using System.Collections.Generic;
using System.Linq;
using Comal.Classes;
using InABox.Core;
using System;

namespace Comal.Stores
{
    internal class GPSTrackerStore : BaseStore<GPSTracker>
    {
        protected override void AfterSave(GPSTracker entity)
        {
            UpdateLinkedEquipment(entity);

            UpdateLinkedJob(entity);

            base.AfterSave(entity);
        }

        private void UpdateLinkedEquipment(GPSTracker entity)
        {
            if (entity.Equipment.HasOriginalValue(x => x.ID))
            {
                var oldID = entity.Equipment.GetOriginalValue(x => x.ID);
                var newID = entity.Equipment.ID;

                // If there are any other trackers linked to this new equipment item
                // blank them out - a tracker can only be attached to one equipment item
                var trackers = Provider.Query(
                    new Filter<GPSTracker>(x => x.Equipment.ID).IsEqualTo(newID).And(x => x.ID)
                        .IsNotEqualTo(entity.ID),
                    Columns.None<GPSTracker>().Add(x => x.ID).Add(x => x.Equipment.ID)
                ).ToList<GPSTracker>();
                if (trackers.Any())
                {
                    foreach (var tracker in trackers)
                        tracker.Equipment.ID = Guid.Empty;
                    Provider.Save(trackers);
                }

                var equips = Provider.Query(
                    new Filter<Equipment>(x => x.ID).IsEqualTo(oldID).Or(x => x.ID).IsEqualTo(newID).Or(x=>x.TrackerLink.ID).IsEqualTo(entity.ID),
                    Columns.None<Equipment>().Add(x => x.ID, x => x.TrackerLink.ID)
                ).ToList<Equipment>();
                
                // If there are any other trackers attached to this equipment item,
                // clear them out - an equipment item can only have one tracker
                foreach (var equip in equips)
                    equip.TrackerLink.ID = Guid.Empty;
                
                // Update the equipment item with the new Tracker ID
                var curr = equips.FirstOrDefault(x => x.ID.Equals(newID));
                if (curr != null)
                    curr.TrackerLink.ID = entity.ID;

                // Save any changes
                if (equips.Any(x=>x.IsChanged()))
                    Provider.Save(equips);
            }
        }

        private void UpdateLinkedJob(GPSTracker entity)
        {
            if (entity.JobTracker.HasOriginalValue(x => x.ID))
            {
                var oldID = entity.JobTracker.GetOriginalValue(x => x.ID);
                var newID = entity.JobTracker.ID;

                var trackers = Provider.Query(
                    new Filter<JobTracker>(x => x.ID).IsEqualTo(oldID).Or(x => x.ID).IsEqualTo(newID),
                    Columns.None<JobTracker>().Add(x => x.ID, x => x.TrackerLink.ID)
                );

                var updates = new List<JobTracker>();
                var prev = trackers.Rows.FirstOrDefault(r => r.Get<JobTracker, Guid>(c => c.ID).Equals(oldID));
                if (prev != null)
                {
                    var target = prev.ToObject<JobTracker>();
                    target.TrackerLink.ID = Guid.Empty;
                    updates.Add(target);
                }

                var curr = trackers.Rows.FirstOrDefault(r => r.Get<JobTracker, Guid>(c => c.ID).Equals(newID));
                if (curr != null)
                {
                    var tracker = curr.ToObject<JobTracker>();
                    tracker.TrackerLink.ID = entity.ID;
                    updates.Add(tracker);
                }

                if (updates.Any())
                    Provider.Save(updates);
            }
        }
    }
}