Inboxintel/src/InboxIntel.Api/Controllers/AuthController.cs

using System.Security.Claims;
using Asp.Versioning;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authentication.Google;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.RateLimiting;

namespace InboxIntel.Api.Controllers;

[ApiController]
[EnableRateLimiting("auth")]  // AUDIT H-2: throttle login/challenge attempts per IP
[ApiVersion("1.0")]
[Route("api/v{version:apiVersion}/[controller]")]
public class AuthController : ControllerBase
{
    /// <summary>Begins the Google OAuth2 login flow.</summary>
    [HttpGet("login")]
    [AllowAnonymous]
    public IActionResult Login([FromQuery] string? returnUrl = "/")
    {
        // V-09: only allow local post-login redirects; reject absolute/off-host targets
        // so the OAuth flow can't be abused as an open redirect for phishing.
        var safe = !string.IsNullOrEmpty(returnUrl) && Url.IsLocalUrl(returnUrl) ? returnUrl : "/app";
        return Challenge(new AuthenticationProperties { RedirectUri = safe }, GoogleDefaults.AuthenticationScheme);
    }

    [HttpPost("logout")]
    [Authorize]
    public async Task<IActionResult> Logout()
    {
        await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
        return NoContent();
    }

    /// <summary>Returns the currently signed-in user, or 401.</summary>
    [HttpGet("me")]
    [Authorize]
    public IActionResult Me() => Ok(new
    {
        UserId = User.FindFirstValue("inboxintel:uid"),
        Email = User.FindFirstValue(ClaimTypes.Email),
        Name = User.FindFirstValue(ClaimTypes.Name)
    });
}