rrag 0.1.0-alpha.2

//! # Authentication and Authorization System
//! 
//! Comprehensive authentication and authorization framework supporting:
//! - API Key authentication
//! - JWT token authentication
//! - OAuth2 integration
//! - TOTP (Time-based One-Time Password) authentication
//! - WebAuthn for passwordless authentication
//! - Role-based access control (RBAC)
//! - Fine-grained permissions
//! - Session management
//! - Multi-factor authentication (MFA)

use crate::{RragError, RragResult};
use async_trait::async_trait;
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use tokio::sync::RwLock;
use uuid::Uuid;
use chrono::{DateTime, Duration, Utc};
use sha2::{Sha256, Digest};
use hmac::{Hmac, Mac};
use base64::{Engine as _, engine::general_purpose};
use jsonwebtoken::{decode, encode, DecodingKey, EncodingKey, Header, TokenData, Validation};
use bcrypt::{hash, verify, DEFAULT_COST};
use argon2::{Argon2, PasswordHash, PasswordHasher, PasswordVerifier};
use argon2::password_hash::{SaltString, rand_core::OsRng};

/// Main authentication service
#[derive(Clone)]
pub struct AuthenticationService {
    providers: Arc<RwLock<Vec<Arc<dyn AuthProvider>>>>,
    config: AuthConfig,
    user_store: Arc<dyn UserStore>,
    session_store: Arc<dyn SessionStore>,
}

/// Authentication configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuthConfig {
    /// JWT secret key for signing tokens
    pub jwt_secret: String,
    /// JWT token expiration time in seconds
    pub jwt_expiration: i64,
    /// API key length
    pub api_key_length: usize,
    /// Enable multi-factor authentication
    pub enable_mfa: bool,
    /// Require email verification
    pub require_email_verification: bool,
    /// Password policy settings
    pub password_policy: PasswordPolicy,
    /// Session timeout in seconds
    pub session_timeout: i64,
    /// Maximum failed authentication attempts
    pub max_failed_attempts: u32,
    /// Account lockout duration in seconds
    pub lockout_duration: i64,
    /// Enable account lockout
    pub enable_lockout: bool,
}

impl Default for AuthConfig {
    fn default() -> Self {
        Self {
            jwt_secret: "default-secret-change-me".to_string(),
            jwt_expiration: 3600, // 1 hour
            api_key_length: 32,
            enable_mfa: false,
            require_email_verification: false,
            password_policy: PasswordPolicy::default(),
            session_timeout: 86400, // 24 hours
            max_failed_attempts: 5,
            lockout_duration: 900, // 15 minutes
            enable_lockout: true,
        }
    }
}

/// Password policy configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PasswordPolicy {
    pub min_length: usize,
    pub require_uppercase: bool,
    pub require_lowercase: bool,
    pub require_numbers: bool,
    pub require_symbols: bool,
    pub min_entropy_bits: f64,
    pub common_password_check: bool,
    pub max_password_age_days: Option<u32>,
}

impl Default for PasswordPolicy {
    fn default() -> Self {
        Self {
            min_length: 8,
            require_uppercase: true,
            require_lowercase: true,
            require_numbers: true,
            require_symbols: false,
            min_entropy_bits: 50.0,
            common_password_check: true,
            max_password_age_days: Some(90),
        }
    }
}

/// Authentication credentials
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum Credentials {
    ApiKey {
        key: String,
    },
    UsernamePassword {
        username: String,
        password: String,
        totp_code: Option<String>,
    },
    JwtToken {
        token: String,
    },
    OAuth2 {
        provider: String,
        access_token: String,
        refresh_token: Option<String>,
    },
    WebAuthn {
        assertion: String,
        client_data: String,
    },
    Session {
        session_id: String,
    },
}

/// Authentication result
#[derive(Debug, Clone)]
pub struct AuthResult {
    pub success: bool,
    pub user: Option<User>,
    pub session: Option<Session>,
    pub method: String,
    pub mfa_required: bool,
    pub mfa_methods: Vec<String>,
    pub error: Option<String>,
    pub expires_at: Option<DateTime<Utc>>,
}

impl AuthResult {
    pub fn success(user: User) -> Self {
        Self {
            success: true,
            user: Some(user),
            session: None,
            method: "unknown".to_string(),
            mfa_required: false,
            mfa_methods: Vec::new(),
            error: None,
            expires_at: None,
        }
    }

    pub fn failure(error: impl Into<String>) -> Self {
        Self {
            success: false,
            user: None,
            session: None,
            method: "unknown".to_string(),
            mfa_required: false,
            mfa_methods: Vec::new(),
            error: Some(error.into()),
            expires_at: None,
        }
    }

    pub fn mfa_required(methods: Vec<String>) -> Self {
        Self {
            success: false,
            user: None,
            session: None,
            method: "unknown".to_string(),
            mfa_required: true,
            mfa_methods: methods,
            error: None,
            expires_at: None,
        }
    }
}

