server/MareSynchronosServer/MareSynchronosAuthService/Controllers/OAuthController.cs

using MareSynchronos.API.Routes;
using MareSynchronosAuthService.Services;
using MareSynchronosShared;
using MareSynchronosShared.Data;
using MareSynchronosShared.Services;
using MareSynchronosShared.Utils;
using MareSynchronosShared.Utils.Configuration;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using StackExchange.Redis;
using StackExchange.Redis.Extensions.Core.Abstractions;
using System.Collections.Concurrent;
using System.Globalization;
using System.Security.Claims;
using System.Text.Json;
using System.Web;

namespace MareSynchronosAuthService.Controllers;

[Route(MareAuth.OAuth)]
public class OAuthController : AuthControllerBase
{
    private const string _discordOAuthCall = "discordCall";
    private const string _discordOAuthCallback = "discordCallback";
    private static readonly ConcurrentDictionary<string, string> _cookieOAuthResponse = [];

    public OAuthController(ILogger<OAuthController> logger,
    IHttpContextAccessor accessor, MareDbContext mareDbContext,
    SecretKeyAuthenticatorService secretKeyAuthenticatorService,
    IConfigurationService<AuthServiceConfiguration> configuration,
    IRedisDatabase redisDb, GeoIPService geoIPProvider)
        : base(logger, accessor, mareDbContext, secretKeyAuthenticatorService,
            configuration, redisDb, geoIPProvider)
    {
    }

    [AllowAnonymous]
    [HttpGet(_discordOAuthCall)]
    public IActionResult DiscordOAuthSetCookieAndRedirect([FromQuery] string sessionId)
    {
        var discordOAuthUri = Configuration.GetValueOrDefault<Uri?>(nameof(AuthServiceConfiguration.PublicOAuthBaseUri), null);
        var discordClientSecret = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientSecret), null);
        var discordClientId = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientId), null);
        if (discordClientSecret == null || discordClientId == null || discordOAuthUri == null)
            return BadRequest("Server does not support OAuth2");

        var cookieOptions = new CookieOptions
        {
            HttpOnly = true,
            Secure = true,
            Expires = DateTime.UtcNow.AddMinutes(30)
        };
        Response.Cookies.Append("DiscordOAuthSessionCookie", sessionId, cookieOptions);

        var parameters = new Dictionary<string, string>
        {
            { "client_id", discordClientId },
            { "response_type", "code" },
            { "redirect_uri", new Uri(discordOAuthUri, _discordOAuthCallback).ToString() },
            { "scope", "identify"},
        };
        using var content = new FormUrlEncodedContent(parameters);
        UriBuilder builder = new UriBuilder("https://discord.com/oauth2/authorize");
        var query = HttpUtility.ParseQueryString(builder.Query);
        foreach (var param in parameters)
        {
            query[param.Key] = param.Value;
        }
        builder.Query = query.ToString();

        return Redirect(builder.ToString());
    }

    [AllowAnonymous]
    [HttpGet(_discordOAuthCallback)]
    public async Task<IActionResult> DiscordOAuthCallback([FromQuery] string code)
    {
        var reqId = Request.Cookies["DiscordOAuthSessionCookie"];

        var discordOAuthUri = Configuration.GetValueOrDefault<Uri?>(nameof(AuthServiceConfiguration.PublicOAuthBaseUri), null);
        var discordClientSecret = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientSecret), null);
        var discordClientId = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientId), null);
        if (discordClientSecret == null || discordClientId == null || discordOAuthUri == null)
            return BadRequest("Server does not support OAuth2");
        if (string.IsNullOrEmpty(reqId)) return BadRequest("No session cookie found");
        if (string.IsNullOrEmpty(code)) return BadRequest("No Discord OAuth2 code found");

        var query = HttpUtility.ParseQueryString(discordOAuthUri.Query);
        using var client = new HttpClient();
        var parameters = new Dictionary<string, string>
        {
            { "client_id", discordClientId },
            { "client_secret", discordClientSecret },
            { "grant_type", "authorization_code" },
            { "code", code },
            { "redirect_uri", new Uri(discordOAuthUri, _discordOAuthCallback).ToString() }
        };

        using var content = new FormUrlEncodedContent(parameters);
        using var response = await client.PostAsync("https://discord.com/api/oauth2/token", content);
        using var responseBody = await response.Content.ReadAsStreamAsync().ConfigureAwait(false);

        if (!response.IsSuccessStatusCode)
        {
            return BadRequest("Failed to get Discord token");
        }

        using var tokenJson = await JsonDocument.ParseAsync(responseBody).ConfigureAwait(false);
        var token = tokenJson.RootElement.GetProperty("access_token").GetString();

        using var httpClient = new HttpClient();
        httpClient.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
        using var meResponse = await httpClient.GetAsync("https://discord.com/api/users/@me");
        using var meBody = await meResponse.Content.ReadAsStreamAsync().ConfigureAwait(false);

        if (!meResponse.IsSuccessStatusCode)
        {
            return BadRequest("Failed to get Discord user info");
        }

        ulong discordUserId = 0;
        string discordUserName = string.Empty;
        try
        {
            using var jsonResponse = await JsonDocument.ParseAsync(meBody).ConfigureAwait(false);
            discordUserId = ulong.Parse(jsonResponse.RootElement.GetProperty("id").GetString()!);
            discordUserName = jsonResponse.RootElement.GetProperty("username").GetString()!;
        }
        catch (Exception ex)
        {
            return BadRequest("Failed to parse user id from @me response for token");
        }

        if (discordUserId == 0)
            return BadRequest("Failed to get Discord ID from login token");

        var mareUser = await MareDbContext.LodeStoneAuth.Include(u => u.User).SingleOrDefaultAsync(u => u.DiscordId == discordUserId);
        if (mareUser == null)
            return BadRequest("Could not find a Mare user associated to this Discord account.");

        var jwt = CreateJwt([
            new Claim(MareClaimTypes.Uid, mareUser.User!.UID),
            new Claim(MareClaimTypes.Expires, DateTime.UtcNow.AddDays(14).Ticks.ToString(CultureInfo.InvariantCulture)),
            new Claim(MareClaimTypes.DiscordId, discordUserId.ToString()),
            new Claim(MareClaimTypes.DiscordUser, discordUserName),
            new Claim(MareClaimTypes.OAuthLoginToken, true.ToString())
            ]);

