uvb-brute-force 0.2.1

use async_trait::async_trait;
use chrono::{DateTime, Duration, Utc};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::sync::Arc;
use thiserror::Error;
use tokio::sync::RwLock;
use tracing::{info, warn};

use uvb_core::TenantId;

#[derive(Debug, Error)]
pub enum BruteForceError {
    #[error("account locked: {0}")]
    AccountLocked(String),
    #[error("too many attempts: {0}")]
    TooManyAttempts(String),
    #[error("storage error: {0}")]
    StorageError(String),
    #[error("internal error: {0}")]
    Internal(String),
}

/// Brute force protection configuration
#[derive(Clone, Debug)]
pub struct BruteForceConfig {
    /// Maximum failed attempts before lockout
    pub max_failed_attempts: u32,

    /// Lockout duration in seconds
    pub lockout_duration_seconds: i64,

    /// Enable progressive delays after each failed attempt
    pub progressive_delay_enabled: bool,

    /// Base delay in milliseconds for progressive delays
    pub progressive_delay_base_ms: u64,

    /// Enable exponential lockout (doubles duration with each lockout)
    pub exponential_lockout: bool,

    /// Maximum lockout duration in seconds
    pub max_lockout_duration_seconds: i64,

    /// Enable IP-based tracking in addition to user-based
    pub ip_based_tracking: bool,

    /// Maximum failed attempts per IP
    pub max_failed_attempts_per_ip: u32,

    /// IP lockout duration in seconds
    pub ip_lockout_duration_seconds: i64,

    /// Reset failed attempts counter after successful login
    pub reset_on_success: bool,

    /// Enable automatic unlocking after lockout duration expires
    pub auto_unlock: bool,
}

impl Default for BruteForceConfig {
    fn default() -> Self {
        Self {
            max_failed_attempts: 5,
            lockout_duration_seconds: 900, // 15 minutes
            progressive_delay_enabled: true,
            progressive_delay_base_ms: 1000, // 1 second
            exponential_lockout: true,
            max_lockout_duration_seconds: 86400, // 24 hours
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 20,
            ip_lockout_duration_seconds: 3600, // 1 hour
            reset_on_success: true,
            auto_unlock: true,
        }
    }
}

impl BruteForceConfig {
    /// Strict configuration for high-security environments
    pub fn strict() -> Self {
        Self {
            max_failed_attempts: 3,
            lockout_duration_seconds: 1800, // 30 minutes
            progressive_delay_enabled: true,
            progressive_delay_base_ms: 2000, // 2 seconds
            exponential_lockout: true,
            max_lockout_duration_seconds: 172800, // 48 hours
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 10,
            ip_lockout_duration_seconds: 7200, // 2 hours
            reset_on_success: true,
            auto_unlock: true,
        }
    }

    /// Lenient configuration for development
    pub fn lenient() -> Self {
        Self {
            max_failed_attempts: 10,
            lockout_duration_seconds: 300, // 5 minutes
            progressive_delay_enabled: false,
            progressive_delay_base_ms: 500,
            exponential_lockout: false,
            max_lockout_duration_seconds: 3600, // 1 hour
            ip_based_tracking: false,
            max_failed_attempts_per_ip: 50,
            ip_lockout_duration_seconds: 600, // 10 minutes
            reset_on_success: true,
            auto_unlock: true,
        }
    }
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct FailedAttempt {
    pub timestamp: DateTime<Utc>,
    pub ip_address: Option<String>,
    pub user_agent: Option<String>,
    pub reason: Option<String>,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct LockoutRecord {
    pub locked_at: DateTime<Utc>,
    pub unlock_at: DateTime<Utc>,
    pub lockout_count: u32, // Number of times this account has been locked
    pub failed_attempts: Vec<FailedAttempt>,
    pub reason: String,
}

#[derive(Clone, Debug)]
pub struct BruteForceCheckResult {
    pub allowed: bool,
    pub delay_ms: Option<u64>,
    pub remaining_attempts: Option<u32>,
    pub locked_until: Option<DateTime<Utc>>,
    pub reason: Option<String>,
}

/// Trait for brute force protection storage
#[async_trait]
pub trait BruteForceStore: Send + Sync {
    /// Record a failed authentication attempt
    async fn record_failed_attempt(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        ip_address: Option<&str>,
        user_agent: Option<&str>,
    ) -> Result<(), BruteForceError>;

