using AsbCloudApp.Services;
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
{
    public class WitsRecordRepository<TDto, TEntity> : IWitsRecordRepository<TDto>
        where TEntity : class, ITelemetryData
        where TDto: AsbCloudApp.Data.ITelemetryData
    {
        private readonly DbSet<TEntity> dbset;
        private readonly IAsbCloudDbContext db;
        private readonly ITelemetryService telemetryService;

        public WitsRecordRepository(IAsbCloudDbContext db, ITelemetryService telemetryService)
        {
            dbset = db.Set<TEntity>();
            this.db = db;
            this.telemetryService = telemetryService;
        }

        public async Task<(DateTime begin, DateTime end, int count)?> GetStatAsync(int idTelemetry, CancellationToken token)
        {
            var timezoneHours = telemetryService.GetTimezone(idTelemetry).Hours;
            var stat = await dbset.Where(d => d.IdTelemetry == idTelemetry)
                .GroupBy(d => d.IdTelemetry)
                .Select(g => new Tuple<DateTimeOffset, DateTimeOffset, int>(g.Min(d => d.DateTime), g.Max(d => d.DateTime), g.Count()))
                .FirstOrDefaultAsync(token);

            if (stat is null || stat.Item3 == 0)
                return null;

            return (
                stat.Item1.ToRemoteDateTime(timezoneHours),
                stat.Item2.ToRemoteDateTime(timezoneHours),
                stat.Item3);
        }

        public async Task<IEnumerable<TDto>> GetAsync(int idTelemetry, DateTime begin, DateTime end, CancellationToken token)
        {
            var timezoneHours = telemetryService.GetTimezone(idTelemetry).Hours;
            var query = dbset
                .Where(d => d.IdTelemetry == idTelemetry)
                .Where(d => d.DateTime >= begin)
                .Where(d => d.DateTime <= end)
                .AsNoTracking();
            var data = await query.ToListAsync(token);
            return data.Select(d => Convert(d, timezoneHours));
        }

        public Task SaveDataAsync(int idTelemetry, IEnumerable<TDto> dtos, CancellationToken token)
        {
            if (dtos?.Any() != true)
                return Task.CompletedTask;

            var timezoneHours = telemetryService.GetTimezone(idTelemetry).Hours;
            var entities = dtos.Select(dto => Convert(dto, idTelemetry, timezoneHours));

            dbset.AddRange(entities);
            return db.SaveChangesAsync(token);
        }

        private static TEntity Convert(TDto dto, int idTelemetry, double timezoneHours)
        {
            if (dto is null)
                return null;

            var entity = dto.Adapt<TEntity>();
            entity.IdTelemetry = idTelemetry;
            entity.DateTime = dto.DateTime.ToUtcDateTimeOffset(timezoneHours);
            return entity;
        }

        private static TDto Convert(TEntity entity, double timezoneHours)
        {
            if (entity is null)
                return default;

            var data = entity.Adapt<TDto>();
            data.DateTime = entity.DateTime.ToRemoteDateTime(timezoneHours);
            return data;
        }
    }
}