foxhunt/trading_engine/tests/compliance_audit_trails_tests.rs

// Comprehensive Audit Trails Testing
// Wave 117 Agent 1 - Complete coverage of trading_engine/src/compliance/audit_trails.rs
//
// This test suite validates:
// - Audit log creation for all event types
// - Event tracking and lifecycle
// - Query functionality with various filters
// - Completeness validation and integrity checks
// - Error handling and edge cases
//
// Target: 70-75% coverage of audit_trails.rs (892 lines)

#![allow(unused_crate_dependencies)]

use chrono::{Utc, Duration};
use rust_decimal::Decimal;
use std::collections::HashMap;
use std::sync::Arc;

use trading_engine::compliance::audit_trails::{
    AuditEventDetails, AuditEventType, AuditTrailConfig, AuditTrailEngine, AuditTrailQuery,
    AsyncAuditQueue, CompressionAlgorithm, CompressionEngine, EncryptionAlgorithm,
    EncryptionEngine, ExecutionDetails, OrderDetails, RiskLevel, SortOrder,
    StorageBackendConfig, StorageType, PartitioningStrategy, ComplianceRequirements,
    TransactionAuditEvent,
};
use trading_engine::persistence::postgres::{PostgresConfig, PostgresPool};

// ============================================================================
// TEST HELPERS
// ============================================================================

/// Create test PostgreSQL pool (skips test if DB unavailable)
async fn create_test_pool() -> Option<Arc<PostgresPool>> {
    let postgres_config = PostgresConfig {
        url: std::env::var("DATABASE_URL")
            .unwrap_or_else(|_| "postgresql://postgres:password@localhost:5432/foxhunt_test".to_owned()),
        max_connections: 5,
        min_connections: 1,
        connect_timeout_ms: 5000,
        query_timeout_micros: 100_000,
        acquire_timeout_ms: 1000,
        max_lifetime_seconds: 300,
        idle_timeout_seconds: 60,
        enable_prewarming: false,
        enable_prepared_statements: true,
        enable_slow_query_logging: false,
        slow_query_threshold_micros: 10_000,
    };

    match PostgresPool::new(postgres_config).await {
        Ok(pool) => Some(Arc::new(pool)),
        Err(e) => {
            eprintln!("Skipping test: Database not available: {}", e);
            None
        }
    }
}

/// Create test audit trail configuration
fn create_test_config() -> AuditTrailConfig {
    AuditTrailConfig {
        real_time_persistence: true,
        buffer_size: 10_000,
        batch_size: 100,
        flush_interval_ms: 100,
        retention_days: 2555, // 7 years for SOX
        compression_enabled: true,
        encryption_enabled: true,
        storage_backend: StorageBackendConfig {
            primary_storage: StorageType::PostgreSQL,
            backup_storage: None,
            connection_string: "postgresql://localhost/foxhunt_test".to_owned(),
            table_name: "transaction_audit_events".to_owned(),
            partitioning: PartitioningStrategy::Daily,
        },
        compliance_requirements: ComplianceRequirements {
            sox_enabled: true,
            mifid_ii_enabled: true,
            immutable_required: true,
            digital_signatures_enabled: false,
            tamper_detection: true,
        },
    }
}

/// Create test transaction audit event
fn create_test_event(id: &str) -> TransactionAuditEvent {
    TransactionAuditEvent {
        event_id: format!("TEST-{}", id),
        timestamp: Utc::now(),
        timestamp_nanos: 1234567890,
        event_type: AuditEventType::OrderCreated,
        transaction_id: format!("TX-{}", id),
        order_id: format!("ORD-{}", id),
        actor: "trader_001".to_owned(),
        session_id: Some(format!("SESSION-{}", id)),
        client_ip: Some("192.168.1.100".to_owned()),
        details: AuditEventDetails {
            symbol: Some("AAPL".to_owned()),
            quantity: Some(Decimal::from(100)),
            price: Some(Decimal::from(150)),
            side: Some("BUY".to_owned()),
            order_type: Some("LIMIT".to_owned()),
            venue: Some("NASDAQ".to_owned()),
            account_id: Some("ACC-001".to_owned()),
            strategy_id: Some("STRAT-001".to_owned()),
            metadata: HashMap::new(),
            performance_metrics: None,
        },
        before_state: None,
        after_state: None,
        compliance_tags: vec!["SOX".to_owned(), "MIFID2".to_owned()],
        risk_level: RiskLevel::Low,
        digital_signature: None,
        checksum: String::new(),
    }
}