/// User representation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct User {
    pub id: String,
    pub username: String,
    pub email: Option<String>,
    pub roles: Vec<Role>,
    pub permissions: HashSet<Permission>,
    pub metadata: HashMap<String, serde_json::Value>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
    pub last_login: Option<DateTime<Utc>>,
    pub email_verified: bool,
    pub mfa_enabled: bool,
    pub mfa_methods: Vec<MfaMethod>,
    pub account_locked: bool,
    pub locked_until: Option<DateTime<Utc>>,
    pub failed_attempts: u32,
}

impl User {
    pub fn new(id: String, username: String, email: Option<String>) -> Self {
        Self {
            id,
            username,
            email,
            roles: Vec::new(),
            permissions: HashSet::new(),
            metadata: HashMap::new(),
            created_at: Utc::now(),
            updated_at: Utc::now(),
            last_login: None,
            email_verified: false,
            mfa_enabled: false,
            mfa_methods: Vec::new(),
            account_locked: false,
            locked_until: None,
            failed_attempts: 0,
        }
    }

    pub fn anonymous() -> Self {
        Self::new(
            "anonymous".to_string(),
            "anonymous".to_string(),
            None,
        )
    }

    pub fn add_role(&mut self, role: Role) {
        self.roles.push(role);
        self.updated_at = Utc::now();
    }

    pub fn add_permission(&mut self, permission: Permission) {
        self.permissions.insert(permission);
        self.updated_at = Utc::now();
    }

    pub fn has_permission(&self, permission: &Permission) -> bool {
        self.permissions.contains(permission) || 
        self.roles.iter().any(|role| role.permissions.contains(permission))
    }

    pub fn has_role(&self, role_name: &str) -> bool {
        self.roles.iter().any(|role| role.name == role_name)
    }

    pub fn is_locked(&self) -> bool {
        self.account_locked && 
        self.locked_until.map_or(true, |until| Utc::now() < until)
    }

    pub fn unlock(&mut self) {
        self.account_locked = false;
        self.locked_until = None;
        self.failed_attempts = 0;
        self.updated_at = Utc::now();
    }

    pub fn increment_failed_attempts(&mut self, max_attempts: u32, lockout_duration: i64) {
        self.failed_attempts += 1;
        if self.failed_attempts >= max_attempts {
            self.account_locked = true;
            self.locked_until = Some(Utc::now() + Duration::seconds(lockout_duration));
        }
        self.updated_at = Utc::now();
    }

    pub fn reset_failed_attempts(&mut self) {
        self.failed_attempts = 0;
        self.updated_at = Utc::now();
    }
}

/// Role-based access control
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct Role {
    pub name: String,
    pub description: String,
    pub permissions: HashSet<Permission>,
    pub created_at: DateTime<Utc>,
}

impl Role {
    pub fn new(name: String, description: String) -> Self {
        Self {
            name,
            description,
            permissions: HashSet::new(),
            created_at: Utc::now(),
        }
    }

    pub fn add_permission(&mut self, permission: Permission) {
        self.permissions.insert(permission);
    }
}

/// Fine-grained permissions
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq, Hash)]
pub enum Permission {
    // System-level permissions
    SystemAdmin,
    SystemRead,
    SystemWrite,
    
    // User management permissions
    UserCreate,
    UserRead,
    UserUpdate,
    UserDelete,
    UserManageRoles,
    
    // Document management permissions
    DocumentCreate,
    DocumentRead,
    DocumentUpdate,
    DocumentDelete,
    DocumentIngest,
    
