using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Model
{
    public class Question
    {
        /// <summary>
        /// represent a mathematical question
        /// attributes :
        ///     id : identifier of the question in the database
        ///     content : the content of the question
        ///     difficulty : difficulty (between 1 and 3 included) of the question
        ///     nbFails : number of time that people fail on this question
        ///     idChapter : identifier of the chapter of the question
        ///     idAnswerGood : identifier of the right answer to this question
        ///     chapter : the chapter of the question
        ///     answerGood : the right answer to this question
        /// </summary>
        private int id;
        private string? content;
        private int difficulty;
        private int nbFalls;
        private int idChapter;
        private int idAnswerGood;
        private Chapter? chapter;
        private Answer? answerGood;

        public int? Id
        {
            get => id == -1 ? null : id;
            private set { id = value == null || value < -1 ? -1 : value.Value; }
        }
        public string Content
        {
            get => content == null ? "" : content;
            set { content = value == "" ? null : value;}
        }
        public int Difficulty
        {
            get => difficulty;
            set { difficulty = value < 0 ? 0 : value; }
        }
        public int NbFalls
        {
            get => nbFalls;
            set { nbFalls = value < 0 ? 0 : value; }
        }
        public int? IdChapter
        {
            get => idChapter == -1 ? null : idChapter;
            private set { idChapter = value == null || value < -1 ? -1 : value.Value; }
        }
        public int? IdAnswerGood
        {
            get => idAnswerGood == -1 ? null : idAnswerGood;
            set { idAnswerGood = value == null || value < -1 ? -1 : value.Value; }
        }

        public Chapter? Chapter
        {
            get => chapter;
            set { chapter = value; IdChapter = value == null ? -1 : value.Id; }
        }

        public Answer? AnswerGood
        {
            get => answerGood;
            set { answerGood = value; IdAnswerGood = value == null ? -1 : value.Id; }
        }

        public Question(string content, Chapter? chapter = null, int id = -1, Answer? answerGood = null)
        {
            Id = id;
            Content = content;
            Difficulty = 1;
            NbFalls = 0;
            Chapter = chapter;
            AnswerGood = answerGood;
        }
    }
}