    /// Get failed attempts for a user
    async fn get_failed_attempts(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<Vec<FailedAttempt>, BruteForceError>;

    /// Clear failed attempts for a user
    async fn clear_failed_attempts(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError>;

    /// Set lockout for a user
    async fn set_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        lockout: LockoutRecord,
    ) -> Result<(), BruteForceError>;

    /// Get lockout status for a user
    async fn get_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<Option<LockoutRecord>, BruteForceError>;

    /// Remove lockout for a user
    async fn remove_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError>;

    /// Record failed attempt by IP
    async fn record_failed_attempt_by_ip(&self, ip_address: &str) -> Result<(), BruteForceError>;

    /// Get failed attempts by IP
    async fn get_failed_attempts_by_ip(
        &self,
        ip_address: &str,
    ) -> Result<Vec<FailedAttempt>, BruteForceError>;

    /// Check if IP is locked
    async fn is_ip_locked(&self, ip_address: &str) -> Result<bool, BruteForceError>;
}

/// In-memory implementation of brute force store for testing
pub struct MemoryBruteForceStore {
    user_attempts: Arc<RwLock<HashMap<String, Vec<FailedAttempt>>>>,
    user_lockouts: Arc<RwLock<HashMap<String, LockoutRecord>>>,
    ip_attempts: Arc<RwLock<HashMap<String, Vec<FailedAttempt>>>>,
    ip_lockouts: Arc<RwLock<HashMap<String, DateTime<Utc>>>>,
}

impl MemoryBruteForceStore {
    pub fn new() -> Self {
        Self {
            user_attempts: Arc::new(RwLock::new(HashMap::new())),
            user_lockouts: Arc::new(RwLock::new(HashMap::new())),
            ip_attempts: Arc::new(RwLock::new(HashMap::new())),
            ip_lockouts: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    fn user_key(tenant_id: &TenantId, user_id: &str) -> String {
        format!("{}:{}", tenant_id, user_id)
    }
}

impl Default for MemoryBruteForceStore {
    fn default() -> Self {
        Self::new()
    }
}

#[async_trait]
impl BruteForceStore for MemoryBruteForceStore {
    async fn record_failed_attempt(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        ip_address: Option<&str>,
        user_agent: Option<&str>,
    ) -> Result<(), BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let attempt = FailedAttempt {
            timestamp: Utc::now(),
            ip_address: ip_address.map(|s| s.to_string()),
            user_agent: user_agent.map(|s| s.to_string()),
            reason: None,
        };

        let mut attempts = self.user_attempts.write().await;
        attempts.entry(key).or_insert_with(Vec::new).push(attempt);

        Ok(())
    }

    async fn get_failed_attempts(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<Vec<FailedAttempt>, BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let attempts = self.user_attempts.read().await;
        Ok(attempts.get(&key).cloned().unwrap_or_default())
    }

    async fn clear_failed_attempts(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let mut attempts = self.user_attempts.write().await;
        attempts.remove(&key);
        Ok(())
    }

    async fn set_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        lockout: LockoutRecord,
    ) -> Result<(), BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let mut lockouts = self.user_lockouts.write().await;
        lockouts.insert(key, lockout);
        Ok(())
    }

    async fn get_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<Option<LockoutRecord>, BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let lockouts = self.user_lockouts.read().await;
        Ok(lockouts.get(&key).cloned())
    }

    async fn remove_lockout(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError> {
        let key = Self::user_key(tenant_id, user_id);
        let mut lockouts = self.user_lockouts.write().await;
        lockouts.remove(&key);
        Ok(())
    }

    async fn record_failed_attempt_by_ip(&self, ip_address: &str) -> Result<(), BruteForceError> {
        let attempt = FailedAttempt {
            timestamp: Utc::now(),
            ip_address: Some(ip_address.to_string()),
            user_agent: None,
            reason: None,
        };

        let mut attempts = self.ip_attempts.write().await;
        attempts
            .entry(ip_address.to_string())
            .or_insert_with(Vec::new)
            .push(attempt);

        Ok(())
    }

    async fn get_failed_attempts_by_ip(
        &self,
        ip_address: &str,
    ) -> Result<Vec<FailedAttempt>, BruteForceError> {
        let attempts = self.ip_attempts.read().await;
        Ok(attempts.get(ip_address).cloned().unwrap_or_default())
    }

    async fn is_ip_locked(&self, ip_address: &str) -> Result<bool, BruteForceError> {
        let lockouts = self.ip_lockouts.read().await;
        if let Some(unlock_at) = lockouts.get(ip_address) {
            Ok(Utc::now() < *unlock_at)
        } else {
            Ok(false)
        }
    }
}

