using Akka.Actor;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Shouldly;
using Xunit;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
using ZB.MOM.WW.OtOpcUa.ControlPlane.Retention;
using ZB.MOM.WW.OtOpcUa.ControlPlane.Tests.Harness;

namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests;

/// <summary>
///     R03:1.2 — every deploy stored the whole fleet snapshot forever. The retention sweep empties the
///     blob on old terminal rows (never deletes a row, never touches an in-flight one, never the newest N,
///     never one a node applied recently).
/// </summary>
public sealed class DeploymentRetentionTests : ControlPlaneActorTestBase
{
    private static readonly DateTime SweepNow = new(2026, 10, 22, 12, 0, 0, DateTimeKind.Utc);

    [Fact]
    public async Task Sweep_empties_blobs_beyond_the_keep_window_and_leaves_the_newest_intact()
    {
        var f = NewInMemoryDbFactory();
        var ids = Seed(f, sealedCount: 12);   // ids[0] newest … ids[11] oldest
        var options = new DeploymentRetentionOptions { KeepSealed = 5, ReferencedDays = 30, MaxRowsPerSweep = 200 };

        int pruned;
        await using (var db = f.CreateDbContext())
            pruned = await DeploymentRetentionActor.SweepAsync(db, options, SweepNow);

        pruned.ShouldBe(7);
        await using var verify = f.CreateDbContext();
        foreach (var id in ids.Take(5))
            (await verify.Deployments.SingleAsync(d => d.DeploymentId == id)).ArtifactBlob.Length.ShouldBeGreaterThan(0, "newest 5 keep their blob");
        foreach (var id in ids.Skip(5))
            (await verify.Deployments.SingleAsync(d => d.DeploymentId == id)).ArtifactBlob.ShouldBeEmpty("older rows are emptied");
        // Rows survive: the audit record is intact.
        (await verify.Deployments.CountAsync()).ShouldBe(12);

        // Idempotent: a second sweep finds nothing.
        await using var again = f.CreateDbContext();
        (await DeploymentRetentionActor.SweepAsync(again, options, SweepNow)).ShouldBe(0);
    }

    [Fact]
    public async Task Sweep_keeps_a_row_a_node_applied_recently_and_never_touches_an_in_flight_row()
    {
        var f = NewInMemoryDbFactory();
        var ids = Seed(f, sealedCount: 4);
        var inFlight = Guid.NewGuid();
        await using (var db = f.CreateDbContext())
        {
            db.ClusterNodes.Add(new ClusterNode
            {
                NodeId = "site-a-1:4053", ClusterId = "SITE-A", Host = "site-a-1",
                ApplicationUri = "urn:x", Enabled = true, CreatedBy = "test",
            });
            // ids[3] is the oldest; a node applied it yesterday, so it stays.
            db.NodeDeploymentStates.Add(new NodeDeploymentState
            {
                NodeId = "site-a-1:4053", DeploymentId = ids[3], Status = NodeDeploymentStatus.Applied,
                StartedAtUtc = SweepNow.AddDays(-1), AppliedAtUtc = SweepNow.AddDays(-1),
            });
            // ids[2]: applied long ago — not protected.
            db.NodeDeploymentStates.Add(new NodeDeploymentState
            {
                NodeId = "site-a-1:4053", DeploymentId = ids[2], Status = NodeDeploymentStatus.Applied,
                StartedAtUtc = SweepNow.AddDays(-90), AppliedAtUtc = SweepNow.AddDays(-90),
            });
            // An ancient in-flight row with a blob — never touched.
            db.Deployments.Add(new Deployment
            {
                DeploymentId = inFlight, RevisionHash = new string('f', 64), Status = DeploymentStatus.AwaitingApplyAcks,
                CreatedBy = "test", CreatedAtUtc = SweepNow.AddDays(-400), ArtifactBlob = new byte[] { 1, 2, 3 },
            });
            await db.SaveChangesAsync();
        }
        var options = new DeploymentRetentionOptions { KeepSealed = 1, ReferencedDays = 30 };

        await using (var db = f.CreateDbContext())
            (await DeploymentRetentionActor.SweepAsync(db, options, SweepNow)).ShouldBe(2);   // ids[1], ids[2]

