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

namespace AsbCloudInfrastructure.Services
{
    public class TelemetryService : ITelemetryService
    {
        private readonly CacheTable<Telemetry> cacheTelemetry;
        private readonly CacheTable<Well> cacheWells;//TODO: use wellService insad of this
        private readonly IAsbCloudDbContext db;
        private readonly ITelemetryTracker telemetryTracker;
        private readonly ITimeZoneService timeZoneService;

        public ITimeZoneService TimeZoneService => timeZoneService;
        public ITelemetryTracker TelemetryTracker => telemetryTracker;

        public TelemetryService(
            IAsbCloudDbContext db, 
            ITelemetryTracker telemetryTracker,
            ITimeZoneService timeZoneService,
            CacheDb cacheDb)
        {
            cacheTelemetry = cacheDb.GetCachedTable<Telemetry>((AsbCloudDbContext)db);
            cacheWells = cacheDb.GetCachedTable<Well>(
                (AsbCloudDbContext)db, 
                $"{nameof(Well.Cluster)}.{nameof(Cluster.Deposit)}",
                nameof(Well.Telemetry),
                $"{nameof(Well.RelationCompaniesWells)}.{nameof(RelationCompanyWell.Company)}",
                nameof(Well.WellType));
            this.db = db;
            this.telemetryTracker = telemetryTracker;
            this.timeZoneService = timeZoneService;
        }
        
        public IEnumerable<TelemetryDto> GetTransmittingTelemetries()
        {
            var telemetryDtos = new List<TelemetryDto>();
            var activeTelemetriesUids = telemetryTracker.GetTransmittingTelemetriesUids();
            if (!activeTelemetriesUids.Any())
                return telemetryDtos;
            var telemetries = cacheTelemetry
                .Where(t => activeTelemetriesUids.Contains(t.RemoteUid));
            telemetryDtos = telemetries.Adapt<TelemetryDto>().ToList();

            return telemetryDtos;
        }

        public void SaveRequestDate(string uid, DateTime remoteDate) =>
            telemetryTracker.SaveRequestDate(uid, remoteDate);

        public DateTime GetLastTelemetryDate(string telemetryUid) =>
            telemetryTracker.GetLastTelemetryDateByUid(telemetryUid);

        public DateTime GetLastTelemetryDate(int telemetryId)
        {
            var lastTelemetryDate = DateTime.MinValue;
            var telemetry = cacheTelemetry.FirstOrDefault(t => t.Id == telemetryId);

            if (telemetry is null)
                return lastTelemetryDate;

            var uid = telemetry.RemoteUid;

            lastTelemetryDate = GetLastTelemetryDate(uid);
            return lastTelemetryDate;
        }

        public int GetOrCreateTelemetryIdByUid(string uid)
            => GetOrCreateTelemetryByUid(uid).Id;

        public int? GetIdWellByTelemetryUid(string uid)
            => GetWellByTelemetryUid(uid)?.Id;

        public double GetTimezoneOffsetByTelemetryId(int idTelemetry) =>
            cacheTelemetry.FirstOrDefault(t => t.Id == idTelemetry).Info?.TimeZoneOffsetTotalHours ?? 0d;

        public async Task UpdateInfoAsync(string uid, TelemetryInfoDto info,
            CancellationToken token)
        {
            var telemetry = GetOrCreateTelemetryByUid(uid);
            telemetry.Info = info.Adapt<TelemetryInfo>();

            if (!string.IsNullOrEmpty(info.TimeZoneId) &&
                telemetry.TelemetryTimeZone?.IsOverride != true)
                telemetry.TelemetryTimeZone = new TelemetryTimeZone()
                {
                    Hours = info.TimeZoneOffsetTotalHours,
                    TimeZoneId = info.TimeZoneId
                };
            
            await cacheTelemetry.UpsertAsync(telemetry, token)
                .ConfigureAwait(false);
        }

        public async Task<double?> GetTelemetryTimeZoneOffsetAsync(int idTelemetry, CancellationToken token)
        {
            var telemetry = 
                await cacheTelemetry.FirstOrDefaultAsync(t => t.Id == idTelemetry, token);

            if (!string.IsNullOrEmpty(telemetry.TelemetryTimeZone?.TimeZoneId))
                return telemetry.TelemetryTimeZone.Hours;

            if (!string.IsNullOrEmpty(telemetry.Info?.TimeZoneId))
            {
                telemetry.TelemetryTimeZone = new TelemetryTimeZone
                {
                    Hours = telemetry.Info.TimeZoneOffsetTotalHours,
                    IsOverride = false,
                    TimeZoneId = telemetry.Info.TimeZoneId,
                };
            }
            else
            {
                var well = await cacheWells.FirstOrDefaultAsync(t => t.IdTelemetry == telemetry.Id, token)
                    .ConfigureAwait(false);

                if (well is null)
                    return null;

