using System.Security.Claims;
using Microsoft.AspNetCore.Components.Authorization;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using NSubstitute;
using ZB.MOM.WW.Audit;
using ZB.MOM.WW.ScadaBridge.CentralUI.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
using ZB.MOM.WW.ScadaBridge.Communication;
using ZB.MOM.WW.ScadaBridge.Security;

namespace ZB.MOM.WW.ScadaBridge.CentralUI.Tests.Services;

/// <summary>Gitea #43: the Central UI cert-trust facade records every trust decision in the central audit log.</summary>
public class CertManagementServiceAuditTests
{
    private readonly ICentralAuditWriter _audit = Substitute.For<ICentralAuditWriter>();

    private sealed class FakeComm(CertTrustResult? result, Exception? throws = null)
        : CommunicationService(Options.Create(new CommunicationOptions()), NullLogger<CommunicationService>.Instance)
    {
        public override Task<CertTrustResult> TrustServerCertAsync(string siteId, TrustServerCertCommand command, CancellationToken cancellationToken = default)
            => throws is null ? Task.FromResult(result!) : Task.FromException<CertTrustResult>(throws);

        public override Task<CertTrustResult> RemoveServerCertAsync(string siteId, RemoveServerCertCommand command, CancellationToken cancellationToken = default)
            => throws is null ? Task.FromResult(result!) : Task.FromException<CertTrustResult>(throws);
    }

    private sealed class AuthStub(ClaimsPrincipal user) : AuthenticationStateProvider
    {
        public override Task<AuthenticationState> GetAuthenticationStateAsync() => Task.FromResult(new AuthenticationState(user));
    }

    private static ClaimsPrincipal Admin() => new(new ClaimsIdentity(
    [
        new Claim(JwtTokenService.UsernameClaimType, "alice"),
        new Claim(JwtTokenService.RoleClaimType, Roles.Administrator),
    ], "test"));

    private CertManagementService Sut(CommunicationService comm, ClaimsPrincipal? user = null)
        => new(comm, new AuthStub(user ?? Admin()), _audit, NullLogger<CertManagementService>.Instance);

    private AuditEvent Captured() => Assert.Single(_audit.ReceivedCalls()
        .Where(c => c.GetMethodInfo().Name == nameof(ICentralAuditWriter.WriteAsync))
        .Select(c => (AuditEvent)c.GetArguments()[0]!));

    /// <summary>A successful trust writes a Delivered CertTrust row naming the actor, site and thumbprint.</summary>
    [Fact]
    public async Task Trust_Success_WritesDeliveredRow()
    {
        var r = await Sut(new FakeComm(new CertTrustResult(true, null, null))).TrustAsync("SITE1", "conn", "ZGVy", "AB12");

        Assert.True(r.Success);
        var evt = Captured();
        Assert.Equal("alice", evt.Actor);
        Assert.Equal("SITE1/AB12", evt.Target);
        Assert.Contains("\"kind\":\"CertTrust\"", evt.DetailsJson);
        Assert.Contains("\"status\":\"Delivered\"", evt.DetailsJson);
    }

    /// <summary>A failed relay is audited as Failed with the error, and the page still gets its inline result.</summary>
    [Fact]
    public async Task Trust_RelayThrows_WritesFailedRow_AndReturnsInlineError()
    {
        var r = await Sut(new FakeComm(null, new TimeoutException("site unreachable"))).TrustAsync("SITE1", "conn", "ZGVy", "AB12");

        Assert.False(r.Success);
        var evt = Captured();
        Assert.Contains("\"status\":\"Failed\"", evt.DetailsJson);
        Assert.Contains("site unreachable", evt.DetailsJson);
    }

    /// <summary>A removal writes a CertTrustRemove row.</summary>
    [Fact]
    public async Task Remove_Success_WritesRemoveRow()
    {
        await Sut(new FakeComm(new CertTrustResult(true, null, null))).RemoveAsync("SITE1", "AB12");

        Assert.Contains("\"kind\":\"CertTrustRemove\"", Captured().DetailsJson);
    }

    /// <summary>An unauthorized caller never reaches the site and writes no audit row.</summary>
    [Fact]
    public async Task Trust_Unauthorized_WritesNothing()
    {
        var viewer = new ClaimsPrincipal(new ClaimsIdentity([new Claim(JwtTokenService.UsernameClaimType, "bob")], "test"));

        var r = await Sut(new FakeComm(new CertTrustResult(true, null, null)), viewer).TrustAsync("SITE1", "conn", "ZGVy", "AB12");

        Assert.False(r.Success);
        Assert.Empty(_audit.ReceivedCalls());
    }

    /// <summary>An audit-writer failure never changes the trust result.</summary>
    [Fact]
    public async Task Trust_AuditWriterThrows_ResultUnaffected()
    {
        _audit.WriteAsync(Arg.Any<AuditEvent>(), Arg.Any<CancellationToken>()).Returns(Task.FromException(new InvalidOperationException("db down")));

        var r = await Sut(new FakeComm(new CertTrustResult(true, null, null))).TrustAsync("SITE1", "conn", "ZGVy", "AB12");

        Assert.True(r.Success);
    }
}