config

type Config struct {
	// Server settings
	ServerAddr  string
	BaseURL     string
	TLSCertFile string // Both TLSCertFile and TLSKeyFile must be set to serve HTTPS.
	TLSKeyFile  string

	// Environment detection
	IsProduction bool

	// JWT settings
	JWTSecret           string
	JWTExpiration       time.Duration
	JWTSigningAlgorithm string        // "HS256" (default), "RS256", or "ES256"
	JWTPrivateKeyPath   string        // PEM file path (required for RS256/ES256)
	JWTKeyID            string        // "kid" header for JWKS key rotation (auto-generated if empty)
	JWTExpirationJitter time.Duration // Max random jitter added to access token expiry (default: 30m)

	// Session settings
	SessionSecret            string
	SessionMaxAge            int  // Session max age in seconds (default: 3600 = 1 hour)
	SessionIdleTimeout       int  // Session idle timeout in seconds (0 = disabled, default: 1800 = 30 minutes)
	SessionFingerprint       bool // Enable session fingerprinting (IP + User-Agent validation, default: true)
	SessionFingerprintIP     bool // Include IP address in fingerprint (default: false, due to dynamic IPs)
	SessionRememberMeEnabled bool // Enable "Remember Me" checkbox on login (default: true)
	SessionRememberMeMaxAge  int  // Remember Me session max age in seconds (default: 2592000 = 30 days)

	// Device code settings
	DeviceCodeExpiration time.Duration
	PollingInterval      int // seconds

	// Database
	DatabaseDriver string // "sqlite" or "postgres"
	DatabaseDSN    string // Database connection string (DSN or path)

	// Database connection pool settings
	DBMaxOpenConns    int           // Maximum number of open connections (default: 25)
	DBMaxIdleConns    int           // Maximum number of idle connections (default: 10)
	DBConnMaxLifetime time.Duration // Maximum connection lifetime (default: 5 minutes)
	DBConnMaxIdleTime time.Duration // Maximum connection idle time (default: 10 minutes)
	DBLogLevel        string        // GORM log level: "silent", "error", "warn", "info" (default: "warn")

	// Default Admin User
	DefaultAdminPassword string // Default admin password (if empty, random password is generated)

	// Authentication
	AuthMode string // "local" or "http_api"

	// HTTP API Authentication
	HTTPAPIURL                string
	HTTPAPITimeout            time.Duration
	HTTPAPIInsecureSkipVerify bool
	HTTPAPIAuthMode           string // Authentication mode: "none", "simple", or "hmac"
	HTTPAPIAuthSecret         string // Shared secret for authentication
	HTTPAPIAuthHeader         string // Custom header name for simple mode (default: "X-API-Secret")
	HTTPAPIMaxRetries         int    // Maximum retry attempts (default: 3)
	HTTPAPIRetryDelay         time.Duration
	HTTPAPIMaxRetryDelay      time.Duration

	// Refresh Token settings
	RefreshTokenExpiration time.Duration // Refresh token lifetime (default: 720h = 30 days)
	EnableRefreshTokens    bool          // Feature flag to enable/disable refresh tokens (default: true)
	EnableTokenRotation    bool          // Enable token rotation mode (default: false, fixed mode)

	// Client Credentials Flow settings (RFC 6749 §4.4)
	ClientCredentialsTokenExpiration time.Duration // Access token lifetime for client_credentials grant (default: 1h, same as JWTExpiration)

	// OAuth settings
	// GitHub OAuth
	GitHubOAuthEnabled     bool
	GitHubClientID         string
	GitHubClientSecret     string
	GitHubOAuthRedirectURL string
	GitHubOAuthScopes      []string

	// Gitea OAuth
	GiteaOAuthEnabled     bool
	GiteaURL              string
	GiteaClientID         string
	GiteaClientSecret     string
	GiteaOAuthRedirectURL string
	GiteaOAuthScopes      []string