/// Create test order details
fn create_test_order_details(id: &str) -> OrderDetails {
    OrderDetails {
        transaction_id: format!("TX-{}", id),
        user_id: "user_001".to_owned(),
        session_id: Some(format!("SESSION-{}", id)),
        client_ip: Some("192.168.1.100".to_owned()),
        symbol: "AAPL".to_owned(),
        quantity: Decimal::from(100),
        price: Some(Decimal::from(150)),
        side: "BUY".to_owned(),
        order_type: "LIMIT".to_owned(),
        venue: Some("NASDAQ".to_owned()),
        account_id: "ACC-001".to_owned(),
        strategy_id: Some("STRAT-001".to_owned()),
        metadata: HashMap::new(),
    }
}

/// Create test execution details
fn create_test_execution_details(id: &str) -> ExecutionDetails {
    ExecutionDetails {
        transaction_id: format!("TX-{}", id),
        order_id: format!("ORD-{}", id),
        symbol: "AAPL".to_owned(),
        executed_quantity: Decimal::from(100),
        execution_price: Decimal::from(150),
        side: "BUY".to_owned(),
        venue: "NASDAQ".to_owned(),
        account_id: "ACC-001".to_owned(),
        strategy_id: Some("STRAT-001".to_owned()),
        metadata: HashMap::new(),
        processing_latency_ns: 1_000,
        queue_time_ns: 500,
        system_load: 0.5,
        memory_usage_bytes: 1_000_000,
    }
}

// ============================================================================
// SECTION 1: AUDIT LOG CREATION TESTS (8-10 tests)
// ============================================================================

#[tokio::test]
async fn test_audit_log_creation_order_created() {
    // Test audit log creation for order creation events
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let order = create_test_order_details("001");

    let result = engine.log_order_created("ORD-001", &order);

    assert!(result.is_ok(), "Should successfully log order created event");
}

#[tokio::test]
async fn test_audit_log_creation_order_executed() {
    // Test audit log creation for order execution events
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let execution = create_test_execution_details("001");

    let result = engine.log_order_executed(&execution);

    assert!(result.is_ok(), "Should successfully log order executed event");
}

#[tokio::test]
async fn test_audit_log_creation_all_event_types() {
    // Test audit log creation for all event types
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let event_types = vec![
        AuditEventType::OrderCreated,
        AuditEventType::OrderModified,
        AuditEventType::OrderCancelled,
        AuditEventType::OrderExecuted,
        AuditEventType::TradeSettled,
        AuditEventType::RiskCheck,
        AuditEventType::ComplianceValidation,
        AuditEventType::PositionUpdate,
        AuditEventType::AccountModified,
        AuditEventType::UserAuthenticated,
        AuditEventType::AuthorizationCheck,
        AuditEventType::SystemEvent,
        AuditEventType::ErrorEvent,
    ];

    for (i, event_type) in event_types.into_iter().enumerate() {
        let mut event = create_test_event(&format!("TYPE-{:03}", i));
        event.event_type = event_type.clone();

        let result = engine.log_event(event);
        assert!(result.is_ok(), "Should log event type: {:?}", event_type);
    }
}

#[tokio::test]
async fn test_audit_log_timestamp_accuracy() {
    // Test timestamp accuracy and timezone handling (UTC)
    let event = create_test_event("TS-001");

    let now = Utc::now();
    assert!(event.timestamp <= now, "Timestamp should not be in the future");
    assert!(
        (now - event.timestamp).num_seconds() < 1,
        "Timestamp should be within 1 second of now"
    );
    assert!(event.timestamp_nanos > 0, "Nanosecond timestamp should be set");
}

#[tokio::test]
async fn test_audit_log_user_attribution() {
    // Test user attribution and session tracking
    let order = create_test_order_details("USER-001");
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let result = engine.log_order_created("ORD-USER-001", &order);
    assert!(result.is_ok());

    // Verify user_id is captured in actor field (indirectly via order details)
    assert_eq!(order.user_id, "user_001");
    assert!(order.session_id.is_some());
    assert_eq!(order.session_id.unwrap(), "SESSION-USER-001");
}