    // Query permissions
    QueryExecute,
    QueryAdvanced,
    QueryBulk,
    
    // Configuration permissions
    ConfigRead,
    ConfigWrite,
    ConfigSecrets,
    
    // Monitoring permissions
    MonitoringRead,
    MonitoringWrite,
    
    // API permissions
    ApiKeyCreate,
    ApiKeyRevoke,
    
    // Custom permission
    Custom(String),
}

impl std::fmt::Display for Permission {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::SystemAdmin => write!(f, "system:admin"),
            Self::SystemRead => write!(f, "system:read"),
            Self::SystemWrite => write!(f, "system:write"),
            Self::UserCreate => write!(f, "user:create"),
            Self::UserRead => write!(f, "user:read"),
            Self::UserUpdate => write!(f, "user:update"),
            Self::UserDelete => write!(f, "user:delete"),
            Self::UserManageRoles => write!(f, "user:manage_roles"),
            Self::DocumentCreate => write!(f, "document:create"),
            Self::DocumentRead => write!(f, "document:read"),
            Self::DocumentUpdate => write!(f, "document:update"),
            Self::DocumentDelete => write!(f, "document:delete"),
            Self::DocumentIngest => write!(f, "document:ingest"),
            Self::QueryExecute => write!(f, "query:execute"),
            Self::QueryAdvanced => write!(f, "query:advanced"),
            Self::QueryBulk => write!(f, "query:bulk"),
            Self::ConfigRead => write!(f, "config:read"),
            Self::ConfigWrite => write!(f, "config:write"),
            Self::ConfigSecrets => write!(f, "config:secrets"),
            Self::MonitoringRead => write!(f, "monitoring:read"),
            Self::MonitoringWrite => write!(f, "monitoring:write"),
            Self::ApiKeyCreate => write!(f, "api_key:create"),
            Self::ApiKeyRevoke => write!(f, "api_key:revoke"),
            Self::Custom(name) => write!(f, "custom:{}", name),
        }
    }
}

/// Multi-factor authentication methods
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum MfaMethod {
    Totp {
        secret: String,
        backup_codes: Vec<String>,
    },
    WebAuthn {
        credential_id: String,
        public_key: String,
    },
    Sms {
        phone_number: String,
    },
    Email {
        email: String,
    },
}

/// Session representation
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Session {
    pub id: String,
    pub user_id: String,
    pub created_at: DateTime<Utc>,
    pub expires_at: DateTime<Utc>,
    pub last_accessed: DateTime<Utc>,
    pub ip_address: Option<String>,
    pub user_agent: Option<String>,
    pub metadata: HashMap<String, serde_json::Value>,
}

impl Session {
    pub fn new(user_id: String, timeout_seconds: i64) -> Self {
        let now = Utc::now();
        Self {
            id: Uuid::new_v4().to_string(),
            user_id,
            created_at: now,
            expires_at: now + Duration::seconds(timeout_seconds),
            last_accessed: now,
            ip_address: None,
            user_agent: None,
            metadata: HashMap::new(),
        }
    }

    pub fn is_expired(&self) -> bool {
        Utc::now() > self.expires_at
    }

    pub fn refresh(&mut self, timeout_seconds: i64) {
        self.expires_at = Utc::now() + Duration::seconds(timeout_seconds);
        self.last_accessed = Utc::now();
    }
}

/// Authentication provider trait
#[async_trait]
pub trait AuthProvider: Send + Sync {
    async fn authenticate(&self, credentials: &Credentials) -> RragResult<AuthResult>;
    async fn validate_token(&self, token: &str) -> RragResult<User>;
    async fn supports_credentials(&self, credentials: &Credentials) -> bool;
    fn provider_name(&self) -> &str;
    async fn health_check(&self) -> RragResult<crate::security::HealthStatus>;
}

/// User storage trait
#[async_trait]
pub trait UserStore: Send + Sync {
    async fn get_user_by_id(&self, id: &str) -> RragResult<Option<User>>;
    async fn get_user_by_username(&self, username: &str) -> RragResult<Option<User>>;
    async fn get_user_by_email(&self, email: &str) -> RragResult<Option<User>>;
    async fn create_user(&self, user: &User) -> RragResult<()>;
    async fn update_user(&self, user: &User) -> RragResult<()>;
    async fn delete_user(&self, id: &str) -> RragResult<()>;
    async fn get_user_roles(&self, user_id: &str) -> RragResult<Vec<Role>>;
    async fn add_user_role(&self, user_id: &str, role: &Role) -> RragResult<()>;
    async fn remove_user_role(&self, user_id: &str, role_name: &str) -> RragResult<()>;
}

/// Session storage trait
#[async_trait]
pub trait SessionStore: Send + Sync {
    async fn create_session(&self, session: &Session) -> RragResult<()>;
    async fn get_session(&self, session_id: &str) -> RragResult<Option<Session>>;
    async fn update_session(&self, session: &Session) -> RragResult<()>;
    async fn delete_session(&self, session_id: &str) -> RragResult<()>;
    async fn delete_user_sessions(&self, user_id: &str) -> RragResult<()>;
    async fn cleanup_expired_sessions(&self) -> RragResult<u64>;
}

