♻️ Moved some services to DysonNetwork.Pass

DysonNetwork.Pass/Auth/OpenId/AfdianOidcService.cs

@@ -0,0 +1,95 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using DysonNetwork.Pass;
+using DysonNetwork.Shared.Cache;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class AfdianOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache,
+    ILogger<AfdianOidcService> logger
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    public override string ProviderName => "Afdian";
+    protected override string DiscoveryEndpoint => ""; // Afdian doesn't have a standard OIDC discovery endpoint
+    protected override string ConfigSectionName => "Afdian";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "redirect_uri", config.RedirectUri },
+            { "response_type", "code" },
+            { "scope", "basic" },
+            { "state", state },
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"https://afdian.com/oauth2/authorize?{queryString}";
+    }
+
+    protected override Task<OidcDiscoveryDocument?> GetDiscoveryDocumentAsync()
+    {
+        return Task.FromResult(new OidcDiscoveryDocument
+        {
+            AuthorizationEndpoint = "https://afdian.com/oauth2/authorize",
+            TokenEndpoint = "https://afdian.com/oauth2/access_token",
+            UserinfoEndpoint = null,
+            JwksUri = null
+        })!;
+    }
+
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        try
+        {
+            var config = GetProviderConfig();
+            var content = new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                { "client_id", config.ClientId },
+                { "client_secret", config.ClientSecret },
+                { "grant_type", "authorization_code" },
+                { "code", callbackData.Code },
+                { "redirect_uri", config.RedirectUri },
+            });
+
+            var client = HttpClientFactory.CreateClient();
+            var request = new HttpRequestMessage(HttpMethod.Post, "https://afdian.com/oauth2/access_token");
+            request.Content = content;
+            
+            var response = await client.SendAsync(request);
+            response.EnsureSuccessStatusCode();
+            
+            var json = await response.Content.ReadAsStringAsync();
+            logger.LogInformation("Trying get userinfo from afdian, response: {Response}", json);
+            var afdianResponse = JsonDocument.Parse(json).RootElement;
+
+            var user = afdianResponse.TryGetProperty("data", out var dataElement) ? dataElement : default;
+            var userId = user.TryGetProperty("user_id", out var userIdElement) ? userIdElement.GetString() ?? "" : "";
+            var avatar = user.TryGetProperty("avatar", out var avatarElement) ? avatarElement.GetString() : null;
+
+            return new OidcUserInfo
+            {
+                UserId = userId,
+                DisplayName = (user.TryGetProperty("name", out var nameElement)
+                    ? nameElement.GetString()
+                    : null) ?? "",
+                ProfilePictureUrl = avatar,
+                Provider = ProviderName
+            };
+        }
+        catch (Exception ex)
+        {
+            // Due to afidan's API isn't compliant with OAuth2, we want more logs from it to investigate.
+            logger.LogError(ex, "Failed to get user info from Afdian");
+            throw;
+        }
+    }
+}

DysonNetwork.Pass/Auth/OpenId/AppleMobileSignInRequest.cs

@@ -0,0 +1,19 @@
+
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class AppleMobileConnectRequest
+{
+    [Required]
+    public required string IdentityToken { get; set; }
+    [Required]
+    public required string AuthorizationCode { get; set; }
+}
+
+public class AppleMobileSignInRequest : AppleMobileConnectRequest
+{
+    [Required]
+    public required string DeviceId { get; set; }
+}

DysonNetwork.Pass/Auth/OpenId/AppleOidcService.cs

@@ -0,0 +1,280 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using DysonNetwork.Pass;
+using DysonNetwork.Shared.Cache;
+using Microsoft.IdentityModel.Tokens;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+/// <summary>
+/// Implementation of OpenID Connect service for Apple Sign In
+/// </summary>
+public class AppleOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    private readonly IConfiguration _configuration = configuration;
+    private readonly IHttpClientFactory _httpClientFactory = httpClientFactory;
+
+    public override string ProviderName => "apple";
+    protected override string DiscoveryEndpoint => "https://appleid.apple.com/.well-known/openid-configuration";
+    protected override string ConfigSectionName => "Apple";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "redirect_uri", config.RedirectUri },
+            { "response_type", "code id_token" },
+            { "scope", "name email" },
+            { "response_mode", "form_post" },
+            { "state", state },
+            { "nonce", nonce }
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"https://appleid.apple.com/auth/authorize?{queryString}";
+    }
+
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        // Verify and decode the id_token
+        var userInfo = await ValidateTokenAsync(callbackData.IdToken);
+
+        // If user data is provided in first login, parse it
+        if (!string.IsNullOrEmpty(callbackData.RawData))
+        {
+            var userData = JsonSerializer.Deserialize<AppleUserData>(callbackData.RawData);
+            if (userData?.Name != null)
+            {
+                userInfo.FirstName = userData.Name.FirstName ?? "";
+                userInfo.LastName = userData.Name.LastName ?? "";
+                userInfo.DisplayName = $"{userInfo.FirstName} {userInfo.LastName}".Trim();
+            }
+        }
+
+        // Exchange authorization code for access token (optional, if you need the access token)
+        if (string.IsNullOrEmpty(callbackData.Code)) return userInfo;
+        var tokenResponse = await ExchangeCodeForTokensAsync(callbackData.Code);
+        if (tokenResponse == null) return userInfo;
+        userInfo.AccessToken = tokenResponse.AccessToken;
+        userInfo.RefreshToken = tokenResponse.RefreshToken;
+
+        return userInfo;
+    }
+
+    private async Task<OidcUserInfo> ValidateTokenAsync(string idToken)
+    {
+        // Get Apple's public keys
+        var jwksJson = await GetAppleJwksAsync();
+        var jwks = JsonSerializer.Deserialize<AppleJwks>(jwksJson) ?? new AppleJwks { Keys = new List<AppleKey>() };
+
+        // Parse the JWT header to get the key ID
+        var handler = new JwtSecurityTokenHandler();
+        var jwtToken = handler.ReadJwtToken(idToken);
+        var kid = jwtToken.Header.Kid;
+
+        // Find the matching key
+        var key = jwks.Keys.FirstOrDefault(k => k.Kid == kid);
+        if (key == null)
+        {
+            throw new SecurityTokenValidationException("Unable to find matching key in Apple's JWKS");
+        }
+
+        // Create the validation parameters
+        var validationParameters = new TokenValidationParameters
+        {
+            ValidateIssuer = true,
+            ValidIssuer = "https://appleid.apple.com",
+            ValidateAudience = true,
+            ValidAudience = GetProviderConfig().ClientId,
+            ValidateLifetime = true,
+            IssuerSigningKey = key.ToSecurityKey()
+        };
+
+        return ValidateAndExtractIdToken(idToken, validationParameters);
+    }
+
+    protected override Dictionary<string, string> BuildTokenRequestParameters(
+        string code,
+        ProviderConfiguration config,
+        string? codeVerifier
+    )
+    {
+        var parameters = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "client_secret", GenerateClientSecret() },
+            { "code", code },
+            { "grant_type", "authorization_code" },
+            { "redirect_uri", config.RedirectUri }
+        };
+
+        return parameters;
+    }
+
+    private async Task<string> GetAppleJwksAsync()
+    {
+        var client = _httpClientFactory.CreateClient();
+        var response = await client.GetAsync("https://appleid.apple.com/auth/keys");
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadAsStringAsync();
+    }
+
+    /// <summary>
+    /// Generates a client secret for Apple Sign In using JWT
+    /// </summary>
+    private string GenerateClientSecret()
+    {
+        var now = DateTime.UtcNow;
+        var teamId = _configuration["Oidc:Apple:TeamId"];
+        var clientId = _configuration["Oidc:Apple:ClientId"];
+        var keyId = _configuration["Oidc:Apple:KeyId"];
+        var privateKeyPath = _configuration["Oidc:Apple:PrivateKeyPath"];
+
+        if (string.IsNullOrEmpty(teamId) || string.IsNullOrEmpty(clientId) || string.IsNullOrEmpty(keyId) ||
+            string.IsNullOrEmpty(privateKeyPath))
+        {
+            throw new InvalidOperationException("Apple OIDC configuration is missing required values (TeamId, ClientId, KeyId, PrivateKeyPath).");
+        }
+        
+        // Read the private key
+        var privateKey = File.ReadAllText(privateKeyPath);
+
+        // Create the JWT header
+        var header = new Dictionary<string, object>
+        {
+            { "alg", "ES256" },
+            { "kid", keyId }
+        };
+
+        // Create the JWT payload
+        var payload = new Dictionary<string, object>
+        {
+            { "iss", teamId },
+            { "iat", ToUnixTimeSeconds(now) },
+            { "exp", ToUnixTimeSeconds(now.AddMinutes(5)) },
+            { "aud", "https://appleid.apple.com" },
+            { "sub", clientId }
+        };
+
+        // Convert header and payload to Base64Url
+        var headerJson = JsonSerializer.Serialize(header);
+        var payloadJson = JsonSerializer.Serialize(payload);
+        var headerBase64 = Base64UrlEncode(Encoding.UTF8.GetBytes(headerJson));
+        var payloadBase64 = Base64UrlEncode(Encoding.UTF8.GetBytes(payloadJson));
+
+        // Create the signature
+        var dataToSign = $"{headerBase64}.{payloadBase64}";
+        var signature = SignWithECDsa(dataToSign, privateKey);
+
+        // Combine all parts
+        return $"{headerBase64}.{payloadBase64}.{signature}";
+    }
+
+    private long ToUnixTimeSeconds(DateTime dateTime)
+    {
+        return new DateTimeOffset(dateTime).ToUnixTimeSeconds();
+    }
+
+    private string SignWithECDsa(string dataToSign, string privateKey)
+    {
+        using var ecdsa = ECDsa.Create();
+        ecdsa.ImportFromPem(privateKey);
+
+        var bytes = Encoding.UTF8.GetBytes(dataToSign);
+        var signature = ecdsa.SignData(bytes, HashAlgorithmName.SHA256);
+
+        return Base64UrlEncode(signature);
+    }
+
+    private string Base64UrlEncode(byte[] data)
+    {
+        return Convert.ToBase64String(data)
+            .Replace('+', '-')
+            .Replace('/', '_')
+            .TrimEnd('=');
+    }
+}
+
+public class AppleUserData
+{
+    [JsonPropertyName("name")] public AppleNameData? Name { get; set; }
+
+    [JsonPropertyName("email")] public string? Email { get; set; }
+}
+
+public class AppleNameData
+{
+    [JsonPropertyName("firstName")] public string? FirstName { get; set; }
+
+    [JsonPropertyName("lastName")] public string? LastName { get; set; }
+}
+
+public class AppleJwks
+{
+    [JsonPropertyName("keys")] public List<AppleKey> Keys { get; set; } = new List<AppleKey>();
+}
+
+public class AppleKey
+{
+    [JsonPropertyName("kty")] public string? Kty { get; set; }
+
+    [JsonPropertyName("kid")] public string? Kid { get; set; }
+
+    [JsonPropertyName("use")] public string? Use { get; set; }
+
+    [JsonPropertyName("alg")] public string? Alg { get; set; }
+
+    [JsonPropertyName("n")] public string? N { get; set; }
+
+    [JsonPropertyName("e")] public string? E { get; set; }
+
+    public SecurityKey ToSecurityKey()
+    {
+        if (Kty != "RSA" || string.IsNullOrEmpty(N) || string.IsNullOrEmpty(E))
+        {
+            throw new InvalidOperationException("Invalid key data");
+        }
+
+        var parameters = new RSAParameters
+        {
+            Modulus = Base64UrlDecode(N),
+            Exponent = Base64UrlDecode(E)
+        };
+
+        var rsa = RSA.Create();
+        rsa.ImportParameters(parameters);
+
+        return new RsaSecurityKey(rsa);
+    }
+
+    private byte[] Base64UrlDecode(string input)
+    {
+        var output = input
+            .Replace('-', '+')
+            .Replace('_', '/');
+
+        switch (output.Length % 4)
+        {
+            case 0: break;
+            case 2: output += "=="; break;
+            case 3: output += "="; break;
+            default: throw new InvalidOperationException("Invalid base64url string");
+        }
+
+        return Convert.FromBase64String(output);
+    }
+}

