//! Comprehensive security integration tests
//!
//! Tests for:
//! - Checkpoint signature verification
//! - Prediction validation and model poisoning detection
//! - Ensemble anomaly detection
//! - End-to-end security workflows

use ml::checkpoint::{CheckpointConfig, CheckpointMetadata, CheckpointSigner};
use ml::ensemble::{EnsembleDecision, ModelVote, TradingAction};
use ml::security::{
    EnsembleAnomalyDetector, PredictionValidator, ValidationConfig,
};
use ml::ModelType;
use std::collections::HashMap;
use tempfile::TempDir;

#[tokio::test]
async fn test_checkpoint_signing_workflow() {
    // Create checkpoint config with temporary directory
    let temp_dir = TempDir::new().unwrap();
    let config = CheckpointConfig {
        base_dir: temp_dir.path().to_path_buf(),
        ..Default::default()
    };
    
    // Create checkpoint metadata
    let mut metadata = CheckpointMetadata::new(
        ModelType::DQN,
        "test_model".to_string(),
        "1.0.0".to_string(),
    );

    // Create mock checkpoint data
    let checkpoint_data = vec![1u8, 2, 3, 4, 5];

    // Save checkpoint (should sign automatically)
    let signer = CheckpointSigner::new(None);
    let sig_info = signer
        .sign_checkpoint(&checkpoint_data, ModelType::DQN)
        .await
        .unwrap();

    // Update metadata with signature
    metadata.signature = Some(sig_info.signature.clone());
    metadata.signature_algorithm = sig_info.algorithm.clone();
    metadata.signing_key_id = sig_info.key_id.clone();
    metadata.signed_at = Some(sig_info.signed_at);

    // Verify signature
    let result = signer
        .verify_signature(
            &checkpoint_data,
            &sig_info.signature,
            &sig_info.key_id,
            ModelType::DQN,
        )
        .await;

    assert!(result.is_ok(), "Signature verification should succeed");
}

#[tokio::test]
async fn test_checkpoint_tampering_detection() {
    let signer = CheckpointSigner::new(None);
    let data = b"original checkpoint data";

    // Sign original data
    let sig_info = signer.sign_checkpoint(data, ModelType::DQN).await.unwrap();

    // Tamper with data
    let tampered_data = b"tampered checkpoint data";

    // Verification should fail
    let result = signer
        .verify_signature(
            tampered_data,
            &sig_info.signature,
            &sig_info.key_id,
            ModelType::DQN,
        )
        .await;

    assert!(
        result.is_err(),
        "Tampered checkpoint should fail verification"
    );
}

#[tokio::test]
async fn test_prediction_validation_normal() {
    let validator = PredictionValidator::new();

    // Add bootstrap samples
    for i in 0..1000 {
        let value = (i as f64 / 1000.0) - 0.5; // Range: -0.5 to 0.5
        validator.update_statistics(value).await;
    }

    // Validate normal prediction
    let result = validator.validate(0.3, 0.8, "DQN").await;

    assert!(result.is_ok(), "Normal prediction should pass validation");

    let validated = result.unwrap();
    assert!(!validated.should_override, "Normal prediction should not be overridden");
    assert!(validated.validation_flags.is_empty(), "No flags should be set");
}

#[tokio::test]
async fn test_prediction_validation_outlier() {
    let validator = PredictionValidator::new();

    // Build statistics around 0.0
    for _ in 0..1000 {
        validator.update_statistics(0.0).await;
    }

    // Inject extreme outlier
    let result = validator.validate(0.95, 0.8, "DQN").await;

    assert!(result.is_ok(), "Outlier should be detected but not rejected");

    let validated = result.unwrap();
    assert!(validated.is_outlier, "Should be flagged as outlier");
    assert!(validated.z_score.abs() > 3.0, "Z-score should exceed threshold");
    assert!(validated.should_override, "Should recommend override");
}

#[tokio::test]
async fn test_prediction_validation_out_of_bounds() {
    let validator = PredictionValidator::new();

    // Test upper bound
    let result = validator.validate(1.5, 0.8, "DQN").await;
    assert!(result.is_err(), "Out of bounds prediction should be rejected");

    // Test lower bound
    let result = validator.validate(-1.5, 0.8, "DQN").await;
    assert!(result.is_err(), "Out of bounds prediction should be rejected");
}

#[tokio::test]
async fn test_extreme_rate_limiting() {
    let mut config = ValidationConfig::default();
    config.max_extreme_rate = 0.05; // 5%
    config.window_duration = std::time::Duration::from_secs(1);

    let validator = PredictionValidator::with_config(config);

    // Inject many extreme predictions quickly
    let mut rejection_count = 0;
    for i in 0..100 {
        let result = validator.validate(0.95, 0.8, "DQN").await;

        if result.is_err() {
            rejection_count += 1;
            // Should eventually hit rate limit
            assert!(
                result
                    .unwrap_err()
                    .to_string()
                    .contains("extreme predictions"),
                "Should be rate limit error"
            );
        }

        tokio::time::sleep(std::time::Duration::from_millis(5)).await;
    }

    assert!(
        rejection_count > 0,
        "Rate limit should have been triggered"
    );
}

#[tokio::test]
async fn test_ensemble_sudden_shift_detection() {
    let detector = EnsembleAnomalyDetector::new();

    // Build history with stable predictions
    for _ in 0..20 {
        let decision = create_test_decision(0.1, HashMap::new());
        detector.update_history(&decision).await;
    }