/// API Key authentication provider
pub struct ApiKeyAuth {
    api_keys: Arc<RwLock<HashMap<String, (String, Vec<Permission>)>>>, // key -> (user_id, permissions)
    user_store: Arc<dyn UserStore>,
}

impl ApiKeyAuth {
    pub fn new(user_store: Arc<dyn UserStore>) -> Self {
        Self {
            api_keys: Arc::new(RwLock::new(HashMap::new())),
            user_store,
        }
    }

    pub async fn create_api_key(&self, user_id: &str, permissions: Vec<Permission>) -> RragResult<String> {
        let api_key = self.generate_api_key().await?;
        let mut keys = self.api_keys.write().await;
        keys.insert(api_key.clone(), (user_id.to_string(), permissions));
        Ok(api_key)
    }

    pub async fn revoke_api_key(&self, api_key: &str) -> RragResult<()> {
        let mut keys = self.api_keys.write().await;
        keys.remove(api_key);
        Ok(())
    }

    async fn generate_api_key(&self) -> RragResult<String> {
        let mut key_bytes = vec![0u8; 32];
        use rand_core::RngCore;
        OsRng.fill_bytes(&mut key_bytes);
        Ok(format!("rrag_{}", general_purpose::URL_SAFE_NO_PAD.encode(&key_bytes)))
    }
}

#[async_trait]
impl AuthProvider for ApiKeyAuth {
    async fn authenticate(&self, credentials: &Credentials) -> RragResult<AuthResult> {
        if let Credentials::ApiKey { key } = credentials {
            let keys = self.api_keys.read().await;
            if let Some((user_id, permissions)) = keys.get(key) {
                let user = self.user_store.get_user_by_id(user_id).await?;
                if let Some(mut user) = user {
                    // Add API key permissions to user
                    for perm in permissions {
                        user.add_permission(perm.clone());
                    }
                    
                    return Ok(AuthResult {
                        success: true,
                        user: Some(user),
                        session: None,
                        method: "api_key".to_string(),
                        mfa_required: false,
                        mfa_methods: Vec::new(),
                        error: None,
                        expires_at: None,
                    });
                }
            }
        }
        Ok(AuthResult::failure("Invalid API key"))
    }

    async fn validate_token(&self, token: &str) -> RragResult<User> {
        let keys = self.api_keys.read().await;
        if let Some((user_id, permissions)) = keys.get(token) {
            let user = self.user_store.get_user_by_id(user_id).await?;
            if let Some(mut user) = user {
                for perm in permissions {
                    user.add_permission(perm.clone());
                }
                return Ok(user);
            }
        }
        Err(RragError::validation("token", "valid API key", token))
    }

    async fn supports_credentials(&self, credentials: &Credentials) -> bool {
        matches!(credentials, Credentials::ApiKey { .. })
    }

    fn provider_name(&self) -> &str {
        "api_key"
    }

    async fn health_check(&self) -> RragResult<crate::security::HealthStatus> {
        Ok(crate::security::HealthStatus::Healthy)
    }
}

/// JWT authentication provider
pub struct JwtAuth {
    encoding_key: EncodingKey,
    decoding_key: DecodingKey,
    validation: Validation,
    user_store: Arc<dyn UserStore>,
}

#[derive(Debug, Serialize, Deserialize)]
struct JwtClaims {
    sub: String,    // Subject (user ID)
    exp: usize,     // Expiration time
    iat: usize,     // Issued at
    iss: String,    // Issuer
    permissions: Vec<String>,
}

impl JwtAuth {
    pub fn new(secret: &str, user_store: Arc<dyn UserStore>) -> Self {
        let encoding_key = EncodingKey::from_secret(secret.as_ref());
        let decoding_key = DecodingKey::from_secret(secret.as_ref());
        let mut validation = Validation::default();
        validation.set_issuer(&["rrag"]);
        
        Self {
            encoding_key,
            decoding_key,
            validation,
            user_store,
        }
    }

    pub async fn create_token(&self, user: &User, expiration_seconds: i64) -> RragResult<String> {
        let now = Utc::now().timestamp() as usize;
        let exp = (now as i64 + expiration_seconds) as usize;

        let permissions: Vec<String> = user.permissions
            .iter()
            .map(|p| p.to_string())
            .collect();

        let claims = JwtClaims {
            sub: user.id.clone(),
            exp,
            iat: now,
            iss: "rrag".to_string(),
            permissions,
        };

        encode(&Header::default(), &claims, &self.encoding_key)
            .map_err(|e| RragError::rsllm_client("jwt_encode", e))
    }
}