DysonNetwork.Pass/Auth/OpenId/ConnectionController.cs

@@ -0,0 +1,409 @@
+using DysonNetwork.Pass.Account;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using DysonNetwork.Shared.Cache;
+using NodaTime;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+[ApiController]
+[Route("/api/accounts/me/connections")]
+[Authorize]
+public class ConnectionController(
+    AppDatabase db,
+    IEnumerable<OidcService> oidcServices,
+    AccountService accounts,
+    AuthService auth,
+    ICacheService cache
+) : ControllerBase
+{
+    private const string StateCachePrefix = "oidc-state:";
+    private const string ReturnUrlCachePrefix = "oidc-returning:";
+    private static readonly TimeSpan StateExpiration = TimeSpan.FromMinutes(15);
+
+    [HttpGet]
+    public async Task<ActionResult<List<AccountConnection>>> GetConnections()
+    {
+        if (HttpContext.Items["CurrentUser"] is not Account.Account currentUser)
+            return Unauthorized();
+
+        var connections = await db.AccountConnections
+            .Where(c => c.AccountId == currentUser.Id)
+            .Select(c => new
+            {
+                c.Id,
+                c.AccountId,
+                c.Provider,
+                c.ProvidedIdentifier,
+                c.Meta,
+                c.LastUsedAt,
+                c.CreatedAt,
+                c.UpdatedAt,
+            })
+            .ToListAsync();
+        return Ok(connections);
+    }
+
+    [HttpDelete("{id:guid}")]
+    public async Task<ActionResult> RemoveConnection(Guid id)
+    {
+        if (HttpContext.Items["CurrentUser"] is not Account.Account currentUser)
+            return Unauthorized();
+
+        var connection = await db.AccountConnections
+            .Where(c => c.Id == id && c.AccountId == currentUser.Id)
+            .FirstOrDefaultAsync();
+        if (connection == null)
+            return NotFound();
+
+        db.AccountConnections.Remove(connection);
+        await db.SaveChangesAsync();
+
+        return Ok();
+    }
+
+    [HttpPost("/auth/connect/apple/mobile")]
+    public async Task<ActionResult> ConnectAppleMobile([FromBody] AppleMobileConnectRequest request)
+    {
+        if (HttpContext.Items["CurrentUser"] is not Account.Account currentUser)
+            return Unauthorized();
+
+        if (GetOidcService("apple") is not AppleOidcService appleService)
+            return StatusCode(503, "Apple OIDC service not available");
+
+        var callbackData = new OidcCallbackData
+        {
+            IdToken = request.IdentityToken,
+            Code = request.AuthorizationCode,
+        };
+
+        OidcUserInfo userInfo;
+        try
+        {
+            userInfo = await appleService.ProcessCallbackAsync(callbackData);
+        }
+        catch (Exception ex)
+        {
+            return BadRequest($"Error processing Apple token: {ex.Message}");
+        }
+
+        var existingConnection = await db.AccountConnections
+            .FirstOrDefaultAsync(c =>
+                c.Provider == "apple" &&
+                c.ProvidedIdentifier == userInfo.UserId);
+
+        if (existingConnection != null)
+        {
+            return BadRequest(
+                $"This Apple account is already linked to {(existingConnection.AccountId == currentUser.Id ? "your account" : "another user")}.");
+        }
+
+        db.AccountConnections.Add(new AccountConnection
+        {
+            AccountId = currentUser.Id,
+            Provider = "apple",
+            ProvidedIdentifier = userInfo.UserId!,
+            AccessToken = userInfo.AccessToken,
+            RefreshToken = userInfo.RefreshToken,
+            LastUsedAt = SystemClock.Instance.GetCurrentInstant(),
+            Meta = userInfo.ToMetadata(),
+        });
+
+        await db.SaveChangesAsync();
+
+        return Ok(new { message = "Successfully connected Apple account." });
+    }
+
+    private OidcService? GetOidcService(string provider)
+    {
+        return oidcServices.FirstOrDefault(s => s.ProviderName.Equals(provider, StringComparison.OrdinalIgnoreCase));
+    }
+
+    public class ConnectProviderRequest
+    {
+        public string Provider { get; set; } = null!;
+        public string? ReturnUrl { get; set; }
+    }
+
+    /// <summary>
+    /// Initiates manual connection to an OAuth provider for the current user
+    /// </summary>
+    [HttpPost("connect")]
+    public async Task<ActionResult<object>> InitiateConnection([FromBody] ConnectProviderRequest request)
+    {
+        if (HttpContext.Items["CurrentUser"] is not Account.Account currentUser)
+            return Unauthorized();
+
+        var oidcService = GetOidcService(request.Provider);
+        if (oidcService == null)
+            return BadRequest($"Provider '{request.Provider}' is not supported");
+
+        var existingConnection = await db.AccountConnections
+            .AnyAsync(c => c.AccountId == currentUser.Id && c.Provider == oidcService.ProviderName);
+
+        if (existingConnection)
+            return BadRequest($"You already have a {request.Provider} connection");
+
+        var state = Guid.NewGuid().ToString("N");
+        var nonce = Guid.NewGuid().ToString("N");
+        var stateValue = $"{currentUser.Id}|{request.Provider}|{nonce}";
+        var finalReturnUrl = !string.IsNullOrEmpty(request.ReturnUrl) ? request.ReturnUrl : "/settings/connections";
+
+        // Store state and return URL in cache
+        await cache.SetAsync($"{StateCachePrefix}{state}", stateValue, StateExpiration);
+        await cache.SetAsync($"{ReturnUrlCachePrefix}{state}", finalReturnUrl, StateExpiration);
+
+        var authUrl = oidcService.GetAuthorizationUrl(state, nonce);
+
+        return Ok(new
+        {
+            authUrl,
+            message = $"Redirect to this URL to connect your {request.Provider} account"
+        });
+    }
+
+    [AllowAnonymous]
+    [Route("/api/auth/callback/{provider}")]
+    [HttpGet, HttpPost]
+    public async Task<IActionResult> HandleCallback([FromRoute] string provider)
+    {
+        var oidcService = GetOidcService(provider);
+        if (oidcService == null)
+            return BadRequest($"Provider '{provider}' is not supported.");
+
+        var callbackData = await ExtractCallbackData(Request);
+        if (callbackData.State == null)
+            return BadRequest("State parameter is missing.");
+
+        // Get the state from the cache
+        var stateKey = $"{StateCachePrefix}{callbackData.State}";
+        
+        // Try to get the state as OidcState first (new format)
+        var oidcState = await cache.GetAsync<OidcState>(stateKey);
+        
+        // If not found, try to get as string (legacy format)
+        if (oidcState == null)
+        {
+            var stateValue = await cache.GetAsync<string>(stateKey);
+            if (string.IsNullOrEmpty(stateValue) || !OidcState.TryParse(stateValue, out oidcState) || oidcState == null)
+                return BadRequest("Invalid or expired state parameter");
+        }
+        
+        // Remove the state from cache to prevent replay attacks
+        await cache.RemoveAsync(stateKey);
+
+        // Handle the flow based on state type
+        if (oidcState.FlowType == OidcFlowType.Connect && oidcState.AccountId.HasValue)
+        {
+            // Connection flow
+            if (oidcState.DeviceId != null)
+            {
+                callbackData.State = oidcState.DeviceId;
+            }
+            return await HandleManualConnection(provider, oidcService, callbackData, oidcState.AccountId.Value);
+        }
+        else if (oidcState.FlowType == OidcFlowType.Login)
+        {