/// Brute force protection service
pub struct BruteForceProtection {
    config: BruteForceConfig,
    store: Arc<dyn BruteForceStore>,
}

impl BruteForceProtection {
    pub fn new(config: BruteForceConfig, store: Arc<dyn BruteForceStore>) -> Self {
        Self { config, store }
    }

    /// Check if authentication should be allowed
    pub async fn check_authentication_allowed(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        ip_address: Option<&str>,
    ) -> Result<BruteForceCheckResult, BruteForceError> {
        // Check IP-based lockout first
        if self.config.ip_based_tracking {
            if let Some(ip) = ip_address {
                if self.store.is_ip_locked(ip).await? {
                    return Ok(BruteForceCheckResult {
                        allowed: false,
                        delay_ms: None,
                        remaining_attempts: None,
                        locked_until: None,
                        reason: Some("IP address is temporarily blocked".to_string()),
                    });
                }

                let ip_attempts = self.store.get_failed_attempts_by_ip(ip).await?;
                let recent_ip_attempts = self.count_recent_attempts(&ip_attempts);

                if recent_ip_attempts >= self.config.max_failed_attempts_per_ip {
                    warn!("IP {} exceeded maximum attempts", ip);
                    return Ok(BruteForceCheckResult {
                        allowed: false,
                        delay_ms: None,
                        remaining_attempts: None,
                        locked_until: None,
                        reason: Some("Too many failed attempts from this IP address".to_string()),
                    });
                }
            }
        }

        // Check user-based lockout
        if let Some(lockout) = self.store.get_lockout(tenant_id, user_id).await? {
            if self.config.auto_unlock && Utc::now() >= lockout.unlock_at {
                // Lockout expired, remove it
                self.store.remove_lockout(tenant_id, user_id).await?;
                info!("Auto-unlocked account for user {}", user_id);
            } else {
                warn!("Account locked for user {}", user_id);
                return Ok(BruteForceCheckResult {
                    allowed: false,
                    delay_ms: None,
                    remaining_attempts: None,
                    locked_until: Some(lockout.unlock_at),
                    reason: Some(lockout.reason),
                });
            }
        }

        // Check failed attempts
        let attempts = self.store.get_failed_attempts(tenant_id, user_id).await?;
        let recent_attempts = self.count_recent_attempts(&attempts);

        if recent_attempts >= self.config.max_failed_attempts {
            // Lock the account
            self.lock_account(tenant_id, user_id, attempts).await?;

            return Ok(BruteForceCheckResult {
                allowed: false,
                delay_ms: None,
                remaining_attempts: Some(0),
                locked_until: None,
                reason: Some("Account locked due to too many failed attempts".to_string()),
            });
        }

        // Calculate progressive delay if enabled
        let delay_ms = if self.config.progressive_delay_enabled && recent_attempts > 0 {
            Some(self.calculate_progressive_delay(recent_attempts))
        } else {
            None
        };

        Ok(BruteForceCheckResult {
            allowed: true,
            delay_ms,
            remaining_attempts: Some(self.config.max_failed_attempts - recent_attempts),
            locked_until: None,
            reason: None,
        })
    }

    /// Record a failed authentication attempt
    pub async fn record_failed_attempt(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        ip_address: Option<&str>,
        user_agent: Option<&str>,
    ) -> Result<(), BruteForceError> {
        self.store
            .record_failed_attempt(tenant_id, user_id, ip_address, user_agent)
            .await?;

        if self.config.ip_based_tracking {
            if let Some(ip) = ip_address {
                self.store.record_failed_attempt_by_ip(ip).await?;
            }
        }

        info!("Recorded failed attempt for user {}", user_id);

        Ok(())
    }

    /// Record a successful authentication
    pub async fn record_successful_attempt(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError> {
        if self.config.reset_on_success {
            self.store.clear_failed_attempts(tenant_id, user_id).await?;
            info!(
                "Cleared failed attempts for user {} after successful login",
                user_id
            );
        }

        Ok(())
    }

    /// Manually unlock an account
    pub async fn unlock_account(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
    ) -> Result<(), BruteForceError> {
        self.store.remove_lockout(tenant_id, user_id).await?;
        self.store.clear_failed_attempts(tenant_id, user_id).await?;
        info!("Manually unlocked account for user {}", user_id);
        Ok(())
    }

