using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

using BeWo.Data.Entities;
using BeWo.Service.Core;
using BeWo.Service.Interfaces;
using BS.Shared;
using BS.Shared.Extensions;

namespace BeWo.Service.DCEntityMapper
{
	public abstract class AbstractIDCEntityMapper<TEntity, TDC> : IDCEntityMapper<TEntity, TDC>
		where TDC : class, new() where TEntity : BeWoEntityBase, new()
	{
		public bool ConcurrencyCheck(long? pDataContractVersion, BeWoEntityBase pEntity)
		{
			return ServiceLogic.ConcurrencyCheck(pDataContractVersion, pEntity);
		}

		public virtual List<TDC> MapToNewDCs(IEnumerable<TEntity> pEntitys)
		{
			List<TDC> lResult = new List<TDC>();
			if (pEntitys != null)
			{
				foreach (TEntity iEntity in pEntitys)
				{
					lResult.Add(this.MergeWithDC(iEntity, CreateNewDC()));
				}
			}
			return lResult;
		}

		public virtual TDC CreateOrMapToNewDC(TEntity pEntity, bool nullDCOnNullEntity = false)
		{
			if (pEntity is object)
				return MapToNewDC(pEntity);

			if (nullDCOnNullEntity)
				return null;

			return CreateNewDC();
		}
		public virtual TDC MapToNewDC(TEntity pEntity, bool dontCreateNewDConNullEntity)
		{
			if (dontCreateNewDConNullEntity || pEntity is object)
				return MapToNewDC(pEntity);

			return CreateNewDC();
		}
		public virtual TDC MapToNewDC(TEntity pEntity)
		{
			return MergeWithDC(pEntity, CreateNewDC());
		}
		public virtual TDC CreateNewDC()
		{
			return new TDC();
		}

		public virtual List<TEntity> MapToNewEntities(IEnumerable<TDC> pDataContracts)
		{
			List<TEntity> lResult = new List<TEntity>();
			if (pDataContracts != null)
			{
				foreach (TDC iDataContract in pDataContracts)
				{
					lResult.Add(this.MergeWithEntity(iDataContract, new TEntity()));
				}
			}
			return lResult;
		}
		public virtual TEntity MapToNewEntity(TDC pDataContract, bool ignoreNullDC)
		{
			if (ignoreNullDC || pDataContract is object)
				return MergeWithEntity(pDataContract, new TEntity());

			return CreateNewEntity();
		}
		public virtual TEntity MapToNewEntity(TDC pDataContract)
		{
			return MergeWithEntity(pDataContract, new TEntity());
		}
		public virtual TEntity CreateNewEntity()
		{
			return new TEntity();
		}

		public abstract TDC MergeWithDC(TEntity pEntity, TDC pDataContract);

		public virtual void MergeWithEntitys(IList<TDC> pDataContractList, IList<TEntity> pEntityList)
		{
			if (pEntityList.Count == 0 && pDataContractList != null && pDataContractList.Count > 0)
			{
				pEntityList.AddRange(pDataContractList.Select(dc => this.MapToNewEntity(dc)));
				return;
			}

			if (pDataContractList == null || pDataContractList.Count == 0)
			{
				pEntityList.Clear();
				return;
			}

			// remove deleted
			pEntityList.RemoveRange(entity => pDataContractList.Count(dc => this.AreDCAndEntityEqual(dc, entity)) == 0);

			// merge same
			var lToMerge = pEntityList.Select(entity => new { Entity = entity, DataContract = pDataContractList.Single(dc => this.AreDCAndEntityEqual(dc, entity)) });

			foreach (var iToMerge in lToMerge)
			{
				MergeWithEntity(iToMerge.DataContract, iToMerge.Entity);
			}

			// add new
			List<TDC> newList = new List<TDC>();

			foreach (TDC dc in pDataContractList)
			{
				bool isnew = true;
				foreach (TEntity entity in pEntityList)
				{
					if (isnew && AreDCAndEntityEqual(dc, entity))
					{
						isnew = false;
					}
				}
				if (isnew)
					newList.Add(dc);
			}

			foreach (TDC newDC in newList)
			{
				pEntityList.Add(MapToNewEntity(newDC));
			}

			//pEntityList.AddRange(
			//    pDataContractList
			//    .Where(dc => pEntityList
			//        .Count(entity => AreDCAndEntityEqual(dc, entity)) == 0)
			//    .Select(dc => MapToNewEntity(dc))); 

		}
		public virtual TEntity MergeOrCreateWithEntity(TDC pDataContract, TEntity pEntity)
		{
			if (pDataContract is object)
			{
				if (pEntity is null)
					pEntity = CreateNewEntity();

				return MergeWithEntity(pDataContract, pEntity);
			}

			return null;
		}
		public abstract TEntity MergeWithEntity(TDC pDataContract, TEntity pEntity);

		protected abstract bool AreDCAndEntityEqual(TDC pDC, TEntity pEntity);

		// Ausgelagert in AiCore - Kann bei Zeit entfernt werden
		//public virtual Dictionary<string, object> ToJsonDictionary(TDC pDC)
		//{
		//	throw new NotImplementedException("ToJsonDictionary");
		//}

		//public Dictionary<string, object> ToJsonDictionary(TEntity pEntity)
		//{
		//	var dc = MapToNewDC(pEntity);
		//	var dict = ToJsonDictionary(dc);
		//	return dict;
		//}		

		//public IList<Dictionary<string, object>> ToJsonDictionary(IList<TEntity> pEntities)
		//{
		//	var dcs = MapToNewDCs(pEntities);
		//	var dicts = ToJsonDictionary(dcs);
		//	return dicts;
		//}

		//public IList<Dictionary<string, object>> ToJsonDictionary(IList<TDC> pDCs)
		//{
		//	var dicts = new List<Dictionary<string, object>>();

		//	if (pDCs == null)
		//		return dicts;

		//	foreach (var dc in pDCs)
		//		dicts.Add(ToJsonDictionary(dc));

		//	return dicts;
		//}
	}
}