using DbConnectionLibrairie;
using Entities;
using ManagerInterfaces;
using Microsoft.EntityFrameworkCore;
using OrderCriterias;
using System.Collections.ObjectModel;

namespace EntityManagers
{
    /// <summary>
    /// a manager for answer entity
    /// </summary>
    public class AnswerEntityManager : IAnswerManager<AnswerEntity>
    {
        private MyDbContext dbContext;

        public int getNbElement()
        {
            return dbContext.Answers.CountAsync().Result;
        }

        public AnswerEntityManager(MyDbContext dbContext)
        {
            this.dbContext = dbContext;
        }

        public AnswerEntity ajouterAnswer(AnswerEntity answer)
        {
            var tmp = dbContext.Answers.Where(a => a.Equals(answer)).FirstOrDefaultAsync().Result;
            if (tmp != null) return tmp;
            dbContext.Answers.Add(answer);
            dbContext.SaveChangesAsync();
            return dbContext.Answers.Where(a => a.Equals(answer)).FirstAsync().Result;
        }

        public IEnumerable<AnswerEntity> getAnswers(int nb, int count, AnswerOrderCriteria orderCriteria = AnswerOrderCriteria.ById)
        {
            if ((nb - 1) * count >= getNbElement()) throw new Exception("too many page skiped");
            if (orderCriteria == AnswerOrderCriteria.ById)
            {
                return dbContext.Answers.OrderBy(a => a.Id).Skip((nb - 1) * count).Take(count).ToListAsync().Result;
            }
            else
            {
                return dbContext.Answers.OrderBy(a => a.Content).Skip((nb - 1) * count).Take(count).ToListAsync().Result;
            }
        }

        private AnswerEntity? getAnswer(long id)
        {
            return dbContext.Answers.Where(a => a.Id == id).FirstOrDefaultAsync().Result;
        }

        public AnswerEntity? modifierAnswer(long id, AnswerEntity answer)
        {
            var tmp = getAnswer(id);
            if (tmp == null) return null;
            tmp.Content = answer.Content;
            dbContext.SaveChangesAsync();
            return tmp;
        }

        public AnswerEntity? supprimerAnswer(long id)
        {
            var tmp = getAnswer(id);
            if (tmp == null) return null;
            dbContext.Answers.Remove(tmp);
            dbContext.SaveChangesAsync();
            return tmp;
        }

        public void supprimerAnswer(AnswerEntity answer)
        {
            dbContext.Answers.Remove(answer);
            dbContext.SaveChangesAsync();
        }

        public ReadOnlyCollection<AnswerEntity>? getAnswersByIdQuestion(long id)
        {
            throw new NotImplementedException();
        }
    }
}