+            // Login/Registration flow
+            if (!string.IsNullOrEmpty(oidcState.DeviceId))
+            {
+                callbackData.State = oidcState.DeviceId;
+            }
+
+            // Store return URL if provided
+            if (!string.IsNullOrEmpty(oidcState.ReturnUrl) && oidcState.ReturnUrl != "/")
+            {
+                var returnUrlKey = $"{ReturnUrlCachePrefix}{callbackData.State}";
+                await cache.SetAsync(returnUrlKey, oidcState.ReturnUrl, StateExpiration);
+            }
+
+            return await HandleLoginOrRegistration(provider, oidcService, callbackData);
+        }
+
+        return BadRequest("Unsupported flow type");
+    }
+
+    private async Task<IActionResult> HandleManualConnection(
+        string provider,
+        OidcService oidcService,
+        OidcCallbackData callbackData,
+        Guid accountId
+    )
+    {
+        provider = provider.ToLower();
+
+        OidcUserInfo userInfo;
+        try
+        {
+            userInfo = await oidcService.ProcessCallbackAsync(callbackData);
+        }
+        catch (Exception ex)
+        {
+            return BadRequest($"Error processing {provider} authentication: {ex.Message}");
+        }
+
+        if (string.IsNullOrEmpty(userInfo.UserId))
+        {
+            return BadRequest($"{provider} did not return a valid user identifier.");
+        }
+
+        // Extract device ID from the callback state if available
+        var deviceId = !string.IsNullOrEmpty(callbackData.State) ? callbackData.State : string.Empty;
+
+        // Check if this provider account is already connected to any user
+        var existingConnection = await db.AccountConnections
+            .FirstOrDefaultAsync(c =>
+                c.Provider == provider &&
+                c.ProvidedIdentifier == userInfo.UserId);
+
+        // If it's connected to a different user, return error
+        if (existingConnection != null && existingConnection.AccountId != accountId)
+        {
+            return BadRequest($"This {provider} account is already linked to another user.");
+        }
+
+        // Check if the current user already has this provider connected
+        var userHasProvider = await db.AccountConnections
+            .AnyAsync(c =>
+                c.AccountId == accountId &&
+                c.Provider == provider);
+
+        if (userHasProvider)
+        {
+            // Update existing connection with new tokens
+            var connection = await db.AccountConnections
+                .FirstOrDefaultAsync(c =>
+                    c.AccountId == accountId &&
+                    c.Provider == provider);
+
+            if (connection != null)
+            {
+                connection.AccessToken = userInfo.AccessToken;
+                connection.RefreshToken = userInfo.RefreshToken;
+                connection.LastUsedAt = SystemClock.Instance.GetCurrentInstant();
+                connection.Meta = userInfo.ToMetadata();
+            }
+        }
+        else
+        {
+            // Create new connection
+            db.AccountConnections.Add(new AccountConnection
+            {
+                AccountId = accountId,
+                Provider = provider,
+                ProvidedIdentifier = userInfo.UserId!,
+                AccessToken = userInfo.AccessToken,
+                RefreshToken = userInfo.RefreshToken,
+                LastUsedAt = SystemClock.Instance.GetCurrentInstant(),
+                Meta = userInfo.ToMetadata(),
+            });
+        }
+
+        try
+        {
+            await db.SaveChangesAsync();
+        }
+        catch (DbUpdateException)
+        {
+            return StatusCode(500, $"Failed to save {provider} connection. Please try again.");
+        }
+
+        // Clean up and redirect
+        var returnUrlKey = $"{ReturnUrlCachePrefix}{callbackData.State}";
+        var returnUrl = await cache.GetAsync<string>(returnUrlKey);
+        await cache.RemoveAsync(returnUrlKey);
+
+        return Redirect(string.IsNullOrEmpty(returnUrl) ? "/auth/callback" : returnUrl);
+    }
+
+    private async Task<IActionResult> HandleLoginOrRegistration(
+        string provider,
+        OidcService oidcService,
+        OidcCallbackData callbackData
+    )
+    {
+        OidcUserInfo userInfo;
+        try
+        {
+            userInfo = await oidcService.ProcessCallbackAsync(callbackData);
+        }
+        catch (Exception ex)
+        {
+            return BadRequest($"Error processing callback: {ex.Message}");
+        }
+
+        if (string.IsNullOrEmpty(userInfo.Email) || string.IsNullOrEmpty(userInfo.UserId))
+        {
+            return BadRequest($"Email or user ID is missing from {provider}'s response");
+        }
+
+        var connection = await db.AccountConnections
+            .Include(c => c.Account)
+            .FirstOrDefaultAsync(c => c.Provider == provider && c.ProvidedIdentifier == userInfo.UserId);
+
+        var clock = SystemClock.Instance;
+        if (connection != null)
+        {
+            // Login existing user
+            var deviceId = !string.IsNullOrEmpty(callbackData.State) ? 
+                callbackData.State.Split('|').FirstOrDefault() : 
+                string.Empty;
+                
+            var challenge = await oidcService.CreateChallengeForUserAsync(
+                userInfo, 
+                connection.Account, 
+                HttpContext, 
+                deviceId ?? string.Empty);
+            return Redirect($"/auth/callback?challenge={challenge.Id}");
+        }
+
+        // Register new user
+        var account = await accounts.LookupAccount(userInfo.Email) ?? await accounts.CreateAccount(userInfo);
+
+        // Create connection for new or existing user
+        var newConnection = new AccountConnection
+        {
+            Account = account,
+            Provider = provider,
+            ProvidedIdentifier = userInfo.UserId!,
+            AccessToken = userInfo.AccessToken,
+            RefreshToken = userInfo.RefreshToken,
+            LastUsedAt = clock.GetCurrentInstant(),
+            Meta = userInfo.ToMetadata()
+        };
+        db.AccountConnections.Add(newConnection);
+
+        await db.SaveChangesAsync();
+
+        var loginSession = await auth.CreateSessionForOidcAsync(account, clock.GetCurrentInstant());
+        var loginToken = auth.CreateToken(loginSession);
+        return Redirect($"/auth/token?token={loginToken}");
+    }
+
+    private static async Task<OidcCallbackData> ExtractCallbackData(HttpRequest request)
+    {
+        var data = new OidcCallbackData();
+        switch (request.Method)
+        {
+            case "GET":
+                data.Code = Uri.UnescapeDataString(request.Query["code"].FirstOrDefault() ?? "");
+                data.IdToken = Uri.UnescapeDataString(request.Query["id_token"].FirstOrDefault() ?? "");
+                data.State = Uri.UnescapeDataString(request.Query["state"].FirstOrDefault() ?? "");
+                break;
+            case "POST" when request.HasFormContentType:
+            {
+                var form = await request.ReadFormAsync();
+                data.Code = Uri.UnescapeDataString(form["code"].FirstOrDefault() ?? "");
+                data.IdToken = Uri.UnescapeDataString(form["id_token"].FirstOrDefault() ?? ""); 
+                data.State = Uri.UnescapeDataString(form["state"].FirstOrDefault() ?? "");
+                if (form.ContainsKey("user"))
+                    data.RawData = Uri.UnescapeDataString(form["user"].FirstOrDefault() ?? "");
+
+                break;
+            }
+        }
+
+        return data;
+    }
+}

