using AsbCloudApp.Data;
using AsbCloudApp.Requests;
using AsbCloudApp.Services;
using AsbCloudDb;
using AsbCloudDb.Model;
using Mapster;
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 DetectedOperationService : IDetectedOperationService
    {
        public const int IdOperationRotor = 1;
        public const int IdOperationSlide = 3;
        public const int IdOperationSlipsTime = 14;

        private readonly IAsbCloudDbContext db;
        private readonly IWellService wellService;
        private readonly IOperationValueService operationValueService;
        private readonly IScheduleService scheduleService;

        public DetectedOperationService(IAsbCloudDbContext db, IWellService wellService,
            IOperationValueService operationValueService, IScheduleService scheduleService)
        {
            this.db = db;
            this.wellService = wellService;
            this.operationValueService = operationValueService;
            this.scheduleService = scheduleService;
        }

        public async Task<DetectedOperationListDto> GetAsync(DetectedOperationRequest request, CancellationToken token)
        {
            var well = await wellService.GetOrDefaultAsync(request.IdWell, token);
            if (well?.IdTelemetry is null || well.Timezone is null)
                return null;

            var query = BuildQuery(well, request)
                .AsNoTracking();

            var data = await query.ToListAsync(token);

            var operationValues = await operationValueService.GetByIdWellAsync(request.IdWell, token);
            var schedules = await scheduleService.GetByIdWellAsync(request.IdWell, token);
            var dtos = data.Select(o => Convert(o, well, operationValues, schedules));
            var groups = dtos.GroupBy(o => o.Driller);

            var stats = new List<DetectedOperationStatDto>(groups.Count());
            foreach (var group in groups)
            {
                var itemsWithTarget = group.Where(i => i.OperationValue is not null);
                var stat = new DetectedOperationStatDto
                {
                    Driller = group.Key,
                    AverageValue = group.Sum(e => e.Value) / group.Count(),
                    Count = group.Count(),
                };
                if (itemsWithTarget.Any())
                {
                    var itemsOutOfTarget = itemsWithTarget.Where(o => !IsTargetOk(o));
                    stat.AverageTargetValue = itemsWithTarget.Average(e => e.OperationValue.TargetValue);
                    stat.Efficiency = 100d * itemsOutOfTarget.Count() / itemsWithTarget.Count();
                    stat.Loss = itemsOutOfTarget.Sum(DeltaToTarget);
                }

                stats.Add(stat);
            }

            var result = new DetectedOperationListDto
            {
                Operations = dtos,
                Stats = stats
            };
            return result;
        }

        public async Task<int> DeleteAsync(DetectedOperationRequest request, CancellationToken token)
        {
            var well = await wellService.GetOrDefaultAsync(request.IdWell, token);
            if (well?.IdTelemetry is null || well.Timezone is null)
                return 0;

            var query = BuildQuery(well, request);
            db.DetectedOperations.RemoveRange(query);
            return await db.SaveChangesAsync(token);
        }

        private static bool IsTargetOk(DetectedOperationDto op)
        {
            return (op.IdCategory) switch
            {
                IdOperationRotor => op.Value > op.OperationValue.TargetValue,
                IdOperationSlide => op.Value > op.OperationValue.TargetValue,
                IdOperationSlipsTime => op.Value > op.OperationValue.TargetValue,
                _ => op.Value > op.OperationValue.TargetValue,
            };
        }

        private static double DeltaToTarget(DetectedOperationDto op)
        {
            return (op.IdCategory) switch
            {
                IdOperationRotor => 0,
                IdOperationSlide => 0,
                IdOperationSlipsTime => op.Value - op.OperationValue.TargetValue,
                _ => 0,
            };
        }

        private IQueryable<DetectedOperation> BuildQuery(WellDto well, DetectedOperationRequest request)
        {
            if (well?.IdTelemetry is null || well.Timezone is null)
                return null;

            var query = db.Set<DetectedOperation>()
                .Include(o => o.OperationCategory)
                .Where(o => o.IdTelemetry == well.IdTelemetry);

            if (request is not null)
            {
               query = query.Where(o => request.IdCategory == o.IdCategory);

                if (request.GtDate is not null)
                    query = query.Where(o => o.DateStart >= request.GtDate.Value.ToUtcDateTimeOffset(well.Timezone.Hours));

                if (request.LtDate is not null)
                    query = query.Where(o => o.DateEnd <= request.LtDate.Value.ToUtcDateTimeOffset(well.Timezone.Hours));

                if (request.GtDepth is not null)
                    query = query.Where(o => o.DepthStart >= request.GtDepth);

                if (request.LtDepth is not null)
                    query = query.Where(o => o.DepthEnd <= request.LtDepth);

                if (request.EqIdTelemetryUser is not null)
                    query = query.Where(o => o.IdUsersAtStart == request.EqIdTelemetryUser);
            }

            if (request?.SortFields?.Any() == true)
            {
                query = query.SortBy(request.SortFields);
            }
            else
                query = query
                    .OrderBy(o => o.DateStart)
                    .ThenBy(o => o.DepthStart);

            if (request?.Skip > 0)
                query = query.Skip((int)request.Skip);

            if (request?.Take > 0)
                query = query.Take((int)request.Take);

            return query;
        }

        private DetectedOperationDto Convert(DetectedOperation operation, WellDto well, IEnumerable<OperationValueDto> operationValues, IEnumerable<ScheduleDto> schedules)
        {
            var dto = operation.Adapt<DetectedOperationDto>();
            dto.IdWell = well.Id;
            var dateStart = operation.DateStart.ToRemoteDateTime(well.Timezone.Hours);
            dto.DateStart = dateStart;
            dto.DateEnd = operation.DateEnd.ToRemoteDateTime(well.Timezone.Hours);
            dto.OperationValue = operationValues.FirstOrDefault(v => v.IdOperationCategory == dto.IdCategory
                  && v.DepthStart <= dto.DepthStart
                  && v.DepthEnd > dto.DepthStart);

            var timeStart = new TimeDto(dateStart);
            var driller = schedules.FirstOrDefault(s =>
                s.DrillStart <= dateStart &&
                s.DrillEnd > dateStart && (
                s.ShiftStart > s.ShiftEnd
                ) ^ (s.ShiftStart <= timeStart &&
                s.ShiftEnd > timeStart
                ))
                ?.Driller;
            dto.Driller = driller;
            return dto;
        }

        public async Task<IEnumerable<WellOperationCategoryDto>> GetCategoriesAsync(int? idWell, CancellationToken token)
        {
            IQueryable<WellOperationCategory> query = null;
            if(idWell is null)
            {
                query = db.WellOperationCategories;
            }
            else
            {
                var well = await wellService.GetOrDefaultAsync((int )idWell, token);
                if (well?.IdTelemetry is null)
                    return null;
                var idTelemetry = (int)well.IdTelemetry;
                query = db.DetectedOperations
                    .Include(o => o.OperationCategory)
                    .Where(o => o.IdTelemetry == idTelemetry)
                    .Select(o => o.OperationCategory)
                    .Distinct();
            }

            var result = await query
                .Where(c => c.Id < 1000)
                .AsNoTracking()
                .Select(c => c.Adapt<WellOperationCategoryDto>())
                .ToArrayAsync(token);
            return result;
        }
    }
}