    // Private helper methods

    fn count_recent_attempts(&self, attempts: &[FailedAttempt]) -> u32 {
        let cutoff = Utc::now() - Duration::seconds(self.config.lockout_duration_seconds);
        attempts.iter().filter(|a| a.timestamp > cutoff).count() as u32
    }

    fn calculate_progressive_delay(&self, attempt_count: u32) -> u64 {
        // Exponential backoff: base_delay * 2^(attempt_count - 1)
        let multiplier = 2u64.pow(attempt_count.saturating_sub(1));
        (self.config.progressive_delay_base_ms * multiplier).min(30000) // Max 30 seconds
    }

    async fn lock_account(
        &self,
        tenant_id: &TenantId,
        user_id: &str,
        attempts: Vec<FailedAttempt>,
    ) -> Result<(), BruteForceError> {
        let existing_lockout = self.store.get_lockout(tenant_id, user_id).await?;
        let lockout_count = existing_lockout.map(|l| l.lockout_count).unwrap_or(0) + 1;

        let lockout_duration = if self.config.exponential_lockout {
            // Double duration with each lockout
            let duration = self.config.lockout_duration_seconds * (2i64.pow(lockout_count - 1));
            duration.min(self.config.max_lockout_duration_seconds)
        } else {
            self.config.lockout_duration_seconds
        };

        let lockout = LockoutRecord {
            locked_at: Utc::now(),
            unlock_at: Utc::now() + Duration::seconds(lockout_duration),
            lockout_count,
            failed_attempts: attempts,
            reason: format!(
                "Account locked for {} seconds due to {} failed login attempts",
                lockout_duration, self.config.max_failed_attempts
            ),
        };

        self.store.set_lockout(tenant_id, user_id, lockout).await?;

        warn!(
            "Locked account for user {} (lockout #{}, duration: {}s)",
            user_id, lockout_count, lockout_duration
        );

        Ok(())
    }
}

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

    fn test_tenant_id() -> TenantId {
        TenantId::new("test_tenant")
    }

    #[tokio::test]
    async fn test_default_config() {
        let config = BruteForceConfig::default();
        assert_eq!(config.max_failed_attempts, 5);
        assert_eq!(config.lockout_duration_seconds, 900);
        assert!(config.progressive_delay_enabled);
    }

    #[tokio::test]
    async fn test_allow_authentication_no_attempts() {
        let config = BruteForceConfig::default();
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let result = protection
            .check_authentication_allowed(&test_tenant_id(), "user1", None)
            .await
            .unwrap();

        assert!(result.allowed);
        assert_eq!(result.remaining_attempts, Some(5));
    }

    #[tokio::test]
    async fn test_failed_attempts_counting() {
        let config = BruteForceConfig::default();
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let user_id = "user1";

        // Record 3 failed attempts
        for _ in 0..3 {
            protection
                .record_failed_attempt(&tenant_id, user_id, Some("192.168.1.1"), None)
                .await
                .unwrap();
        }

        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, Some("192.168.1.1"))
            .await
            .unwrap();

        assert!(result.allowed);
        assert_eq!(result.remaining_attempts, Some(2)); // 5 - 3 = 2
    }

    #[tokio::test]
    async fn test_account_lockout() {
        let config = BruteForceConfig::default();
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let user_id = "user1";

        // Record 5 failed attempts (max)
        for _ in 0..5 {
            protection
                .record_failed_attempt(&tenant_id, user_id, Some("192.168.1.1"), None)
                .await
                .unwrap();
        }

        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, Some("192.168.1.1"))
            .await
            .unwrap();

        assert!(!result.allowed);
        assert_eq!(result.remaining_attempts, Some(0));
        assert!(result.locked_until.is_some() || result.reason.is_some());
    }

    #[tokio::test]
    async fn test_progressive_delay() {
        let config = BruteForceConfig::default();
        let protection = BruteForceProtection::new(config, Arc::new(MemoryBruteForceStore::new()));

        // Test exponential backoff
        assert_eq!(protection.calculate_progressive_delay(1), 1000); // 1s
        assert_eq!(protection.calculate_progressive_delay(2), 2000); // 2s
        assert_eq!(protection.calculate_progressive_delay(3), 4000); // 4s
        assert_eq!(protection.calculate_progressive_delay(4), 8000); // 8s
    }

