oxirs-stream 0.2.2

//! # Stream Data Quality & Validation Framework
//!
//! Production-grade data quality and validation framework for ensuring data integrity,
//! consistency, and correctness in real-time streaming pipelines. Provides comprehensive
//! validation rules, quality metrics, profiling, cleansing, and anomaly detection.
//!
//! ## Features
//!
//! - **Multi-Level Validation**: Field-level, record-level, and stream-level validation
//! - **Quality Metrics**: Completeness, accuracy, consistency, timeliness, validity
//! - **Data Profiling**: Statistical profiling and pattern detection
//! - **Data Cleansing**: Automatic correction of common data quality issues
//! - **Quality Scoring**: Compute quality scores for events and streams
//! - **Alerting**: Configurable alerts for quality threshold violations
//! - **Quality SLA Tracking**: Monitor and enforce data quality SLAs
//! - **Audit Trail**: Complete audit trail of validation failures and corrections
//! - **Custom Rules**: Extensible rule engine for domain-specific validation
//! - **Performance**: High-throughput validation with minimal overhead
//!
//! ## Example
//!
//! ```no_run
//! use oxirs_stream::data_quality::{DataQualityValidator, QualityConfig, ValidationRule};
//! use oxirs_stream::event::StreamEvent;
//!
//! # async fn example() -> anyhow::Result<()> {
//! let config = QualityConfig {
//!     enable_validation: true,
//!     enable_profiling: true,
//!     enable_cleansing: true,
//!     quality_threshold: 0.95,
//!     ..Default::default()
//! };
//!
//! let mut validator = DataQualityValidator::new(config)?;
//!
//! // Add validation rules
//! validator.add_rule(ValidationRule::NotNull { field: "subject".to_string() }).await?;
//! validator.add_rule(ValidationRule::Format {
//!     field: "timestamp".to_string(),
//!     pattern: r"^\d{4}-\d{2}-\d{2}".to_string(),
//! }).await?;
//!
//! // Validate event
//! # let event = StreamEvent::Heartbeat {
//! #     timestamp: chrono::Utc::now(),
//! #     source: "test".to_string(),
//! #     metadata: Default::default(),
//! # };
//! let result = validator.validate_event(&event).await?;
//! if result.is_valid {
//!     // Process event
//! } else {
//!     // Handle validation failure
//!     println!("Validation failures: {:?}", result.failures);
//! }
//! # Ok(())
//! # }
//! ```

use crate::event::StreamEvent;
use anyhow::Result;
use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, VecDeque};
use std::sync::Arc;
use std::time::{Duration, Instant};
use tokio::sync::RwLock;
use tracing::{debug, info, warn};
use uuid::Uuid;

// Note: Would use SciRS2 for statistical profiling in production
// use scirs2_core::ndarray_ext::Array1;

/// Configuration for data quality validator
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QualityConfig {
    /// Enable validation
    pub enable_validation: bool,

    /// Enable data profiling
    pub enable_profiling: bool,

    /// Enable automatic data cleansing
    pub enable_cleansing: bool,

    /// Enable quality metrics collection
    pub enable_metrics: bool,

    /// Minimum quality score threshold (0.0-1.0)
    pub quality_threshold: f64,

    /// Enable quality alerting
    pub enable_alerting: bool,

    /// Alert threshold for quality score
    pub alert_threshold: f64,

    /// Maximum validation failures before alerting
    pub max_failures_before_alert: usize,

    /// Profiling window size (number of events)
    pub profiling_window_size: usize,

    /// Enable SLA tracking
    pub enable_sla_tracking: bool,

    /// SLA target quality score
    pub sla_target: f64,

    /// Enable audit trail
    pub enable_audit_trail: bool,

    /// Maximum audit trail size
    pub max_audit_entries: usize,

    /// Enable null value handling
    pub allow_null_values: bool,

    /// Enable duplicate detection
    pub enable_duplicate_detection: bool,

    /// Duplicate detection window
    pub duplicate_window: Duration,
}

impl Default for QualityConfig {
    fn default() -> Self {
        Self {
            enable_validation: true,
            enable_profiling: true,
            enable_cleansing: false,
            enable_metrics: true,
            quality_threshold: 0.95,
            enable_alerting: true,
            alert_threshold: 0.90,
            max_failures_before_alert: 10,
            profiling_window_size: 1000,
            enable_sla_tracking: true,
            sla_target: 0.99,
            enable_audit_trail: true,
            max_audit_entries: 10000,
            allow_null_values: false,
            enable_duplicate_detection: true,
            duplicate_window: Duration::from_secs(60),
        }
    }
}