#[tokio::test]
async fn test_audit_log_event_severity_levels() {
    // Test event severity levels (risk levels: Low, Medium, High, Critical)
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let risk_levels = vec![
        RiskLevel::Low,
        RiskLevel::Medium,
        RiskLevel::High,
        RiskLevel::Critical,
    ];

    for (i, risk_level) in risk_levels.into_iter().enumerate() {
        let mut event = create_test_event(&format!("RISK-{:03}", i));
        event.risk_level = risk_level.clone();

        let result = engine.log_event(event);
        assert!(result.is_ok(), "Should log event with risk level: {:?}", risk_level);
    }
}

#[tokio::test]
async fn test_audit_log_compliance_tags() {
    // Test SOX and MiFID II compliance tags
    let event = create_test_event("COMP-001");

    assert!(event.compliance_tags.contains(&"SOX".to_owned()));
    assert!(event.compliance_tags.contains(&"MIFID2".to_owned()));
    assert_eq!(event.compliance_tags.len(), 2);
}

#[tokio::test]
async fn test_audit_log_performance_metrics() {
    // Test performance metrics tracking in execution events
    let execution = create_test_execution_details("PERF-001");

    assert_eq!(execution.processing_latency_ns, 1_000);
    assert_eq!(execution.queue_time_ns, 500);
    assert_eq!(execution.system_load, 0.5);
    assert_eq!(execution.memory_usage_bytes, 1_000_000);
}

#[tokio::test]
async fn test_audit_log_empty_event_data() {
    // Edge case: Empty/null event data
    let mut event = create_test_event("EMPTY-001");
    event.details = AuditEventDetails {
        symbol: None,
        quantity: None,
        price: None,
        side: None,
        order_type: None,
        venue: None,
        account_id: None,
        strategy_id: None,
        metadata: HashMap::new(),
        performance_metrics: None,
    };
    event.session_id = None;
    event.client_ip = None;

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let result = engine.log_event(event);

    assert!(result.is_ok(), "Should handle empty/null event data");
}

#[tokio::test]
async fn test_audit_log_client_ip_tracking() {
    // Test client IP tracking
    let order = create_test_order_details("IP-001");

    assert!(order.client_ip.is_some());
    assert_eq!(order.client_ip.unwrap(), "192.168.1.100");
}

// ============================================================================
// SECTION 2: EVENT TRACKING TESTS (6-8 tests)
// ============================================================================

#[tokio::test]
async fn test_event_tracking_trade_execution() {
    // Test trade execution audit trail
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let execution = create_test_execution_details("EXEC-001");

    let result = engine.log_order_executed(&execution);

    assert!(result.is_ok());
    assert_eq!(execution.order_id, "ORD-EXEC-001");
    assert_eq!(execution.symbol, "AAPL");
    assert_eq!(execution.executed_quantity, Decimal::from(100));
}

#[tokio::test]
async fn test_event_tracking_order_lifecycle() {
    // Test order lifecycle tracking (NEW → FILLED → CANCELLED)
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    // Order created
    let mut event1 = create_test_event("LIFECYCLE-001");
    event1.event_type = AuditEventType::OrderCreated;
    assert!(engine.log_event(event1).is_ok());

    // Order modified
    let mut event2 = create_test_event("LIFECYCLE-001");
    event2.event_type = AuditEventType::OrderModified;
    assert!(engine.log_event(event2).is_ok());

    // Order executed
    let mut event3 = create_test_event("LIFECYCLE-001");
    event3.event_type = AuditEventType::OrderExecuted;
    assert!(engine.log_event(event3).is_ok());

    // Order cancelled (alternative path)
    let mut event4 = create_test_event("LIFECYCLE-002");
    event4.event_type = AuditEventType::OrderCancelled;
    assert!(engine.log_event(event4).is_ok());
}

#[tokio::test]
async fn test_event_tracking_position_changes() {
    // Test position opening/closing events
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut event = create_test_event("POSITION-001");
    event.event_type = AuditEventType::PositionUpdate;
    event.details.symbol = Some("MSFT".to_owned());
    event.details.quantity = Some(Decimal::from(200));
    event.details.side = Some("BUY".to_owned());

    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should log position update event");
}

#[tokio::test]
async fn test_event_tracking_account_changes() {
    // Test account balance changes
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut event = create_test_event("ACCOUNT-001");
    event.event_type = AuditEventType::AccountModified;
    event.details.account_id = Some("ACC-001".to_owned());
    event.before_state = Some(serde_json::json!({ "balance": 100000 }));
    event.after_state = Some(serde_json::json!({ "balance": 95000 }));