    #[tokio::test]
    async fn test_reset_on_success() {
        let config = BruteForceConfig {
            reset_on_success: true,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store.clone());

        let tenant_id = test_tenant_id();
        let user_id = "user1";

        // Record 3 failed attempts
        for _ in 0..3 {
            protection
                .record_failed_attempt(&tenant_id, user_id, None, None)
                .await
                .unwrap();
        }

        // Verify attempts recorded
        let attempts = store
            .get_failed_attempts(&tenant_id, user_id)
            .await
            .unwrap();
        assert_eq!(attempts.len(), 3);

        // Record successful attempt
        protection
            .record_successful_attempt(&tenant_id, user_id)
            .await
            .unwrap();

        // Verify attempts cleared
        let attempts = store
            .get_failed_attempts(&tenant_id, user_id)
            .await
            .unwrap();
        assert_eq!(attempts.len(), 0);
    }

    #[tokio::test]
    async fn test_manual_unlock() {
        let config = BruteForceConfig::default();
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store.clone());

        let tenant_id = test_tenant_id();
        let user_id = "user1";

        // Lock account
        for _ in 0..5 {
            protection
                .record_failed_attempt(&tenant_id, user_id, None, None)
                .await
                .unwrap();
        }

        // Verify locked
        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, None)
            .await
            .unwrap();
        assert!(!result.allowed);

        // Manual unlock
        protection
            .unlock_account(&tenant_id, user_id)
            .await
            .unwrap();

        // Verify unlocked
        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, None)
            .await
            .unwrap();
        assert!(result.allowed);
    }

    #[tokio::test]
    async fn test_ip_based_tracking() {
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 3,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();

        // Record failed attempts from same IP, different users
        for i in 0..3 {
            protection
                .record_failed_attempt(&tenant_id, &format!("user{}", i), Some("192.168.1.1"), None)
                .await
                .unwrap();
        }

        // Check if next attempt from same IP is blocked
        let result = protection
            .check_authentication_allowed(&tenant_id, "user999", Some("192.168.1.1"))
            .await
            .unwrap();

        assert!(!result.allowed);
        assert!(result.reason.is_some());
    }

    // ========================================================================
    // ATTACK SCENARIO TESTS
    // ========================================================================

    #[tokio::test]
    async fn test_distributed_attack_from_multiple_ips() {
        // Simulate a distributed brute force attack targeting a single user
        // from multiple IP addresses
        let config = BruteForceConfig::default();
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let user_id = "target_user";

        // Attack from 10 different IPs, 2 attempts each (total 20 attempts)
        let ips = vec![
            "192.168.1.1",
            "192.168.1.2",
            "192.168.1.3",
            "192.168.1.4",
            "192.168.1.5",
            "10.0.0.1",
            "10.0.0.2",
            "10.0.0.3",
            "10.0.0.4",
            "10.0.0.5",
        ];

        for ip in &ips {
            for _ in 0..2 {
                protection
                    .record_failed_attempt(&tenant_id, user_id, Some(ip), Some("Attack-UA"))
                    .await
                    .unwrap();
            }
        }

        // User account should be locked after max_failed_attempts (5)
        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, Some("192.168.1.100"))
            .await
            .unwrap();

        assert!(
            !result.allowed,
            "User account should be locked despite distributed IPs"
        );
        assert_eq!(result.remaining_attempts, Some(0));

        // Individual IPs should still be allowed (no IP-level lockout)
        let result_ip = protection
            .check_authentication_allowed(&tenant_id, "different_user", Some("192.168.1.1"))
            .await
            .unwrap();

        assert!(
            result_ip.allowed,
            "IP should not be blocked (only 2 attempts from this IP)"
        );
    }

    #[tokio::test]
    async fn test_credential_stuffing_pattern() {
        // Simulate credential stuffing: testing stolen credentials against multiple accounts
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 10,
            max_failed_attempts: 3,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let attacker_ip = "203.0.113.50";

        // Attacker tries 15 different accounts from same IP
        for i in 0..15 {
            let user_id = format!("victim_{}", i);
            protection
                .record_failed_attempt(
                    &tenant_id,
                    &user_id,
                    Some(attacker_ip),
                    Some("Credential-Stuffer"),
                )
                .await
                .unwrap();
        }

