using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using InABox.Clients;
using InABox.Core;

namespace Comal.Classes
{
    public abstract class BaseKanbanSubscriberSet
    {
        private readonly List<KanbanSubscriber> _subscribers = new List<KanbanSubscriber>();

        protected BaseKanbanSubscriberSet(IEnumerable<Guid> kanbanids)
        {
            _subscribers.Clear();
            var result = DoQuery(
                new Filter<KanbanSubscriber>(x => x.Kanban.ID).InList(kanbanids.ToArray()),
                new Columns<KanbanSubscriber>(x => x.ID).Add(x => x.Kanban.ID).Add(x => x.Employee.ID).Add(x => x.Assignee).Add(x => x.Manager)
                    .Add(x => x.Observer));
            if (result.Rows.Any())
                _subscribers.AddRange(result.Rows.Select(x => x.ToObject<KanbanSubscriber>()));
        }
        
        public void Save(bool wait = true)
        {
            var update = Task.Run(() =>
            {
                var updates = _subscribers.Where(x => (x.Manager || x.Assignee || x.Observer) && (x.IsChanged() || Equals(x.ID, Guid.Empty))).ToArray();
                if (updates.Any())
                    DoSave(updates);
            });
            var delete = Task.Run(() =>
            {
                var deletes = _subscribers.Where(x => !x.Manager && !x.Assignee && !x.Observer).ToArray();
                if (deletes.Any())
                    DoDelete(deletes);
            });
            if (wait)
                Task.WaitAll(update, delete);
        }
        
        private KanbanSubscriber EnsureSubscriber(Guid kanbanid, Guid employeeid)
        {
            var subscriber = _subscribers.FirstOrDefault(x => Equals(x.Kanban.ID, kanbanid) && Equals(x.Employee.ID, employeeid));
            if (subscriber == null)
            {
                subscriber = new KanbanSubscriber();
                subscriber.Kanban.ID = kanbanid;
                subscriber.Employee.ID = employeeid;
                _subscribers.Add(subscriber);
            }

            return subscriber;
        }

        public void EnsureManager(Guid kanbanid, Guid employeeid)
        {
            if(employeeid == Guid.Empty)
            {
                return;
            }
            var manager = EnsureSubscriber(kanbanid, employeeid);

            // No-one else can be a manager
            var others = _subscribers.Where(x => Equals(x.Kanban.ID, kanbanid)).ToArray();
            foreach (var other in others)
            {
                if(other != manager)
                {
                    other.Manager = false;
                }
            }

            // only this one!
            manager.Manager = true;
        }

        public void EnsureAssignee(Guid kanbanid, Guid employeeid)
        {
            if (employeeid == Guid.Empty)
            {
                return;
            }
            var assignee = EnsureSubscriber(kanbanid, employeeid);

            // No-one else can be a assignee
            var others = _subscribers.Where(x => Equals(x.Kanban.ID, kanbanid)).ToArray();
            foreach (var other in others)
            {
                if (other != assignee)
                {
                    other.Assignee = false;
                }
            }

            // only this one!
            assignee.Assignee = true;
        }

        public void EnsureObserver(Guid kanbanid, Guid employeeid)
        {
            if (employeeid == Guid.Empty)
            {
                return;
            }
            var observer = EnsureSubscriber(kanbanid, employeeid);

            // Employee can only be an observer once
            var subscribers = _subscribers.Where(x => Equals(x.Kanban.ID, kanbanid) && Equals(x.Employee.ID, employeeid)).ToArray();
            foreach (var subscriber in subscribers)
            {
                if (subscriber != observer)
                {
                    subscriber.Observer = false;
                }
            }

            observer.Observer = true;
        }
        
        protected abstract CoreTable DoQuery(Filter<KanbanSubscriber> filter, Columns<KanbanSubscriber> columns);
        
        protected abstract void DoSave(IEnumerable<KanbanSubscriber> updates);
        
        protected abstract void DoDelete(KanbanSubscriber[] deletes);

    }
    
    public class ClientKanbanSubscriberSet : BaseKanbanSubscriberSet
    {
        
        public ClientKanbanSubscriberSet(IEnumerable<Guid> kanbanids) : base(kanbanids)
        {
            
        }
        
        protected override void DoSave(IEnumerable<KanbanSubscriber> updates)
            => new Client<KanbanSubscriber>().Save(updates, "");

        protected override void DoDelete(KanbanSubscriber[] deletes)
            => new Client<KanbanSubscriber>().Delete(deletes, "");

        protected override CoreTable DoQuery(Filter<KanbanSubscriber> filter, Columns<KanbanSubscriber> columns)
         => new Client<KanbanSubscriber>().Query(filter, columns);
        
    }
}