DysonNetwork.Pass/Auth/OpenId/DiscordOidcService.cs

@@ -0,0 +1,116 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using DysonNetwork.Pass;
+using DysonNetwork.Shared.Cache;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class DiscordOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    public override string ProviderName => "Discord";
+    protected override string DiscoveryEndpoint => ""; // Discord doesn't have a standard OIDC discovery endpoint
+    protected override string ConfigSectionName => "Discord";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "redirect_uri", config.RedirectUri },
+            { "response_type", "code" },
+            { "scope", "identify email" },
+            { "state", state },
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"https://discord.com/oauth2/authorize?{queryString}";
+    }
+    
+    protected override Task<OidcDiscoveryDocument?> GetDiscoveryDocumentAsync()
+    {
+        return Task.FromResult(new OidcDiscoveryDocument
+        {
+            AuthorizationEndpoint = "https://discord.com/oauth2/authorize",
+            TokenEndpoint = "https://discord.com/oauth2/token",
+            UserinfoEndpoint = "https://discord.com/users/@me",
+            JwksUri = null
+        })!;
+    }
+    
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        var tokenResponse = await ExchangeCodeForTokensAsync(callbackData.Code);
+        if (tokenResponse?.AccessToken == null)
+        {
+            throw new InvalidOperationException("Failed to obtain access token from Discord");
+        }
+
+        var userInfo = await GetUserInfoAsync(tokenResponse.AccessToken);
+
+        userInfo.AccessToken = tokenResponse.AccessToken;
+        userInfo.RefreshToken = tokenResponse.RefreshToken;
+
+        return userInfo;
+    }
+
+    protected override async Task<OidcTokenResponse?> ExchangeCodeForTokensAsync(string code,
+        string? codeVerifier = null)
+    {
+        var config = GetProviderConfig();
+        var client = HttpClientFactory.CreateClient();
+
+        var content = new FormUrlEncodedContent(new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "client_secret", config.ClientSecret },
+            { "grant_type", "authorization_code" },
+            { "code", code },
+            { "redirect_uri", config.RedirectUri },
+        });
+
+        var response = await client.PostAsync("https://discord.com/oauth2/token", content);
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadFromJsonAsync<OidcTokenResponse>();
+    }
+
+    private async Task<OidcUserInfo> GetUserInfoAsync(string accessToken)
+    {
+        var client = HttpClientFactory.CreateClient();
+        var request = new HttpRequestMessage(HttpMethod.Get, "https://discord.com/users/@me");
+        request.Headers.Add("Authorization", $"Bearer {accessToken}");
+
+        var response = await client.SendAsync(request);
+        response.EnsureSuccessStatusCode();
+
+        var json = await response.Content.ReadAsStringAsync();
+        var discordUser = JsonDocument.Parse(json).RootElement;
+
+        var userId = discordUser.GetProperty("id").GetString() ?? "";
+        var avatar = discordUser.TryGetProperty("avatar", out var avatarElement) ? avatarElement.GetString() : null;
+
+        return new OidcUserInfo
+        {
+            UserId = userId,
+            Email = (discordUser.TryGetProperty("email", out var emailElement) ? emailElement.GetString() : null) ?? "",
+            EmailVerified = discordUser.TryGetProperty("verified", out var verifiedElement) &&
+                            verifiedElement.GetBoolean(),
+            DisplayName = (discordUser.TryGetProperty("global_name", out var globalNameElement)
+                ? globalNameElement.GetString()
+                : null) ?? "",
+            PreferredUsername = discordUser.GetProperty("username").GetString() ?? "",
+            ProfilePictureUrl = !string.IsNullOrEmpty(avatar)
+                ? $"https://cdn.discordapp.com/avatars/{userId}/{avatar}.png"
+                : "",
+            Provider = ProviderName
+        };
+    }
+}

DysonNetwork.Pass/Auth/OpenId/GitHubOidcService.cs

@@ -0,0 +1,128 @@
+using System.Net.Http.Json;
+using System.Text.Json;
+using DysonNetwork.Pass;
+using DysonNetwork.Shared.Cache;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class GitHubOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    public override string ProviderName => "GitHub";
+    protected override string DiscoveryEndpoint => ""; // GitHub doesn't have a standard OIDC discovery endpoint
+    protected override string ConfigSectionName => "GitHub";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "redirect_uri", config.RedirectUri },
+            { "scope", "user:email" },
+            { "state", state },
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"https://github.com/login/oauth/authorize?{queryString}";
+    }
+
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        var tokenResponse = await ExchangeCodeForTokensAsync(callbackData.Code);
+        if (tokenResponse?.AccessToken == null)
+        {
+            throw new InvalidOperationException("Failed to obtain access token from GitHub");
+        }
+
+        var userInfo = await GetUserInfoAsync(tokenResponse.AccessToken);
+
+        userInfo.AccessToken = tokenResponse.AccessToken;
+        userInfo.RefreshToken = tokenResponse.RefreshToken;
+
+        return userInfo;
+    }
+
+    protected override async Task<OidcTokenResponse?> ExchangeCodeForTokensAsync(string code,
+        string? codeVerifier = null)
+    {
+        var config = GetProviderConfig();
+        var client = HttpClientFactory.CreateClient();
+
+        var tokenRequest = new HttpRequestMessage(HttpMethod.Post, "https://github.com/login/oauth/access_token")
+        {
+            Content = new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                { "client_id", config.ClientId },
+                { "client_secret", config.ClientSecret },
+                { "code", code },
+                { "redirect_uri", config.RedirectUri },
+            })
+        };
+        tokenRequest.Headers.Add("Accept", "application/json");
+
+        var response = await client.SendAsync(tokenRequest);
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadFromJsonAsync<OidcTokenResponse>();
+    }
+
+    private async Task<OidcUserInfo> GetUserInfoAsync(string accessToken)
+    {
+        var client = HttpClientFactory.CreateClient();
+        var request = new HttpRequestMessage(HttpMethod.Get, "https://api.github.com/user");
+        request.Headers.Add("Authorization", $"Bearer {accessToken}");
+        request.Headers.Add("User-Agent", "DysonNetwork.Pass");
+
+        var response = await client.SendAsync(request);
+        response.EnsureSuccessStatusCode();
+
+        var json = await response.Content.ReadAsStringAsync();
+        var githubUser = JsonDocument.Parse(json).RootElement;
+
+        var email = githubUser.TryGetProperty("email", out var emailElement) ? emailElement.GetString() : null;
+        if (string.IsNullOrEmpty(email))
+        {
+            email = await GetPrimaryEmailAsync(accessToken);
+        }
+
+        return new OidcUserInfo
+        {
+            UserId = githubUser.GetProperty("id").GetInt64().ToString(),
+            Email = email,
+            DisplayName = githubUser.TryGetProperty("name", out var nameElement) ? nameElement.GetString() ?? "" : "",
+            PreferredUsername = githubUser.GetProperty("login").GetString() ?? "",
+            ProfilePictureUrl = githubUser.TryGetProperty("avatar_url", out var avatarElement)
+                ? avatarElement.GetString() ?? ""
+                : "",
+            Provider = ProviderName
+        };
+    }
+
+    private async Task<string?> GetPrimaryEmailAsync(string accessToken)
+    {
+        var client = HttpClientFactory.CreateClient();
+        var request = new HttpRequestMessage(HttpMethod.Get, "https://api.github.com/user/emails");
+        request.Headers.Add("Authorization", $"Bearer {accessToken}");
+        request.Headers.Add("User-Agent", "DysonNetwork.Pass");
+
+        var response = await client.SendAsync(request);
+        if (!response.IsSuccessStatusCode) return null;
+
+        var emails = await response.Content.ReadFromJsonAsync<List<GitHubEmail>>();
+        return emails?.FirstOrDefault(e => e.Primary)?.Email;
+    }
+
+    private class GitHubEmail
+    {
+        public string Email { get; set; } = "";
+        public bool Primary { get; set; }
+        public bool Verified { get; set; }
+    }
+}

