using AsbCloudApp.Data;
using AsbCloudApp.Services;
using AsbCloudDb.Model;
using AsbCloudInfrastructure.Services.Cache;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace AsbCloudInfrastructure.Services
{
    class OperationParams
    {
        public OperationParams() { }

        public OperationParams(WellOperation operation)
        {
            Id = operation.Id;
            IdWellSectionType = operation.IdWellSectionType;
            IdCategory = operation.IdCategory;

            WellDepth = operation.WellDepth;
            Start = operation.StartDate;
            DurationHours = operation.DurationHours;

            WellDepthReal = operation.WellDepth;
            DeltaDepth = 0;
            DurationToNextOperationHours = operation.DurationHours;
        }
        public int IdWellSectionType { get; }
        public int IdCategory { get; }
        public int Id { get; }
        public DateTime Start { get; }
        public double WellDepth { get; }
        public double DurationHours { get; }
        public double WellDepthReal { get; set; }
        public double DeltaDepth { get; set; }
        public double DurationToNextOperationHours { get; set; }
    }

    class Race
    {
        public DateTime StartDate { get; set; }
        public double StartWellDepth { get; set; }
        public DateTime EndDate { get; set; }
        public double EndWellDepth { get; set; }
        public double DrillingTime { get; set; }
        public double NonProductiveHours { get; set; }
        public double DeltaDepth => EndWellDepth - StartWellDepth;
        public double DeltaHoursTimeNoNpt => (EndDate - StartDate).TotalHours - NonProductiveHours;
        public double Speed => DeltaDepth / (DeltaHoursTimeNoNpt + double.Epsilon);
    }

    public class WellOperationsStatService : IWellOperationsStatService
    {
        private readonly IAsbCloudDbContext db;
        private readonly CacheTable<WellSectionType> cachedSectionsTypes;
        private const int idOperationBhaAssembly = 1025;
        private const int idOperationBhaDisassembly = 1026;
        private const int idOperationNonProductiveTime = 1043;
        private const int idOperationDrilling = 1001;
        private const int idOperationBhaDown = 1046;
        private const int idOperationBhaUp = 1047;
        private const int IdOperationCasingDown = 1048;

        public WellOperationsStatService(IAsbCloudDbContext db, Cache.CacheDb cache)
        {
            this.db = db;
            cachedSectionsTypes = cache.GetCachedTable<WellSectionType>((DbContext)db);
        }

        public async Task<StatClusterDto> GetOperationStatByClusterAsync(int idCluster, CancellationToken token = default)
        {
            var operations = await db.WellOperations
                .Include(o => o.Well)
                .Where(o => o.Well.IdCluster == idCluster)
                .OrderBy(o => o.StartDate)
                .AsNoTracking()
                .ToListAsync(token);

            var wellsIds = operations.Select(o => o.IdWell).Distinct();
            var sectionsStats = new List<StatOperationDto>(wellsIds.Count() * 3);
            var wellsTotals = new List<StatOperationDto>(wellsIds.Count());

            foreach(var idWell in wellsIds)
            {
                var wellOperations = operations.Where(o => o.IdWell == idWell);
                sectionsStats.AddRange(GetWellSectionsStats(wellOperations));
                wellsTotals.Add(GetWellStats(wellOperations));
            }

            var statClusterDto = new StatClusterDto
            {
                Sections = sectionsStats,
                WellsTotals = wellsTotals,
            };
            return statClusterDto;
        }

        public async Task<StatWellDto> GetOperationStatByWellAsync(int idWell,
            CancellationToken token = default)
        {
            var operations = await db.WellOperations
                .Where(o => o.IdWell == idWell)
                .OrderBy(o => o.StartDate) // ускорит дальнейшие сортировки
                .AsNoTracking()
                .ToListAsync(token);

            var statWellDto = new StatWellDto
            {
                Sections = GetWellSectionsStats(operations),
                Total = GetWellStats(operations),
            };
            return statWellDto;
        }

        private IEnumerable<StatOperationDto> GetWellSectionsStats(IEnumerable<WellOperation> operations)
        {
            var sectionTypesIds = operations.Select(o => o.IdWellSectionType).Distinct();
            var sections = new List<StatOperationDto>(sectionTypesIds.Count());
            var operationsPlan = MakeOperationsExt(operations.Where(o => o.IdType == 0));
            var operationsFact = MakeOperationsExt(operations.Where(o => o.IdType == 0));

            foreach (var idSectionType in sectionTypesIds)
            {
                var statPlan = CalcSectionStat(operationsPlan, idSectionType);             
                var statFact = CalcSectionStat(operationsFact, idSectionType);
                StatOperationDto section = MakeWellSectionDto(idSectionType, statPlan, statFact);
                sections.Add(section);
            }
            return sections;
        }

        private static StatOperationDto GetWellStats(IEnumerable<WellOperation> operations)
        {
            var operationsPlan = MakeOperationsExt(operations.Where(o => o.IdType == 0));
            var operationsFact = MakeOperationsExt(operations.Where(o => o.IdType == 0));
            var section = new StatOperationDto
            {
                Plan = CalcStat(operationsPlan),
                Fact = CalcStat(operationsFact),
            };
            return section;
        }

