, bool>> predicate = null)
        {
            if (predicate != null)
                return await dbSet.Where(predicate).FirstOrDefaultAsync();
            return await dbSet.FirstOrDefaultAsync();
        }

        public async Task<IEnumerable<Res>> GetDistinctAsync<Res>(Expression<Func<T, Res>> selector)
        {
            var res = await dbSet.Select(selector).Distinct().ToListAsync();
            return res;
        }

        public async Task AddOrUpdateAsync(IEnumerable<T> entity)
        {
            if (entity.First().Id == 0)
            {
                foreach (var item in entity)
                {
                    item.CreateTime = DateTime.Now;
                    item.UpdateTime= DateTime.Now;  
                }
                await dbSet.AddRangeAsync(entity);
            }
            else
            {
                foreach (var item in entity)
                {
                    item.UpdateTime = DateTime.Now;
                }
                dbSet.UpdateRange(entity);
            }
        }

        public async Task<T> AddOrUpdateAsync(T entity)
        {
            if (entity.Id == 0)
            {
                var res = await dbSet.AddAsync(entity);
                return res.Entity;
            }
            else
            {
                var res = dbSet.Update(entity);
                return res.Entity;
            }
        }

        public async Task<int> DeleteAsync(T entity)
        {
            return await dbSet.Where(p => p.Id == entity.Id).ExecuteDeleteAsync();
        }

        public async Task<int> DeleteAsync(IEnumerable<T> entities)
        {
            var ids = entities.Select(p => p.Id);
            return await DeleteAsync(p => ids.Contains(p.Id));
        }

        public async Task<int> DeleteAsync(Expression<Func<T, bool>> predicate = null)
        {
            return await dbSet.Where(predicate).ExecuteDeleteAsync();
        }

        public async Task<bool> AnyAsync(Expression<Func<T, bool>> predicate = null)
        {
            return await dbSet.AnyAsync(predicate);
        }

        public T MaxBy<TResult>(Expression<Func<T, TResult>> selector, Expression<Func<T, bool>> predicate = null)
        {
            if (predicate == null)
                return dbSet.MaxBy(selector);
            else
                return dbSet.Where(predicate).MaxBy(selector);
        }

        
        public async Task<int> UpdatePropAsync<TProperty>(Expression<Func<T, bool>> predicate, Func<T, TProperty> propertyExpression, TProperty value)
        {
            return await dbSet.Where(predicate)
                .ExecuteUpdateAsync(setters => setters.SetProperty(propertyExpression, value));
        }
    }
}