    // Inject sudden shift
    let decision = create_test_decision(0.8, HashMap::new());
    let report = detector.detect_anomaly(&decision).await;

    assert!(report.has_anomalies, "Sudden shift should be detected");
    assert!(
        report.severity >= ml::security::AnomalySeverity::Medium,
        "Should have medium or higher severity"
    );
}

#[tokio::test]
async fn test_ensemble_coordinated_attack_detection() {
    let detector = EnsembleAnomalyDetector::new();

    // Create decision with all models predicting extreme values
    let mut model_votes = HashMap::new();
    for i in 1..=4 {
        model_votes.insert(
            format!("model{}", i),
            ModelVote::new(
                format!("model{}", i),
                0.95,
                0.9,
                0.25,
            ),
        );
    }

    let decision = create_test_decision(0.95, model_votes);
    let report = detector.detect_anomaly(&decision).await;

    assert!(
        report.has_anomalies,
        "Coordinated attack should be detected"
    );
    assert_eq!(
        report.severity,
        ml::security::AnomalySeverity::Critical,
        "Should have critical severity"
    );
}

#[tokio::test]
async fn test_ensemble_model_drift_detection() {
    let detector = EnsembleAnomalyDetector::new();

    // Build history with stable model behavior
    for _ in 0..30 {
        let mut model_votes = HashMap::new();
        model_votes.insert(
            "model1".to_string(),
            ModelVote::new(
                "model1".to_string(),
                0.1,
                0.8,
                1.0,
            ),
        );

        let decision = create_test_decision(0.1, model_votes);
        detector.update_history(&decision).await;
    }

    // Inject drift
    let mut model_votes = HashMap::new();
    model_votes.insert(
        "model1".to_string(),
        ModelVote::new(
            "model1".to_string(),
            0.9,
            0.8,
            1.0,
        ),
    );

    let decision = create_test_decision(0.9, model_votes);
    let report = detector.detect_anomaly(&decision).await;

    assert!(report.has_anomalies, "Model drift should be detected");

    // Check for drift anomaly
    let has_drift = report.anomalies.iter().any(|a| {
        matches!(
            a,
            ml::security::Anomaly::ModelDrift { .. }
        )
    });
    assert!(has_drift, "Should contain model drift anomaly");
}

#[tokio::test]
async fn test_end_to_end_security_workflow() {
    // Test complete security workflow:
    // 1. Sign checkpoint
    // 2. Validate predictions
    // 3. Detect ensemble anomalies

    // 1. Checkpoint signing
    let signer = CheckpointSigner::new(None);
    let checkpoint_data = vec![1, 2, 3, 4, 5];
    let sig_info = signer
        .sign_checkpoint(&checkpoint_data, ModelType::DQN)
        .await
        .unwrap();

    let verify_result = signer
        .verify_signature(
            &checkpoint_data,
            &sig_info.signature,
            &sig_info.key_id,
            ModelType::DQN,
        )
        .await;
    assert!(verify_result.is_ok(), "Checkpoint signature should verify");

    // 2. Prediction validation
    let validator = PredictionValidator::new();
    for i in 0..100 {
        validator.update_statistics(i as f64 / 100.0).await;
    }

    let pred_result = validator.validate(0.5, 0.8, "DQN").await;
    assert!(pred_result.is_ok(), "Prediction should be valid");

    // 3. Ensemble anomaly detection
    let detector = EnsembleAnomalyDetector::new();
    for i in 0..10 {
        let decision = create_test_decision(0.5, HashMap::new());
        detector.update_history(&decision).await;
    }

    let decision = create_test_decision(0.52, HashMap::new());
    let anomaly_report = detector.detect_anomaly(&decision).await;

    assert!(
        !anomaly_report.has_anomalies,
        "Normal decision should not trigger anomalies"
    );
}

#[tokio::test]
async fn test_adversarial_prediction_sequence() {
    // Simulate adversarial attack with gradually increasing predictions
    let validator = PredictionValidator::new();

    // Build normal baseline with tighter distribution
    for _ in 0..500 {
        validator.update_statistics(0.0).await;
    }

    // Test with sudden extreme predictions (mimicking adversarial attack)
    let mut outlier_count = 0;
    for _ in 0..50 {
        let value = 0.9; // Consistently extreme value
        let result = validator.validate(value, 0.8, "adversarial_model").await;

        if let Ok(validated) = result {
            if validated.is_outlier {
                outlier_count += 1;
            }
        }
    }

    assert!(
        outlier_count > 10,
        "Should detect outliers in adversarial sequence (detected: {})",
        outlier_count
    );
}

#[tokio::test]
async fn test_statistics_bootstrap_phase() {
    let mut config = ValidationConfig::default();
    config.bootstrap_samples = 50;

    let validator = PredictionValidator::with_config(config);

    // Add bootstrap samples
    for i in 0..50 {
        validator.update_statistics(i as f64 / 50.0).await;
    }

    let stats = validator.get_statistics().await;

    assert_eq!(stats.sample_count, 50, "Should have 50 samples");
    assert!(stats.std_dev > 0.0, "Should have non-zero std dev");
    assert!(
        stats.mean > 0.0 && stats.mean < 1.0,
        "Mean should be in valid range"
    );
}

// Helper function to create test ensemble decision
fn create_test_decision(signal: f64, model_votes: HashMap<String, ModelVote>) -> EnsembleDecision {
    let action = if signal > 0.5 {
        TradingAction::Buy
    } else if signal < -0.5 {
        TradingAction::Sell
    } else {
        TradingAction::Hold
    };
    
    EnsembleDecision::new(
        action,
        0.8,
        signal,
        0.0,
        model_votes,
    )
}