using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Comal.Classes;
using InABox.Core;

namespace Comal.Stores
{
    internal class LeaveRequestStore : BaseStore<LeaveRequest>
    {
        private void UpdateAssignments(IEnumerable<LeaveRequest> entities)
        {
            var empids = entities.Select(x => x.EmployeeLink.ID).ToArray();
            var ids = entities.Select(x => x.ID).ToArray();

            var empquery = Task.Run(() =>
            {
                return Provider.Query(
                    new Filter<Employee>(x => x.ID).InList(empids),
                    new Columns<Employee>(x => x.ID, x => x.UsualStart, x => x.UsualFinish)
                );
            });

            var assquery = Task.Run(() =>
            {
                return Provider.Query(
                    new Filter<Assignment>(x => x.LeaveRequestLink.ID).InList(ids),
                    new Columns<Assignment>(x => x.ID, x => x.LeaveRequestLink.ID, x => x.Date)
                );
            });

            var timequery = Task.Run(() =>
            {
                return Provider.Query(
                    new Filter<TimeSheet>(x => x.LeaveRequestLink.ID).InList(ids),
                    new Columns<TimeSheet>(x => x.ID, x => x.LeaveRequestLink.ID, x => x.Date)
                );
            });

            Task.WaitAll(empquery, assquery, timequery);

            var assignments = assquery.Result;
            var timesheets = timequery.Result;
            var employees = empquery.Result;

            var Updates = new Dictionary<TimeSheet, Assignment>();

            foreach (var entity in entities)
            {
                var emp = employees.Rows.FirstOrDefault(x => x.Get<Employee, Guid>(c => c.ID).Equals(entity.EmployeeLink.ID))?.ToObject<Employee>();
                var normalStart = emp != null && emp.UsualStart.Ticks > 0 ? emp.UsualStart : new TimeSpan(8, 0, 0);
                var normalFinish = emp != null && emp.UsualFinish.Ticks > 0 ? emp.UsualFinish : normalStart.Add(new TimeSpan(8, 30, 0));

                var leavedays = new List<LeaveDay>();
                if (entity.Status == LeaveRequestStatus.Approved)
                    for (var date = entity.From; date <= entity.To; date = date.AddDays(1))
                        if (date.DayOfWeek != DayOfWeek.Saturday && date.DayOfWeek != DayOfWeek.Sunday)
                        {
                            var start = date == entity.From && entity.FromTime > normalStart ? entity.FromTime : normalStart;
                            var finish = date == entity.To && entity.ToTime < normalFinish ? entity.ToTime : normalFinish;
                            leavedays.Add(new LeaveDay(date, start, finish));
                        }

                var approval = DateTime.Now;
                var note = string.Format("{0}\nApproved on {1:dd MMM yy} by {2}", entity.Notes, approval, entity.LastUpdateBy);

                foreach (var leaveday in leavedays)
                {
                    var assignment = new Assignment();
                    var assrow = assignments.Rows.FirstOrDefault(r =>
                        r.Get<Assignment, Guid>(c => c.LeaveRequestLink.ID) == entity.ID &&
                        r.Get<Assignment, DateTime>(c => c.Date) == leaveday.Date);

                    if (assrow != null)
                    {
                        // Don't Delete this Assignment!
                        assignments.Rows.Remove(assrow);
                        assignment.ID = assrow.Get<Assignment, Guid>(c => c.ID);
                        //assignment.CommitChanges();
                    }

                    assignment.EmployeeLink.ID = entity.EmployeeLink.ID;
                    assignment.Date = leaveday.Date;
                    assignment.Start = leaveday.Start;
                    assignment.Finish = leaveday.Finish;
                    assignment.Duration = leaveday.Finish - leaveday.Start;
                    assignment.ActivityLink.ID = entity.LeaveType.ID;
                    assignment.Description = note;
                    assignment.Completed = approval;
                    assignment.LeaveRequestLink.ID = entity.ID;

                    var timesheet = new TimeSheet();
                    var timerow = timesheets.Rows.FirstOrDefault(r =>
                        r.Get<TimeSheet, Guid>(c => c.LeaveRequestLink.ID) == entity.ID && r.Get<TimeSheet, DateTime>(c => c.Date) == leaveday.Date);
                    if (timerow != null)
                    {
                        // Don't Delete this Timesheet!
                        timesheets.Rows.Remove(timerow);
                        timesheet.ID = timerow.Get<TimeSheet, Guid>(c => c.ID);
                        //timesheet.CommitChanges();
                    }

                    timesheet.EmployeeLink.ID = entity.EmployeeLink.ID;
                    timesheet.Date = leaveday.Date;
                    timesheet.Start = leaveday.Start;
                    timesheet.Finish = leaveday.Finish;
                    timesheet.Duration = leaveday.Finish - leaveday.Start;
                    timesheet.ActivityLink.ID = entity.LeaveType.ID;
                    timesheet.Approved = approval;
                    timesheet.ApprovedStart = leaveday.Start;
                    timesheet.ApprovedFinish = leaveday.Finish;
                    timesheet.ApprovedDuration = leaveday.Finish - leaveday.Start;
                    timesheet.Notes = note;
                    timesheet.Confirmed = approval;
                    timesheet.LeaveRequestLink.ID = entity.ID;

