using Bogus;
using BulletinBoardContracts.BindingModels;
using BulletinBoardContracts.SearchModels;
using BulletinBoardContracts.StoragesContracts;
using BulletinBoardContracts.ViewModels;
using BulletinBoardDatabase.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BulletinBoardDatabase.Implements
{
	public class AnnouncementStorage : IAnnouncementStorage
	{
		public void ClearEntity()
		{
			using var context = new BulletinBoardDatabase();

			string deleteAllQuery = "DELETE FROM \"Announcements\"";
			context.Database.ExecuteSqlRaw(deleteAllQuery);
		}

		public string TestInsertList(int num)
		{
			Random rnd = new Random();
			var faker = new Faker("ru");
			using var context = new BulletinBoardDatabase();

			var users = context.Users
				.Select(x => x.GetViewModel)
				.ToList();

			var categories = context.Announcements
                .Include(x => x.Category)
				.Select(x => x.GetViewModel)
				.ToList();

            var regions = context.Announcements
            .Include(x => x.Region)
            .Select(x => x.GetViewModel)
            .ToList();

            for (int i = 0; i < num; ++i)
			{
				var model = new AnnouncementBindingModel
				{
					StartDate = DateTime.SpecifyKind(faker.Date.Past(), DateTimeKind.Utc),
					UserId = users[rnd.Next(users.Count)].Id,
					CategoryId = categories[rnd.Next(categories.Count)].Id,
                    RegionId = regions[rnd.Next(regions.Count)].Id,
                };
				context.Announcements.Add(Announcement.Create(model));
			}
			Stopwatch stopwatch = new();

			stopwatch.Start();

			context.SaveChanges();

			stopwatch.Stop();
			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public string TestReadList(int num)
		{
			using var context = new BulletinBoardDatabase();

			Stopwatch stopwatch = new();

			stopwatch.Start();

			List<AnnouncementViewModel> list = context.Announcements
					.Take(num)
					.Select(x => x.GetViewModel)
					.ToList();
			stopwatch.Stop();

			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public string TestJoinReadList(int num)
		{
			using var context = new BulletinBoardDatabase();
			Stopwatch stopwatch = new();

			stopwatch.Start();

			var list = context.Announcements
                    .Include(x => x.Category)
					.Include(x => x.User)
                    .Include(x => x.Region)
                    .Join(context.Users, 
						a => a.UserId, 
						u => u.Id, 
						(a, u) => new { Announcement = a, User = u })
					.Join(context.Categories, 
						ac => ac.Announcement.CategoryId, 
						category => category.Id, 
						(ac, category) => new { ac.Announcement, ac.User, Category = category })
                    .Join(context.Regions,
                        ar => ar.Announcement.RegionId,
                        region => region.Id,
                        (ar, region) => new { ar.Announcement, ar.User, ar.Category, Region = region })
                    .Select(rc => new
					{
                        Announcement = rc.Announcement.GetViewModel,
						User = rc.User.GetViewModel,
						Category = rc.Category.GetViewModel,
                        Region = rc.Region.GetViewModel,
                    })
					.Take(num)
					.ToList();
			stopwatch.Stop();

			return stopwatch.ElapsedMilliseconds.ToString();
		}

		public AnnouncementViewModel? GetElement(AnnouncementSearchModel model)
		{
			if (!model.Id.HasValue)
			{
				return null;
			}

			using var context = new BulletinBoardDatabase();
			return context.Announcements
                .Include(x => x.Category)
				.Include(x => x.User)
                .Include(x => x.Region)
                .FirstOrDefault(x =>
				(model.Id.HasValue && x.Id == model.Id))
				?.GetViewModel;
		}

		public List<AnnouncementViewModel> GetFilteredList(AnnouncementSearchModel model)
		{
			if (!model.Id.HasValue && !model.UserId.HasValue)
			{
				return new();
			}

			using var context = new BulletinBoardDatabase();
			return context.Announcements
                .Include(x => x.Category)
				.Include(x => x.User)
                .Include(x => x.Region)
                .Where(x => x.UserId == model.UserId)
				.Select(x => x.GetViewModel)
				.ToList();
		}

		public List<AnnouncementViewModel> GetFullList()
		{
			using var context = new BulletinBoardDatabase();

			return context.Announcements
                .Include(x => x.Category)
				.Include(x => x.User)
                .Include(x => x.Region)
                .Select(x => x.GetViewModel)
				.ToList();
		}

		public AnnouncementViewModel? Insert(AnnouncementBindingModel model)
        {
			var newAnnouncement = Announcement.Create(model);
			if (newAnnouncement == null)
			{
				return null;
			}

			using var context = new BulletinBoardDatabase();
			context.Announcements.Add(newAnnouncement);
			context.SaveChanges();
			return newAnnouncement.GetViewModel;
		}

		public AnnouncementViewModel? Update(AnnouncementBindingModel model)
		{	
			using var context = new BulletinBoardDatabase();

			var component = context.Announcements.FirstOrDefault(x => x.Id == model.Id);
			if (component == null)
			{
				return null;
			}
			component.Update(model);
			context.SaveChanges();
			return component.GetViewModel;
		}

		public AnnouncementViewModel? Delete(AnnouncementBindingModel model)
		{
			using var context = new BulletinBoardDatabase();

			var element = context.Announcements.FirstOrDefault(rec => rec.Id == model.Id);
			if (element != null)
			{
				context.Announcements.Remove(element);
				context.SaveChanges();
				return element.GetViewModel;
			}
			return null;
		}
	}
}