using System;
using System.Linq;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;

await using var connection = new SqliteConnection("Data Source=:memory:;Foreign Keys=True");
await connection.OpenAsync();
var options = new DbContextOptionsBuilder<LabDb>().UseSqlite(connection).Options;
var factory = new Microsoft.EntityFrameworkCore.Infrastructure.PooledDbContextFactory<LabDb>(options, poolSize: 1);
Guid firstInstance;
await using (var first = await factory.CreateDbContextAsync())
{
    await first.Database.EnsureCreatedAsync(); first.Items.Add(new Item { Name = "rune" }); await first.SaveChangesAsync();
    Check(first.ChangeTracker.Entries().Count() == 1, "first lease tracks entity"); first.CustomNote = "lease-one"; firstInstance = first.ContextId.InstanceId;
}
await using (var second = await factory.CreateDbContextAsync())
{
    Check(second.ContextId.InstanceId == firstInstance, "controlled sequential pool reuse");
    Check(!second.ChangeTracker.Entries().Any(), "EF tracker reset"); Check(second.CustomNote == "lease-one", "custom field persists");
    Check(await second.Items.CountAsync() == 1, "SQLite still shared through open connection");
    Console.WriteLine("tracked-after-return:0"); Console.WriteLine("custom-field:" + second.CustomNote); second.CustomNote = "";
}

static void Check(bool condition, string name) { if (!condition) throw new InvalidOperationException("CHECK: " + name); }