#[async_trait]
impl AuthProvider for JwtAuth {
    async fn authenticate(&self, credentials: &Credentials) -> RragResult<AuthResult> {
        if let Credentials::JwtToken { token } = credentials {
            let token_data = decode::<JwtClaims>(token, &self.decoding_key, &self.validation)
                .map_err(|e| RragError::validation("jwt_token", "valid JWT", &e.to_string()))?;

            let user = self.user_store.get_user_by_id(&token_data.claims.sub).await?;
            if let Some(user) = user {
                return Ok(AuthResult {
                    success: true,
                    user: Some(user),
                    session: None,
                    method: "jwt".to_string(),
                    mfa_required: false,
                    mfa_methods: Vec::new(),
                    error: None,
                    expires_at: Some(DateTime::from_timestamp(token_data.claims.exp as i64, 0)
                        .unwrap_or_else(|| Utc::now())),
                });
            }
        }
        Ok(AuthResult::failure("Invalid JWT token"))
    }

    async fn validate_token(&self, token: &str) -> RragResult<User> {
        let token_data = decode::<JwtClaims>(token, &self.decoding_key, &self.validation)
            .map_err(|e| RragError::validation("jwt_token", "valid JWT", &e.to_string()))?;

        let user = self.user_store.get_user_by_id(&token_data.claims.sub).await?;
        user.ok_or_else(|| RragError::validation("user_id", "existing user", &token_data.claims.sub))
    }

    async fn supports_credentials(&self, credentials: &Credentials) -> bool {
        matches!(credentials, Credentials::JwtToken { .. })
    }

    fn provider_name(&self) -> &str {
        "jwt"
    }

    async fn health_check(&self) -> RragResult<crate::security::HealthStatus> {
        Ok(crate::security::HealthStatus::Healthy)
    }
}

/// Username/Password authentication provider
pub struct UsernamePasswordAuth {
    user_store: Arc<dyn UserStore>,
    password_hasher: PasswordHasher,
    totp_validator: Option<TotpValidator>,
}

pub enum PasswordHasher {
    Bcrypt,
    Argon2,
}

impl UsernamePasswordAuth {
    pub fn new(user_store: Arc<dyn UserStore>) -> Self {
        Self {
            user_store,
            password_hasher: PasswordHasher::Argon2,
            totp_validator: None,
        }
    }

    pub fn with_totp(mut self, totp_validator: TotpValidator) -> Self {
        self.totp_validator = Some(totp_validator);
        self
    }

    pub async fn hash_password(&self, password: &str) -> RragResult<String> {
        match &self.password_hasher {
            PasswordHasher::Bcrypt => {
                hash(password, DEFAULT_COST).map_err(|e| RragError::validation("password", "hashable", &e.to_string()))
            }
            PasswordHasher::Argon2 => {
                let salt = SaltString::generate(&mut OsRng);
                let argon2 = Argon2::default();
                let password_hash = argon2
                    .hash_password(password.as_bytes(), &salt)
                    .map_err(|e| RragError::validation("password", "hashable", &e.to_string()))?;
                Ok(password_hash.to_string())
            }
        }
    }

    pub async fn verify_password(&self, password: &str, hash: &str) -> RragResult<bool> {
        match &self.password_hasher {
            PasswordHasher::Bcrypt => {
                verify(password, hash).map_err(|e| RragError::validation("password", "verifiable", &e.to_string()))
            }
            PasswordHasher::Argon2 => {
                let parsed_hash = PasswordHash::new(hash)
                    .map_err(|e| RragError::validation("hash", "valid hash", &e.to_string()))?;
                let argon2 = Argon2::default();
                Ok(argon2.verify_password(password.as_bytes(), &parsed_hash).is_ok())
            }
        }
    }
}

#[async_trait]
impl AuthProvider for UsernamePasswordAuth {
    async fn authenticate(&self, credentials: &Credentials) -> RragResult<AuthResult> {
        if let Credentials::UsernamePassword { username, password, totp_code } = credentials {
            let user = self.user_store.get_user_by_username(username).await?;
            if let Some(user) = user {
                if user.is_locked() {
                    return Ok(AuthResult::failure("Account is locked"));
                }

                // Here you would verify the password hash stored in user metadata
                // For now, we'll assume password verification succeeds
                let password_valid = true; // This should be: self.verify_password(password, &stored_hash).await?;

                if !password_valid {
                    return Ok(AuthResult::failure("Invalid credentials"));
                }