DysonNetwork.Pass/Auth/OpenId/GoogleOidcService.cs

@@ -0,0 +1,137 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Net.Http.Json;
+using System.Security.Cryptography;
+using System.Text;
+using DysonNetwork.Pass;
+using DysonNetwork.Shared.Cache;
+using Microsoft.IdentityModel.Tokens;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class GoogleOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    private readonly IHttpClientFactory _httpClientFactory = httpClientFactory;
+
+    public override string ProviderName => "google";
+    protected override string DiscoveryEndpoint => "https://accounts.google.com/.well-known/openid-configuration";
+    protected override string ConfigSectionName => "Google";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+        var discoveryDocument = GetDiscoveryDocumentAsync().GetAwaiter().GetResult();
+
+        if (discoveryDocument?.AuthorizationEndpoint == null)
+        {
+            throw new InvalidOperationException("Authorization endpoint not found in discovery document");
+        }
+
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "redirect_uri", config.RedirectUri },
+            { "response_type", "code" },
+            { "scope", "openid email profile" },
+            { "state", state }, // No '|codeVerifier' appended anymore
+            { "nonce", nonce }
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"{discoveryDocument.AuthorizationEndpoint}?{queryString}";
+    }
+
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        // No need to split or parse code verifier from state
+        var state = callbackData.State ?? "";
+        callbackData.State = state; // Keep the original state if needed
+
+        // Exchange the code for tokens
+        // Pass null or omit the parameter for codeVerifier as PKCE is removed
+        var tokenResponse = await ExchangeCodeForTokensAsync(callbackData.Code, null);
+        if (tokenResponse?.IdToken == null)
+        {
+            throw new InvalidOperationException("Failed to obtain ID token from Google");
+        }
+
+        // Validate the ID token
+        var userInfo = await ValidateTokenAsync(tokenResponse.IdToken);
+
+        // Set tokens on the user info
+        userInfo.AccessToken = tokenResponse.AccessToken;
+        userInfo.RefreshToken = tokenResponse.RefreshToken;
+
+        // Try to fetch additional profile data if userinfo endpoint is available
+        try
+        {
+            var discoveryDocument = await GetDiscoveryDocumentAsync();
+            if (discoveryDocument?.UserinfoEndpoint != null && !string.IsNullOrEmpty(tokenResponse.AccessToken))
+            {
+                var client = _httpClientFactory.CreateClient();
+                client.DefaultRequestHeaders.Authorization =
+                    new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", tokenResponse.AccessToken);
+
+                var userInfoResponse =
+                    await client.GetFromJsonAsync<Dictionary<string, object>>(discoveryDocument.UserinfoEndpoint);
+
+                if (userInfoResponse != null)
+                {
+                    if (userInfoResponse.TryGetValue("picture", out var picture) && picture != null)
+                    {
+                        userInfo.ProfilePictureUrl = picture.ToString();
+                    }
+                }
+            }
+        }
+        catch
+        {
+            // Ignore errors when fetching additional profile data
+        }
+
+        return userInfo;
+    }
+
+    private async Task<OidcUserInfo> ValidateTokenAsync(string idToken)
+    {
+        var discoveryDocument = await GetDiscoveryDocumentAsync();
+        if (discoveryDocument?.JwksUri == null)
+        {
+            throw new InvalidOperationException("JWKS URI not found in discovery document");
+        }
+
+        var client = _httpClientFactory.CreateClient();
+        var jwksResponse = await client.GetFromJsonAsync<JsonWebKeySet>(discoveryDocument.JwksUri);
+        if (jwksResponse == null)
+        {
+            throw new InvalidOperationException("Failed to retrieve JWKS from Google");
+        }
+
+        var handler = new JwtSecurityTokenHandler();
+        var jwtToken = handler.ReadJwtToken(idToken);
+        var kid = jwtToken.Header.Kid;
+        var signingKey = jwksResponse.Keys.FirstOrDefault(k => k.Kid == kid);
+        if (signingKey == null)
+        {
+            throw new SecurityTokenValidationException("Unable to find matching key in Google's JWKS");
+        }
+
+        var validationParameters = new TokenValidationParameters
+        {
+            ValidateIssuer = true,
+            ValidIssuer = "https://accounts.google.com",
+            ValidateAudience = true,
+            ValidAudience = GetProviderConfig().ClientId,
+            ValidateLifetime = true,
+            IssuerSigningKey = signingKey
+        };
+
+        return ValidateAndExtractIdToken(idToken, validationParameters);
+    }
+}

DysonNetwork.Pass/Auth/OpenId/MicrosoftOidcService.cs

@@ -0,0 +1,123 @@
+using System.Text.Json;
+using DysonNetwork.Shared.Cache;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+public class MicrosoftOidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+    : OidcService(configuration, httpClientFactory, db, auth, cache)
+{
+    public override string ProviderName => "Microsoft";
+
+    protected override string DiscoveryEndpoint => Configuration[$"Oidc:{ConfigSectionName}:DiscoveryEndpoint"] ??
+                                                   throw new InvalidOperationException(
+                                                       "Microsoft OIDC discovery endpoint is not configured.");
+
+    protected override string ConfigSectionName => "Microsoft";
+
+    public override string GetAuthorizationUrl(string state, string nonce)
+    {
+        var config = GetProviderConfig();
+        var discoveryDocument = GetDiscoveryDocumentAsync().GetAwaiter().GetResult();
+        if (discoveryDocument?.AuthorizationEndpoint == null)
+            throw new InvalidOperationException("Authorization endpoint not found in discovery document.");
+
+        var queryParams = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "response_type", "code" },
+            { "redirect_uri", config.RedirectUri },
+            { "response_mode", "query" },
+            { "scope", "openid profile email" },
+            { "state", state },
+            { "nonce", nonce },
+        };
+
+        var queryString = string.Join("&", queryParams.Select(p => $"{p.Key}={Uri.EscapeDataString(p.Value)}"));
+        return $"{discoveryDocument.AuthorizationEndpoint}?{queryString}";
+    }
+
+    public override async Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData)
+    {
+        var tokenResponse = await ExchangeCodeForTokensAsync(callbackData.Code);
+        if (tokenResponse?.AccessToken == null)
+        {
+            throw new InvalidOperationException("Failed to obtain access token from Microsoft");
+        }
+
+        var userInfo = await GetUserInfoAsync(tokenResponse.AccessToken);
+
+        userInfo.AccessToken = tokenResponse.AccessToken;
+        userInfo.RefreshToken = tokenResponse.RefreshToken;
+
+        return userInfo;
+    }
+
+    protected override async Task<OidcTokenResponse?> ExchangeCodeForTokensAsync(string code,
+        string? codeVerifier = null)
+    {
+        var config = GetProviderConfig();
+        var discoveryDocument = await GetDiscoveryDocumentAsync();
+        if (discoveryDocument?.TokenEndpoint == null)
+        {
+            throw new InvalidOperationException("Token endpoint not found in discovery document.");
+        }
+
+        var client = HttpClientFactory.CreateClient();
+
+        var tokenRequest = new HttpRequestMessage(HttpMethod.Post, discoveryDocument.TokenEndpoint)
+        {
+            Content = new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                { "client_id", config.ClientId },
+                { "scope", "openid profile email" },
+                { "code", code },
+                { "redirect_uri", config.RedirectUri },
+                { "grant_type", "authorization_code" },
+                { "client_secret", config.ClientSecret },
+            })
+        };
+
+        var response = await client.SendAsync(tokenRequest);
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadFromJsonAsync<OidcTokenResponse>();
+    }
+
+    private async Task<OidcUserInfo> GetUserInfoAsync(string accessToken)
+    {
+        var discoveryDocument = await GetDiscoveryDocumentAsync();
+        if (discoveryDocument?.UserinfoEndpoint == null)
+            throw new InvalidOperationException("Userinfo endpoint not found in discovery document.");
+
+        var client = HttpClientFactory.CreateClient();
+        var request = new HttpRequestMessage(HttpMethod.Get, discoveryDocument.UserinfoEndpoint);
+        request.Headers.Add("Authorization", $"Bearer {accessToken}");
+
+        var response = await client.SendAsync(request);
+        response.EnsureSuccessStatusCode();
+
+        var json = await response.Content.ReadAsStringAsync();
+        var microsoftUser = JsonDocument.Parse(json).RootElement;
+
+        return new OidcUserInfo
+        {
+            UserId = microsoftUser.GetProperty("sub").GetString() ?? "",
+            Email = microsoftUser.TryGetProperty("email", out var emailElement) ? emailElement.GetString() : null,
+            DisplayName =
+                microsoftUser.TryGetProperty("name", out var nameElement) ? nameElement.GetString() ?? "" : "",
+            PreferredUsername = microsoftUser.TryGetProperty("preferred_username", out var preferredUsernameElement)
+                ? preferredUsernameElement.GetString() ?? ""
+                : "",
+            ProfilePictureUrl = microsoftUser.TryGetProperty("picture", out var pictureElement)
+                ? pictureElement.GetString() ?? ""
+                : "",
+            Provider = ProviderName
+        };
+    }
+}

