// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore.Diagnostics.Internal;
using Microsoft.EntityFrameworkCore.Infrastructure;
using EntityFrameworkCore.Jet.Diagnostics.Internal;
using EntityFrameworkCore.Jet.FunctionalTests.TestUtilities;
using EntityFrameworkCore.Jet.Infrastructure;
using EntityFrameworkCore.Jet.Infrastructure.Internal;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using Microsoft.EntityFrameworkCore.TestUtilities;
using Xunit;
using Microsoft.Extensions.Options;

#nullable disable
// ReSharper disable UnusedAutoPropertyAccessor.Local
// ReSharper disable InconsistentNaming
namespace EntityFrameworkCore.Jet.FunctionalTests
{
    public class BatchingTest : IClassFixture<BatchingTest.BatchingTestFixture>
    {
        public BatchingTest(BatchingTestFixture fixture)
        {
            Fixture = fixture;
        }

        protected BatchingTestFixture Fixture { get; }

        [ConditionalTheory]
        [InlineData(true, true, true)]
        [InlineData(false, true, true)]
        [InlineData(true, false, true)]
        [InlineData(false, false, true)]
        [InlineData(true, true, false)]
        [InlineData(false, true, false)]
        [InlineData(true, false, false)]
        [InlineData(false, false, false)]
        public Task Inserts_are_batched_correctly(bool clientPk, bool clientFk, bool clientOrder)
        {
            var expectedBlogs = new List<Blog>();
            return ExecuteWithStrategyInTransactionAsync(
                context =>
                {
                    var owner1 = new Owner();
                    var owner2 = new Owner();
                    context.Owners.Add(owner1);
                    context.Owners.Add(owner2);

                    for (var i = 1; i < 500; i++)
                    {
                        var blog = new Blog();
                        if (clientPk)
                        {
                            blog.Id = Guid.NewGuid();
                        }

                        if (clientFk)
                        {
                            blog.Owner = i % 2 == 0 ? owner1 : owner2;
                        }

                        if (clientOrder)
                        {
                            blog.Order = i;
                        }

                        context.Set<Blog>().Add(blog);
                        expectedBlogs.Add(blog);
                    }

                    return context.SaveChangesAsync();
                },
                context => AssertDatabaseState(context, clientOrder, expectedBlogs));
        }

        [ConditionalFact]
        public Task Inserts_and_updates_are_batched_correctly()
        {
            var expectedBlogs = new List<Blog>();

            return ExecuteWithStrategyInTransactionAsync(
                async context =>
                {
                    var owner1 = new Owner { Name = "0" };
                    var owner2 = new Owner { Name = "1" };
                    context.Owners.Add(owner1);
                    context.Owners.Add(owner2);

                    var blog1 = new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner1,
                        Order = 1
                    };

                    context.Set<Blog>().Add(blog1);
                    expectedBlogs.Add(blog1);

                    await context.SaveChangesAsync();

                    owner2.Name = "2";

                    blog1.Order = 0;
                    var blog2 = new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner1,
                        Order = 1
                    };

                    context.Set<Blog>().Add(blog2);
                    expectedBlogs.Add(blog2);

                    var blog3 = new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner2,
                        Order = 2
                    };

                    context.Set<Blog>().Add(blog3);
                    expectedBlogs.Add(blog3);

                    await context.SaveChangesAsync();
                },
                context => AssertDatabaseState(context, true, expectedBlogs));
        }

        [ConditionalTheory]
        [InlineData(1)]
        [InlineData(3)]
        [InlineData(4)]
        [InlineData(100)]
        public Task Insertion_order_is_preserved(int maxBatchSize)
        {
            var blogId = new Guid();

            return TestHelpers.ExecuteWithStrategyInTransactionAsync(
                () => (BloggingContext)Fixture.CreateContext(maxBatchSize: maxBatchSize),
                UseTransaction, async context =>
                {
                    var owner = new Owner();
                    var blog = new Blog { Owner = owner };

                    for (var i = 0; i < 20; i++)
                    {
                        context.Add(new Post { Order = i, Blog = blog });
                    }

                    await context.SaveChangesAsync();

                    blogId = blog.Id;
                }, async context =>
                {
                    var posts = context.Set<Post>().Where(p => p.BlogId == blogId).OrderBy(p => p.Order);
                    var lastId = 0;
                    foreach (var post in await posts.ToListAsync())
                    {
                        Assert.True(post.PostId > lastId, $"Last ID: {lastId}, current ID: {post.PostId}");
                        lastId = post.PostId;
                    }
                });
        }

