using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Data.SqlClient;
using SQLInsight.Collectors.Instance;
using SQLInsight.Core.Data;
using SQLInsight.Core.Instances;
using SQLInsight.Repository;

namespace SQLInsight.IntegrationTests;

/// <summary>The error log as the least-privilege agent sees it: ring buffer without ALTER TRACE, default trace with it.</summary>
[Collection(SqlServerTestGroup.Name)]
[Trait("Category", "Integration")]
public class ErrorLogTests(SqlServerFixture sql)
{
    private static async Task<ErrorLogSnapshot> UntilAsync(AgentSession session, ErrorLogCollector collector, ErrorLogSnapshot previous, Func<ErrorLogSnapshot, bool> done,
        int seconds = 30)
    {
        var latest = previous;
        // SQL Server writes the default trace in buffers: events can take a while to become readable.
        for (var i = 0; i < seconds; i++)
        {
            await Task.Delay(1000);
            latest = await session.CollectAsync(collector, latest with { Recent = latest.Recent });
            if (done(latest))
            {
                break;
            }
        }

        return latest;
    }

    [Fact]
    public async Task Without_alter_trace_failed_logins_come_from_the_ring_buffer_with_the_reason()
    {
        await using var session = await AgentSession.OpenAsync(sql);
        var collector = new ErrorLogCollector();
        var first = await session.CollectAsync<ErrorLogSnapshot>(collector);
        for (var i = 0; i < 3; i++)
        {
            var wrong = new SqlConnectionStringBuilder(sql.AgentConnectionString) { Password = "forkert-" + i, Pooling = false };
            await using var connection = new SqlConnection(wrong.ConnectionString);
            await Assert.ThrowsAsync<SqlException>(() => connection.OpenAsync());
        }

        var latest = await UntilAsync(session, collector, first, s => s.Recent.Any(g => g.Category == ErrorLogCategory.LoginFailed && g.Count >= 3));

        Assert.Equal(ErrorLogSource.RingBuffer, first.Source);
        Assert.Contains("ALTER TRACE", first.Coverage, StringComparison.Ordinal);
        var logins = Assert.Single(latest.Recent, g => g.Category == ErrorLogCategory.LoginFailed);
        Assert.True(logins.Count >= 3);
        Assert.Contains("state 8", logins.Sample, StringComparison.Ordinal);
    }

    [Fact]
    public async Task With_alter_trace_the_error_log_and_failed_logins_are_read_from_the_default_trace()
    {
        await sql.ExecuteAsSaAsync($"GRANT ALTER TRACE TO [{SqlServerFixture.AgentLogin}];");
        try
        {
            await using var session = await AgentSession.OpenAsync(sql);
            var collector = new ErrorLogCollector(loginFailureBurst: 3);
            var first = await session.CollectAsync<ErrorLogSnapshot>(collector);
            await Assert.ThrowsAsync<SqlException>(() => sql.ExecuteAsSaAsync("RAISERROR (N'SQLInsight test written to the error log', 20, 1) WITH LOG;"));
            for (var i = 0; i < 4; i++)
            {
                var wrong = new SqlConnectionStringBuilder(sql.AgentConnectionString) { Password = "forkert-" + i, Pooling = false };
                await using var connection = new SqlConnection(wrong.ConnectionString);
                await Assert.ThrowsAsync<SqlException>(() => connection.OpenAsync());
            }

            var latest = await UntilAsync(session, collector, first,
                s => s.Recent.Any(g => g.Error == 50000) && s.Recent.Any(g => g.Category == ErrorLogCategory.LoginFailed && g.Count >= 4), seconds: 120);

            Assert.Equal(ErrorLogSource.DefaultTrace, latest.Source);
            Assert.Contains("securityadmin", latest.Coverage, StringComparison.Ordinal);
            var logged = Assert.Single(latest.Recent, g => g.Error == 50000);
            Assert.Contains("SQLInsight test written to the error log", logged.Sample, StringComparison.Ordinal);
            Assert.True(latest.Recent.Single(g => g.Category == ErrorLogCategory.LoginFailed).Count >= 4);
        }
        finally
        {
            await sql.ExecuteAsSaAsync($"REVOKE ALTER TRACE FROM [{SqlServerFixture.AgentLogin}];");
        }
    }

    [Fact]
    public async Task Page_and_api_show_events_with_the_sample_left_out_of_the_api()
    {
        var database = "SQLInsightLog_" + Guid.NewGuid().ToString("N")[..8];
        await sql.ExecuteAsSaAsync($"CREATE DATABASE [{database}];");
        try
        {
            var repository = new InsightRepository(sql.DatabaseConnectionString(database));
            await repository.MigrateAsync();
            var now = DateTimeOffset.UtcNow;
            var id = await repository.UpsertInstanceAsync("prod-sql01", new InstanceInfo
            {
                ServerName = "SQL01", Version = SqlServerVersion.Parse("16.0.4135.4"), ProductLevel = "RTM", Edition = "Standard Edition", EngineEdition = EngineEdition.Standard,
            }, "SqlClient", false, now);
            var groups = new[] { new ErrorLogGroup(ErrorLogCategory.Corruption, 824, 24, 2, now.AddMinutes(-4), now.AddMinutes(-1), "incorrect checksum in AX.mdf") };
            await repository.SaveCollectedAsync(id, "error-log", new ErrorLogSnapshot
            {
                CapturedAt = now, Source = ErrorLogSource.DefaultTrace, ReadUntil = now, Groups = groups, Recent = groups,
            });

            await using var factory = new WebApplicationFactory<Program>().WithWebHostBuilder(b =>
            {
                b.UseEnvironment("Development");
                b.UseSetting("SQLInsight:Repository:ConnectionString", sql.DatabaseConnectionString(database));
                b.UseSetting("SQLInsight:Web:Authentication", "None");
            });
            var client = factory.CreateClient();
            var page = await client.GetStringAsync("/instanser/prod-sql01/fejllog");
            var api = await client.GetStringAsync("/api/v1/instances/prod-sql01/error-log");

            Assert.Contains("Beskadigede sider", page, StringComparison.Ordinal);
            Assert.Contains("incorrect checksum", page, StringComparison.Ordinal);
            Assert.Contains("824", api, StringComparison.Ordinal);
            Assert.Contains("[udeladt]", api, StringComparison.Ordinal);
            Assert.DoesNotContain("incorrect checksum", api, StringComparison.Ordinal);
        }
        finally
        {
            await sql.ExecuteAsSaAsync($"ALTER DATABASE [{database}] SET SINGLE_USER WITH ROLLBACK IMMEDIATE; DROP DATABASE [{database}];");
        }
    }
}