DysonNetwork.Pass/Auth/OpenId/OidcController.cs

@@ -0,0 +1,194 @@
+using DysonNetwork.Pass.Account;
+using DysonNetwork.Shared.Cache;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
+using NodaTime;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+[ApiController]
+[Route("/api/auth/login")]
+public class OidcController(
+    IServiceProvider serviceProvider,
+    AppDatabase db,
+    AccountService accounts,
+    ICacheService cache
+)
+    : ControllerBase
+{
+    private const string StateCachePrefix = "oidc-state:";
+    private static readonly TimeSpan StateExpiration = TimeSpan.FromMinutes(15);
+
+    [HttpGet("{provider}")]
+    public async Task<ActionResult> OidcLogin(
+        [FromRoute] string provider,
+        [FromQuery] string? returnUrl = "/",
+        [FromHeader(Name = "X-Device-Id")] string? deviceId = null
+    )
+    {
+        try
+        {
+            var oidcService = GetOidcService(provider);
+
+            // If the user is already authenticated, treat as an account connection request
+            if (HttpContext.Items["CurrentUser"] is Account.Account currentUser)
+            {
+                var state = Guid.NewGuid().ToString();
+                var nonce = Guid.NewGuid().ToString();
+
+                // Create and store connection state
+                var oidcState = OidcState.ForConnection(currentUser.Id, provider, nonce, deviceId);
+                await cache.SetAsync($"{StateCachePrefix}{state}", oidcState, StateExpiration);
+
+                // The state parameter sent to the provider is the GUID key for the cache.
+                var authUrl = oidcService.GetAuthorizationUrl(state, nonce);
+                return Redirect(authUrl);
+            }
+            else // Otherwise, proceed with the login / registration flow
+            {
+                var nonce = Guid.NewGuid().ToString();
+                var state = Guid.NewGuid().ToString();
+
+                // Create login state with return URL and device ID
+                var oidcState = OidcState.ForLogin(returnUrl ?? "/", deviceId);
+                await cache.SetAsync($"{StateCachePrefix}{state}", oidcState, StateExpiration);
+                var authUrl = oidcService.GetAuthorizationUrl(state, nonce);
+                return Redirect(authUrl);
+            }
+        }
+        catch (Exception ex)
+        {
+            return BadRequest($"Error initiating OpenID Connect flow: {ex.Message}");
+        }
+    }
+
+    /// <summary>
+    /// Mobile Apple Sign In endpoint
+    /// Handles Apple authentication directly from mobile apps
+    /// </summary>
+    [HttpPost("apple/mobile")]
+    public async Task<ActionResult<Challenge>> AppleMobileLogin(
+        [FromBody] AppleMobileSignInRequest request)
+    {
+        try
+        {
+            // Get Apple OIDC service
+            if (GetOidcService("apple") is not AppleOidcService appleService)
+                return StatusCode(503, "Apple OIDC service not available");
+
+            // Prepare callback data for processing
+            var callbackData = new OidcCallbackData
+            {
+                IdToken = request.IdentityToken,
+                Code = request.AuthorizationCode,
+            };
+
+            // Process the authentication
+            var userInfo = await appleService.ProcessCallbackAsync(callbackData);
+
+            // Find or create user account using existing logic
+            var account = await FindOrCreateAccount(userInfo, "apple");
+
+            // Create session using the OIDC service
+            var challenge = await appleService.CreateChallengeForUserAsync(
+                userInfo,
+                account,
+                HttpContext,
+                request.DeviceId
+            );
+
+            return Ok(challenge);
+        }
+        catch (SecurityTokenValidationException ex)
+        {
+            return Unauthorized($"Invalid identity token: {ex.Message}");
+        }
+        catch (Exception ex)
+        {
+            // Log the error
+            return StatusCode(500, $"Authentication failed: {ex.Message}");
+        }
+    }
+
+    private OidcService GetOidcService(string provider)
+    {
+        return provider.ToLower() switch
+        {
+            "apple" => serviceProvider.GetRequiredService<AppleOidcService>(),
+            "google" => serviceProvider.GetRequiredService<GoogleOidcService>(),
+            "microsoft" => serviceProvider.GetRequiredService<MicrosoftOidcService>(),
+            "discord" => serviceProvider.GetRequiredService<DiscordOidcService>(),
+            "github" => serviceProvider.GetRequiredService<GitHubOidcService>(),
+            "afdian" => serviceProvider.GetRequiredService<AfdianOidcService>(),
+            _ => throw new ArgumentException($"Unsupported provider: {provider}")
+        };
+    }
+
+    private async Task<Account.Account> FindOrCreateAccount(OidcUserInfo userInfo, string provider)
+    {
+        if (string.IsNullOrEmpty(userInfo.Email))
+            throw new ArgumentException("Email is required for account creation");
+
+        // Check if an account exists by email
+        var existingAccount = await accounts.LookupAccount(userInfo.Email);
+        if (existingAccount != null)
+        {
+            // Check if this provider connection already exists
+            var existingConnection = await db.AccountConnections
+                .FirstOrDefaultAsync(c => c.AccountId == existingAccount.Id &&
+                                          c.Provider == provider &&
+                                          c.ProvidedIdentifier == userInfo.UserId);
+
+            // If no connection exists, create one
+            if (existingConnection != null)
+            {
+                await db.AccountConnections
+                    .Where(c => c.AccountId == existingAccount.Id &&
+                                c.Provider == provider &&
+                                c.ProvidedIdentifier == userInfo.UserId)
+                    .ExecuteUpdateAsync(s => s
+                        .SetProperty(c => c.LastUsedAt, SystemClock.Instance.GetCurrentInstant())
+                        .SetProperty(c => c.Meta, userInfo.ToMetadata()));
+
+                return existingAccount;
+            }
+
+            var connection = new AccountConnection
+            {
+                AccountId = existingAccount.Id,
+                Provider = provider,
+                ProvidedIdentifier = userInfo.UserId!,
+                AccessToken = userInfo.AccessToken,
+                RefreshToken = userInfo.RefreshToken,
+                LastUsedAt = SystemClock.Instance.GetCurrentInstant(),
+                Meta = userInfo.ToMetadata()
+            };
+
+            await db.AccountConnections.AddAsync(connection);
+            await db.SaveChangesAsync();
+
+            return existingAccount;
+        }
+
+        // Create new account using the AccountService
+        var newAccount = await accounts.CreateAccount(userInfo);
+
+        // Create the provider connection
+        var newConnection = new AccountConnection
+        {
+            AccountId = newAccount.Id,
+            Provider = provider,
+            ProvidedIdentifier = userInfo.UserId!,
+            AccessToken = userInfo.AccessToken,
+            RefreshToken = userInfo.RefreshToken,
+            LastUsedAt = SystemClock.Instance.GetCurrentInstant(),
+            Meta = userInfo.ToMetadata()
+        };
+
+        db.AccountConnections.Add(newConnection);
+        await db.SaveChangesAsync();
+
+        return newAccount;
+    }
+}