    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should log account modification event");
}

#[tokio::test]
async fn test_event_tracking_regulatory_flags() {
    // Test regulatory flag events (compliance validation)
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut event = create_test_event("COMPLIANCE-001");
    event.event_type = AuditEventType::ComplianceValidation;
    event.compliance_tags = vec![
        "SOX".to_owned(),
        "MIFID2".to_owned(),
        "BEST_EXECUTION".to_owned(),
    ];
    event.risk_level = RiskLevel::High;

    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should log compliance validation event");
}

#[tokio::test]
async fn test_event_tracking_high_frequency() {
    // Edge case: High-frequency event tracking (1000+ events/sec)
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut success_count = 0;
    for i in 0..1000 {
        let event = create_test_event(&format!("HFT-{:04}", i));
        if engine.log_event(event).is_ok() {
            success_count += 1;
        }
    }

    // Should successfully log most events (allow some buffer overflow at high volume)
    assert!(
        success_count >= 900,
        "Should log at least 90% of high-frequency events: {} logged",
        success_count
    );
}

#[tokio::test]
async fn test_event_tracking_risk_check() {
    // Test risk check event tracking
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut event = create_test_event("RISK-001");
    event.event_type = AuditEventType::RiskCheck;
    event.risk_level = RiskLevel::Critical;
    event.details.metadata.insert(
        "violation".to_owned(),
        serde_json::json!("Position limit exceeded"),
    );

    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should log risk check event");
}

#[tokio::test]
async fn test_event_tracking_authentication() {
    // Test user authentication event tracking
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut event = create_test_event("AUTH-001");
    event.event_type = AuditEventType::UserAuthenticated;
    event.actor = "user_001".to_owned();
    event.client_ip = Some("192.168.1.100".to_owned());

    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should log authentication event");
}

// ============================================================================
// SECTION 3: AUDIT QUERY TESTS (5-7 tests)
// ============================================================================

#[tokio::test]
async fn test_query_by_time_range() {
    // Test query by time range
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    let query = AuditTrailQuery {
        start_time: Utc::now() - Duration::hours(1),
        end_time: Utc::now(),
        event_types: None,
        transaction_id: None,
        order_id: None,
        actor: None,
        symbol: None,
        account_id: None,
        risk_level: None,
        compliance_tags: None,
        limit: Some(100),
        offset: None,
        sort_order: SortOrder::TimestampDesc,
    };

    let result = engine.query(query).await;

    // Query should succeed (may return 0 events if no data)
    assert!(result.is_ok(), "Query by time range should succeed");
    if let Ok(query_result) = result {
        assert!(query_result.execution_time_ms < 5000, "Query should complete within 5 seconds");
    }
}

#[tokio::test]
async fn test_query_by_actor() {
    // Test query by actor (user ID)
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    let query = AuditTrailQuery {
        start_time: Utc::now() - Duration::hours(24),
        end_time: Utc::now(),
        event_types: None,
        transaction_id: None,
        order_id: None,
        actor: Some("trader_001".to_owned()),
        symbol: None,
        account_id: None,
        risk_level: None,
        compliance_tags: None,
        limit: Some(100),
        offset: None,
        sort_order: SortOrder::TimestampDesc,
    };

    let result = engine.query(query).await;
    assert!(result.is_ok(), "Query by actor should succeed");
}

#[tokio::test]
async fn test_query_by_event_type() {
    // Test query by event type
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    let query = AuditTrailQuery {
        start_time: Utc::now() - Duration::hours(24),
        end_time: Utc::now(),
        event_types: Some(vec![AuditEventType::OrderExecuted]),
        transaction_id: None,
        order_id: None,
        actor: None,
        symbol: None,
        account_id: None,
        risk_level: None,
        compliance_tags: None,
        limit: Some(50),
        offset: None,
        sort_order: SortOrder::TimestampDesc,
    };

    let result = engine.query(query).await;
    assert!(result.is_ok(), "Query by event type should succeed");
}

#[tokio::test]
async fn test_query_by_risk_level() {
    // Test query by risk level
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    let query = AuditTrailQuery {
        start_time: Utc::now() - Duration::hours(24),
        end_time: Utc::now(),
        event_types: None,
        transaction_id: None,
        order_id: None,
        actor: None,
        symbol: None,
        account_id: None,
        risk_level: Some(RiskLevel::High),
        compliance_tags: None,
        limit: Some(100),
        offset: None,
        sort_order: SortOrder::RiskLevel,
    };

    let result = engine.query(query).await;
    assert!(result.is_ok(), "Query by risk level should succeed");
}

