using System.Security.Claims;
using Microsoft.AspNetCore.Http;
using ZB.MOM.WW.Auth.AspNetCore;
using ZB.MOM.WW.ScadaBridge.Security;

namespace ZB.MOM.WW.ScadaBridge.Security.Tests;

/// <summary>
/// Phase 3 (wire audit Actor from the Auth principal): unit tests for
/// <see cref="HttpAuditActorAccessor"/>. The accessor resolves the audit
/// <c>Actor</c> from the authenticated principal on the ambient
/// <see cref="IHttpContextAccessor.HttpContext"/> — the canonical username claim
/// with an <see cref="System.Security.Principal.IIdentity.Name"/> fallback — and
/// returns <c>null</c> whenever there is no authenticated interactive user, so the
/// caller keeps its existing actor/fallback rather than echoing an unauthenticated
/// principal.
/// </summary>
public class HttpAuditActorAccessorTests
{
    /// <summary>
    /// Minimal <see cref="IHttpContextAccessor"/> test double returning a fixed
    /// (possibly null) <see cref="HttpContext"/>.
    /// </summary>
    private sealed class StubHttpContextAccessor : IHttpContextAccessor
    {
        public HttpContext? HttpContext { get; set; }
    }

    private static HttpContext AuthenticatedContext(params Claim[] claims)
    {
        var ctx = new DefaultHttpContext
        {
            User = new ClaimsPrincipal(new ClaimsIdentity(claims, authenticationType: "TestAuth")),
        };
        return ctx;
    }

    [Fact]
    public void CurrentActor_Authenticated_ReturnsUsernameClaim()
    {
        var ctx = AuthenticatedContext(
            new Claim(JwtTokenService.UsernameClaimType, "alice"),
            // A different Identity.Name proves the username claim is preferred.
            new Claim(ClaimTypes.Name, "Alice Liddell"));
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = ctx });

        Assert.Equal("alice", accessor.CurrentActor);
    }

    [Fact]
    public void CurrentActor_Authenticated_NoUsernameClaim_FallsBackToIdentityName()
    {
        // No canonical username claim; Identity.Name (pinned to ZbClaimTypes.Name)
        // is the documented fallback. DefaultHttpContext maps the ClaimTypes.Name
        // claim onto Identity.Name.
        var ctx = AuthenticatedContext(new Claim(ClaimTypes.Name, "bob"));
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = ctx });

        Assert.Equal("bob", accessor.CurrentActor);
    }

    [Fact]
    public void CurrentActor_Authenticated_PrefersUsernameOverZbName()
    {
        // Both the canonical username and the canonical name claim present — the
        // username claim wins.
        var ctx = AuthenticatedContext(
            new Claim(JwtTokenService.UsernameClaimType, "svc-user"),
            new Claim(ZbClaimTypes.Name, "Service User"));
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = ctx });

        Assert.Equal("svc-user", accessor.CurrentActor);
    }

    [Fact]
    public void CurrentActor_Unauthenticated_ReturnsNull()
    {
        // An anonymous identity (no authenticationType) is NOT authenticated —
        // never echo it back as an actor even if a name claim is somehow present.
        var ctx = new DefaultHttpContext
        {
            User = new ClaimsPrincipal(
                new ClaimsIdentity(new[] { new Claim(ClaimTypes.Name, "ghost") })),
        };
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = ctx });

        Assert.Null(accessor.CurrentActor);
    }

    [Fact]
    public void CurrentActor_NoAmbientHttpContext_ReturnsNull()
    {
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = null });

        Assert.Null(accessor.CurrentActor);
    }

    [Fact]
    public void CurrentActor_AuthenticatedButNoUsableName_ReturnsNull()
    {
        // Authenticated identity carrying only an unrelated claim (no username,
        // no name) — there is nothing usable to record, so fall back to null.
        var ctx = AuthenticatedContext(new Claim(ZbClaimTypes.Role, "Administrator"));
        var accessor = new HttpAuditActorAccessor(
            new StubHttpContextAccessor { HttpContext = ctx });

        Assert.Null(accessor.CurrentActor);
    }
}