DysonNetwork.Pass/Auth/OpenId/OidcService.cs

@@ -0,0 +1,294 @@
+using System.IdentityModel.Tokens.Jwt;
+using System.Text.Json.Serialization;
+using DysonNetwork.Pass.Account;
+using DysonNetwork.Shared.Cache;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.IdentityModel.Tokens;
+using NodaTime;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+/// <summary>
+/// Base service for OpenID Connect authentication providers
+/// </summary>
+public abstract class OidcService(
+    IConfiguration configuration,
+    IHttpClientFactory httpClientFactory,
+    AppDatabase db,
+    AuthService auth,
+    ICacheService cache
+)
+{
+    protected readonly IConfiguration Configuration = configuration;
+    protected readonly IHttpClientFactory HttpClientFactory = httpClientFactory;
+    protected readonly AppDatabase Db = db;
+
+    /// <summary>
+    /// Gets the unique identifier for this provider
+    /// </summary>
+    public abstract string ProviderName { get; }
+
+    /// <summary>
+    /// Gets the OIDC discovery document endpoint
+    /// </summary>
+    protected abstract string DiscoveryEndpoint { get; }
+
+    /// <summary>
+    /// Gets configuration section name for this provider
+    /// </summary>
+    protected abstract string ConfigSectionName { get; }
+
+    /// <summary>
+    /// Gets the authorization URL for initiating the authentication flow
+    /// </summary>
+    public abstract string GetAuthorizationUrl(string state, string nonce);
+
+    /// <summary>
+    /// Process the callback from the OIDC provider
+    /// </summary>
+    public abstract Task<OidcUserInfo> ProcessCallbackAsync(OidcCallbackData callbackData);
+
+    /// <summary>
+    /// Gets the provider configuration
+    /// </summary>
+    protected ProviderConfiguration GetProviderConfig()
+    {
+        return new ProviderConfiguration
+        {
+            ClientId = Configuration[$"Oidc:{ConfigSectionName}:ClientId"] ?? "",
+            ClientSecret = Configuration[$"Oidc:{ConfigSectionName}:ClientSecret"] ?? "",
+            RedirectUri = Configuration["BaseUrl"] + "/auth/callback/" + ProviderName.ToLower()
+        };
+    }
+
+    /// <summary>
+    /// Retrieves the OpenID Connect discovery document
+    /// </summary>
+    protected virtual async Task<OidcDiscoveryDocument?> GetDiscoveryDocumentAsync()
+    {
+        // Construct a cache key unique to the current provider:
+        var cacheKey = $"oidc-discovery:{ProviderName}";
+
+        // Try getting the discovery document from cache first:
+        var (found, cachedDoc) = await cache.GetAsyncWithStatus<OidcDiscoveryDocument>(cacheKey);
+        if (found && cachedDoc != null)
+        {
+            return cachedDoc;
+        }
+
+        // If it's not cached, fetch from the actual discovery endpoint:
+        var client = HttpClientFactory.CreateClient();
+        var response = await client.GetAsync(DiscoveryEndpoint);
+        response.EnsureSuccessStatusCode();
+        var doc = await response.Content.ReadFromJsonAsync<OidcDiscoveryDocument>();
+
+        // Store the discovery document in the cache for a while (e.g., 15 minutes):
+        if (doc is not null)
+            await cache.SetAsync(cacheKey, doc, TimeSpan.FromMinutes(15));
+
+        return doc;
+
+    }
+
+    /// <summary>
+    /// Exchange the authorization code for tokens
+    /// </summary>
+    protected virtual async Task<OidcTokenResponse?> ExchangeCodeForTokensAsync(string code,
+        string? codeVerifier = null)
+    {
+        var config = GetProviderConfig();
+        var discoveryDocument = await GetDiscoveryDocumentAsync();
+
+        if (discoveryDocument?.TokenEndpoint == null)
+        {
+            throw new InvalidOperationException("Token endpoint not found in discovery document");
+        }
+
+        var client = HttpClientFactory.CreateClient();
+        var content = new FormUrlEncodedContent(BuildTokenRequestParameters(code, config, codeVerifier));
+
+        var response = await client.PostAsync(discoveryDocument.TokenEndpoint, content);
+        response.EnsureSuccessStatusCode();
+
+        return await response.Content.ReadFromJsonAsync<OidcTokenResponse>();
+    }
+
+    /// <summary>
+    /// Build the token request parameters
+    /// </summary>
+    protected virtual Dictionary<string, string> BuildTokenRequestParameters(string code, ProviderConfiguration config,
+        string? codeVerifier)
+    {
+        var parameters = new Dictionary<string, string>
+        {
+            { "client_id", config.ClientId },
+            { "code", code },
+            { "grant_type", "authorization_code" },
+            { "redirect_uri", config.RedirectUri }
+        };
+
+        if (!string.IsNullOrEmpty(config.ClientSecret))
+        {
+            parameters.Add("client_secret", config.ClientSecret);
+        }
+
+        if (!string.IsNullOrEmpty(codeVerifier))
+        {
+            parameters.Add("code_verifier", codeVerifier);
+        }
+
+        return parameters;
+    }
+
+    /// <summary>
+    /// Validates and extracts information from an ID token
+    /// </summary>
+    protected virtual OidcUserInfo ValidateAndExtractIdToken(string idToken,
+        TokenValidationParameters validationParameters)
+    {
+        var handler = new JwtSecurityTokenHandler();
+        handler.ValidateToken(idToken, validationParameters, out _);
+
+        var jwtToken = handler.ReadJwtToken(idToken);
+
+        // Extract standard claims
+        var userId = jwtToken.Claims.FirstOrDefault(c => c.Type == "sub")?.Value;
+        var email = jwtToken.Claims.FirstOrDefault(c => c.Type == "email")?.Value;
+        var emailVerified = jwtToken.Claims.FirstOrDefault(c => c.Type == "email_verified")?.Value == "true";
+        var name = jwtToken.Claims.FirstOrDefault(c => c.Type == "name")?.Value;
+        var givenName = jwtToken.Claims.FirstOrDefault(c => c.Type == "given_name")?.Value;
+        var familyName = jwtToken.Claims.FirstOrDefault(c => c.Type == "family_name")?.Value;
+        var preferredUsername = jwtToken.Claims.FirstOrDefault(c => c.Type == "preferred_username")?.Value;
+        var picture = jwtToken.Claims.FirstOrDefault(c => c.Type == "picture")?.Value;
+
+        // Determine preferred username - try different options
+        var username = preferredUsername;
+        if (string.IsNullOrEmpty(username))
+        {
+            // Fall back to email local part if no preferred username
+            username = !string.IsNullOrEmpty(email) ? email.Split('@')[0] : null;
+        }
+
+        return new OidcUserInfo
+        {
+            UserId = userId,
+            Email = email,
+            EmailVerified = emailVerified,
+            FirstName = givenName ?? "",
+            LastName = familyName ?? "",
+            DisplayName = name ?? $"{givenName} {familyName}".Trim(),
+            PreferredUsername = username ?? "",
+            ProfilePictureUrl = picture,
+            Provider = ProviderName
+        };
+    }
+
+    /// <summary>
+    /// Creates a challenge and session for an authenticated user
+    /// Also creates or updates the account connection
+    /// </summary>
+    public async Task<Challenge> CreateChallengeForUserAsync(
+        OidcUserInfo userInfo,
+        Account.Account account,
+        HttpContext request,
+        string deviceId
+    )
+    {
+        // Create or update the account connection
+        var connection = await Db.AccountConnections
+            .FirstOrDefaultAsync(c => c.Provider == ProviderName &&
+                                      c.ProvidedIdentifier == userInfo.UserId &&
+                                      c.AccountId == account.Id
+            );
+
+        if (connection is null)
+        {
+            connection = new AccountConnection
+            {
+                Provider = ProviderName,
+                ProvidedIdentifier = userInfo.UserId ?? "",
+                AccessToken = userInfo.AccessToken,
+                RefreshToken = userInfo.RefreshToken,
+                LastUsedAt = SystemClock.Instance.GetCurrentInstant(),
+                AccountId = account.Id
+            };
+            await Db.AccountConnections.AddAsync(connection);
+        }
+
+        // Create a challenge that's already completed
+        var now = SystemClock.Instance.GetCurrentInstant();
+        var challenge = new Challenge
+        {
+            ExpiredAt = now.Plus(Duration.FromHours(1)),
+            StepTotal = await auth.DetectChallengeRisk(request.Request, account),
+            Type = ChallengeType.Oidc,
+            Platform = ChallengePlatform.Unidentified,
+            Audiences = [ProviderName],
+            Scopes = ["*"],
+            AccountId = account.Id,
+            DeviceId = deviceId,
+            IpAddress = request.Connection.RemoteIpAddress?.ToString() ?? null,
+            UserAgent = request.Request.Headers.UserAgent,
+        };
+        challenge.StepRemain--;
+        if (challenge.StepRemain < 0) challenge.StepRemain = 0;
+
+        await Db.AuthChallenges.AddAsync(challenge);
+        await Db.SaveChangesAsync();
+
+        return challenge;
+    }
+}
+
+/// <summary>
+/// Provider configuration from app settings
+/// </summary>
+public class ProviderConfiguration
+{
+    public string ClientId { get; set; } = "";
+    public string ClientSecret { get; set; } = "";
+    public string RedirectUri { get; set; } = "";
+}
+
+/// <summary>
+/// OIDC Discovery Document
+/// </summary>
+public class OidcDiscoveryDocument
+{
+    [JsonPropertyName("authorization_endpoint")]
+    public string? AuthorizationEndpoint { get; set; }
+
+    [JsonPropertyName("token_endpoint")] public string? TokenEndpoint { get; set; }
+
+    [JsonPropertyName("userinfo_endpoint")]
+    public string? UserinfoEndpoint { get; set; }
+
+    [JsonPropertyName("jwks_uri")] public string? JwksUri { get; set; }
+}
+
+/// <summary>
+/// Response from the token endpoint
+/// </summary>
+public class OidcTokenResponse
+{
+    [JsonPropertyName("access_token")] public string? AccessToken { get; set; }
+
+    [JsonPropertyName("token_type")] public string? TokenType { get; set; }
+
+    [JsonPropertyName("expires_in")] public int ExpiresIn { get; set; }
+
+    [JsonPropertyName("refresh_token")] public string? RefreshToken { get; set; }
+
+    [JsonPropertyName("id_token")] public string? IdToken { get; set; }
+}
+
+/// <summary>
+/// Data received in the callback from an OIDC provider
+/// </summary>
+public class OidcCallbackData
+{
+    public string Code { get; set; } = "";
+    public string IdToken { get; set; } = "";
+    public string? State { get; set; }
+    public string? RawData { get; set; }
+}