	// Microsoft Entra ID OAuth
	MicrosoftOAuthEnabled     bool
	MicrosoftTenantID         string // "common", "organizations", or tenant UUID
	MicrosoftClientID         string
	MicrosoftClientSecret     string
	MicrosoftOAuthRedirectURL string
	MicrosoftOAuthScopes      []string

	// GitLab OAuth
	GitLabOAuthEnabled     bool
	GitLabURL              string // Base URL; defaults to "https://gitlab.com" for cloud
	GitLabClientID         string
	GitLabClientSecret     string
	GitLabOAuthRedirectURL string
	GitLabOAuthScopes      []string

	// OAuth Auto Registration
	OAuthAutoRegister bool // Allow OAuth to auto-create accounts (default: true)

	// OAuth HTTP Client Settings
	OAuthTimeout            time.Duration // HTTP client timeout for OAuth requests (default: 15s)
	OAuthInsecureSkipVerify bool          // Skip TLS verification for OAuth (dev/testing only, default: false)

	// Rate Limiting settings
	EnableRateLimit          bool   // Enable rate limiting (default: true)
	RateLimitStore           string // Rate limit store: "memory" or "redis" (default: "memory")
	RateLimitCleanupInterval time.Duration
	LoginRateLimit           int // Requests per minute for /login endpoint (default: 5)
	DeviceCodeRateLimit      int // Requests per minute for /oauth/device/code (default: 10)
	TokenRateLimit           int // Requests per minute for /oauth/token (default: 20)
	DeviceVerifyRateLimit    int // Requests per minute for /device/verify (default: 10)
	IntrospectRateLimit      int // Requests per minute for /oauth/introspect (default: 20)

	// Redis settings (only used when RateLimitStore = "redis")
	RedisAddr     string // Redis address for rate limiting (e.g., "localhost:6379")
	RedisPassword string // Redis password (empty for no auth)
	RedisDB       int    // Redis database number (default: 0)

	// Audit Logging settings
	EnableAuditLogging      bool          // Enable audit logging (default: true)
	AuditLogRetention       time.Duration // Retention period for audit logs (default: 90 days)
	AuditLogBufferSize      int           // Async buffer size (default: 1000)
	AuditLogCleanupInterval time.Duration // Cleanup interval (default: 24 hours)

	// Token/Device Code cleanup settings
	EnableExpiredTokenCleanup   bool          // Enable periodic cleanup of expired tokens and device codes (default: false)
	ExpiredTokenCleanupInterval time.Duration // How often to purge expired rows (default: 1h)

	// Prometheus Metrics settings
	MetricsEnabled             bool          // Enable Prometheus metrics endpoint (default: false)
	MetricsToken               string        // Bearer token for /metrics (empty = no auth, recommended for production)
	MetricsGaugeUpdateEnabled  bool          // Enable gauge metric updates (default: true, disable on all but one replica)
	MetricsGaugeUpdateInterval time.Duration // Gauge update interval (default: 5m)
	MetricsCacheType           string        // Cache backend: memory, redis, redis-aside (default: memory)
	MetricsCacheClientTTL      time.Duration // Client-side cache TTL for redis-aside (default: 30s)
	MetricsCacheSizePerConn    int           // Client-side cache size per connection in MB for redis-aside (default: 32MB)

	// User Cache settings
	UserCacheType        string        // USER_CACHE_TYPE: memory|redis|redis-aside (default: memory)
	UserCacheTTL         time.Duration // USER_CACHE_TTL (default: 5m)
	UserCacheClientTTL   time.Duration // USER_CACHE_CLIENT_TTL for redis-aside client-side TTL (default: 30s)
	UserCacheSizePerConn int           // USER_CACHE_SIZE_PER_CONN: client-side cache size per connection in MB for redis-aside (default: 32MB)

