using System.Security.Claims;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using Shouldly;
using Xunit;
using ZB.MOM.WW.Audit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Audit;
using ZB.MOM.WW.OtOpcUa.AdminUI.Browsing;
using ZB.MOM.WW.OtOpcUa.AdminUI.Clients;
using ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Uns;
using ZB.MOM.WW.OtOpcUa.Commons.Browsing;
using ZB.MOM.WW.OtOpcUa.Commons.Interfaces;
using ZB.MOM.WW.OtOpcUa.Commons.Messages.Admin;
using ZB.MOM.WW.OtOpcUa.Configuration;
using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
using ZB.MOM.WW.OtOpcUa.Core.Abstractions;

namespace ZB.MOM.WW.OtOpcUa.AdminUI.Tests.Browsing;

/// <summary>
///     lmxopcua#835 security review: I-1 (an UNSAVED endpoint may not borrow the named owner's own secrets; every
///     credential-carrying Test Connect / browse is audited) and L-2 (a ConfigDb fault in the browse check is a refusal,
///     not an exception).
/// </summary>
[Trait("Category", "Unit")]
public sealed class CredentialUseReviewTests
{
    private static CancellationToken Ct => TestContext.Current.CancellationToken;

    private const string StoredEndpoint = "http://gw-victim:5001";

    private static string Galaxy(string endpoint, string reference) =>
        """{"Gateway":{"Endpoint":"EP","ApiKeySecretRef":"REF"}}""".Replace("EP", endpoint).Replace("REF", reference);

    /// <summary>The victim's driver stores no endpoint; its device stores <see cref="StoredEndpoint"/> (v3 layout).</summary>
    private static IDbContextFactory<OtOpcUaConfigDbContext> VictimFactory()
    {
        var name = $"i1-{Guid.NewGuid():N}";
        using (var db = RawTreeTestDb.CreateNamed(name))
        {
            db.DriverInstances.Add(new DriverInstance
            {
                DriverInstanceId = "DRV-victim", ClusterId = "c", Name = "Victim", DriverType = DriverTypeNames.Galaxy,
                DriverConfig = """{"Gateway":{"ApiKeySecretRef":"secret:galaxy/DRV-victim/apikey"}}""",
            });
            db.Devices.Add(new Device
            {
                DeviceId = "DEV-victim", DriverInstanceId = "DRV-victim", Name = "gw",
                DeviceConfig = Galaxy(StoredEndpoint, "secret:galaxy/DRV-victim/apikey"),
            });
            db.SaveChanges();
        }

        return RawTreeTestDb.Factory(name);
    }

    private static BrowserSessionService Service(
        RecordingBrowser browser, IDbContextFactory<OtOpcUaConfigDbContext>? factory, IAuditWriter? audit = null) =>
        new([browser], new BrowseSessionRegistry(), NullLogger<BrowserSessionService>.Instance, new NoUniversal(), null!,
            new FixedUser("designer1"), factory, audit);

    [Fact]
    public async Task Browse_from_the_owners_device_with_an_unsaved_endpoint_cannot_use_the_owners_secret()
    {
        var browser = new RecordingBrowser();
        var result = await Service(browser, VictimFactory()).OpenAsync(DriverTypeNames.Galaxy,
            Galaxy("http://attacker:5001", "secret:galaxy/DRV-victim/apikey"), "DRV-victim", Ct);

        result.Ok.ShouldBeFalse();
        result.Message.ShouldNotBeNull().ShouldContain("lmxopcua#835");
        result.Message.ShouldContain("save the change first");
        browser.Opens.ShouldBe(0);
    }

    [Fact]
    public async Task Browse_with_the_saved_endpoint_may_use_the_owners_secret()
    {
        var browser = new RecordingBrowser();
        await Service(browser, VictimFactory()).OpenAsync(DriverTypeNames.Galaxy,
            Galaxy(StoredEndpoint, "secret:galaxy/DRV-victim/apikey"), "DRV-victim", Ct);
        browser.Opens.ShouldBe(1);
    }

    [Fact]
    public async Task Browse_naming_an_owner_of_another_type_gets_no_owner()
    {
        var browser = new RecordingBrowser();
        var result = await Service(browser, VictimFactory()).OpenAsync(DriverTypeNames.Galaxy,
            Galaxy(StoredEndpoint, "secret:galaxy/DRV-victim/apikey"), "DRV-does-not-exist", Ct);
        result.Ok.ShouldBeFalse();
        browser.Opens.ShouldBe(0);
    }

    [Fact]
    public async Task A_config_db_fault_in_the_browse_check_is_a_refusal_not_an_exception()
    {
        var browser = new RecordingBrowser();
        var result = await Service(browser, new ThrowingFactory()).OpenAsync(DriverTypeNames.Galaxy,
            Galaxy(StoredEndpoint, "secret:galaxy/shared/apikey"), "DRV-victim", Ct);

        result.Ok.ShouldBeFalse();
        result.Message.ShouldNotBeNull().ShouldContain("could not be read");
        browser.Opens.ShouldBe(0);
    }