                // Check MFA if enabled
                if user.mfa_enabled {
                    if let Some(totp_code) = totp_code {
                        if let Some(validator) = &self.totp_validator {
                            if !validator.verify_totp(&user, totp_code).await? {
                                return Ok(AuthResult::failure("Invalid TOTP code"));
                            }
                        } else {
                            return Ok(AuthResult::failure("TOTP validator not configured"));
                        }
                    } else {
                        return Ok(AuthResult::mfa_required(vec!["totp".to_string()]));
                    }
                }

                return Ok(AuthResult::success(user));
            }
        }
        Ok(AuthResult::failure("Invalid credentials"))
    }

    async fn validate_token(&self, _token: &str) -> RragResult<User> {
        Err(RragError::validation("token", "not supported for username/password auth", ""))
    }

    async fn supports_credentials(&self, credentials: &Credentials) -> bool {
        matches!(credentials, Credentials::UsernamePassword { .. })
    }

    fn provider_name(&self) -> &str {
        "username_password"
    }

    async fn health_check(&self) -> RragResult<crate::security::HealthStatus> {
        Ok(crate::security::HealthStatus::Healthy)
    }
}

/// TOTP validator
pub struct TotpValidator {
    // In a real implementation, you would use a TOTP library
}

impl TotpValidator {
    pub fn new() -> Self {
        Self {}
    }

    pub async fn verify_totp(&self, _user: &User, _code: &str) -> RragResult<bool> {
        // This would implement TOTP verification
        // For now, we'll return true as a placeholder
        Ok(true)
    }
}

/// OAuth2 authentication provider
pub struct OAuth2Auth {
    // OAuth2 implementation would go here
}

/// WebAuthn authentication provider  
pub struct WebAuthnAuth {
    // WebAuthn implementation would go here
}

/// TOTP authentication provider
pub struct TotpAuth {
    // TOTP implementation would go here
}

// Placeholder implementations for OAuth2, WebAuthn, and TOTP
impl OAuth2Auth {
    pub fn new() -> Self {
        Self {}
    }
}

impl WebAuthnAuth {
    pub fn new() -> Self {
        Self {}
    }
}

impl TotpAuth {
    pub fn new() -> Self {
        Self {}
    }
}

// Additional trait implementations would go here...

/// Authentication service implementation
impl AuthenticationService {
    pub fn new(config: AuthConfig) -> Self {
        Self {
            providers: Arc::new(RwLock::new(Vec::new())),
            config,
            user_store: Arc::new(InMemoryUserStore::new()),
            session_store: Arc::new(InMemorySessionStore::new()),
        }
    }

    pub async fn add_provider(&self, provider: Arc<dyn AuthProvider>) {
        let mut providers = self.providers.write().await;
        providers.push(provider);
    }

    pub async fn authenticate(&self, credentials: Credentials) -> RragResult<AuthResult> {
        let providers = self.providers.read().await;
        
        for provider in providers.iter() {
            if provider.supports_credentials(&credentials).await {
                return provider.authenticate(&credentials).await;
            }
        }

        Ok(AuthResult::failure("No suitable authentication provider found"))
    }

    pub async fn health_check(&self) -> RragResult<crate::security::HealthStatus> {
        Ok(crate::security::HealthStatus::Healthy)
    }
}

/// Authorization service
pub struct AuthorizationService {
    // Authorization logic would go here
}

impl AuthorizationService {
    pub fn new() -> Self {
        Self {}
    }

    pub async fn authorize(
        &self,
        user: &User,
        operation: &crate::security::SecurityOperation,
        resource: Option<&str>,
    ) -> RragResult<AuthorizationResult> {
        // Simple permission-based authorization
        let required_permission = self.get_required_permission(operation, resource);
        
        if user.has_permission(&required_permission) {
            Ok(AuthorizationResult::allowed())
        } else {
            Ok(AuthorizationResult::denied("Insufficient permissions".to_string()))
        }
    }

    fn get_required_permission(&self, operation: &crate::security::SecurityOperation, _resource: Option<&str>) -> Permission {
        match operation {
            crate::security::SecurityOperation::Authentication => Permission::SystemRead,
            crate::security::SecurityOperation::Authorization => Permission::SystemRead,
            crate::security::SecurityOperation::DataAccess => Permission::DocumentRead,
            crate::security::SecurityOperation::DocumentIngestion => Permission::DocumentIngest,
            crate::security::SecurityOperation::QueryExecution => Permission::QueryExecute,
            crate::security::SecurityOperation::AdminOperation => Permission::SystemAdmin,
            crate::security::SecurityOperation::ConfigurationChange => Permission::ConfigWrite,
            crate::security::SecurityOperation::SystemMonitoring => Permission::MonitoringRead,
        }
    }
}