                var coordinates = await GetWellCoordinatesAsync(well.Id, token);

                if (coordinates is null)
                    return null;

                var requestedTimeZone =  await timeZoneService.GetByCoordinatesAsync(coordinates.Value.latitude, coordinates.Value.longitude, token)
                    .ConfigureAwait(false);

                if (requestedTimeZone is null)
                    return null;

                telemetry.TelemetryTimeZone = requestedTimeZone.Adapt<TelemetryTimeZone>();
            }

            await cacheTelemetry.UpsertAsync(telemetry, token).ConfigureAwait(false);
            
            return telemetry.TelemetryTimeZone.Hours;
        }
        
        public async Task<DatesRangeDto> FixDatesRangeByTimeZoneAsync(int idTelemetry, DatesRangeDto range,
            CancellationToken token)
        {
            var offset = await GetTelemetryTimeZoneOffsetAsync(idTelemetry, token);

            if (offset is null)
                return range;

            return new DatesRangeDto()
            {
                From = timeZoneService.DateToTimeZone(range.From, offset ?? default),
                To = timeZoneService.DateToTimeZone(range.To, offset ?? default),                
            };
        }

        public async Task UpdateTimeZoneAsync(string uid, TelemetryTimeZoneDto timeZoneInfo, 
            CancellationToken token)
        {
            var telemetry = GetOrCreateTelemetryByUid(uid);            
            var newTelemetryTimeZone = timeZoneInfo.Adapt<TelemetryTimeZone>();
            if (newTelemetryTimeZone?.Equals(telemetry.TelemetryTimeZone) == true)
                return;            
            await cacheTelemetry.UpsertAsync(telemetry, token)
                .ConfigureAwait(false);
        }

        public int? GetIdTelemetryByIdWell(int idWell)
        {
            var well = cacheWells.FirstOrDefault(w => w.Id == idWell);
            return well?.IdTelemetry;
        }

        private async Task<(double latitude, double longitude)?> GetWellCoordinatesAsync(int idWell,
            CancellationToken token)
        {
            var well = await cacheWells.FirstOrDefaultAsync(w => w.Id == idWell, token)
                .ConfigureAwait(false);
            
            if (well is null)
                return null;

            var latitude = well.Latitude ??
                well.Cluster?.Latitude ??
                well.Cluster?.Deposit?.Latitude;

            var longitude = well.Longitude ??
                well.Cluster?.Longitude ??
                well.Cluster?.Deposit?.Longitude;

            if (latitude is not null && longitude is not null)
                return ((double)latitude, (double)longitude);

            return null;
        }

        private Well GetWellByTelemetryUid(string uid)
        {
            var tele = cacheTelemetry.FirstOrDefault(t => t.RemoteUid == uid);
            if (tele is null)
                return null;

            return cacheWells.FirstOrDefault(w => w?.IdTelemetry == tele.Id);
        }

        private Telemetry GetOrCreateTelemetryByUid(string uid)
            => cacheTelemetry.GetOrCreate(t => t.RemoteUid == uid, () => new Telemetry { RemoteUid = uid });

        public async Task<int> MergeAsync(int from, int to, CancellationToken token)
        {
            if (from == to)
                return -2;

            var stopwath = new System.Diagnostics.Stopwatch();
            stopwath.Start();

            var transaction = await db.Database.BeginTransactionAsync(token).ConfigureAwait(false);            
            try
            {
                var affected = 0;
                
                var wellFrom = await db.Wells.FirstOrDefaultAsync(w => w.IdTelemetry == from, token)
                    .ConfigureAwait(false);
                var wellTo = await db.Wells.FirstOrDefaultAsync(w => w.IdTelemetry == to, token)
                    .ConfigureAwait(false);

                if (wellTo is not null && wellFrom is not null)
                    return -2;

                if (wellTo is null && wellFrom is not null)
                {
                    wellFrom.IdTelemetry = to;
                    affected += await db.SaveChangesAsync(token);
                }

                affected += await MergeEventsAndMessagesAndUsersAsync(from, to, token);
                affected += await MergeDataAsync<TelemetryDataSaub>(from, to, token);
                affected += await MergeDataAsync<TelemetryDataSpin>(from, to, token);
                
                affected += await db.Database.ExecuteSqlRawAsync($"DELETE FROM t_telemetry_analysis WHERE id_telemetry = {from} OR id_telemetry = {to};", token)
                    .ConfigureAwait(false);
                affected += await db.Database.ExecuteSqlRawAsync($"DELETE FROM t_telemetry WHERE id = {from};", token)
                    .ConfigureAwait(false);
                await transaction.CommitAsync(token).ConfigureAwait(false);

                stopwath.Stop();
                Console.WriteLine($"Successfully commited in {1d * stopwath.ElapsedMilliseconds / 1000d: #0.00} sec. Affected {affected} rows.");
                return affected;
            }
            catch(Exception ex)
            {
                System.Diagnostics.Trace.WriteLine($"Merge() Fail. Rollback. Reason is:{ex.Message}");
                await transaction.RollbackAsync(token).ConfigureAwait(false);
                return -1;
            }
        }