    [Fact]
    public async Task Every_credential_carrying_browse_is_audited_with_user_driver_host_and_outcome()
    {
        var audit = new RecordingAudit();
        var browser = new RecordingBrowser();
        var svc = Service(browser, VictimFactory(), audit);

        await svc.OpenAsync(DriverTypeNames.Galaxy, Galaxy("http://attacker:5001", "secret:galaxy/DRV-victim/apikey"), "DRV-victim", Ct);
        await svc.OpenAsync(DriverTypeNames.Galaxy, Galaxy(StoredEndpoint, "env:OTOPCUA_GALAXY_KEY"), "DRV-victim", Ct);
        await svc.OpenAsync(DriverTypeNames.Galaxy, Galaxy(StoredEndpoint, "dev:literal"), "DRV-victim", Ct); // no reference ⇒ no row

        audit.Events.Count.ShouldBe(2);
        var refused = audit.Events[0];
        refused.Category.ShouldBe(CredentialUseAudit.Category);
        refused.Action.ShouldBe(CredentialUseAudit.BrowseAction);
        refused.Actor.ShouldBe("designer1");
        refused.Target.ShouldBe("DRV-victim");
        refused.Outcome.ShouldBe(AuditOutcome.Failure);
        refused.DetailsJson.ShouldNotBeNull().ShouldContain("attacker:5001");
        refused.DetailsJson.ShouldNotContain("DRV-victim/apikey"); // the reference itself is never recorded
        audit.Events[1].DetailsJson.ShouldNotBeNull().ShouldContain("gw-victim:5001");
    }

    [Fact]
    public async Task Every_credential_carrying_test_connect_is_audited()
    {
        var audit = new RecordingAudit();
        var probe = new AdminProbeService(
            new FixedReplyClient(new TestDriverConnectResult(false, "Test Connect refused: x", null, Guid.Empty)),
            audit, new FixedUser("designer2"), NullLogger<AdminProbeService>.Instance);

        await probe.TestAsync(DriverTypeNames.Galaxy, Galaxy("http://attacker:5001", "secret:galaxy/DRV-victim/apikey"), 5, Ct, "DRV-victim");
        await probe.TestAsync(DriverTypeNames.Modbus, """{"Host":"plc"}""", 5, Ct);

        var e = audit.Events.ShouldHaveSingleItem();
        e.Action.ShouldBe(CredentialUseAudit.TestConnectAction);
        e.Actor.ShouldBe("designer2");
        e.Target.ShouldBe("DRV-victim");
        e.Outcome.ShouldBe(AuditOutcome.Failure);
        e.DetailsJson.ShouldNotBeNull().ShouldContain("attacker:5001");
    }

    [Fact]
    public void Hosts_drop_uri_user_info()
    {
        CredentialUseAudit.Hosts(DriverTypeNames.OpcUaClient, """{"EndpointUrl":"opc.tcp://user:pw@plc1:4840/x"}""")
            .ShouldHaveSingleItem().ShouldBe("plc1:4840");
    }

    private sealed class RecordingBrowser : IDriverBrowser
    {
        public int Opens { get; private set; }

        public string DriverType => DriverTypeNames.Galaxy;

        public Task<IBrowseSession> OpenAsync(string configJson, CancellationToken cancellationToken)
        {
            Opens++;
            throw new InvalidOperationException("opened");
        }
    }

    private sealed class NoUniversal : IUniversalDriverBrowser
    {
        public bool CanBrowse(string driverType, string configJson) => false;

        public Task<IBrowseSession> OpenAsync(string driverType, string configJson, CancellationToken ct) =>
            throw new InvalidOperationException("opened");
    }

    private sealed class FixedUser(string name) : AuthenticationStateProvider
    {
        public override Task<AuthenticationState> GetAuthenticationStateAsync() =>
            Task.FromResult(new AuthenticationState(new ClaimsPrincipal(new ClaimsIdentity([new Claim(ClaimTypes.Name, name)], "test"))));
    }

    private sealed class RecordingAudit : IAuditWriter
    {
        public List<AuditEvent> Events { get; } = [];

        public Task WriteAsync(AuditEvent evt, CancellationToken ct = default)
        {
            Events.Add(evt);
            return Task.CompletedTask;
        }
    }

    private sealed class ThrowingFactory : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        public OtOpcUaConfigDbContext CreateDbContext() => throw new InvalidOperationException("ConfigDb unreachable");
    }

    private sealed class FixedReplyClient(TestDriverConnectResult reply) : IAdminOperationsClient
    {
        public Task<StartDeploymentResult> StartDeploymentAsync(string createdBy, CancellationToken ct) => throw new NotSupportedException();

        public Task<AcknowledgeAlarmResult> AcknowledgeAlarmAsync(string alarmId, string user, string? comment, CancellationToken ct) =>
            throw new NotSupportedException();

        public Task<ShelveAlarmResult> ShelveAlarmAsync(
            string alarmId, string user, ShelveKind kind, DateTime? unshelveAtUtc, string? comment, CancellationToken ct) =>
            throw new NotSupportedException();

        public Task<T> AskAsync<T>(object message, CancellationToken ct) => Task.FromResult((T)(object)reply);
    }
}