///
/// Copyright (c) 2020 Sensus Slovensko a.s.
///
using System;
using Config.Resources;

namespace Config.CalendarEvent
{
    /// <summary>
    /// Enumeration of calendar event actions
    /// </summary>
    public enum AutoAction
    {
        Undefined,
        None,               /// No action at all
        Notification,       /// Trigger a notification event
        Warning,            /// Trigger a warning event
        Error,              /// Trigger an error event and stop test bench function
        FatalErr,           /// Trigger a fatal error and stop test bench function
        InvokeBeforeCycle,  /// Invoke a maintenance procedure before a cycle after entering order number
        InvokeInsideCycle,  /// Invoke conditional tests inside a cycle (if any)
        InvokeAfterCycle,   /// Invoke a maintenance procedure after a cycle after saving results
        BackupData,
        Count,
    }


    /// <summary>
    /// Enumeration of built-in recurring event frequencies
    /// </summary>
    public enum Frequency
    {
        Undefined,
        Once,               /// Indicates that the event is non recurring will occur only one time
        Yearly,             /// Indicates that the event will occur once a year, on the month and day specified
        Monthly,            /// Indicates that the event will occur every month
        Weekly,             /// Indicates that the event will occur every week
        EveryTuTh,          /// Indicates that the event will occur every Tuesday and Thursday
        EveryMoWeFr,        /// Indicates that the event will occur every Mon, Wed and Fri
        EveryWkday,         /// Indicates that the event will occur every week day (Mon - Fri)
        Daily,              /// Indicates that the event will occur every day
        EveryShift,
        Custom,             /// Indicates that the recuring schedule of this event is unique
        Count
    }

    public class Utils
    {
        public static string Action2String(AutoAction action)
        {
            return action.ToString();
        }

        public static AutoAction String2Action(string astr)
        {
            for (AutoAction a = AutoAction.None; a < AutoAction.Count; a++)
            {
                if (Action2String(a) == astr) return a;
            }
            return AutoAction.Undefined;
        }

        public static string Freq2String(Frequency f)
        {
            switch (f)
            {
                case Frequency.Custom:      return Strings.Custom;
                case Frequency.Daily:       return Strings.Daily;
                case Frequency.EveryMoWeFr: return Strings.Every_Mon_Wed_and_Fri;
                case Frequency.EveryTuTh:   return Strings.Every_Tue_and_Thu;
                case Frequency.EveryWkday:  return Strings.Every_Week_Day;
                case Frequency.EveryShift:  return Strings.Every_shift;
                case Frequency.Monthly:     return Strings.Every_Month;
                case Frequency.Once:        return Strings.Once;
                case Frequency.Weekly:      return Strings.Every_week;
                case Frequency.Yearly:      return Strings.Every_year;
                default:                    return string.Empty;
            }
        }

        public static Frequency String2Freq(string fstr)
        {
            for (Frequency f = Frequency.Once; f < Frequency.Count; f++)
            {
                if (Freq2String(f) == fstr) return f;
            }
            return Frequency.Undefined;
        }


        /// <summary>
        /// Determine whether an event date matches given day and time (dt)
        /// (whether an event needs to be rendered on a specific day).
        /// </summary>
        /// <param name="evnt">Calendar event</param>
        /// <param name="dt">Day and time</param>
        /// <returns>true = needs to be rendered</returns>
        public static bool DayMatchesExactly(ICalendarEvent evnt, DateTime dt)
        {
            DayOfWeek dow = dt.DayOfWeek;

            switch (evnt.Frequency)
            {
                case Frequency.EveryShift:  return (dow == DayOfWeek.Sunday && evnt.Date.Hour >= 22) ||
                                                   dow == DayOfWeek.Monday ||
                                                   dow == DayOfWeek.Tuesday ||
                                                   dow == DayOfWeek.Wednesday ||
                                                   dow == DayOfWeek.Thursday ||
                                                   (dow == DayOfWeek.Friday && evnt.Date.Hour < 22);

