using System;
using System.Linq;
using System.Threading.Tasks;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;
using Bogus;
using Bogus.DataSets;
using LinqToDB;
using LinqToDB.Configuration;
using LinqToDB.Data;
using LinqToDB.Mapping;
using Microsoft.EntityFrameworkCore;

namespace BulkInsertBench
{
    [MemoryDiagnoser]
    public class BulkInsertBench
    {
        private readonly Faker<User> _faker = new Faker<User>()
            .RuleFor(u => u.Id, _ => 0)
            .RuleFor(u => u.Gender, f => f.PickRandom<Name.Gender>())
            .RuleFor(u => u.FirstName, (f, u) => f.Name.FirstName(u.Gender))
            .RuleFor(u => u.LastName, (f, u) => f.Name.LastName(u.Gender))
            .RuleFor(u => u.Avatar, f => f.Internet.Avatar())
            .RuleFor(u => u.UserName, (f, u) => f.Internet.UserName(u.FirstName, u.LastName))
            .RuleFor(u => u.Email, (f, u) => f.Internet.Email(u.FirstName, u.LastName))
            .RuleFor(u => u.DateOfBirth, f => f.Date.Past(100, DateTime.Parse("1/1/2010")));

        private User[] _users;

        [Params(10_000, 100_000)]
        public int N;

        [IterationSetup]
        public void IterationSetup()
        {
            _users = Enumerable.Range(0, N).Select(_ => _faker.Generate()).ToArray();
        }

        [IterationCleanup]
        public void IterationCleanup()
        {
            using var db = new LinqToDb();
            db.Users.Delete();
        }

        private async Task EfAdd(EfContext context)
        {
            foreach (var user in _users) await context.AddAsync(user);
            await context.SaveChangesAsync();
        }

        [Benchmark]
        public async Task EfAdd()
        {
            await using var context = new EfContext();
            await EfAdd(context);
        }

        [Benchmark]
        public async Task EfAddNoTracking()
        {
            await using var context = new EfContext {ChangeTracker = {AutoDetectChangesEnabled = false}};
            await EfAdd(context);
        }

        private async Task EfAddRange(EfContext context)
        {
            await context.Users.AddRangeAsync(_users);
            await context.SaveChangesAsync();
        }

        [Benchmark]
        public async Task EfAddRange()
        {
            await using var context = new EfContext();
            await EfAddRange(context);
        }

        [Benchmark]
        public async Task EfAddRangeNoTracking()
        {
            await using var context = new EfContext {ChangeTracker = {AutoDetectChangesEnabled = false}};
            await EfAddRange(context);
        }

        [Benchmark]
        public async Task EfExtensionsBulkInsert()
        {
            await using var db = new EfContext();
            await db.BulkInsertAsync(_users);
        }

        [Benchmark]
        public async Task LinqToDbBulkCopy()
        {
            await using var db = new LinqToDb();
            await db.BulkCopyAsync(_users);
        }
    }

    class Program
    {
        static void Main()
        {
            BenchmarkRunner.Run<BulkInsertBench>();
        }
    }

    class EfContext : DbContext
    {
        public DbSet<User> Users { get; set; }
        protected override void OnConfiguring(DbContextOptionsBuilder options)
        {
            options.UseSqlServer(@"Data Source=(LocalDb)\MSSQLLocalDB;Database=BulkInsertBenchDb;");
        }
    }

    public class LinqToDb : DataConnection
    {
        public LinqToDb() : base(new LinqToDbConnectionOptionsBuilder()
            .UseSqlServer(@"Data Source=(LocalDb)\MSSQLLocalDB;Database=BulkInsertBenchDb;").Build()) { }
        public ITable<User> Users => GetTable<User>();
    }

    [Table(Name = "Users")]
    public class User
    {
        [PrimaryKey] public int Id { get; set; }
        [Column] public string FirstName { get; set; }
        [Column] public string LastName { get; set; }
        [Column] public string UserName { get; set; }
        [Column] public string Email { get; set; }
        [Column] public string Avatar { get; set; }
        [Column] public Name.Gender Gender { get; set; }
        [Column] public DateTime DateOfBirth { get; set; }
    }
}