using AsbCloudDb.Model;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace AsbCloudInfrastructure.Services.DetectOperations
{
    public class DetectorService
    {
        readonly IEnumerable<DetectorAbstract> detectors = new List<DetectorAbstract>
        {
            new Detectors.DetectorSlipsTime(),
            // new Detectors.DetectorDrillingRotor(),
            // new Detectors.DetectorDrillingSlide(),
        };

        private readonly int minStepLength;
        private readonly int minFragmentLength;

        public DetectorService()
        {
            minStepLength = detectors.Min(d => d.StepLength);
            minStepLength = minStepLength > 0 ? minStepLength : 3;

            minFragmentLength = detectors.Min(d => d.FragmentLength);
            minFragmentLength = minFragmentLength > 0 ? minFragmentLength : 6;
        }

        public async Task<IEnumerable<DetectedOperation>> DetectOperationsAsync(int idTelemetry, DateTimeOffset begin, IAsbCloudDbContext db, CancellationToken token)
        {
            var query = db.TelemetryDataSaub
                .AsNoTracking()
                .Where(d => d.IdTelemetry == idTelemetry)
                .Select(d => new DetectableTelemetry{                 
                    DateTime = d.DateTime,
                    IdUser = d.IdUser,
                    WellDepth = d.WellDepth,
                    Pressure = d.Pressure,
                    HookWeight = d.HookWeight,
                    BlockPosition = d.BlockPosition,
                    BitDepth = d.BitDepth,
                    RotorSpeed = d.RotorSpeed,
                })
                .OrderBy(d => d.DateTime);

            var take = 4 * 86_400;
            var startDate = begin;
            var detectedOperations = new List<DetectedOperation>(8);

            var dbRequests_ = 0;
            var dbTime_ = 0d;
            var sw_ = new System.Diagnostics.Stopwatch();
            var otherTime_ = 0d;
            
            while (true)
            {
                sw_.Restart();
                var data = await query
                    .Where(d => d.DateTime > startDate)
                    .Take(take)
                    .ToArrayAsync(token);

                sw_.Stop();
                dbTime_ += sw_.ElapsedMilliseconds;
                dbRequests_++;
                sw_.Restart();
                
                if (data.Length < minFragmentLength)
                    break;

                var skip = 0;

                var isDetected = false;

                while (data.Length > skip + minFragmentLength)
                {
                    var isDetected1 = false;

                    foreach (var detector in detectors)
                    {
                        if(data.Length < skip + detector.StepLength + detector.FragmentLength)
                            continue;

                        var detectedOperation = detector.DetectOrDefault(data, ref skip);
                        if (detectedOperation is not null)
                        {
                            isDetected1 = true;
                            isDetected = true;
                            detectedOperations.Add(detectedOperation);
                            startDate = detectedOperation.End;
                            break;
                        }
                    }

                    if (!isDetected1)
                        skip += minStepLength;
                }

                sw_.Stop();
                otherTime_ += sw_.ElapsedMilliseconds;
                
                if (!isDetected)
                {
                    if (data.Length < take)
                        break;
                    
                    var lastPartDate = data.Last().DateTime;
                    startDate = startDate + (0.75 * (lastPartDate - startDate));
                } 
            }

            return detectedOperations;
        }
    }
}