                    Updates[timesheet] = assignment;
                }
            }

            var AssignmentsToDelete = new List<Assignment>();
            foreach (var row in assignments.Rows)
                AssignmentsToDelete.Add(new Assignment { ID = row.Get<Assignment, Guid>(x => x.ID) });
            Provider.Delete(AssignmentsToDelete, UserID);

            var TimeSheetsToDelete = new List<TimeSheet>();
            foreach (var row in timesheets.Rows)
                TimeSheetsToDelete.Add(new TimeSheet { ID = row.Get<TimeSheet, Guid>(x => x.ID) });
            Provider.Delete(TimeSheetsToDelete, UserID);

            Provider.Save(Updates.Keys.Where(x => x.IsChanged()));
            foreach (var update in Updates)
                update.Value.TimeSheetLink.ID = update.Key.ID;

            Provider.Save(Updates.Values.Where(x => x.IsChanged()));


            #region Old Code

            //Filter<Assignment> assfilter = new Filter<Assignment>(x => x.LeaveRequestLink.ID).IsEqualTo(entity.ID);
            //assfilter.Ors.Add(new Filter<Assignment>(x => x.Date).IsGreaterThanOrEqualTo(entity.From)
            //    .And(x => x.Date).IsLessThanOrEqualTo(entity.To)
            //    .And(x=>x.EmployeeLink.ID).IsEqualTo(entity.EmployeeLink.ID)
            //);
            //List<Assignment> assignments = assStore.Load(assfilter).ToList();
            //Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: {0} Assignments Found", assignments.Count));

            //List<Assignment> deletes = new List<Assignment>();
            //List<Tuple<TimeSheet, Assignment>> updates = new List<Tuple<TimeSheet, Assignment>>();

            //if (entity.Approved == DateTime.MinValue)
            //{
            //    // Clear Out All Assignments / Timesheets for Unapproved Requests
            //    foreach (var unapproved in assignments.Where(x => x.LeaveRequestLink.ID.Equals(entity.ID)))
            //        deletes.Add(unapproved);
            //}
            //else
            //{


            //    TimeSpan normalDuration = normalFinish - normalStart;
            //    Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: Normal Duration is {0} hours", normalDuration.TotalHours));

            //    // Clear out any existing assignments / timesheets that fall outside the requested dates
            //    foreach (var excluded in assignments.Where(x => (x.LeaveRequestLink.ID == entity.ID) && ((x.Date.Date < entity.From.Date) || (x.Date.Date > entity.To.Date))))
            //        deletes.Add(excluded);

            //    Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: Scanning from {0} to {1}", entity.From, entity.To));

            //    DateTime date = entity.From;
            //    while (date <= entity.To)
            //    {
            //        Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: Scanning {0}", date));

            //        if ((date.DayOfWeek != DayOfWeek.Saturday) && (date.DayOfWeek != DayOfWeek.Sunday))
            //        {

            //            var current = assignments.FirstOrDefault(x => x.Date.Date.Equals(date) && x.LeaveRequestLink.ID.Equals(entity.ID));

            //            // Are there any other assignments for the current day
            //            var others = assignments.Where(x => x.Date.Date.Equals(date) && !x.LeaveRequestLink.ID.Equals(entity.ID));

            //            TimeSpan start = date.Equals(entity.From) ? entity.FromTime > normalStart ? entity.FromTime : normalStart : normalStart;
            //            TimeSpan balance = (date.Equals(entity.To) ? (entity.ToTime < normalFinish ? entity.ToTime : normalFinish) : normalFinish) - start;
            //            Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: Starting Balance is {0}", balance.TotalHours));

            //            foreach (var other in others)
            //            {
            //                TimeSpan otherdur = other.Duration;
            //                DateTime otherdate = other.Date;
            //                if (otherdate.TimeOfDay.Add(otherdur) > start)
            //                    start = otherdate.TimeOfDay.Add(otherdur);
            //                balance = balance.Subtract(otherdur);
            //            }