        private async Task<int> MergeEventsAndMessagesAndUsersAsync(int from, int to, CancellationToken token)
        {
            var messagesFrom = await db.TelemetryMessages
                .Where(d => d.IdTelemetry == from)
                .ToListAsync(token)
                .ConfigureAwait(false);

            var usersFromQuery = db.TelemetryUsers
                .Where(d => d.IdTelemetry == from);
            var usersFrom = await usersFromQuery
                .ToListAsync(token)
                .ConfigureAwait(false);

            var usersTo = await db.TelemetryUsers
                .Where(d => d.IdTelemetry == to)
                .AsNoTracking()
                .ToListAsync(token)
                .ConfigureAwait(false);

            var usersToNextId = usersTo.Max(u => u.IdUser) + 100;

            messagesFrom.ForEach(m => m.IdTelemetry = to);

            foreach (var userFrom in usersFrom)
            {
                var userTo = usersTo
                    .FirstOrDefault(u=>u.IdUser == userFrom.IdUser);

                if (userTo is null ||
                    userTo.Name != userFrom.Name ||
                    userTo.Surname != userFrom.Surname ||
                    userTo.Patronymic != userFrom.Patronymic)
                {
                    messagesFrom
                        .Where(m => m.IdTelemetryUser == userFrom.IdUser)
                        .ToList()
                        .ForEach(m => m.IdTelemetryUser = usersToNextId);
                    userFrom.IdUser = usersToNextId;
                    userFrom.IdTelemetry = to;
                    usersToNextId++;
                }
            }

            var eventsFromQuery = db.TelemetryEvents
                .Where(d => d.IdTelemetry == from);
            var eventsFrom = await eventsFromQuery
                .ToListAsync(token)
                .ConfigureAwait(false);

            var eventsTo = await db.TelemetryEvents
                .Where(d => d.IdTelemetry == to)
                .AsNoTracking()
                .ToListAsync(token)
                .ConfigureAwait(false);

            var eventsToNextId = eventsTo.Max(e => e.IdEvent) + 1;

            foreach (var eventFrom in eventsFrom)
            {
                var eventTo = eventsTo
                    .FirstOrDefault(e => e.IdEvent == eventFrom.IdEvent);

                if (eventTo is null ||
                    eventTo.IdCategory != eventFrom.IdCategory ||
                    eventTo.MessageTemplate != eventFrom.MessageTemplate)
                {
                    messagesFrom
                        .Where(m => m.IdEvent == eventFrom.IdEvent)
                        .ToList()
                        .ForEach(m => m.IdEvent = eventsToNextId);
                    eventFrom.IdEvent = eventsToNextId;
                    eventFrom.IdTelemetry = to;
                    eventsToNextId++;
                }
            }

            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_user DISABLE TRIGGER ALL;", token).ConfigureAwait(false);
            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_event DISABLE TRIGGER ALL;", token).ConfigureAwait(false);
            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_message DISABLE TRIGGER ALL;", token).ConfigureAwait(false);
            var affected = await db.SaveChangesAsync(token).ConfigureAwait(false);
            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_user ENABLE TRIGGER ALL;", token).ConfigureAwait(false);
            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_event ENABLE TRIGGER ALL;", token).ConfigureAwait(false);
            await db.Database.ExecuteSqlRawAsync($"ALTER TABLE t_telemetry_message ENABLE TRIGGER ALL;", token).ConfigureAwait(false);
            db.TelemetryUsers.RemoveRange(usersFromQuery);
            db.TelemetryEvents.RemoveRange(eventsFromQuery);
            affected += await db.SaveChangesAsync(token).ConfigureAwait(false);
            return affected;
        }

        private async Task<int> MergeDataAsync<TEntity>(int from, int to, CancellationToken token)
            where TEntity: class, AsbCloudDb.Model.ITelemetryData
        {
            const string IdTelemetryColumnName = "\"id_telemetry\"";
            var dbSet = db.Set<TEntity>();
            var tableName = dbSet.GetTableName();
            var columns = dbSet.GetColumnsNames().ToList();
            var index = columns.FindIndex(c => c.ToLower() == IdTelemetryColumnName.ToLower());
            if (index < 0)
                return -5;
            columns[index] = $"{to} as {IdTelemetryColumnName}";
            var columnsString = string.Join(',', columns);
            var sql = $"INSERT INTO {tableName} " +
                $"select {columnsString} " +
                $"from {tableName} " +
                $"where {IdTelemetryColumnName} = {from};" +
                $"delete from {tableName} where {IdTelemetryColumnName} = {from};";

            var affected = await db.Database.ExecuteSqlRawAsync(sql, token)
                .ConfigureAwait(false);

            return affected;
        }
    }
}