#[tokio::test]
async fn test_query_pagination() {
    // Test pagination with large result sets
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    // Page 1
    let query1 = AuditTrailQuery {
        start_time: Utc::now() - Duration::days(7),
        end_time: Utc::now(),
        event_types: None,
        transaction_id: None,
        order_id: None,
        actor: None,
        symbol: None,
        account_id: None,
        risk_level: None,
        compliance_tags: None,
        limit: Some(10),
        offset: Some(0),
        sort_order: SortOrder::TimestampDesc,
    };

    let result1 = engine.query(query1).await;
    assert!(result1.is_ok(), "First page query should succeed");

    // Page 2
    let query2 = AuditTrailQuery {
        start_time: Utc::now() - Duration::days(7),
        end_time: Utc::now(),
        event_types: None,
        transaction_id: None,
        order_id: None,
        actor: None,
        symbol: None,
        account_id: None,
        risk_level: None,
        compliance_tags: None,
        limit: Some(10),
        offset: Some(10),
        sort_order: SortOrder::TimestampDesc,
    };

    let result2 = engine.query(query2).await;
    assert!(result2.is_ok(), "Second page query should succeed");
}

#[tokio::test]
async fn test_query_filter_combinations() {
    // Test filter combinations (actor + time + event type)
    let pool = match create_test_pool().await {
        Some(p) => p,
        None => return,
    };

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    engine.set_postgres_pool(pool).await;

    let query = AuditTrailQuery {
        start_time: Utc::now() - Duration::hours(24),
        end_time: Utc::now(),
        event_types: Some(vec![
            AuditEventType::OrderCreated,
            AuditEventType::OrderExecuted,
        ]),
        transaction_id: None,
        order_id: None,
        actor: Some("trader_001".to_owned()),
        symbol: Some("AAPL".to_owned()),
        account_id: Some("ACC-001".to_owned()),
        risk_level: None,
        compliance_tags: None,
        limit: Some(100),
        offset: None,
        sort_order: SortOrder::TimestampDesc,
    };

    let result = engine.query(query).await;
    assert!(result.is_ok(), "Complex filter query should succeed");
}

#[tokio::test]
async fn test_query_sort_orders() {
    // Test all sort order variants
    let sorts = vec![
        SortOrder::TimestampAsc,
        SortOrder::TimestampDesc,
        SortOrder::EventType,
        SortOrder::RiskLevel,
    ];

    for sort in sorts {
        let query = AuditTrailQuery {
            start_time: Utc::now() - Duration::hours(1),
            end_time: Utc::now(),
            event_types: None,
            transaction_id: None,
            order_id: None,
            actor: None,
            symbol: None,
            account_id: None,
            risk_level: None,
            compliance_tags: None,
            limit: Some(100),
            offset: None,
            sort_order: sort.clone(),
        };

        assert!(query.limit.is_some(), "Sort order {:?} should work in query", sort);
    }
}

// ============================================================================
// SECTION 4: COMPLETENESS VALIDATION TESTS (4-6 tests)
// ============================================================================

#[tokio::test]
async fn test_checksum_calculation() {
    // Test checksum calculation for tamper detection
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let order = create_test_order_details("CHECKSUM-001");

    let result = engine.log_order_created("ORD-CHECKSUM-001", &order);
    assert!(result.is_ok());

    // Checksum should be calculated automatically by log_event
    // This tests the internal calculate_checksum method
}

#[tokio::test]
async fn test_event_ordering_chronological() {
    // Test event ordering validation (chronological)
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let mut timestamps = Vec::new();
    for i in 0..10 {
        let event = create_test_event(&format!("ORDER-{:03}", i));
        timestamps.push(event.timestamp);
        let _ = engine.log_event(event);
    }

    // Verify timestamps are in chronological order (or equal)
    for i in 1..timestamps.len() {
        assert!(
            timestamps[i] >= timestamps[i - 1],
            "Events should be in chronological order"
        );
    }
}

#[tokio::test]
async fn test_duplicate_event_handling() {
    // Test duplicate event detection
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    let event1 = create_test_event("DUP-001");
    let event2 = create_test_event("DUP-001"); // Same ID

    assert!(engine.log_event(event1).is_ok());
    assert!(engine.log_event(event2).is_ok()); // Should still log (no dedup at this layer)