/// Authorization result
#[derive(Debug, Clone)]
pub struct AuthorizationResult {
    pub allowed: bool,
    pub reason: Option<String>,
    pub required_permissions: Vec<Permission>,
}

impl AuthorizationResult {
    pub fn allowed() -> Self {
        Self {
            allowed: true,
            reason: None,
            required_permissions: Vec::new(),
        }
    }

    pub fn denied(reason: String) -> Self {
        Self {
            allowed: false,
            reason: Some(reason),
            required_permissions: Vec::new(),
        }
    }
}

/// In-memory user store implementation
pub struct InMemoryUserStore {
    users: Arc<RwLock<HashMap<String, User>>>,
    username_index: Arc<RwLock<HashMap<String, String>>>, // username -> user_id
    email_index: Arc<RwLock<HashMap<String, String>>>,    // email -> user_id
}

impl InMemoryUserStore {
    pub fn new() -> Self {
        Self {
            users: Arc::new(RwLock::new(HashMap::new())),
            username_index: Arc::new(RwLock::new(HashMap::new())),
            email_index: Arc::new(RwLock::new(HashMap::new())),
        }
    }
}

#[async_trait]
impl UserStore for InMemoryUserStore {
    async fn get_user_by_id(&self, id: &str) -> RragResult<Option<User>> {
        let users = self.users.read().await;
        Ok(users.get(id).cloned())
    }

    async fn get_user_by_username(&self, username: &str) -> RragResult<Option<User>> {
        let username_index = self.username_index.read().await;
        if let Some(user_id) = username_index.get(username) {
            self.get_user_by_id(user_id).await
        } else {
            Ok(None)
        }
    }

    async fn get_user_by_email(&self, email: &str) -> RragResult<Option<User>> {
        let email_index = self.email_index.read().await;
        if let Some(user_id) = email_index.get(email) {
            self.get_user_by_id(user_id).await
        } else {
            Ok(None)
        }
    }

    async fn create_user(&self, user: &User) -> RragResult<()> {
        let mut users = self.users.write().await;
        let mut username_index = self.username_index.write().await;
        let mut email_index = self.email_index.write().await;

        users.insert(user.id.clone(), user.clone());
        username_index.insert(user.username.clone(), user.id.clone());
        
        if let Some(email) = &user.email {
            email_index.insert(email.clone(), user.id.clone());
        }

        Ok(())
    }

    async fn update_user(&self, user: &User) -> RragResult<()> {
        let mut users = self.users.write().await;
        users.insert(user.id.clone(), user.clone());
        Ok(())
    }

    async fn delete_user(&self, id: &str) -> RragResult<()> {
        let mut users = self.users.write().await;
        let mut username_index = self.username_index.write().await;
        let mut email_index = self.email_index.write().await;

        if let Some(user) = users.remove(id) {
            username_index.remove(&user.username);
            if let Some(email) = &user.email {
                email_index.remove(email);
            }
        }

        Ok(())
    }

    async fn get_user_roles(&self, user_id: &str) -> RragResult<Vec<Role>> {
        if let Some(user) = self.get_user_by_id(user_id).await? {
            Ok(user.roles)
        } else {
            Ok(Vec::new())
        }
    }

    async fn add_user_role(&self, user_id: &str, role: &Role) -> RragResult<()> {
        if let Some(mut user) = self.get_user_by_id(user_id).await? {
            user.add_role(role.clone());
            self.update_user(&user).await?;
        }
        Ok(())
    }

    async fn remove_user_role(&self, user_id: &str, role_name: &str) -> RragResult<()> {
        if let Some(mut user) = self.get_user_by_id(user_id).await? {
            user.roles.retain(|r| r.name != role_name);
            user.updated_at = Utc::now();
            self.update_user(&user).await?;
        }
        Ok(())
    }
}

/// In-memory session store implementation
pub struct InMemorySessionStore {
    sessions: Arc<RwLock<HashMap<String, Session>>>,
    user_sessions: Arc<RwLock<HashMap<String, HashSet<String>>>>, // user_id -> session_ids
}

impl InMemorySessionStore {
    pub fn new() -> Self {
        Self {
            sessions: Arc::new(RwLock::new(HashMap::new())),
            user_sessions: Arc::new(RwLock::new(HashMap::new())),
        }
    }
}

#[async_trait]
impl SessionStore for InMemorySessionStore {
    async fn create_session(&self, session: &Session) -> RragResult<()> {
        let mut sessions = self.sessions.write().await;
        let mut user_sessions = self.user_sessions.write().await;

        sessions.insert(session.id.clone(), session.clone());
        user_sessions
            .entry(session.user_id.clone())
            .or_insert_with(HashSet::new)
            .insert(session.id.clone());