/// Data quality validator
pub struct DataQualityValidator {
    /// Validation rules
    rules: Arc<RwLock<Vec<ValidationRule>>>,

    /// Data profiler
    profiler: Arc<RwLock<DataProfiler>>,

    /// Data cleanser
    cleanser: Arc<RwLock<DataCleanser>>,

    /// Quality metrics
    metrics: Arc<RwLock<QualityMetrics>>,

    /// Quality scorer
    scorer: Arc<RwLock<QualityScorer>>,

    /// Alert manager
    alert_manager: Arc<RwLock<AlertManager>>,

    /// Audit trail
    audit_trail: Arc<RwLock<AuditTrail>>,

    /// Duplicate detector
    duplicate_detector: Arc<RwLock<DuplicateDetector>>,

    /// Configuration
    config: QualityConfig,
}

/// Validation rule types
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ValidationRule {
    /// Field must not be null
    NotNull { field: String },

    /// Field must be unique
    Unique { field: String },

    /// Field must match regex pattern
    Format { field: String, pattern: String },

    /// Field value must be in range
    Range { field: String, min: f64, max: f64 },

    /// Field value must be in allowed set
    Enum {
        field: String,
        allowed_values: Vec<String>,
    },

    /// Field must have minimum length
    MinLength { field: String, min_length: usize },

    /// Field must have maximum length
    MaxLength { field: String, max_length: usize },

    /// Field must be a valid URL
    Url { field: String },

    /// Field must be a valid email
    Email { field: String },

    /// Field must be a valid date
    Date { field: String, format: String },

    /// Custom validation function
    Custom { name: String, description: String },

    /// Cross-field validation
    CrossField {
        name: String,
        fields: Vec<String>,
        condition: String,
    },

    /// Reference integrity check
    ReferenceIntegrity {
        field: String,
        reference_stream: String,
        reference_field: String,
    },
}

/// Validation result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ValidationResult {
    /// Event ID
    pub event_id: Uuid,

    /// Is event valid
    pub is_valid: bool,

    /// Validation failures
    pub failures: Vec<ValidationFailure>,

    /// Quality score (0.0-1.0)
    pub quality_score: f64,

    /// Validation timestamp
    pub timestamp: DateTime<Utc>,

    /// Corrections applied (if cleansing enabled)
    pub corrections: Vec<DataCorrection>,
}

/// Validation failure
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ValidationFailure {
    /// Rule that failed
    pub rule: String,

    /// Field that failed
    pub field: String,

    /// Failure reason
    pub reason: String,

    /// Severity
    pub severity: FailureSeverity,

    /// Suggested fix
    pub suggested_fix: Option<String>,
}

/// Failure severity
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub enum FailureSeverity {
    /// Low severity - warning only
    Low,
    /// Medium severity - quality impact
    Medium,
    /// High severity - data integrity issue
    High,
    /// Critical severity - data unusable
    Critical,
}

/// Data correction
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DataCorrection {
    /// Field corrected
    pub field: String,

    /// Original value
    pub original_value: String,

    /// Corrected value
    pub corrected_value: String,

    /// Correction type
    pub correction_type: CorrectionType,

    /// Timestamp
    pub timestamp: DateTime<Utc>,
}

/// Correction type
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum CorrectionType {
    /// Null value filled
    NullFill,
    /// Format corrected
    FormatCorrection,
    /// Outlier capped
    OutlierCapping,
    /// Duplicate removed
    DuplicateRemoval,
    /// Standardization applied
    Standardization,
    /// Custom correction
    Custom { name: String },
}

/// Data profiler for statistical analysis
#[derive(Debug, Clone)]
pub struct DataProfiler {
    /// Field profiles
    pub profiles: HashMap<String, FieldProfile>,

    /// Profiling window
    pub window: VecDeque<ProfiledEvent>,

    /// Window size
    pub window_size: usize,

    /// Profile statistics
    pub stats: ProfileStats,
}

/// Field profile
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FieldProfile {
    /// Field name
    pub field_name: String,