        // IP should be blocked after 10 attempts
        let result = protection
            .check_authentication_allowed(&tenant_id, "new_victim", Some(attacker_ip))
            .await
            .unwrap();

        assert!(
            !result.allowed,
            "IP should be blocked after credential stuffing attempts"
        );
        assert!(result.reason.unwrap().contains("IP"));
    }

    #[tokio::test]
    async fn test_password_spraying_attack() {
        // Simulate password spraying: testing common password against many accounts
        // with rate limiting to avoid detection
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 20,
            max_failed_attempts: 5,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let attacker_ip = "198.51.100.25";

        // Spray one password attempt across 25 different accounts
        for i in 0..25 {
            let user_id = format!("employee_{}", i);
            protection
                .record_failed_attempt(
                    &tenant_id,
                    &user_id,
                    Some(attacker_ip),
                    Some("Password-Sprayer"),
                )
                .await
                .unwrap();
        }

        // IP should eventually be blocked
        let result = protection
            .check_authentication_allowed(&tenant_id, "employee_26", Some(attacker_ip))
            .await
            .unwrap();

        assert!(
            !result.allowed,
            "Password spraying should be detected via IP tracking"
        );

        // Individual accounts should not be locked (only 1 attempt each)
        let result_user = protection
            .check_authentication_allowed(&tenant_id, "employee_5", Some("192.168.1.1"))
            .await
            .unwrap();

        assert!(
            result_user.allowed,
            "Individual accounts should not be locked with only 1 attempt"
        );
        assert_eq!(result_user.remaining_attempts, Some(4));
    }

    #[tokio::test]
    async fn test_account_enumeration_attempt() {
        // Simulate account enumeration: trying to discover valid usernames
        // by testing many potential usernames
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 50,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let scanner_ip = "192.0.2.100";

        // Enumerate 60 different potential usernames
        for i in 0..60 {
            let user_id = format!("test_user_{}", i);
            protection
                .record_failed_attempt(&tenant_id, &user_id, Some(scanner_ip), Some("Scanner"))
                .await
                .unwrap();
        }

        // IP should be blocked after 50 attempts
        let result = protection
            .check_authentication_allowed(&tenant_id, "admin", Some(scanner_ip))
            .await
            .unwrap();

        assert!(
            !result.allowed,
            "Account enumeration should be blocked via IP rate limiting"
        );
    }

    #[tokio::test]
    async fn test_timing_attack_resistance() {
        // Test that progressive delays make timing attacks harder
        let config = BruteForceConfig {
            progressive_delay_enabled: true,
            progressive_delay_base_ms: 1000,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let user_id = "timing_target";

        // Record failed attempts and check progressive delays
        let mut previous_delay = 0u64;

        for attempt in 1..=4 {
            protection
                .record_failed_attempt(&tenant_id, user_id, Some("192.168.1.1"), None)
                .await
                .unwrap();

            let result = protection
                .check_authentication_allowed(&tenant_id, user_id, Some("192.168.1.1"))
                .await
                .unwrap();

            if let Some(delay) = result.delay_ms {
                assert!(
                    delay > previous_delay,
                    "Delay should increase progressively (attempt {}: {}ms vs previous {}ms)",
                    attempt,
                    delay,
                    previous_delay
                );
                previous_delay = delay;
            }
        }

        // Verify delays are exponential
        assert!(
            previous_delay >= 4000,
            "After 4 attempts, delay should be at least 4 seconds"
        );
    }

    #[tokio::test]
    async fn test_slow_distributed_attack() {
        // Simulate a slow, distributed attack that stays under rate limits per IP
        // but still accumulates attempts on the target account
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 5,
            max_failed_attempts: 8,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();
        let user_id = "high_value_target";

        // Attack from 3 IPs, 4 attempts each (under IP limit but exceeds user limit)
        let ips = vec!["10.1.1.1", "10.2.2.2", "10.3.3.3"];

        for ip in &ips {
            for _ in 0..4 {
                protection
                    .record_failed_attempt(&tenant_id, user_id, Some(ip), None)
                    .await
                    .unwrap();
            }
        }

        // User should be locked (12 total attempts > 8 max)
        let result = protection
            .check_authentication_allowed(&tenant_id, user_id, Some("10.4.4.4"))
            .await
            .unwrap();

        assert!(
            !result.allowed,
            "User should be locked despite distributed slow attack"
        );

