using ForumContracts.BindingModels;
using ForumContracts.SearchModels;
using ForumContracts.StorageContracts;
using ForumContracts.ViewModels;
using ForumDatabaseImplement.Models;
using MongoDB.Bson;
using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ForumMongoDataBase.Implements
{
	public class AnswerStorage : IAnswerStorage
	{
		private readonly IMongoCollection<Answer> _collection;
		public MongoClient context;

		public AnswerStorage()
		{
			context = ForumMongoDataBase.getInstance().client;
			_collection = context.GetDatabase("forum").GetCollection<Answer>("answers");
		}

		public AnswerViewModel? Delete(AnswerBindingModel model)
		{
			var filter = Builders<Answer>.Filter.Eq(a => a.Id, model.Id);
			var answer = _collection.FindOneAndDelete(filter);

			if (answer == null)
			{
				return null;
			}

			return answer.GetViewModel();
		}

		public AnswerViewModel? GetElement(AnswerSearchModel model)
		{
			if (!model.Id.HasValue)
			{
				return null;
			}

			var answer = _collection.Find(a => a.Id == model.Id.Value)
									 .FirstOrDefault();

			if (answer == null)
			{
				return null;
			}

			return answer.GetViewModel();
		}

		public List<AnswerViewModel> GetFilteredList(AnswerSearchModel model)
		{
			var filter = Builders<Answer>.Filter.Empty;

			if (model.Id.HasValue)
			{
				filter &= Builders<Answer>.Filter.Eq(a => a.Id, model.Id.Value);
			}

			if (model.QuestionId.HasValue)
			{
				filter &= Builders<Answer>.Filter.Eq(a => a.QuestionId, model.QuestionId.Value);
			}
			else
			{
				return new List<AnswerViewModel>();
			}

			var answers = _collection.Find(filter)
									 .ToList()
									 .Select(a => a.GetViewModel())
									 .ToList();

			return answers;
		}

		public List<AnswerViewModel> GetFullList()
		{
			var answers = _collection.Find(_ => true)
									 .ToList()
									 .Select(a => a.GetViewModel())
									 .ToList();

			return answers;
		}

		public AnswerViewModel? Insert(AnswerBindingModel model)
		{
			var answer = Answer.Create(model);

			if (answer == null)
			{
				return null;
			}

			_collection.InsertOne(answer);

			return answer.GetViewModel();
		}

		public AnswerViewModel? Update(AnswerBindingModel model)
		{
			var filter = Builders<Answer>.Filter.Eq(a => a.Id, model.Id);
			var answer = _collection.Find(filter).FirstOrDefault();

			answer.Update(model);
			_collection.ReplaceOne(filter, answer);

			return answer.GetViewModel();
		}
	}
}