        private StatOperationDto MakeWellSectionDto(int idSectionType, StatOperationBase statPlan, StatOperationBase statFact)
        {
            return new StatOperationDto
            {
                Id = idSectionType,
                Caption = cachedSectionsTypes.FirstOrDefault(s => s.Id == idSectionType)?.Caption,
                Plan = statPlan,
                Fact = statFact,
            };
        }

        private static StatOperationBase CalcSectionStat(IEnumerable<OperationParams> operations, int idSectionType)
        {
            var sectionOperations = operations
                .Where(o => o.IdWellSectionType == idSectionType)
                .OrderBy(o => o.Start)
                .ThenBy(o => o.WellDepth);
            return CalcStat(sectionOperations);
        }

        private static StatOperationBase CalcStat(IEnumerable<OperationParams> operations)
        {
            var section = new StatOperationBase
            {
                Start = operations.First().Start,
                End = operations.Max(o => (o.Start.AddHours(o.DurationHours))),
                WellDepthStart = operations.Min(o => o.WellDepthReal),
                WellDepthEnd = operations.Max(o => o.WellDepthReal),
                RouteSpeed = CalcAvgRaceSpeed(operations),
                Rop = CalcROP(operations),
                BhaDownSpeed = CalcSpeedByOperation(operations, idOperationBhaDown),
                BhaUpSpeed = CalcSpeedByOperation(operations, idOperationBhaUp),
                CasingDownSpeed = CalcSpeedByOperation(operations, IdOperationCasingDown),
            };
            return section;
        }

        private static double CalcSpeedByOperation(IEnumerable<OperationParams> operationsProps, int idOperation)
        {
            var ops = operationsProps.Where(o => o.IdCategory == idOperation);
            var maxDepth = 0d;
            var dHours = 0d;
            foreach (var operation in ops)
            {
                if (maxDepth > operation.WellDepthReal)
                    maxDepth = operation.WellDepthReal;
                dHours += operation.DurationHours;
            }
            return maxDepth / (dHours + double.Epsilon);
        }

        private static double CalcROP(IEnumerable<OperationParams> operationsProps)
        {
            var drillingOperations = operationsProps.Where(o => o.IdCategory == idOperationDrilling);
            var dDepth = 0d;
            var dHours = 0d;
            foreach (var operation in drillingOperations)
            {
                dDepth += operation.DeltaDepth;
                dHours += operation.DurationHours;
            }
            return dDepth / (dHours + double.Epsilon);
        }

        private static double CalcAvgRaceSpeed(IEnumerable<OperationParams> operations)
        {
            var races = GetCompleteRaces(operations);
            var dDepth = 0d;
            var dHours = 0d;
            foreach (var race in races)
            {
                dHours += race.DeltaHoursTimeNoNpt;
                dDepth += race.DeltaDepth;
            }
            return dDepth / (dHours + double.Epsilon);
        }

        private static IEnumerable<OperationParams> MakeOperationsExt(IEnumerable<WellOperation> operations)
        {
            var count = operations.Count();
            var ops = new List<OperationParams>(count);
            var item = operations.ElementAt(0);
            var wellDepth = item.WellDepth;
            var pre = new OperationParams(item);
            var current = new OperationParams(item);
            for (int i = 1; i < count; i++)
            {
                item = operations.ElementAt(i);
                current = new OperationParams(item)
                {
                    WellDepthReal = Helper.Max(wellDepth, item.WellDepth) // TODO: учесть операциии с уменьшение глубины ствола.
                };
                pre.DeltaDepth = current.WellDepthReal - wellDepth;
                pre.DurationToNextOperationHours = (current.Start - pre.Start).TotalHours;
                ops.Add(pre);
                pre = current;
            }
            ops.Add(current);
            return ops;
        }

        private static IEnumerable<Race> GetCompleteRaces(IEnumerable<OperationParams> operations)
        {
            var races = new List<Race>();
            var iterator = operations.GetEnumerator();
            while (iterator.MoveNext())
            {
                if (iterator.Current.IdCategory == idOperationBhaAssembly)
                {
                    var race = new Race
                    {
                        StartDate = iterator.Current.Start.AddHours(iterator.Current.DurationHours),
                        StartWellDepth = iterator.Current.WellDepthReal
                    };
                    while (iterator.MoveNext())
                    {
                        if (iterator.Current.IdCategory == idOperationNonProductiveTime)
                        {
                            race.NonProductiveHours += iterator.Current.DurationHours;
                        }
                        if (iterator.Current.IdCategory == idOperationBhaDisassembly)
                        {
                            race.EndDate = iterator.Current.Start.AddHours(iterator.Current.DurationHours);
                            race.EndWellDepth = iterator.Current.WellDepthReal;
                            races.Add(race);
                        }
                    }
                }
            }
            return races;
        }
    }
}