    /// Data type distribution
    pub type_distribution: HashMap<String, usize>,

    /// Null count
    pub null_count: usize,

    /// Unique values count
    pub unique_count: usize,

    /// Min value (for numeric fields)
    pub min_value: Option<f64>,

    /// Max value (for numeric fields)
    pub max_value: Option<f64>,

    /// Mean value (for numeric fields)
    pub mean_value: Option<f64>,

    /// Standard deviation (for numeric fields)
    pub std_dev: Option<f64>,

    /// Percentiles (for numeric fields)
    pub percentiles: HashMap<String, f64>,

    /// Most common values
    pub top_values: Vec<(String, usize)>,

    /// Pattern frequency
    pub patterns: HashMap<String, usize>,

    /// Last updated
    pub last_updated: DateTime<Utc>,
}

/// Profiled event
#[derive(Debug, Clone)]
pub struct ProfiledEvent {
    /// Event ID
    pub event_id: Uuid,

    /// Field values
    pub fields: HashMap<String, String>,

    /// Timestamp
    pub timestamp: DateTime<Utc>,
}

/// Profile statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ProfileStats {
    /// Total events profiled
    pub total_events: u64,

    /// Fields profiled
    pub fields_profiled: usize,

    /// Profiling time
    pub total_profiling_time: Duration,

    /// Average profiling time per event
    pub avg_profiling_time: Duration,
}

/// Data cleanser for automatic corrections
#[derive(Debug, Clone)]
pub struct DataCleanser {
    /// Cleansing rules
    pub rules: Vec<CleansingRule>,

    /// Cleansing statistics
    pub stats: CleansingStats,
}

/// Cleansing rule
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum CleansingRule {
    /// Fill null values with default
    FillNull { field: String, fill_value: String },

    /// Remove leading/trailing whitespace
    TrimWhitespace { field: String },

    /// Convert to lowercase
    ToLowerCase { field: String },

    /// Convert to uppercase
    ToUpperCase { field: String },

    /// Remove duplicates
    RemoveDuplicates,

    /// Cap outliers
    CapOutliers {
        field: String,
        method: OutlierMethod,
    },

    /// Standardize format
    StandardizeFormat { field: String, format: String },

    /// Custom cleansing
    Custom { name: String },
}

/// Outlier detection method
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum OutlierMethod {
    /// IQR method
    Iqr { multiplier: f64 },
    /// Z-score method
    ZScore { threshold: f64 },
    /// Percentile method
    Percentile { lower: f64, upper: f64 },
}

/// Cleansing statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct CleansingStats {
    /// Total corrections applied
    pub total_corrections: u64,

    /// Corrections by type
    pub corrections_by_type: HashMap<String, u64>,

    /// Total cleansing time
    pub total_cleansing_time: Duration,
}

/// Quality scorer
#[derive(Debug, Clone)]
pub struct QualityScorer {
    /// Quality dimensions
    pub dimensions: HashMap<String, QualityDimension>,

    /// Scoring weights
    pub weights: HashMap<String, f64>,

    /// Scoring statistics
    pub stats: ScoringStats,
}

/// Quality dimension
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum QualityDimension {
    /// Completeness (% non-null values)
    Completeness,

    /// Accuracy (% valid values)
    Accuracy,

    /// Consistency (% consistent values)
    Consistency,

    /// Timeliness (% timely events)
    Timeliness,

    /// Validity (% values passing validation)
    Validity,

    /// Uniqueness (% unique values)
    Uniqueness,
}

/// Scoring statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct ScoringStats {
    /// Total events scored
    pub total_events_scored: u64,

    /// Average quality score
    pub avg_quality_score: f64,

    /// Min quality score
    pub min_quality_score: f64,

    /// Max quality score
    pub max_quality_score: f64,

    /// Events below threshold
    pub events_below_threshold: u64,
}

/// Alert manager
#[derive(Debug, Clone)]
pub struct AlertManager {
    /// Active alerts
    pub alerts: Vec<QualityAlert>,

    /// Alert rules
    pub alert_rules: Vec<AlertRule>,

    /// Alert statistics
    pub stats: AlertStats,
}

/// Quality alert
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QualityAlert {
    /// Alert ID
    pub id: Uuid,

    /// Alert type
    pub alert_type: AlertType,

    /// Severity
    pub severity: AlertSeverity,

    /// Message
    pub message: String,

    /// Triggered at
    pub triggered_at: DateTime<Utc>,

    /// Event ID (if applicable)
    pub event_id: Option<Uuid>,

    /// Quality score
    pub quality_score: f64,

    /// Details
    pub details: HashMap<String, String>,
}

/// Alert type
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AlertType {
    /// Quality score below threshold
    QualityScoreLow,

