// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
// Foundation. In accordance with Section 7(a) of the GNU AGPL its Section 15 shall be amended
// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
// This program is distributed WITHOUT ANY WARRANTY, without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
//
// You can contact Ascensio System SIA at Lubanas st. 125a-25, Riga, Latvia, EU, LV-1021.
//
// The  interactive user interfaces in modified source and object code versions of the Program must
// display Appropriate Legal Notices, as required under Section 5 of the GNU AGPL version 3.
//
// Pursuant to Section 7(b) of the License you must retain the original Product logo when
// distributing the program. Pursuant to Section 7(e) we decline to grant you any rights under
// trademark law for use of our trademarks.
//
// All the Product's GUI elements, including illustrations and icon sets, as well as technical writing
// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode

namespace ASC.Web.Core.Calendars;

public abstract class BaseCalendar : ICalendar, ICloneable
{
    protected BaseCalendar(AuthContext authContext, TimeZoneConverter timeZoneConverter)
    {
        this.Context = new CalendarContext();
        this.SharingOptions = new SharingOptions();
        AuthContext = authContext;
        TimeZoneConverter = timeZoneConverter;
    }

    #region ICalendar Members

    public virtual string Id { get; set; }

    public virtual string Name { get; set; }

    public virtual string Description { get; set; }

    public virtual Guid OwnerId { get; set; }

    public virtual EventAlertType EventAlertType { get; set; }

    public abstract List<IEvent> LoadEvents(Guid userId, DateTime utcStartDate, DateTime utcEndDate);
    public abstract List<ITodo> LoadTodos(Guid userId, DateTime utcStartDate, DateTime utcEndDate);

    public virtual SharingOptions SharingOptions { get; set; }

    public virtual TimeZoneInfo TimeZone { get; set; }

    public virtual CalendarContext Context { get; set; }
    protected AuthContext AuthContext { get; }
    protected TimeZoneConverter TimeZoneConverter { get; }

    #endregion

    #region ICloneable Members

    public object Clone()
    {
        var cal = (BaseCalendar)this.MemberwiseClone();
        cal.Context = (CalendarContext)this.Context.Clone();
        cal.SharingOptions = (SharingOptions)this.SharingOptions.Clone();
        return cal;
    }

    #endregion

    #region IiCalFormatView Members

    public string ToiCalFormat()
    {
        var sb = new StringBuilder();

        sb.AppendLine("BEGIN:VCALENDAR");
        sb.AppendLine("PRODID:TeamLab Calendar");
        sb.AppendLine("VERSION:2.0");

        sb.AppendLine("METHOD:PUBLISH");
        sb.AppendLine("CALSCALE:GREGORIAN");
        sb.AppendLine($"X-WR-CALNAME:{Name}");
        sb.AppendLine($"X-WR-TIMEZONE:{TimeZoneConverter.WindowsTzId2OlsonTzId(TimeZone.Id)}");
        //tz
        sb.AppendLine("BEGIN:VTIMEZONE");
        sb.AppendLine($"TZID:{TimeZoneConverter.WindowsTzId2OlsonTzId(TimeZone.Id)}");
        sb.AppendLine("END:VTIMEZONE");

        //events
        foreach (var e in LoadEvents(AuthContext.CurrentAccount.ID, DateTime.MinValue, DateTime.MaxValue))
        {
            if (e is BaseEvent && e.GetType().GetCustomAttributes(typeof(AllDayLongUTCAttribute), true).Length == 0)
            {
                (e as BaseEvent).TimeZone = TimeZone;
            }

            sb.AppendLine(e.ToiCalFormat());
        }

        sb.Append("END:VCALENDAR");

        return sb.ToString();
    }

    #endregion
}