            //            Logger.Send(LogType.Information, UserID, String.Format("* LeaveRequest: Finishing Balance is {0}", balance.TotalHours));

            //            if (balance.Ticks <= 0L)                            
            //            {
            //                // If the day is already fully assigned, skip or delete it
            //                if (current != null)
            //                    deletes.Add(current);
            //            }
            //            else
            //            { 

            //                if (current == null)
            //                {
            //                    current = new Assignment();
            //                    current.LeaveRequestLink.ID = entity.ID;
            //                    current.Date = date;
            //                    current.Description = String.Format("Leave Request Approved on {0:dd MMM yy HH:mm}", entity.Approved);
            //                    assignments.Add(current);
            //                }

            //                current.ActivityLink.ID = entity.LeaveType.ID;
            //                current.EmployeeLink.ID = entity.EmployeeLink.ID;
            //                current.Date = date;
            //                current.Start = start;
            //                current.Duration = balance;

            //                TimeSheet ts = FindSubStore<TimeSheet>().Load(new Filter<TimeSheet>(x => x.ID).IsEqualTo(current.TimeSheetLink.ID)).FirstOrDefault();
            //                if (ts == null)
            //                    ts = new TimeSheet();
            //                ts.EmployeeLink.ID = current.EmployeeLink.ID;
            //                ts.JobLink.ID = current.JobLink.ID;
            //                ts.ActivityLink.ID = current.ActivityLink.ID;
            //                ts.LeaveRequestLink.ID = current.LeaveRequestLink.ID;
            //                ts.Date = current.Date.Date;
            //                ts.Start = current.Date.TimeOfDay;
            //                ts.Finish = current.Date.TimeOfDay.Add(current.Duration);
            //                ts.Notes = String.Format("Leave Request Approved on {0:dd MMM yy HH:mm}", entity.Approved);
            //                updates.Add(new Tuple<TimeSheet, Assignment>(ts,current));

            //            }


            //        }
            //        date = date.AddDays(1);
            //    } 

            //}

            //if (deletes.Any())
            //    assStore.Delete(deletes, "Removing Assignment from Leave Request");

            //var tsupdates = updates.Where(x => x.Item1.IsChanged());
            //if (tsupdates.Any())
            //    FindSubStore<TimeSheet>().Save(tsupdates.Select(x=>x.Item1), "Creating TimeSheet for Leave Request");

            //foreach (var update in updates)
            //    update.Item2.TimeSheetLink.ID = update.Item1.ID;

            //var assupdates = updates.Where(x => x.Item2.IsChanged());
            //if (assupdates.Any())
            //    assStore.Save(assupdates.Select(x=>x.Item2), "Assignment Generated from Approved Leave Request");

            #endregion
        }

        protected override void OnSave(LeaveRequest entity, ref string auditnote)
        {
            base.OnSave(entity, ref auditnote);

            UpdateAssignments(new[] { entity });

            if (entity.HasOriginalValue(c => c.Status))
                NotifyEmployee(
                    entity,
                    x => x.EmployeeLink.ID,
                    e => e.HasOriginalValue(x => x.Status),
                    e => string.Format("Leave Request {0}", e.Status),
                    e =>
                    {
                        var sb = new StringBuilder();

                        sb.AppendLine(string.Format(
                            "Your Leave Request submitted {0:dd MMM yyy} for {1:dd MMM yy} - {2:dd MMM yy} has changed from {3} to {4}.",
                            e.Created,
                            e.From,
                            e.To,
                            e.GetOriginalValue(c => c.Status),
                            e.Status
                        ));

                        if (!string.IsNullOrWhiteSpace(e.StatusNotes))
                            sb.AppendLine(string.Format("\nNotes:\n{0}", e.StatusNotes?.Trim()));

                        return sb.ToString();
                    }
                );
        }

        protected override void OnSave(IEnumerable<LeaveRequest> entities, ref string auditnote)
        {
            base.OnSave(entities, ref auditnote);
            UpdateAssignments(entities);
        }

        private class LeaveDay
        {
            public LeaveDay(DateTime date, TimeSpan start, TimeSpan finish)
            {
                Date = date;
                Start = start;
                Finish = finish;
            }

            public DateTime Date { get; }
            public TimeSpan Start { get; }
            public TimeSpan Finish { get; }
        }


        //protected override void BeforeDelete(LeaveRequest entity)
        //{
        //    base.BeforeDelete(entity);
        //    entity.Status = LeaveRequestStatus.Rejected;
        //    UpdateAssignments(new LeaveRequest[] { entity });
        //}
    }
}