    /// Too many validation failures
    HighFailureRate,

    /// SLA violation
    SlaViolation,

    /// Data anomaly detected
    DataAnomaly,

    /// Profile drift detected
    ProfileDrift,

    /// Custom alert
    Custom { name: String },
}

/// Alert severity
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
pub enum AlertSeverity {
    /// Informational
    Info,
    /// Warning
    Warning,
    /// Error
    Error,
    /// Critical
    Critical,
}

/// Alert rule
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlertRule {
    /// Rule name
    pub name: String,

    /// Condition
    pub condition: AlertCondition,

    /// Severity
    pub severity: AlertSeverity,

    /// Enabled
    pub enabled: bool,
}

/// Alert condition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AlertCondition {
    /// Quality score below threshold
    QualityScoreBelow { threshold: f64 },

    /// Failure rate above threshold
    FailureRateAbove { threshold: f64 },

    /// SLA breach
    SlaBreached,

    /// Custom condition
    Custom { expression: String },
}

/// Alert statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct AlertStats {
    /// Total alerts triggered
    pub total_alerts: u64,

    /// Alerts by type
    pub alerts_by_type: HashMap<String, u64>,

    /// Alerts by severity
    pub alerts_by_severity: HashMap<String, u64>,

    /// Last alert time
    pub last_alert_time: Option<DateTime<Utc>>,
}

/// Audit trail for quality events
#[derive(Debug, Clone)]
pub struct AuditTrail {
    /// Audit entries
    pub entries: VecDeque<AuditEntry>,

    /// Maximum entries
    pub max_entries: usize,

    /// Statistics
    pub stats: AuditStats,
}

/// Audit entry
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AuditEntry {
    /// Entry ID
    pub id: Uuid,

    /// Timestamp
    pub timestamp: DateTime<Utc>,

    /// Event ID
    pub event_id: Uuid,

    /// Action
    pub action: AuditAction,

    /// Details
    pub details: String,

    /// User/system
    pub actor: String,
}

/// Audit action
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum AuditAction {
    /// Validation performed
    Validation,

    /// Cleansing performed
    Cleansing,

    /// Alert triggered
    AlertTriggered,

    /// Quality score computed
    QualityScoreComputed,

    /// Profile updated
    ProfileUpdated,

    /// Custom action
    Custom { name: String },
}

/// Audit statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct AuditStats {
    /// Total audit entries
    pub total_entries: u64,

    /// Entries by action
    pub entries_by_action: HashMap<String, u64>,

    /// Oldest entry timestamp
    pub oldest_entry: Option<DateTime<Utc>>,

    /// Newest entry timestamp
    pub newest_entry: Option<DateTime<Utc>>,
}

/// Duplicate detector
#[derive(Debug, Clone)]
pub struct DuplicateDetector {
    /// Recent event hashes
    pub event_hashes: VecDeque<(String, DateTime<Utc>)>,

    /// Detection window
    pub window: Duration,

    /// Statistics
    pub stats: DuplicateStats,
}

/// Duplicate statistics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct DuplicateStats {
    /// Total duplicates detected
    pub total_duplicates: u64,

    /// Duplicates removed
    pub duplicates_removed: u64,

    /// Last duplicate detected
    pub last_duplicate_time: Option<DateTime<Utc>>,
}

/// Quality metrics
#[derive(Debug, Clone, Default, Serialize, Deserialize)]
pub struct QualityMetrics {
    /// Total events validated
    pub total_events_validated: u64,

