using Akka.Actor;
using Akka.TestKit.Xunit2;
using Microsoft.Extensions.Logging.Abstractions;
using ZB.MOM.WW.LocalDb;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Deployment;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums;
using ZB.MOM.WW.ScadaBridge.Commons.Types.Flattening;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Actors;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Persistence;
using ZB.MOM.WW.ScadaBridge.SiteRuntime.Scripts;
using ZB.MOM.WW.ScadaBridge.TestSupport;
using System.Text.Json;

namespace ZB.MOM.WW.ScadaBridge.SiteRuntime.Tests.Actors;

/// <summary>
/// Regression tests for the Medium-severity DeploymentManagerActor findings:
/// SiteRuntime-005 (Success reported before persistence completes) and
/// SiteRuntime-008 (blocking shared-script load on the actor thread).
/// </summary>
public class DeploymentManagerMediumFindingsTests : TestKit, IDisposable
{
    private readonly ScriptCompilationService _compilationService;
    private readonly SharedScriptLibrary _sharedScriptLibrary;
    private readonly TestLocalDb _localDb;

    public DeploymentManagerMediumFindingsTests()
    {
        _localDb = TestLocalDb.CreateTemp("dm-medium-test");
        _compilationService = new ScriptCompilationService(
            NullLogger<ScriptCompilationService>.Instance);
        _sharedScriptLibrary = new SharedScriptLibrary(
            _compilationService, NullLogger<SharedScriptLibrary>.Instance);
    }

    void IDisposable.Dispose()
    {
        // TestKit teardown first, so no in-flight actor can reach a disposed ILocalDb;
        // then dispose the database before deleting — the master connection anchors the WAL.
        Shutdown();
        var path = _localDb.Path;
        _localDb.Dispose();
        TestLocalDb.DeleteFiles(path);
    }

    private SiteStorageService NewStorage(ILocalDb localDb)
        => new(localDb, NullLogger<SiteStorageService>.Instance);

    private IActorRef CreateDeploymentManager(SiteStorageService storage, IActorRef? dclManager = null)
    {
        return ActorOf(Props.Create(() => new DeploymentManagerActor(
            storage,
            _compilationService,
            _sharedScriptLibrary,
            null,
            new SiteRuntimeOptions(),
            NullLogger<DeploymentManagerActor>.Instance,
            dclManager,
            null,
            null,
            null)));
    }

    private static string MakeConfigJsonWithConnection(
        string instanceName, string endpoint, int failoverRetryCount)
    {
        var config = new FlattenedConfiguration
        {
            InstanceUniqueName = instanceName,
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "TestAttr", Value = "1", DataType = "Int32" }
            ],
            Connections = new Dictionary<string, ConnectionConfig>
            {
                ["Conn1"] = new ConnectionConfig
                {
                    Protocol = "Custom",
                    ConfigurationJson = $"{{\"endpoint\":\"{endpoint}\"}}",
                    FailoverRetryCount = failoverRetryCount
                }
            }
        };
        return JsonSerializer.Serialize(config);
    }

    private static string MakeConfigJson(string instanceName)
    {
        var config = new FlattenedConfiguration
        {
            InstanceUniqueName = instanceName,
            Attributes =
            [
                new ResolvedAttribute { CanonicalName = "TestAttr", Value = "1", DataType = "Int32" }
            ]
        };
        return JsonSerializer.Serialize(config);
    }

    /// <summary>
    /// SiteRuntime-005: when SQLite persistence of the deployed config fails, the
    /// Deployment Manager must report <see cref="DeploymentStatus.Failed"/> to central,
    /// not <see cref="DeploymentStatus.Success"/>. Reporting Success on a persistence
    /// failure silently loses the deployment on the next restart/failover.
    /// </summary>
    [Fact]
    public async Task Deploy_PersistenceFailure_ReportsFailedNotSuccess()
    {
        // A storage over a database whose site tables were never created makes every
        // storage operation throw ("no such table"), so StoreDeployedConfigAsync fails.
        //
        // This replaces the old "connection string pointing at an unwritable path" trick:
        // the service now takes an ILocalDb rather than a connection string, and LocalDb
        // opens its file eagerly in its own constructor — so an unopenable path fails
        // while building the fixture, before there is a storage to hand the actor at all.
        // Skipping InitializeAsync is the equivalent lever on the new seam, and fails the
        // same way the old one did: reads AND writes both throw.
        var uninitialized = TestLocalDb.CreateTemp("dm-medium-persist-fail");
        try
        {
            var storage = NewStorage(uninitialized.Db);

            var actor = CreateDeploymentManager(storage);
            await Task.Delay(500); // empty startup

            actor.Tell(new DeployInstanceCommand(
                "dep-fail", "FailPump", "h1", MakeConfigJson("FailPump"), "admin", DateTimeOffset.UtcNow));

            var response = ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(10));
            Assert.Equal("FailPump", response.InstanceUniqueName);
            Assert.Equal(DeploymentStatus.Failed, response.Status);
            Assert.False(string.IsNullOrEmpty(response.ErrorMessage));
        }
        finally
        {
            var path = uninitialized.Path;
            uninitialized.Dispose();
            TestLocalDb.DeleteFiles(path);
        }
    }

