using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.Entities;
using Tango.BL.Enumerations;
using Tango.Telemetry.Mappers;
using Tango.Telemetry.Telemetries;

namespace Tango.Telemetry.Sources
{
    public class TelemetryMachineUpdatesHistorySource : ITelemetryHistorySource
    {
        private bool _isBusy;

        public TelemetryHistorySourceDirection Direction { get; } = TelemetryHistorySourceDirection.Descending;

        public string Name { get; } = "Machine Updates History";

        public bool RequiresTelemetryDuplicationTracking { get; } = true;

        public async Task<bool> CanRequestHistory(DateTime from)
        {
            if (_isBusy)
            {
                return false;
            }
            else
            {
                try
                {
                    using (ObservablesContext db = ObservablesContext.CreateDefault())
                    {
                        return await db.TangoUpdates.CountAsync(x => x.LastUpdated < from) > 0;
                    }
                }
                catch
                {
                    return false;
                }
            }
        }

        public async Task<IEnumerable<ITelemetry>> RequestHistory(DateTime from)
        {
            try
            {
                _isBusy = true;

                using (ObservablesContext db = ObservablesContext.CreateDefault())
                {
                    int[] skipArr = { (int)TangoUpdateStatuses.SynchronizationCompleted, (int)TangoUpdateStatuses.SynchronizationFailed, (int)TangoUpdateStatuses.SynchronizationStarted };
                    var updates = await db.TangoUpdates.Where(x => x.LastUpdated <= from && !skipArr.Contains(x.Status)).Take(10).ToListAsync();

                    List<TelemetryMachineUpdate> tUpdates = new List<TelemetryMachineUpdate>();

                    foreach (var update in updates)
                    {
                        TelemetryMachineUpdate tUpdate = MachineUpdateMapper.MapMachineUpdate(update);
                        tUpdates.Add(tUpdate);
                    }
                     
                    return tUpdates;
                }
            }
            finally
            {
                _isBusy = false;
            }
        }

        public void Dispose()
        {

        }
    }
}