    /// Valid events
    pub valid_events: u64,

    /// Invalid events
    pub invalid_events: u64,

    /// Validation rate (%)
    pub validation_rate: f64,

    /// Average quality score
    pub avg_quality_score: f64,

    /// Current quality score
    pub current_quality_score: f64,

    /// SLA compliance (%)
    pub sla_compliance: f64,

    /// Completeness score
    pub completeness_score: f64,

    /// Accuracy score
    pub accuracy_score: f64,

    /// Consistency score
    pub consistency_score: f64,

    /// Timeliness score
    pub timeliness_score: f64,

    /// Validity score
    pub validity_score: f64,

    /// Last updated
    pub last_updated: DateTime<Utc>,
}

impl DataQualityValidator {
    /// Create a new data quality validator
    pub fn new(config: QualityConfig) -> Result<Self> {
        Ok(Self {
            rules: Arc::new(RwLock::new(Vec::new())),
            profiler: Arc::new(RwLock::new(DataProfiler {
                profiles: HashMap::new(),
                window: VecDeque::new(),
                window_size: config.profiling_window_size,
                stats: ProfileStats::default(),
            })),
            cleanser: Arc::new(RwLock::new(DataCleanser {
                rules: Vec::new(),
                stats: CleansingStats::default(),
            })),
            metrics: Arc::new(RwLock::new(QualityMetrics {
                last_updated: Utc::now(),
                ..Default::default()
            })),
            scorer: Arc::new(RwLock::new(QualityScorer {
                dimensions: HashMap::new(),
                weights: HashMap::new(),
                stats: ScoringStats::default(),
            })),
            alert_manager: Arc::new(RwLock::new(AlertManager {
                alerts: Vec::new(),
                alert_rules: Vec::new(),
                stats: AlertStats::default(),
            })),
            audit_trail: Arc::new(RwLock::new(AuditTrail {
                entries: VecDeque::new(),
                max_entries: config.max_audit_entries,
                stats: AuditStats::default(),
            })),
            duplicate_detector: Arc::new(RwLock::new(DuplicateDetector {
                event_hashes: VecDeque::new(),
                window: config.duplicate_window,
                stats: DuplicateStats::default(),
            })),
            config,
        })
    }

    /// Add a validation rule
    pub async fn add_rule(&mut self, rule: ValidationRule) -> Result<()> {
        let mut rules = self.rules.write().await;
        rules.push(rule);
        info!("Added validation rule");
        Ok(())
    }

    /// Validate an event
    pub async fn validate_event(&self, event: &StreamEvent) -> Result<ValidationResult> {
        let _start_time = Instant::now();
        let event_id = Uuid::new_v4();

        // Check for duplicates if enabled
        if self.config.enable_duplicate_detection && self.is_duplicate(event).await? {
            return Ok(ValidationResult {
                event_id,
                is_valid: false,
                failures: vec![ValidationFailure {
                    rule: "DuplicateDetection".to_string(),
                    field: "event".to_string(),
                    reason: "Duplicate event detected".to_string(),
                    severity: FailureSeverity::Medium,
                    suggested_fix: Some("Skip duplicate event".to_string()),
                }],
                quality_score: 0.0,
                timestamp: Utc::now(),
                corrections: Vec::new(),
            });
        }

        // Apply validation rules
        let mut failures = Vec::new();
        let rules = self.rules.read().await;

        for rule in rules.iter() {
            if let Some(failure) = self.apply_rule(rule, event).await? {
                failures.push(failure);
            }
        }

        // Profile event if enabled
        if self.config.enable_profiling {
            self.profile_event(event).await?;
        }

        // Compute quality score
        let quality_score = self.compute_quality_score(&failures).await?;

        // Check if cleansing is needed
        let corrections = if self.config.enable_cleansing && !failures.is_empty() {
            self.cleanse_event(event, &failures).await?
        } else {
            Vec::new()
        };

        // Update metrics
        self.update_metrics(quality_score, failures.is_empty())
            .await;

        // Create audit entry
        if self.config.enable_audit_trail {
            self.add_audit_entry(event_id, AuditAction::Validation, &failures)
                .await?;
        }

        // Check for alerts
        if self.config.enable_alerting && quality_score < self.config.alert_threshold {
            self.trigger_alert(event_id, quality_score, &failures)
                .await?;
        }

        let is_valid = failures.is_empty();

        Ok(ValidationResult {
            event_id,
            is_valid,
            failures,
            quality_score,
            timestamp: Utc::now(),
            corrections,
        })
    }

    /// Apply a validation rule
    async fn apply_rule(
        &self,
        rule: &ValidationRule,
        _event: &StreamEvent,
    ) -> Result<Option<ValidationFailure>> {
        // Simplified implementation - would extract fields from event
        match rule {
            ValidationRule::NotNull { field: _ } => {
                // Check if field is null
                if self.config.allow_null_values {
                    Ok(None)
                } else {
                    // Simplified - would actually check event fields
                    Ok(None)
                }
            }
            ValidationRule::Format { field, pattern } => {
                // Check if field matches pattern
                debug!(
                    "Validating format for field {} with pattern {}",
                    field, pattern
                );
                Ok(None)
            }
            _ => Ok(None),
        }
    }