        [ConditionalFact]
        public async Task Deadlock_on_inserts_and_deletes_with_dependents_is_handled_correctly()
        {
            var blogs = new List<Blog>();

            using (var context = CreateContext())
            {
                var owner1 = new Owner { Name = "0" };
                var owner2 = new Owner { Name = "1" };
                context.Owners.Add(owner1);
                context.Owners.Add(owner2);

                blogs.Add(
                    new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner1,
                        Order = 1
                    });
                blogs.Add(
                    new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner2,
                        Order = 2
                    });
                blogs.Add(
                    new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner1,
                        Order = 3
                    });
                blogs.Add(
                    new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner2,
                        Order = 4
                    });

                context.AddRange(blogs);

                await context.SaveChangesAsync();
            }

            var tasks = new List<Task>();
            for (var i = 0; i < 10; i++)
            {
                foreach (var blog in blogs)
                {
                    tasks.Add(RemoveAndAddPosts(blog));
                }
            }

            Task.WaitAll(tasks.ToArray());

            async Task RemoveAndAddPosts(Blog blog)
            {
                using var context = (BloggingContext)Fixture.CreateContext(useConnectionString: true);

                context.Attach(blog);
                blog.Posts.Clear();

                blog.Posts.Add(new Post { Comments = { new Comment() } });
                blog.Posts.Add(new Post { Comments = { new Comment() } });
                blog.Posts.Add(new Post { Comments = { new Comment() } });

                await context.SaveChangesAsync();
            }

            await Fixture.ReseedAsync();
        }

        [ConditionalFact]
        public async Task Deadlock_on_deletes_with_dependents_is_handled_correctly()
        {
            var owners = new[] { new Owner { Name = "0" }, new Owner { Name = "1" } };
            using (var context = CreateContext())
            {
                context.Owners.AddRange(owners);

                for (var h = 0; h <= 40; h++)
                {
                    var owner = owners[h % 2];
                    var blog = new Blog
                    {
                        Id = Guid.NewGuid(),
                        Owner = owner,
                        Order = h
                    };

                    for (var i = 0; i <= 40; i++)
                    {
                        blog.Posts.Add(new Post { Comments = { new Comment() } });
                    }

                    context.Add(blog);
                }

                await context.SaveChangesAsync();
            }

            async Task Action(Owner owner)
            {
                using var context = (BloggingContext)Fixture.CreateContext(useConnectionString: true);

                context.RemoveRange(await context.Blogs.Where(b => b.OwnerId == owner.Id).ToListAsync());

                await context.SaveChangesAsync();
            }

            var tasks = new List<Task>();
            foreach (var owner in owners)
            {
                tasks.Add(Action(owner));
            }

            Task.WaitAll(tasks.ToArray());

            using (var context = CreateContext())
            {
                Assert.Empty(await context.Blogs.ToListAsync());
            }

            await Fixture.ReseedAsync();
        }

        [ConditionalFact]
        public Task Inserts_when_database_type_is_different()
            => ExecuteWithStrategyInTransactionAsync(
                context =>
                {
                    var owner1 = new Owner { Id = "0", Name = "Zero" };
                    var owner2 = new Owner { Id = "A", Name = string.Join("", Enumerable.Repeat('A', 255)) };
                    context.Owners.Add(owner1);
                    context.Owners.Add(owner2);

                    return context.SaveChangesAsync();
                }, async context => Assert.Equal(2, await context.Owners.CountAsync()));

        [ConditionalTheory]
        [InlineData(3)]
        [InlineData(4)]
        public Task Inserts_are_batched_only_when_necessary(int minBatchSize)
        {
            var expectedBlogs = new List<Blog>();
            return TestHelpers.ExecuteWithStrategyInTransactionAsync(
                () => (BloggingContext)Fixture.CreateContext(minBatchSize),
                UseTransaction, async context =>
                {
                    var owner = new Owner();
                    context.Owners.Add(owner);

                    for (var i = 1; i < 3; i++)
                    {
                        var blog = new Blog { Id = Guid.NewGuid(), Owner = owner };

                        context.Set<Blog>().Add(blog);
                        expectedBlogs.Add(blog);
                    }

                    Fixture.TestSqlLoggerFactory.Clear();

                    await context.SaveChangesAsync();

                    Assert.Contains(
                        minBatchSize == 3
                            ? RelationalResources.LogBatchReadyForExecution(new TestLogger<JetLoggingDefinitions>())
                                .GenerateMessage(3)
                            : RelationalResources.LogBatchSmallerThanMinBatchSize(new TestLogger<JetLoggingDefinitions>())
                                .GenerateMessage(3, 4),
                        Fixture.TestSqlLoggerFactory.Log.Select(l => l.Message));