    // Note: Duplicate prevention would be at database layer via unique constraints
}

#[tokio::test]
async fn test_event_sequence_gap_detection() {
    // Test gap detection in event sequences
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    // Log events with gaps in sequence
    for i in &[1, 2, 5, 6, 10] {
        let event = create_test_event(&format!("SEQ-{:03}", i));
        let _ = engine.log_event(event);
    }

    // Gap detection would be application-level logic
    // This test validates that events can be logged with non-sequential IDs
}

#[tokio::test]
async fn test_audit_trail_completeness_check() {
    // Test audit trail completeness validation
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    // Create a complete order lifecycle
    let lifecycle_events = vec![
        AuditEventType::OrderCreated,
        AuditEventType::RiskCheck,
        AuditEventType::ComplianceValidation,
        AuditEventType::OrderExecuted,
        AuditEventType::TradeSettled,
    ];

    for (i, event_type) in lifecycle_events.into_iter().enumerate() {
        let mut event = create_test_event(&format!("COMPLETE-{:03}", i));
        event.event_type = event_type.clone();
        event.order_id = "ORD-COMPLETE-001".to_owned();

        let result = engine.log_event(event);
        assert!(result.is_ok(), "Complete lifecycle event should be logged");
    }
}

#[tokio::test]
async fn test_missing_event_detection() {
    // Test detection of missing events in lifecycle
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    // Create incomplete lifecycle (missing execution)
    let incomplete_events = vec![
        AuditEventType::OrderCreated,
        AuditEventType::RiskCheck,
        // Missing: OrderExecuted
        AuditEventType::TradeSettled, // Settled without execution!
    ];

    for (i, event_type) in incomplete_events.into_iter().enumerate() {
        let mut event = create_test_event(&format!("INCOMPLETE-{:03}", i));
        event.event_type = event_type.clone();
        event.order_id = "ORD-INCOMPLETE-001".to_owned();

        let _ = engine.log_event(event);
    }

    // Missing event detection would be application-level logic
    // This validates that events can be logged in any order
}

// ============================================================================
// SECTION 5: ERROR HANDLING TESTS (2-3 tests)
// ============================================================================

#[tokio::test]
async fn test_buffer_full_error() {
    // Test storage failure recovery (buffer full)
    let mut config = create_test_config();
    config.buffer_size = 10; // Very small buffer
    let engine = AuditTrailEngine::new(config);

    let mut success_count = 0;
    let mut error_count = 0;

    // Try to overflow buffer
    for i in 0..100 {
        let event = create_test_event(&format!("OVERFLOW-{:03}", i));
        match engine.log_event(event) {
            Ok(_) => success_count += 1,
            Err(_) => error_count += 1,
        }
    }

    // Should have some errors due to buffer overflow
    assert!(error_count > 0, "Should encounter buffer full errors");
    assert!(success_count > 0, "Should successfully log some events");
}

#[tokio::test]
async fn test_invalid_event_data_rejection() {
    // Test invalid event data handling
    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);

    // Create event with invalid data (extremely large values)
    let mut event = create_test_event("INVALID-001");
    event.details.quantity = Some(Decimal::from(i64::MAX));
    event.details.price = Some(Decimal::from(i64::MAX));

    // Should still accept (validation would be at business logic layer)
    let result = engine.log_event(event);
    assert!(result.is_ok(), "Should accept large decimal values");
}

#[tokio::test]
async fn test_concurrent_audit_logging() {
    // Test concurrent audit logging from multiple tasks
    let config = create_test_config();
    let engine = Arc::new(AuditTrailEngine::new(config));

    let mut handles = vec![];

    for task_id in 0..10 {
        let engine_clone = Arc::clone(&engine);
        let handle = tokio::spawn(async move {
            for i in 0..10 {
                let event = create_test_event(&format!("CONCURRENT-{}-{:03}", task_id, i));
                let _ = engine_clone.log_event(event);
            }
        });
        handles.push(handle);
    }

    // Wait for all tasks
    for handle in handles {
        let _ = handle.await;
    }

    // Should complete without panics or deadlocks
}

// ============================================================================
// SECTION 6: COMPRESSION AND ENCRYPTION TESTS (5 tests)
// ============================================================================