        await using var verify = f.CreateDbContext();
        (await verify.Deployments.SingleAsync(d => d.DeploymentId == ids[0])).ArtifactBlob.ShouldNotBeEmpty("newest");
        (await verify.Deployments.SingleAsync(d => d.DeploymentId == ids[1])).ArtifactBlob.ShouldBeEmpty();
        (await verify.Deployments.SingleAsync(d => d.DeploymentId == ids[2])).ArtifactBlob.ShouldBeEmpty("applied 90 days ago");
        (await verify.Deployments.SingleAsync(d => d.DeploymentId == ids[3])).ArtifactBlob.ShouldNotBeEmpty("applied yesterday");
        (await verify.Deployments.SingleAsync(d => d.DeploymentId == inFlight)).ArtifactBlob.ShouldNotBeEmpty("in flight");
    }

    [Fact]
    public async Task Sweep_is_bounded_per_call_and_drains_a_backlog_over_calls()
    {
        var f = NewInMemoryDbFactory();
        Seed(f, sealedCount: 10);
        var options = new DeploymentRetentionOptions { KeepSealed = 2, MaxRowsPerSweep = 3 };

        await using (var db = f.CreateDbContext())
            (await DeploymentRetentionActor.SweepAsync(db, options, SweepNow)).ShouldBe(3);
        await using (var db = f.CreateDbContext())
            (await DeploymentRetentionActor.SweepAsync(db, options, SweepNow)).ShouldBe(3);
        await using (var db = f.CreateDbContext())
            (await DeploymentRetentionActor.SweepAsync(db, options, SweepNow)).ShouldBe(2);
        await using (var db = f.CreateDbContext())
            (await DeploymentRetentionActor.SweepAsync(db, options, SweepNow)).ShouldBe(0);
    }

    /// <summary>The actor runs the same rule off its thread and reports back.</summary>
    [Fact]
    public void Actor_sweeps_on_request_and_reports_the_count()
    {
        var f = NewInMemoryDbFactory();
        Seed(f, sealedCount: 6);
        var actor = Sys.ActorOf(DeploymentRetentionActor.Props(f, new DeploymentRetentionOptions
        {
            KeepSealed = 4, InitialDelaySeconds = 3600, IntervalMinutes = 60,
        }));

        actor.Tell(DeploymentRetentionActor.Sweep.Instance);

        ExpectMsg<DeploymentRetentionActor.SweepCompleted>(PresenceBudget).Pruned.ShouldBe(2);
        using var verify = f.CreateDbContext();
        verify.Deployments.Count(d => d.ArtifactBlob.Length == 0).ShouldBe(2);
    }

    [Fact]
    public void Options_bind_from_configuration_with_defaults()
    {
        var defaults = DeploymentRetentionOptions.Bind(null);
        defaults.Enabled.ShouldBeTrue();
        defaults.KeepSealed.ShouldBe(50);
        defaults.ReferencedDays.ShouldBe(30);
        defaults.IntervalMinutes.ShouldBe(60);

        var config = new ConfigurationBuilder()
            .AddInMemoryCollection(new Dictionary<string, string?>
            {
                ["Deployments:Retention:KeepSealed"] = "7",
                ["Deployments:Retention:Enabled"] = "false",
            })
            .Build();
        var bound = DeploymentRetentionOptions.Bind(config);
        bound.KeepSealed.ShouldBe(7);
        bound.Enabled.ShouldBeFalse();
        bound.ReferencedDays.ShouldBe(30);
    }

    /// <summary>Seeds sealed deployments, newest first; each one hour older than the previous.</summary>
    private static List<Guid> Seed(IDbContextFactory<OtOpcUaConfigDbContext> f, int sealedCount)
    {
        var ids = new List<Guid>();
        using var db = f.CreateDbContext();
        for (var i = 0; i < sealedCount; i++)
        {
            var id = Guid.NewGuid();
            ids.Add(id);
            db.Deployments.Add(new Deployment
            {
                DeploymentId = id,
                RevisionHash = new string('a', 64),
                Status = i % 3 == 2 ? DeploymentStatus.TimedOut : DeploymentStatus.Sealed,
                CreatedBy = "test",
                CreatedAtUtc = SweepNow.AddHours(-i),
                SealedAtUtc = SweepNow.AddHours(-i),
                ArtifactBlob = new byte[] { 0x1f, 0x8b, (byte)i },
            });
        }
        db.SaveChanges();
        return ids;
    }
}