namespace customTypes
{
    /// <summary>
    /// gRPC送信用Date
    /// SqlServerのDate型対応
    /// </summary>
    public partial class Date
    {
        public static readonly int MinValue = 10000101;
        public static readonly DateTime MinDate = DateTime.Parse("1000/01/01");
        public static readonly Date Default = new Date(0);

        /// <summary>
        /// 利用情報のプライマリーキー：1901/01/01
        /// </summary>
        public static readonly Date MinUseDate = new Date(19010101);  

        public Date(int val)
        {
            Value = val;
        }

        public Date(string val)
        {
            Value = int.Parse(val.Replace("/", string.Empty).Replace("-", string.Empty));
        }

        /// <summary>
        /// 暗然変換
        /// DateTime = Date
        /// </summary>
        /// <param name="grpcDecimal"></param>
        public static implicit operator DateTime(Date grpcDate)
        {
            try
            {
                if (grpcDate.Value <= MinValue) { return MinDate; }
                string date = grpcDate.Value.ToString();
                int year = System.Convert.ToInt32(date.Substring(0, 4));
                int mon = System.Convert.ToInt32(date.Substring(4, 2));
                int day = System.Convert.ToInt32(date.Substring(6, 2));
                return new DateTime(year, mon, day);
            }
            catch
            {
                return MinDate;
            }
        }

        /// <summary>
        /// 暗然変換
        /// Date = DateTime
        /// </summary>
        /// <param name="value"></param>
        public static implicit operator Date(DateTime value)
        {
            return new Date(int.Parse(value.ToString("yyyyMMdd")));
        }

        /// <summary>
        /// 比較
        /// </summary>
        /// <param name="val"></param>
        /// <returns></returns>
        public int CompareTo(Date val)
        {
            DateTime self = this;
            DateTime inVal = val;
            return self.CompareTo(inVal);
        }

        /// <summary>
        /// c#基本型の値を返す
        /// </summary>
        /// <returns></returns>
        public DateTime ToDateTime()
        {
            DateTime self = this;
            return self;
        }

        /// <summary>
        /// 文字列
        /// </summary>
        /// <returns></returns>
        public string ToText(string format = "yyyy/MM/dd")
        {
            DateTime self = this;
            if (format.Length > 0) { return self.ToString(format); }
            return self.ToString();
        }

        /// <summary>
        /// SQL文の値セット
        /// </summary>
        /// <returns></returns>
        public string ToSqlValue()
        {
            DateTime self = this;
            return Value <= MinValue || self.CompareTo(MinDate) <= 0 ? "NULL" : $"'{self.ToString("yyyy/MM/dd")}'"; 
        }

        /// <summary>
        /// 日付の±
        /// </summary>
        /// <param name="day"></param>
        /// <returns></returns>
        public Date Add(int day)
        {
            DateTime self = this;
            Date date = self.AddDays((double)day);
            return date;
        }

        /// <summary>
        /// 日付引く
        /// </summary>
        /// <param name="beginDate"></param>
        /// <returns></returns>
        public int Subtract(Date beginDate)
        {
            DateTime end = this;
            DateTime begin = beginDate;
            TimeSpan ts = end - begin;
            return ts.Days;
        }
    }
}