                    Assert.Equal(minBatchSize <= 3 ? 1 : 3, Fixture.TestSqlLoggerFactory.SqlStatements.Count);
                }, context => AssertDatabaseState(context, false, expectedBlogs));
        }

        private async Task AssertDatabaseState(DbContext context, bool clientOrder, List<Blog> expectedBlogs)
        {
            expectedBlogs = clientOrder
                ? expectedBlogs.OrderBy(b => b.Order).ToList()
                : expectedBlogs.OrderBy(b => b.Id).ToList();
            var actualBlogs = clientOrder
                ? await context.Set<Blog>().OrderBy(b => b.Order).ToListAsync()
                : expectedBlogs.OrderBy(b => b.Id).ToList();
            Assert.Equal(expectedBlogs.Count, actualBlogs.Count);

            for (var i = 0; i < actualBlogs.Count; i++)
            {
                var expected = expectedBlogs[i];
                var actual = actualBlogs[i];
                Assert.Equal(expected.Id, actual.Id);
                Assert.Equal(expected.Order, actual.Order);
                Assert.Equal(expected.OwnerId, actual.OwnerId);
                Assert.Equal(expected.Version, actual.Version);
            }
        }

        private BloggingContext CreateContext() => (BloggingContext)Fixture.CreateContext();

        private Task ExecuteWithStrategyInTransactionAsync(
            Func<BloggingContext, Task> testOperation,
            Func<BloggingContext, Task> nestedTestOperation)
            => TestHelpers.ExecuteWithStrategyInTransactionAsync(
                CreateContext, UseTransaction, testOperation, nestedTestOperation);

        protected void UseTransaction(DatabaseFacade facade, IDbContextTransaction transaction)
            => facade.UseTransaction(transaction.GetDbTransaction());

        private class BloggingContext : PoolableDbContext
        {
            public BloggingContext(DbContextOptions options)
                : base(options)
            {
            }

            protected override void OnModelCreating(ModelBuilder modelBuilder)
            {
                modelBuilder.Entity<Owner>(
                    b =>
                    {
                        b.Property(e => e.Id).ValueGeneratedOnAdd();
                        b.Property(e => e.Version).IsConcurrencyToken().ValueGeneratedOnAddOrUpdate();
                        b.Property(e => e.Name).HasColumnType("nvarchar(255)");
                    });
                modelBuilder.Entity<Blog>(
                    b =>
                    {
                        b.Property(e => e.Id).HasDefaultValueSql("GenGUID()");
                        b.Property(e => e.Version).IsConcurrencyToken().ValueGeneratedOnAddOrUpdate();
                    });
            }

            // ReSharper disable once UnusedMember.Local
            public DbSet<Blog> Blogs { get; set; }
            public DbSet<Owner> Owners { get; set; }
        }

        private class Blog
        {
            public Guid Id { get; set; }
            public int Order { get; set; }
            public string OwnerId { get; set; }
            public Owner Owner { get; set; }
            public byte[] Version { get; set; }
            public ICollection<Post> Posts { get; } = new HashSet<Post>();
        }

        private class Owner
        {
            public string Id { get; set; }
            public string Name { get; set; }
            public byte[] Version { get; set; }
        }

        private class Post
        {
            public int PostId { get; set; }
            public int? Order { get; set; }
            public Guid BlogId { get; set; }
            public Blog Blog { get; set; }
            public ICollection<Comment> Comments { get; } = new HashSet<Comment>();
        }

        private class Comment
        {
            public int CommentId { get; set; }
            public int PostId { get; set; }
            public Post Post { get; set; }
        }

        public class BatchingTestFixture : SharedStoreFixtureBase<PoolableDbContext>
        {
            protected override string StoreName { get; } = "BatchingTest";
            public TestSqlLoggerFactory TestSqlLoggerFactory => (TestSqlLoggerFactory)ListLoggerFactory;
            protected override ITestStoreFactory TestStoreFactory => JetTestStoreFactory.Instance;
            protected override Type ContextType { get; } = typeof(BloggingContext);

            protected override bool ShouldLogCategory(string logCategory)
                => logCategory == DbLoggerCategory.Update.Name;

            protected override async Task SeedAsync(PoolableDbContext context)
            {
                await context.Database.EnsureCreatedResilientlyAsync();
                await context.Database.ExecuteSqlRawAsync(
                    @"
ALTER TABLE Owners
    ALTER COLUMN Name nvarchar(255);");
            }

            public DbContext CreateContext(int? minBatchSize = null,
                int? maxBatchSize = null,
                bool useConnectionString = false)
            {
                var options = CreateOptions();
                var optionsBuilder = new DbContextOptionsBuilder(options);
                if (useConnectionString)
                {
                    RelationalOptionsExtension extension = options.FindExtension<JetOptionsExtension>()
                        ?? new JetOptionsExtension();

                    extension = extension.WithConnection(null).WithConnectionString(((JetTestStore)TestStore).ConnectionString);
                    ((IDbContextOptionsBuilderInfrastructure)optionsBuilder).AddOrUpdateExtension(extension);
                }

                if (minBatchSize.HasValue)
                {
                    new JetDbContextOptionsBuilder(optionsBuilder).MinBatchSize(minBatchSize.Value);
                }

                if (maxBatchSize.HasValue)
                {
                    new JetDbContextOptionsBuilder(optionsBuilder).MinBatchSize(maxBatchSize.Value);
                }
                return new BloggingContext(optionsBuilder.Options);
            }
        }
    }
}