        _cookieOAuthResponse[reqId] = jwt.RawData;
        _ = Task.Run(async () =>
        {
            bool isRemoved = false;
            for (int i = 0; i < 10; i++)
            {
                await Task.Delay(TimeSpan.FromSeconds(3)).ConfigureAwait(false);
                if (!_cookieOAuthResponse.ContainsKey(reqId))
                {
                    isRemoved = true;
                    break;
                }
            }
            if (!isRemoved)
                _cookieOAuthResponse.TryRemove(reqId, out _);
        });

        return Ok("The OAuth2 token was generated. The plugin will grab it automatically. You can close this browser tab.");
    }

    [Authorize(Policy = "OAuthToken")]
    [HttpPost(MareAuth.OAuth_RenewOAuthToken)]
    public IActionResult RenewOAuthToken()
    {
        var claims = HttpContext.User.Claims.Where(c => c.Type != MareClaimTypes.Expires).ToList();
        claims.Add(new Claim(MareClaimTypes.Expires, DateTime.UtcNow.AddDays(14).Ticks.ToString(CultureInfo.InvariantCulture)));
        return Content(CreateJwt(claims).RawData);
    }

    [AllowAnonymous]
    [HttpGet(MareAuth.OAuth_GetDiscordOAuthToken)]
    public async Task<IActionResult> GetDiscordOAuthToken([FromQuery] string sessionId)
    {
        using CancellationTokenSource cts = new();
        cts.CancelAfter(TimeSpan.FromSeconds(60));
        while (!_cookieOAuthResponse.ContainsKey(sessionId) && !cts.Token.IsCancellationRequested)
        {
            await Task.Delay(TimeSpan.FromSeconds(1), cts.Token);
        }
        if (cts.IsCancellationRequested)
        {
            return BadRequest("Did not find Discord OAuth2 response");
        }
        _cookieOAuthResponse.TryRemove(sessionId, out var token);
        if (token == null)
            return BadRequest("OAuth session was never established");
        return Content(token);
    }

    [AllowAnonymous]
    [HttpGet(MareAuth.OAuth_GetDiscordOAuthEndpoint)]
    public Uri? GetDiscordOAuthEndpoint()
    {
        var discordOAuthUri = Configuration.GetValueOrDefault<Uri?>(nameof(AuthServiceConfiguration.PublicOAuthBaseUri), null);
        var discordClientSecret = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientSecret), null);
        var discordClientId = Configuration.GetValueOrDefault<string?>(nameof(AuthServiceConfiguration.DiscordOAuthClientId), null);
        if (discordClientSecret == null || discordClientId == null || discordOAuthUri == null)
            return null;
        return new Uri(discordOAuthUri, _discordOAuthCall);
    }

    [Authorize(Policy = "OAuthToken")]
    [HttpGet(MareAuth.OAuth_GetUIDs)]
    public async Task<Dictionary<string, string>> GetAvailableUIDs()
    {
        string primaryUid = HttpContext.User.Claims.Single(c => string.Equals(c.Type, MareClaimTypes.Uid, StringComparison.Ordinal))!.Value;

        var mareUser = await MareDbContext.Auth.Include(u => u.User).FirstOrDefaultAsync(f => f.UserUID == primaryUid);
        if (mareUser == null || mareUser.User == null) return [];
        var uid = mareUser.User.UID;
        var allUids = await MareDbContext.Auth.Include(u => u.User).Where(a => a.UserUID == uid || a.PrimaryUserUID == uid).ToListAsync();
        var result = allUids.OrderBy(u => u.UserUID == uid ? 0 : 1).ThenBy(u => u.UserUID).Select(u => (u.UserUID, u.User.Alias)).ToDictionary();
        return result;
    }

    [Authorize(Policy = "OAuthToken")]
    [HttpPost(MareAuth.OAuth_CreateOAuth)]
    public async Task<IActionResult> CreateTokenWithOAuth(string uid, string charaIdent)
    {
        return await AuthenticateOAuthInternal(uid, charaIdent);
    }

    private async Task<IActionResult> AuthenticateOAuthInternal(string requestedUid, string charaIdent)
    {
        try
        {
            string primaryUid = HttpContext.User.Claims.Single(c => string.Equals(c.Type, MareClaimTypes.Uid, StringComparison.Ordinal))!.Value;
            if (string.IsNullOrEmpty(requestedUid)) return BadRequest("No UID");
            if (string.IsNullOrEmpty(charaIdent)) return BadRequest("No CharaIdent");

            var ip = HttpAccessor.GetIpAddress();

            var authResult = await SecretKeyAuthenticatorService.AuthorizeOauthAsync(ip, primaryUid, requestedUid);

            return await GenericAuthResponse(charaIdent, authResult);
        }
        catch (Exception ex)
        {
            Logger.LogWarning(ex, "Authenticate:UNKNOWN");
            return Unauthorized("Unknown internal server error during authentication");
        }
    }
}