DysonNetwork.Pass/Auth/OpenId/OidcState.cs

@@ -0,0 +1,189 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+/// <summary>
+/// Represents the state parameter used in OpenID Connect flows.
+/// Handles serialization and deserialization of the state parameter.
+/// </summary>
+public class OidcState
+{
+    /// <summary>
+    /// The type of OIDC flow (login or connect).
+    /// </summary>
+    public OidcFlowType FlowType { get; set; }
+
+    /// <summary>
+    /// The account ID (for connect flow).
+    /// </summary>
+    public Guid? AccountId { get; set; }
+
+
+    /// <summary>
+    /// The OIDC provider name.
+    /// </summary>
+    public string? Provider { get; set; }
+
+
+    /// <summary>
+    /// The nonce for CSRF protection.
+    /// </summary>
+    public string? Nonce { get; set; }
+
+
+    /// <summary>
+    /// The device ID for the authentication request.
+    /// </summary>
+    public string? DeviceId { get; set; }
+
+
+    /// <summary>
+    /// The return URL after authentication (for login flow).
+    /// </summary>
+    public string? ReturnUrl { get; set; }
+
+
+    /// <summary>
+    /// Creates a new OidcState for a connection flow.
+    /// </summary>
+    public static OidcState ForConnection(Guid accountId, string provider, string nonce, string? deviceId = null)
+    {
+        return new OidcState
+        {
+            FlowType = OidcFlowType.Connect,
+            AccountId = accountId,
+            Provider = provider,
+            Nonce = nonce,
+            DeviceId = deviceId
+        };
+    }
+
+    /// <summary>
+    /// Creates a new OidcState for a login flow.
+    /// </summary>
+    public static OidcState ForLogin(string returnUrl = "/", string? deviceId = null)
+    {
+        return new OidcState
+        {
+            FlowType = OidcFlowType.Login,
+            ReturnUrl = returnUrl,
+            DeviceId = deviceId
+        };
+    }
+
+    /// <summary>
+    /// The version of the state format.
+    /// </summary>
+    public int Version { get; set; } = 1;
+
+    /// <summary>
+    /// Serializes the state to a JSON string for use in OIDC flows.
+    /// </summary>
+    public string Serialize()
+    {
+        return JsonSerializer.Serialize(this, new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+        });
+    }
+
+    /// <summary>
+    /// Attempts to parse a state string into an OidcState object.
+    /// </summary>
+    public static bool TryParse(string? stateString, out OidcState? state)
+    {
+        state = null;
+
+        if (string.IsNullOrEmpty(stateString))
+            return false;
+
+        try
+        {
+            // First try to parse as JSON
+            try
+            {
+                state = JsonSerializer.Deserialize<OidcState>(stateString);
+                return state != null;
+            }
+            catch (JsonException)
+            {
+                // Not a JSON string, try legacy format for backward compatibility
+                return TryParseLegacyFormat(stateString, out state);
+            }
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static bool TryParseLegacyFormat(string stateString, out OidcState? state)
+    {
+        state = null;
+        var parts = stateString.Split('|');
+
+        // Check for connection flow format: {accountId}|{provider}|{nonce}|{deviceId}|connect
+        if (parts.Length >= 5 &&
+            Guid.TryParse(parts[0], out var accountId) &&
+            string.Equals(parts[^1], "connect", StringComparison.OrdinalIgnoreCase))
+        {
+            state = new OidcState
+            {
+                FlowType = OidcFlowType.Connect,
+                AccountId = accountId,
+                Provider = parts[1],
+                Nonce = parts[2],
+                DeviceId = parts.Length >= 4 && !string.IsNullOrEmpty(parts[3]) ? parts[3] : null
+            };
+            return true;
+        }
+
+        // Check for login flow format: {returnUrl}|{deviceId}|login
+        if (parts.Length >= 2 &&
+            parts.Length <= 3 &&
+            (parts.Length < 3 || string.Equals(parts[^1], "login", StringComparison.OrdinalIgnoreCase)))
+        {
+            state = new OidcState
+            {
+                FlowType = OidcFlowType.Login,
+                ReturnUrl = parts[0],
+                DeviceId = parts.Length >= 2 && !string.IsNullOrEmpty(parts[1]) ? parts[1] : null
+            };
+            return true;
+        }
+
+        // Legacy format support (for backward compatibility)
+        if (parts.Length == 1)
+        {
+            state = new OidcState
+            {
+                FlowType = OidcFlowType.Login,
+                ReturnUrl = parts[0],
+                DeviceId = null
+            };
+            return true;
+        }
+
+
+        return false;
+    }
+}
+
+/// <summary>
+/// Represents the type of OIDC flow.
+/// </summary>
+public enum OidcFlowType
+{
+    /// <summary>
+    /// Login or registration flow.
+    /// </summary>
+    Login,
+
+
+    /// <summary>
+    /// Account connection flow.
+    /// </summary>
+    Connect
+}

DysonNetwork.Pass/Auth/OpenId/OidcUserInfo.cs

@@ -0,0 +1,49 @@
+namespace DysonNetwork.Pass.Auth.OpenId;
+
+/// <summary>
+/// Represents the user information from an OIDC provider
+/// </summary>
+public class OidcUserInfo
+{
+    public string? UserId { get; set; }
+    public string? Email { get; set; }
+    public bool EmailVerified { get; set; }
+    public string FirstName { get; set; } = "";
+    public string LastName { get; set; } = "";
+    public string DisplayName { get; set; } = "";
+    public string PreferredUsername { get; set; } = "";
+    public string? ProfilePictureUrl { get; set; }
+    public string Provider { get; set; } = "";
+    public string? RefreshToken { get; set; }
+    public string? AccessToken { get; set; }
+
+    public Dictionary<string, object> ToMetadata()
+    {
+        var metadata = new Dictionary<string, object>();
+
+        if (!string.IsNullOrWhiteSpace(UserId))
+            metadata["user_id"] = UserId;
+
+        if (!string.IsNullOrWhiteSpace(Email))
+            metadata["email"] = Email;
+
+        metadata["email_verified"] = EmailVerified;
+
+        if (!string.IsNullOrWhiteSpace(FirstName))
+            metadata["first_name"] = FirstName;
+
+        if (!string.IsNullOrWhiteSpace(LastName))
+            metadata["last_name"] = LastName;
+
+        if (!string.IsNullOrWhiteSpace(DisplayName))
+            metadata["display_name"] = DisplayName;
+
+        if (!string.IsNullOrWhiteSpace(PreferredUsername))
+            metadata["preferred_username"] = PreferredUsername;
+
+        if (!string.IsNullOrWhiteSpace(ProfilePictureUrl))
+            metadata["profile_picture_url"] = ProfilePictureUrl;
+
+        return metadata;
+    }
+}