#[tokio::test]
async fn test_compression_gzip() {
    // Test Gzip compression
    let engine = CompressionEngine::new(CompressionAlgorithm::Gzip, 6);
    let data = b"Test audit data for compression. This should compress well due to repetition. Test audit data for compression.";

    let compressed = engine.compress(data);
    assert!(compressed.is_ok(), "Gzip compression should succeed");

    if let Ok(compressed_data) = compressed {
        assert!(compressed_data.len() < data.len(), "Compressed data should be smaller");

        // Test decompression
        let decompressed = engine.decompress(&compressed_data);
        assert!(decompressed.is_ok(), "Gzip decompression should succeed");

        if let Ok(decompressed_data) = decompressed {
            assert_eq!(decompressed_data, data, "Decompressed data should match original");
        }
    }
}

#[tokio::test]
async fn test_compression_lz4_not_implemented() {
    // Test LZ4 compression (not yet implemented)
    let engine = CompressionEngine::new(CompressionAlgorithm::LZ4, 1);
    let data = b"Test data";

    let result = engine.compress(data);
    assert!(result.is_err(), "LZ4 should return not implemented error");
}

#[tokio::test]
async fn test_encryption_aes256gcm() {
    // Test AES-256-GCM encryption
    let engine = EncryptionEngine::new(EncryptionAlgorithm::AES256GCM, "test-key-001".to_owned());
    let key = [0_u8; 32]; // Test key (in production, use proper key derivation)
    let data = b"Sensitive audit event data that should be encrypted";

    let result = engine.encrypt(data, &key);
    assert!(result.is_ok(), "AES-256-GCM encryption should succeed");

    if let Ok((ciphertext, nonce)) = result {
        assert_ne!(ciphertext, data, "Ciphertext should differ from plaintext");
        assert_eq!(nonce.len(), 12, "Nonce should be 12 bytes (96 bits)");

        // Test decryption
        let decrypted = engine.decrypt(&ciphertext, &nonce, &key);
        assert!(decrypted.is_ok(), "AES-256-GCM decryption should succeed");

        if let Ok(decrypted_data) = decrypted {
            assert_eq!(decrypted_data, data, "Decrypted data should match original");
        }
    }
}

#[tokio::test]
async fn test_encryption_tamper_detection() {
    // Test tamper detection via decryption failure
    let engine = EncryptionEngine::new(EncryptionAlgorithm::AES256GCM, "test-key-002".to_owned());
    let key = [0_u8; 32];
    let data = b"Audit event that should detect tampering";

    let (mut ciphertext, nonce) = engine.encrypt(data, &key).expect("Encryption should succeed");

    // Tamper with ciphertext
    if !ciphertext.is_empty() {
        ciphertext[0] ^= 0xFF;
    }

    // Decryption should fail
    let result = engine.decrypt(&ciphertext, &nonce, &key);
    assert!(result.is_err(), "Decryption should fail for tampered data");
}

#[tokio::test]
async fn test_encryption_chacha20_not_implemented() {
    // Test ChaCha20-Poly1305 (not yet implemented)
    let engine = EncryptionEngine::new(
        EncryptionAlgorithm::ChaCha20Poly1305,
        "test-key-003".to_owned(),
    );
    let key = [0_u8; 32];
    let data = b"Test data";

    let result = engine.encrypt(data, &key);
    assert!(result.is_err(), "ChaCha20-Poly1305 should return not implemented error");
}

// ============================================================================
// SECTION 7: ASYNC AUDIT QUEUE TESTS (4 tests)
// ============================================================================

#[tokio::test]
async fn test_async_queue_submission() {
    // Test async queue event submission (non-blocking)
    let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
    let wal_path = temp_dir.path().join("test_async.wal");

    let queue = AsyncAuditQueue::new(wal_path);

    let event = create_test_event("ASYNC-001");
    let result = queue.submit(event);

    assert!(result.is_ok(), "Async submission should succeed");

    let stats = queue.stats();
    assert_eq!(stats.queued, 1, "Should have 1 queued event");
}

#[tokio::test]
async fn test_async_queue_wal_persistence() {
    // Test WAL (Write-Ahead Log) file creation
    let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
    let wal_path = temp_dir.path().join("test_wal.wal");

    let queue = AsyncAuditQueue::new(wal_path.clone());

    // Submit events
    for i in 0..5 {
        let event = create_test_event(&format!("WAL-{:03}", i));
        let _ = queue.submit(event);
    }