	// Client Count Cache settings (pending badge in admin navbar)
	ClientCountCacheType        string        // CLIENT_COUNT_CACHE_TYPE: memory|redis|redis-aside (default: memory)
	ClientCountCacheTTL         time.Duration // CLIENT_COUNT_CACHE_TTL: server-side cache lifetime (default: 1h)
	ClientCountCacheClientTTL   time.Duration // CLIENT_COUNT_CACHE_CLIENT_TTL for redis-aside (default: 10m)
	ClientCountCacheSizePerConn int           // CLIENT_COUNT_CACHE_SIZE_PER_CONN for redis-aside in MB (default: 32MB)

	// Client Cache settings (caches OAuth client lookups by client_id)
	ClientCacheType        string        // CLIENT_CACHE_TYPE: memory|redis|redis-aside (default: memory)
	ClientCacheTTL         time.Duration // CLIENT_CACHE_TTL: cache lifetime (default: 5m)
	ClientCacheClientTTL   time.Duration // CLIENT_CACHE_CLIENT_TTL for redis-aside client-side TTL (default: 30s)
	ClientCacheSizePerConn int           // CLIENT_CACHE_SIZE_PER_CONN: client-side cache size per connection in MB for redis-aside (default: 32MB)

	// Token Cache settings (reduces DB queries for token verification)
	TokenCacheEnabled     bool          // TOKEN_CACHE_ENABLED: enable token verification cache (default: false)
	TokenCacheType        string        // TOKEN_CACHE_TYPE: memory|redis|redis-aside (default: memory)
	TokenCacheTTL         time.Duration // TOKEN_CACHE_TTL: cache lifetime (default: 10h, matches JWT_EXPIRATION)
	TokenCacheClientTTL   time.Duration // TOKEN_CACHE_CLIENT_TTL: redis-aside client-side TTL (default: 1h)
	TokenCacheSizePerConn int           // TOKEN_CACHE_SIZE_PER_CONN: redis-aside size in MB (default: 32MB)

	// Dynamic Client Registration (RFC 7591)
	EnableDynamicClientRegistration    bool   // Enable POST /oauth/register endpoint (default: false)
	DynamicClientRegistrationRateLimit int    // Requests per minute for /oauth/register (default: 5)
	DynamicClientRegistrationToken     string // Initial access token for protected registration (empty = open registration)

	// Authorization Code Flow settings (RFC 6749)
	AuthCodeExpiration time.Duration // Authorization code lifetime (default: 10 minutes)
	PKCERequired       bool          // Force PKCE for all public clients (default: false)
	ConsentRemember    bool          // Skip consent page if user already authorized same scope (default: true)

	// CORS settings
	CORSEnabled        bool          // Enable CORS for API endpoints (default: false)
	CORSAllowedOrigins []string      // Allowed origins (comma-separated via env, e.g. "http://localhost:3000")
	CORSAllowedMethods []string      // Allowed HTTP methods (default: GET,POST,PUT,DELETE,OPTIONS)
	CORSAllowedHeaders []string      // Allowed request headers (default: Origin,Content-Type,Authorization)
	CORSMaxAge         time.Duration // Preflight cache duration (default: 12 hours)

	// Static file caching
	StaticCacheMaxAge time.Duration // Cache-Control max-age for non-hashed static files (default: 24h, 0 disables)

	// Bootstrap and shutdown timeout settings
	DBInitTimeout         time.Duration // Database initialization timeout (default: 30s)
	RedisConnTimeout      time.Duration // Redis connection timeout (default: 5s)
	CacheInitTimeout      time.Duration // Cache initialization timeout (default: 5s)
	ServerShutdownTimeout time.Duration // HTTP server graceful shutdown timeout (default: 5s)
	AuditShutdownTimeout  time.Duration // Audit service shutdown timeout (default: 10s)
	RedisCloseTimeout     time.Duration // Redis close timeout (default: 5s)
	CacheCloseTimeout     time.Duration // Cache close timeout (default: 5s)
	DBCloseTimeout        time.Duration // Database close timeout (default: 5s)
}