using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;
using EnVisage.Models;

namespace EnVisage.Code.BLL
{
    public class VacationManager : ManagerBase<Vacation, VacationModel>
    {
        public VacationManager(EnVisageEntities dbContext)
            : base(dbContext)
        {
        }

        protected override Vacation InitInstance()
        {
            return new Vacation { Id = Guid.NewGuid() };
        }

        protected override Vacation RetrieveReadOnlyById(Guid key)
        {
            return DataTable.AsNoTracking().FirstOrDefault(t => t.Id == key);
        }

        public override DbSet<Vacation> DataTable
        {
            get
            {
                return DbContext.Vacations;
            }
        }

        public override Vacation Save(VacationModel model)
        {
            if (!model.StartDate.HasValue)
                throw new ArgumentNullException("model.StartDate");
            if (!model.EndDate.HasValue)
                throw new ArgumentNullException("model.EndDate");

            var obj = base.Save(model);

            #region Save PeopleResourceVacations
            if (!Guid.Empty.Equals(model.Id))
            {
                var items2Delete = DbContext.PeopleResourceVacations.Where(t => t.VacationId == model.Id);
                foreach (var peopleResourceVacation in items2Delete)
                {
                    DbContext.Entry(peopleResourceVacation).State = EntityState.Deleted;
                }
            }
            var weekEndingSetting = DbContext.SystemSettings.FirstOrDefault(t => t.Type == (int)SystemSettingType.FiscalCalendarWeekEnding);
            var weekEndingDay = weekEndingSetting != null
                                    ? (DayOfWeek)Convert.ToInt16(weekEndingSetting.Value)
                                    : DayOfWeek.Saturday;
            var weekEndingDate = model.StartDate.Value;
            if (weekEndingDate.DayOfWeek != weekEndingDay)
                weekEndingDate = Utils.GetNextDateByWeekDate(weekEndingDate, (short)weekEndingDay, 1, true);
            var rangeEndDate = model.EndDate.Value;
            if (rangeEndDate.DayOfWeek != weekEndingDay)
                rangeEndDate = Utils.GetNextDateByWeekDate(rangeEndDate, (short)weekEndingDay, 1, true);
            var dt = weekEndingDate.AddDays(-6);
            var businessDays = 0;
            var wkEndDts = 0; 
            while (dt <= rangeEndDate)
            {
                if (dt > weekEndingDate)
                {
                    var hoursOff = Convert.ToInt32(businessDays * model.UOMValue * model.HoursOff / ((7 - wkEndDts) * 100));
                    if (hoursOff > 0)
                    {
                        DbContext.PeopleResourceVacations.Add(new PeopleResourceVacation
                        {
                            Id = Guid.NewGuid(),
                            VacationId = obj.Id,
                            WeekEndingDate = weekEndingDate,
                            HoursOff = hoursOff,
                            LastUpdate = DateTime.Now,
                            PeopleResourceId = model.PeopleResourceId
                        });
                    }
                    weekEndingDate = weekEndingDate.AddDays(7);
                    businessDays = 0;
                    wkEndDts = 0;
                }
                if (model.StartDate.Value <= dt && dt <= model.EndDate.Value)
                    businessDays++;
                if (model.Weekends.Any(t => dt == t))
                {
                    wkEndDts++;
                    if (model.StartDate.Value <= dt && dt <= model.EndDate.Value)
                        businessDays--;
                }
                dt = dt.AddDays(1);
            }
            if (wkEndDts != 7)
            {
                var hoursOff = Convert.ToInt32(businessDays * model.UOMValue * model.HoursOff / ((7 - wkEndDts) * 100));
                if (hoursOff > 0)
                {
                    DbContext.PeopleResourceVacations.Add(new PeopleResourceVacation
                    {
                        Id = Guid.NewGuid(),
                        VacationId = obj.Id,
                        WeekEndingDate = weekEndingDate,
                        HoursOff = hoursOff,
                        LastUpdate = DateTime.Now,
                        PeopleResourceId = model.PeopleResourceId
                    });
                }
            }
            #endregion
            
            return obj;
        }

        public static List<VacationModel> GetVacations(Guid peopleResourceId)
        {
            if (Guid.Empty.Equals(peopleResourceId))
                return null;
            var vacations = new Dictionary<Guid, VacationModel>();
            var prevDate = DateTime.MinValue;
            VacationModel item = null;
            using (var db = new EnVisageEntities())
            {
                var uomValue = (from p in db.PeopleResources
                                join ec in db.ExpenditureCategory on p.ExpenditureCategoryId equals ec.Id
                                join uom in db.UOMs on ec.UOMId equals uom.Id
                                where p.Id == peopleResourceId
                                select new {uom.Id, uom.UOMValue}).FirstOrDefault();
                if (uomValue == null || uomValue.UOMValue == 0)
                    throw new UOMNotExistsException();

                var records = (from v in db.Vacations
                               join prv in db.PeopleResourceVacations on v.Id equals prv.VacationId into g
                               from sub in g.DefaultIfEmpty()
                               where v.PeopleResourceId == peopleResourceId
                               select
                                   new
                                       {
                                           v.Id,
                                           v.StartDate,
                                           v.EndDate,
                                           itemId = sub == null ? (Guid?)null : sub.Id,
                                           HoursOff = sub == null ? (int?)null : sub.HoursOff,
                                           WeekEndingDate = sub == null ? (DateTime?)null : sub.WeekEndingDate,
                                           LastUpdate = sub == null ? (DateTime?)null : sub.LastUpdate
                                       });
                foreach (var vacation in records.OrderBy(o => o.WeekEndingDate))
                {
                    if (!vacations.ContainsKey(vacation.Id))
                    {
                        item = new VacationModel
                        {
                            Id = vacation.Id,
                            StartDate = vacation.StartDate,
                            EndDate = vacation.EndDate,
                            PeopleResourceId = peopleResourceId,
                            UOMValue = uomValue.UOMValue
                        };
                        vacations.Add(item.Id, item);
                    }

                    if (vacation.itemId.HasValue)
                    {
                        item.PeopleResourceVacations.Add(new PeopleResourceVacationModel
                        {
                            Id = vacation.itemId.Value,
                            WeekEndingDate = vacation.WeekEndingDate.Value,
                            HoursOff = vacation.HoursOff.Value,
                            LastUpdate = vacation.LastUpdate.Value,
                            PeopleResourceId = peopleResourceId
                        });
                    }
                }
            }
            return vacations.Values.ToList();
        }
    }
}