    /// <summary>
    /// SiteRuntime-005: a successful deployment must still report
    /// <see cref="DeploymentStatus.Success"/>, and only after the config row is
    /// committed to SQLite (so a restart re-creates the instance).
    /// </summary>
    [Fact]
    public async Task Deploy_Success_ReportsSuccessAndPersistsConfig()
    {
        var storage = NewStorage(_localDb.Db);
        await storage.InitializeAsync();

        var actor = CreateDeploymentManager(storage);
        await Task.Delay(500);

        actor.Tell(new DeployInstanceCommand(
            "dep-ok", "OkPump", "h1", MakeConfigJson("OkPump"), "admin", DateTimeOffset.UtcNow));

        var response = ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(10));
        Assert.Equal(DeploymentStatus.Success, response.Status);

        // By the time Success is reported, the config must be durable.
        var configs = await storage.GetAllDeployedConfigsAsync();
        Assert.Contains(configs, c => c.InstanceUniqueName == "OkPump");
    }

    /// <summary>
    /// SiteRuntime-010: when a redeployment changes a connection's configuration
    /// (here the failover retry count and endpoint), the Deployment Manager must
    /// re-issue a <see cref="ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection.CreateConnectionCommand"/>
    /// so the DCL adopts the new configuration rather than keeping the stale one.
    /// </summary>
    [Fact]
    public async Task EnsureDclConnections_ConnectionConfigChanged_ReissuesCreateCommand()
    {
        var storage = NewStorage(_localDb.Db);
        await storage.InitializeAsync();

        var dcl = CreateTestProbe();
        var actor = CreateDeploymentManager(storage, dcl.Ref);
        await Task.Delay(500);

        // Initial deploy with one connection.
        actor.Tell(new DeployInstanceCommand(
            "dep-c1", "ConnPump", "h1",
            MakeConfigJsonWithConnection("ConnPump", "opc.tcp://host-a:4840", 3),
            "admin", DateTimeOffset.UtcNow));
        var firstCreate = dcl.ExpectMsg<ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection.CreateConnectionCommand>(
            TimeSpan.FromSeconds(5));
        Assert.Equal("Conn1", firstCreate.ConnectionName);
        Assert.Equal(3, firstCreate.FailoverRetryCount);
        ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(5));
        await Task.Delay(500);

        // Redeploy with a CHANGED connection configuration.
        actor.Tell(new DeployInstanceCommand(
            "dep-c2", "ConnPump", "h2",
            MakeConfigJsonWithConnection("ConnPump", "opc.tcp://host-b:4840", 7),
            "admin", DateTimeOffset.UtcNow));

        // The DCL must receive a fresh create command reflecting the new config.
        var secondCreate = dcl.ExpectMsg<ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection.CreateConnectionCommand>(
            TimeSpan.FromSeconds(10));
        Assert.Equal("Conn1", secondCreate.ConnectionName);
        Assert.Equal(7, secondCreate.FailoverRetryCount);
    }

    /// <summary>
    /// SiteRuntime-010: an unchanged connection configuration must still be skipped —
    /// re-sending an identical create command on every deploy is wasteful.
    /// </summary>
    [Fact]
    public async Task EnsureDclConnections_UnchangedConfig_DoesNotReissueCreateCommand()
    {
        var storage = NewStorage(_localDb.Db);
        await storage.InitializeAsync();

        var dcl = CreateTestProbe();
        var actor = CreateDeploymentManager(storage, dcl.Ref);
        await Task.Delay(500);

        var json = MakeConfigJsonWithConnection("StablePump", "opc.tcp://host-a:4840", 3);
        actor.Tell(new DeployInstanceCommand(
            "dep-s1", "StablePump", "h1", json, "admin", DateTimeOffset.UtcNow));
        dcl.ExpectMsg<ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection.CreateConnectionCommand>(
            TimeSpan.FromSeconds(5));
        ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(5));
        await Task.Delay(500);

        // Redeploy with the IDENTICAL connection configuration.
        actor.Tell(new DeployInstanceCommand(
            "dep-s2", "StablePump", "h2", json, "admin", DateTimeOffset.UtcNow));
        ExpectMsg<DeploymentStatusResponse>(TimeSpan.FromSeconds(10));

        // No further create command for an unchanged connection.
        dcl.ExpectNoMsg(TimeSpan.FromMilliseconds(800));
    }

    /// <summary>
    /// SiteRuntime-008: startup must not block the Deployment Manager mailbox on a
    /// synchronous shared-script load. With shared scripts present, the actor must
    /// still load deployed configs, create Instance Actors, and remain responsive.
    /// </summary>
    [Fact]
    public async Task Startup_WithSharedScripts_LoadsConfigsAndStaysResponsive()
    {
        var storage = NewStorage(_localDb.Db);
        await storage.InitializeAsync();

        // Several shared scripts to compile during startup.
        for (var i = 0; i < 5; i++)
        {
            await storage.StoreSharedScriptAsync(
                $"Shared{i}", "return 1 + 1;", null, null);
        }

        await storage.StoreDeployedConfigAsync(
            "StartupPump", MakeConfigJson("StartupPump"), "d1", "h1", true);

        var actor = CreateDeploymentManager(storage);
        await Task.Delay(2000);

        // The instance loaded at startup must be operable — proves startup completed
        // and the actor processed messages after the shared-script load.
        actor.Tell(new DeploymentStateQueryRequest("corr-1", "StartupPump", DateTimeOffset.UtcNow));
        var response = ExpectMsg<DeploymentStateQueryResponse>(TimeSpan.FromSeconds(5));
        Assert.True(response.IsDeployed);
    }
}