    // WAL file may not exist yet (requires background flush to be started)
    // This test validates queue creation and submission
}

#[tokio::test]
async fn test_async_queue_statistics() {
    // Test queue statistics tracking
    let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
    let wal_path = temp_dir.path().join("test_stats.wal");

    let queue = AsyncAuditQueue::new(wal_path);

    let initial_stats = queue.stats();
    assert_eq!(initial_stats.queued, 0);
    assert_eq!(initial_stats.persisted, 0);
    assert_eq!(initial_stats.dropped, 0);

    // Submit 10 events
    for i in 0..10 {
        let event = create_test_event(&format!("STATS-{:03}", i));
        let _ = queue.submit(event);
    }

    let updated_stats = queue.stats();
    assert_eq!(updated_stats.queued, 10, "Should track queued events");
}

#[tokio::test]
async fn test_async_queue_flush() {
    // Test explicit flush operation
    let temp_dir = tempfile::tempdir().expect("Failed to create temp dir");
    let wal_path = temp_dir.path().join("test_flush.wal");

    let queue = AsyncAuditQueue::new(wal_path);

    // Submit events
    for i in 0..5 {
        let event = create_test_event(&format!("FLUSH-{:03}", i));
        let _ = queue.submit(event);
    }

    // Test flush (should complete without error)
    let result = queue.flush().await;
    assert!(result.is_ok(), "Flush should succeed");
}

// ============================================================================
// SECTION 8: RISK ASSESSMENT TESTS (2 tests)
// ============================================================================

#[tokio::test]
async fn test_risk_level_assessment_low() {
    // Test risk level assessment for small orders
    let mut order = create_test_order_details("RISK-LOW");
    order.quantity = Decimal::from(10);
    order.price = Some(Decimal::from(100)); // Notional: $1,000

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let result = engine.log_order_created("ORD-RISK-LOW", &order);

    assert!(result.is_ok());
    // Risk level would be assessed internally (Low for < $100k notional)
}

#[tokio::test]
async fn test_risk_level_assessment_high() {
    // Test risk level assessment for large orders
    let mut order = create_test_order_details("RISK-HIGH");
    order.quantity = Decimal::from(10000);
    order.price = Some(Decimal::from(150)); // Notional: $1.5M

    let config = create_test_config();
    let engine = AuditTrailEngine::new(config);
    let result = engine.log_order_created("ORD-RISK-HIGH", &order);

    assert!(result.is_ok());
    // Risk level would be assessed as High (> $1M notional)
}

// ============================================================================
// SECTION 9: CONFIGURATION TESTS (2 tests)
// ============================================================================

#[tokio::test]
async fn test_default_configuration() {
    // Test default audit trail configuration
    let config = AuditTrailConfig::default();

    assert!(config.real_time_persistence);
    assert_eq!(config.buffer_size, 100_000);
    assert_eq!(config.batch_size, 1_000);
    assert_eq!(config.flush_interval_ms, 1_000);
    assert_eq!(config.retention_days, 2555); // 7 years for SOX
    assert!(config.compression_enabled);
    assert!(config.encryption_enabled);
    assert!(config.compliance_requirements.sox_enabled);
    assert!(config.compliance_requirements.mifid_ii_enabled);
}

#[tokio::test]
async fn test_custom_configuration() {
    // Test custom audit trail configuration
    let config = AuditTrailConfig {
        real_time_persistence: false,
        buffer_size: 50_000,
        batch_size: 500,
        flush_interval_ms: 500,
        retention_days: 365, // 1 year
        compression_enabled: false,
        encryption_enabled: false,
        storage_backend: StorageBackendConfig {
            primary_storage: StorageType::ClickHouse,
            backup_storage: Some(StorageType::FileSystem {
                base_path: "/tmp/audit".to_owned(),
            }),
            connection_string: "clickhouse://localhost:9000".to_owned(),
            table_name: "custom_audit_events".to_owned(),
            partitioning: PartitioningStrategy::Monthly,
        },
        compliance_requirements: ComplianceRequirements {
            sox_enabled: false,
            mifid_ii_enabled: false,
            immutable_required: false,
            digital_signatures_enabled: true,
            tamper_detection: false,
        },
    };

    assert!(!config.real_time_persistence);
    assert_eq!(config.buffer_size, 50_000);
    assert!(config.compliance_requirements.digital_signatures_enabled);
}