                case Frequency.Daily:       return true;
                case Frequency.EveryMoWeFr: return (dow == DayOfWeek.Monday) || (dow == DayOfWeek.Wednesday) || (dow == DayOfWeek.Friday);
                case Frequency.EveryTuTh:   return (dow == DayOfWeek.Tuesday) || (dow == DayOfWeek.Thursday);
                case Frequency.EveryWkday:  return (dow != DayOfWeek.Sunday) && (dow != DayOfWeek.Saturday);
                case Frequency.Weekly:      return evnt.Date.DayOfWeek == dow;
                case Frequency.Monthly:     return evnt.Date.Day == dt.Day;
                case Frequency.Yearly:      return evnt.Date.Month == dt.Month && evnt.Date.Day == dt.Day;
                case Frequency.Once:        return evnt.Date.Year == dt.Year && evnt.Date.Month == dt.Month && evnt.Date.Day == dt.Day;
                case Frequency.Custom:      return (evnt.CustomRecurringFunction != null) && evnt.CustomRecurringFunction(evnt, dt);
                default:                    return false;
            }
        }


        public static bool IsCalendarEventTrigerred(ICalendarEvent evnt, DateTime currentDate)
        {
            DateTime evntDT = evnt.AllDay
                            ? new DateTime(evnt.Date.Year, evnt.Date.Month, evnt.Date.Day, 0, 0, 0)
                            : evnt.Date;

            if (evnt.Frequency == Frequency.EveryShift)
            {
                DateTime dt1 = evntDT;
                DateTime dt2 = evntDT + new TimeSpan(8, 0, 0);
                DateTime dt3 = evntDT + new TimeSpan(16, 0, 0);
                return (currentDate >= dt1) || (currentDate >= dt1) || (currentDate >= dt3);
            }
            else if (!evnt.TriggerOnExactDayOnly)
            {
                /// Trigger after event expires
                return (currentDate >= evntDT);
            }
            else
            {
                /// Trigger event on exact date only
                return (currentDate >= evntDT) && DayMatchesExactly(evnt, currentDate);
            }
        }


        /// <summary>
        /// Called to update event.Date after an event was trigerred and a required action was done.
        /// </summary>
        /// <param name="evnt">Calendar event</param>
        /// <param name="currentDate">Current date and time which triggered the event</param>
        /// <returns>true when event.Date was updated</returns>
        public static bool UpdateRecurringDate(ICalendarEvent evnt, DateTime currentDate)
        {
            switch (evnt.Frequency)
            {
                case Frequency.Yearly:
                    do {
                        evnt.Date = evnt.Date.AddYears(1);
                    }
                    while (evnt.Date <= currentDate);
                    return true;

                case Frequency.Monthly:
                    do {
                        evnt.Date = evnt.Date.AddMonths(1);
                    }
                    while (evnt.Date <= currentDate);
                    return true;

                case Frequency.Weekly:
                    do {
                        evnt.Date += new TimeSpan(7, 0, 0, 0);  /// add one week
                    }
                    while (evnt.Date <= currentDate);
                    return true;

                case Frequency.EveryTuTh:
                    do {
                        evnt.Date += new TimeSpan(1, 0, 0, 0);  /// add one day
                    }
                    while ((evnt.Date <= currentDate) || ((evnt.Date.DayOfWeek != DayOfWeek.Tuesday) &&
                                                          (evnt.Date.DayOfWeek != DayOfWeek.Thursday)));
                    return true;

                case Frequency.EveryMoWeFr:
                    do {
                        evnt.Date += new TimeSpan(1, 0, 0, 0);  /// add one day
                    }
                    while ((evnt.Date <= currentDate) || ((currentDate.DayOfWeek != DayOfWeek.Monday) &&
                                                          (currentDate.DayOfWeek != DayOfWeek.Wednesday) &&
                                                          (currentDate.DayOfWeek != DayOfWeek.Friday)));
                    return true;

                case Frequency.EveryWkday:
                    do {
                        evnt.Date += new TimeSpan(1, 0, 0, 0);  /// add one day
                    }
                    while ((evnt.Date <= currentDate) || (currentDate.DayOfWeek == DayOfWeek.Saturday) || (currentDate.DayOfWeek == DayOfWeek.Sunday));
                    return true;

                case Frequency.Daily:
                    do {
                        evnt.Date += new TimeSpan(1, 0, 0, 0);  /// add one day
                    }
                    while (evnt.Date <= currentDate);
                    return true;

                case Frequency.EveryShift:
                    do {
                        evnt.Date += new TimeSpan(8, 0, 0);     /// add eight hours
                    }
                    while (evnt.Date <= currentDate);
                    return true;

                default:
                    /// This is not a recurring calendar event, 'Date' was not updated
                    return false;
            }
        }
    }
}