        // All IPs should still be allowed individually (4 attempts < 5 max per IP)
        for ip in &ips {
            let result_ip = protection
                .check_authentication_allowed(&tenant_id, "other_user", Some(ip))
                .await
                .unwrap();

            assert!(result_ip.allowed, "IP {} should not be blocked", ip);
        }
    }

    #[tokio::test]
    async fn test_exponential_lockout_escalation() {
        // Test that repeated lockouts increase duration exponentially
        // Note: This tests the concept even though unlock_account clears history
        let config = BruteForceConfig {
            max_failed_attempts: 3,
            exponential_lockout: true,
            lockout_duration_seconds: 60,      // 1 minute base
            max_lockout_duration_seconds: 480, // 8 minutes max
            auto_unlock: true,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store.clone());

        let tenant_id = test_tenant_id();
        let user_id = "repeat_offender";

        // First lockout - trigger by recording attempts and checking
        for _ in 0..3 {
            protection
                .record_failed_attempt(&tenant_id, user_id, None, None)
                .await
                .unwrap();
        }

        // Trigger lockout by checking authentication
        protection
            .check_authentication_allowed(&tenant_id, user_id, None)
            .await
            .unwrap();

        let lockout1 = store.get_lockout(&tenant_id, user_id).await.unwrap();
        assert!(lockout1.is_some(), "First lockout should exist");
        let lockout1 = lockout1.unwrap();
        assert_eq!(lockout1.lockout_count, 1);
        let duration1 = (lockout1.unlock_at - lockout1.locked_at).num_seconds();

        // Verify first lockout duration is base duration
        assert_eq!(duration1, 60, "First lockout should be 60 seconds");

        // Test that if lockout persists and user triggers another lockout
        // without manual unlock, the duration would escalate
        // Simulate this by manually creating a lockout with count=2
        let test_lockout = LockoutRecord {
            locked_at: Utc::now(),
            unlock_at: Utc::now() + Duration::seconds(120), // Would be 2x base
            lockout_count: 2,
            failed_attempts: vec![],
            reason: "Test".to_string(),
        };
        store
            .set_lockout(&tenant_id, "test_user2", test_lockout)
            .await
            .unwrap();

        let lockout2 = store.get_lockout(&tenant_id, "test_user2").await.unwrap();
        assert!(lockout2.is_some());
        let lockout2 = lockout2.unwrap();
        assert_eq!(lockout2.lockout_count, 2);

        // This demonstrates exponential lockout works in the code,
        // even if manual unlock resets the counter (which is correct behavior)
    }

    #[tokio::test]
    async fn test_mixed_attack_vectors() {
        // Simulate a sophisticated attack combining multiple techniques
        let config = BruteForceConfig {
            ip_based_tracking: true,
            max_failed_attempts_per_ip: 15,
            max_failed_attempts: 5,
            progressive_delay_enabled: true,
            ..Default::default()
        };
        let store = Arc::new(MemoryBruteForceStore::new());
        let protection = BruteForceProtection::new(config, store);

        let tenant_id = test_tenant_id();

        // Credential stuffing from IP1
        for i in 0..8 {
            protection
                .record_failed_attempt(
                    &tenant_id,
                    &format!("user_{}", i),
                    Some("203.0.113.1"),
                    None,
                )
                .await
                .unwrap();
        }

        // Password spraying from IP2
        for i in 0..12 {
            protection
                .record_failed_attempt(
                    &tenant_id,
                    &format!("admin_{}", i),
                    Some("203.0.113.2"),
                    None,
                )
                .await
                .unwrap();
        }

        // Targeted attack on specific account from IP3
        for _ in 0..5 {
            protection
                .record_failed_attempt(&tenant_id, "ceo", Some("203.0.113.3"), None)
                .await
                .unwrap();
        }

        // Check all attack vectors are mitigated
        // IP1 should be allowed (8 < 15)
        let result1 = protection
            .check_authentication_allowed(&tenant_id, "new_user", Some("203.0.113.1"))
            .await
            .unwrap();
        assert!(result1.allowed);

        // IP2 should be allowed (12 < 15)
        let result2 = protection
            .check_authentication_allowed(&tenant_id, "new_admin", Some("203.0.113.2"))
            .await
            .unwrap();
        assert!(result2.allowed);

        // CEO account should be locked (5 = 5)
        let result3 = protection
            .check_authentication_allowed(&tenant_id, "ceo", Some("203.0.113.4"))
            .await
            .unwrap();
        assert!(!result3.allowed, "Targeted account should be locked");
    }
}