using AsbCloudDb.Model;
using AsbCloudDb.Model.Subsystems;
using AsbCloudInfrastructure.Services.DetectOperations;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace AsbCloudInfrastructure.Services.Subsystems
{
    internal class SubsystemOperationTimeBackgroundService : BackgroundService
    {
        private readonly string connectionString;
        private readonly TimeSpan period = TimeSpan.FromHours(1);
        public SubsystemOperationTimeBackgroundService(IConfiguration configuration)
        {
            connectionString = configuration.GetConnectionString("DefaultConnection");

        }
        protected override async Task ExecuteAsync(CancellationToken token)
        {
            var timeToStartAnalysis = DateTime.Now;
            var options = new DbContextOptionsBuilder<AsbCloudDbContext>()
                .UseNpgsql(connectionString)
                .Options;

            while (!token.IsCancellationRequested)
            {
                if (DateTime.Now > timeToStartAnalysis)
                {
                    timeToStartAnalysis = DateTime.Now + period;
                    try
                    {
                        using var context = new AsbCloudDbContext(options);
                        var added = await OperationTimeAllTelemetriesAsync(context, token);
                        Trace.TraceInformation($"Total operation time subsystem complete. Added {added} operations time.");
                    }
                    catch (Exception ex)
                    {
                        Trace.TraceError(ex.Message);
                    }
                    GC.Collect();
                }
                var ms = (int)(timeToStartAnalysis - DateTime.Now).TotalMilliseconds;
                ms = ms > 100 ? ms : 100;
                await Task.Delay(ms, token).ConfigureAwait(false);
            }
        }        

        public override async Task StopAsync(CancellationToken token)
        {
            await base.StopAsync(token).ConfigureAwait(false);
        }

        private static async Task<int> OperationTimeAllTelemetriesAsync(IAsbCloudDbContext db, CancellationToken token)
        {
            var lastDetectedDates = await db.DetectedOperations
                .GroupBy(o => o.IdTelemetry)
                .Select(g => new
                {
                    IdTelemetry = g.Key,
                    LastDate = g.Max(o => o.DateEnd)
                })
                .ToListAsync(token);

            var telemetryIds = await db.Telemetries
                .Where(t => t.Info != null && t.TimeZone != null)
                .Select(t => t.Id)
                .ToListAsync(token);

            var JounedlastDetectedDates = telemetryIds
                .GroupJoin(lastDetectedDates,
                    t => t,
                    o => o.IdTelemetry,
                    (outer, inner) => new
                    {
                        IdTelemetry = outer,
                        inner.SingleOrDefault()?.LastDate,
                    });
            var affected = 0;
            foreach (var item in JounedlastDetectedDates)
            {
                var stopwatch = Stopwatch.StartNew();
                var newOperationsSaub = await OperationTimeSaubAsync(item.IdTelemetry, item.LastDate ?? DateTimeOffset.MinValue, db, token);
                var newOperationsSpin = await OperationTimeSpinAsync(item.IdTelemetry, item.LastDate ?? DateTimeOffset.MinValue, db, token);
                stopwatch.Stop();
                if (newOperationsSaub.Any())
                {
                    db.SubsystemOperationTimes.AddRange(newOperationsSaub);
                    affected += await db.SaveChangesAsync(token);
                }
                if (newOperationsSpin.Any())
                {
                    db.SubsystemOperationTimes.AddRange(newOperationsSpin);
                    affected += await db.SaveChangesAsync(token);
                }
            }
            return affected;
        }

        private static async Task<IEnumerable<SubsystemOperationTime>> OperationTimeSaubAsync(int idTelemetry, DateTimeOffset begin, IAsbCloudDbContext db, CancellationToken token)
        {
            var query = db.TelemetryDataSaub
                .AsNoTracking()
                .Where(d => d.IdTelemetry == idTelemetry)
                .Select(d => new OperationTimeData
                {
                    DateTime = d.DateTime,                    
                    Mode = d.Mode,
                    Depth = d.WellDepth
                })
                .OrderBy(d => d.DateTime);            

            var take = 4 * 86_400; // 4 дня
            var startDate = begin;            
            var firstItem = query.FirstOrDefault();
            if (firstItem is null)
                return null;
            short? mode = firstItem.Mode;
            DateTimeOffset dateBegin = firstItem.DateTime;
            float? depthStart = firstItem.Depth;
            var resultSubsystemOperationTime = new List<SubsystemOperationTime>();
           
                var data = await query
                    .Where(d => d.DateTime > startDate)                   
                    .Take(take)
                    .ToArrayAsync(token);
                for(int i = 1;i<=data.Length ;i++)
                {
                   if( data[i].Mode!= mode)
                    {
                        var operationTimeItem = new SubsystemOperationTime()
                        {
                            IdTelemetry = idTelemetry,
                            DateStart = dateBegin,
                            IdSubsystem = (int)data[i - 1].Mode, 
                            DateEnd = data[i - 1].DateTime,
                            DepthStart = depthStart,
                            DepthEnd = data[i - 1].Depth

                        };
                        resultSubsystemOperationTime.Add(operationTimeItem);
                        mode = data[i].Mode;
                        dateBegin = data[i].DateTime;
                        depthStart = data[i].Depth;
                    }
                }
                startDate = data.Last().DateTime;
            
            return resultSubsystemOperationTime;
        }


        private static async Task<IEnumerable<SubsystemOperationTime>> OperationTimeSpinAsync(int idTelemetry, DateTimeOffset begin, IAsbCloudDbContext db, CancellationToken token)
        {
            var query = db.TelemetryDataSpin
                .AsNoTracking()
                .Where(d => d.IdTelemetry == idTelemetry)
                .Select(d => new OperationTimeData
                {
                    DateTime = d.DateTime,
                    Mode = d.Mode,
                    Depth = db.TelemetryDataSaub.Where(t => t.DateTime == d.DateTime & t.IdTelemetry ==idTelemetry)
                            .GroupBy(t => t.IdTelemetry)
                            .Select(group => group.Min(t => t.WellDepth))
                            .FirstOrDefault()
                })
                .OrderBy(d => d.DateTime);            

            var take = 4 * 86_400; // 4 дня
            var startDate = begin;
            var firstItem = query.FirstOrDefault();
            if (firstItem is null)
                return null;
            short? mode = firstItem.Mode;
            DateTimeOffset dateBegin = firstItem.DateTime;
            float? depthStart = firstItem.Depth;
            var resultSubsystemOperationTime = new List<SubsystemOperationTime>();            
            var data = await query
                .Where(d => d.DateTime > startDate)
                .Take(take)
                .ToArrayAsync(token);
           
            for (int i = 1; i <= data.Length; i++)
            {
                if (data[i].Mode != mode)
                {
                    var operationTimeItem = new SubsystemOperationTime()
                    {
                        IdTelemetry = idTelemetry,
                        DateStart = dateBegin,
                        IdSubsystem = (int)data[i - 1].Mode,
                        DateEnd = data[i - 1].DateTime,
                        DepthStart = depthStart,
                        DepthEnd = data[i - 1].Depth

                    };
                    resultSubsystemOperationTime.Add(operationTimeItem);
                    mode = data[i].Mode;
                    dateBegin = data[i].DateTime;
                    depthStart = data[i].Depth;
                }
            }
            startDate = data.Last().DateTime;

            return resultSubsystemOperationTime;
        }        
    }
}