        Ok(())
    }

    async fn get_session(&self, session_id: &str) -> RragResult<Option<Session>> {
        let sessions = self.sessions.read().await;
        Ok(sessions.get(session_id).cloned())
    }

    async fn update_session(&self, session: &Session) -> RragResult<()> {
        let mut sessions = self.sessions.write().await;
        sessions.insert(session.id.clone(), session.clone());
        Ok(())
    }

    async fn delete_session(&self, session_id: &str) -> RragResult<()> {
        let mut sessions = self.sessions.write().await;
        let mut user_sessions = self.user_sessions.write().await;

        if let Some(session) = sessions.remove(session_id) {
            if let Some(user_session_set) = user_sessions.get_mut(&session.user_id) {
                user_session_set.remove(session_id);
                if user_session_set.is_empty() {
                    user_sessions.remove(&session.user_id);
                }
            }
        }

        Ok(())
    }

    async fn delete_user_sessions(&self, user_id: &str) -> RragResult<()> {
        let mut sessions = self.sessions.write().await;
        let mut user_sessions = self.user_sessions.write().await;

        if let Some(session_ids) = user_sessions.remove(user_id) {
            for session_id in session_ids {
                sessions.remove(&session_id);
            }
        }

        Ok(())
    }

    async fn cleanup_expired_sessions(&self) -> RragResult<u64> {
        let mut sessions = self.sessions.write().await;
        let mut user_sessions = self.user_sessions.write().await;
        let now = Utc::now();
        let mut expired_count = 0;

        let expired_sessions: Vec<_> = sessions
            .iter()
            .filter_map(|(id, session)| {
                if session.expires_at <= now {
                    Some((id.clone(), session.user_id.clone()))
                } else {
                    None
                }
            })
            .collect();

        for (session_id, user_id) in expired_sessions {
            sessions.remove(&session_id);
            if let Some(user_session_set) = user_sessions.get_mut(&user_id) {
                user_session_set.remove(&session_id);
                if user_session_set.is_empty() {
                    user_sessions.remove(&user_id);
                }
            }
            expired_count += 1;
        }

        Ok(expired_count)
    }
}

/// Authentication and authorization errors
#[derive(Debug, thiserror::Error)]
pub enum AuthenticationError {
    #[error("Invalid credentials")]
    InvalidCredentials,
    #[error("Account locked")]
    AccountLocked,
    #[error("Multi-factor authentication required")]
    MfaRequired,
    #[error("Token expired")]
    TokenExpired,
    #[error("User not found")]
    UserNotFound,
}

#[derive(Debug, thiserror::Error)]
pub enum AuthorizationError {
    #[error("Access denied: {reason}")]
    AccessDenied { reason: String },
    #[error("Insufficient permissions")]
    InsufficientPermissions,
    #[error("Resource not found")]
    ResourceNotFound,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    async fn test_user_creation() {
        let user = User::new(
            "user1".to_string(),
            "testuser".to_string(),
            Some("test@example.com".to_string()),
        );

        assert_eq!(user.id, "user1");
        assert_eq!(user.username, "testuser");
        assert!(!user.is_locked());
        assert!(!user.mfa_enabled);
    }

    #[tokio::test]
    async fn test_permission_checking() {
        let mut user = User::new(
            "user1".to_string(),
            "testuser".to_string(),
            None,
        );

        user.add_permission(Permission::DocumentRead);
        assert!(user.has_permission(&Permission::DocumentRead));
        assert!(!user.has_permission(&Permission::SystemAdmin));
    }

    #[tokio::test]
    async fn test_session_expiration() {
        let session = Session::new("user1".to_string(), 3600);
        assert!(!session.is_expired());

        let expired_session = Session {
            expires_at: Utc::now() - Duration::seconds(1),
            ..session
        };
        assert!(expired_session.is_expired());
    }

    #[tokio::test]
    async fn test_api_key_auth() {
        let user_store = Arc::new(InMemoryUserStore::new());
        let api_key_auth = ApiKeyAuth::new(user_store.clone());

        // Create a test user
        let user = User::new(
            "user1".to_string(),
            "testuser".to_string(),
            None,
        );
        user_store.create_user(&user).await.unwrap();

        // Create API key
        let api_key = api_key_auth.create_api_key("user1", vec![Permission::DocumentRead]).await.unwrap();

        // Test authentication
        let credentials = Credentials::ApiKey { key: api_key };
        let result = api_key_auth.authenticate(&credentials).await.unwrap();

        assert!(result.success);
        assert!(result.user.is_some());
        assert_eq!(result.method, "api_key");
    }
}