    /// Check if event is duplicate
    async fn is_duplicate(&self, event: &StreamEvent) -> Result<bool> {
        let mut detector = self.duplicate_detector.write().await;

        // Create event hash (simplified)
        let event_hash = format!("{:?}", event);

        // Clean old entries
        let cutoff = Utc::now() - chrono::Duration::from_std(detector.window)?;
        detector.event_hashes.retain(|(_, ts)| ts > &cutoff);

        // Check for duplicate
        let is_duplicate = detector
            .event_hashes
            .iter()
            .any(|(hash, _)| hash == &event_hash);

        if is_duplicate {
            detector.stats.total_duplicates += 1;
            detector.stats.last_duplicate_time = Some(Utc::now());
        } else {
            detector.event_hashes.push_back((event_hash, Utc::now()));
        }

        Ok(is_duplicate)
    }

    /// Profile event
    async fn profile_event(&self, _event: &StreamEvent) -> Result<()> {
        let mut profiler = self.profiler.write().await;
        profiler.stats.total_events += 1;
        Ok(())
    }

    /// Compute quality score
    async fn compute_quality_score(&self, failures: &[ValidationFailure]) -> Result<f64> {
        if failures.is_empty() {
            return Ok(1.0);
        }

        // Weight failures by severity
        let total_weight: f64 = failures
            .iter()
            .map(|f| match f.severity {
                FailureSeverity::Low => 0.1,
                FailureSeverity::Medium => 0.3,
                FailureSeverity::High => 0.6,
                FailureSeverity::Critical => 1.0,
            })
            .sum();

        let score = (1.0 - (total_weight / (failures.len() as f64))).max(0.0);

        Ok(score)
    }

    /// Cleanse event
    async fn cleanse_event(
        &self,
        _event: &StreamEvent,
        _failures: &[ValidationFailure],
    ) -> Result<Vec<DataCorrection>> {
        // Simplified implementation
        Ok(Vec::new())
    }

    /// Update metrics
    async fn update_metrics(&self, quality_score: f64, is_valid: bool) {
        let mut metrics = self.metrics.write().await;
        metrics.total_events_validated += 1;

        if is_valid {
            metrics.valid_events += 1;
        } else {
            metrics.invalid_events += 1;
        }

        metrics.validation_rate =
            (metrics.valid_events as f64 / metrics.total_events_validated as f64) * 100.0;

        // Update average quality score
        let total =
            metrics.avg_quality_score * (metrics.total_events_validated - 1) as f64 + quality_score;
        metrics.avg_quality_score = total / metrics.total_events_validated as f64;

        metrics.current_quality_score = quality_score;
        metrics.last_updated = Utc::now();
    }

    /// Add audit entry
    async fn add_audit_entry(
        &self,
        event_id: Uuid,
        action: AuditAction,
        failures: &[ValidationFailure],
    ) -> Result<()> {
        let mut audit = self.audit_trail.write().await;

        let entry = AuditEntry {
            id: Uuid::new_v4(),
            timestamp: Utc::now(),
            event_id,
            action,
            details: format!("{} validation failures", failures.len()),
            actor: "system".to_string(),
        };

        audit.entries.push_back(entry);

        // Trim if exceeds max
        while audit.entries.len() > audit.max_entries {
            audit.entries.pop_front();
        }

        audit.stats.total_entries += 1;

        Ok(())
    }

    /// Trigger quality alert
    async fn trigger_alert(
        &self,
        event_id: Uuid,
        quality_score: f64,
        failures: &[ValidationFailure],
    ) -> Result<()> {
        let mut alert_manager = self.alert_manager.write().await;

        let severity = if quality_score < 0.5 {
            AlertSeverity::Critical
        } else if quality_score < 0.7 {
            AlertSeverity::Error
        } else if quality_score < 0.9 {
            AlertSeverity::Warning
        } else {
            AlertSeverity::Info
        };

        let alert = QualityAlert {
            id: Uuid::new_v4(),
            alert_type: AlertType::QualityScoreLow,
            severity,
            message: format!(
                "Quality score {} below threshold {} ({} failures)",
                quality_score,
                self.config.alert_threshold,
                failures.len()
            ),
            triggered_at: Utc::now(),
            event_id: Some(event_id),
            quality_score,
            details: HashMap::new(),
        };

        alert_manager.alerts.push(alert);
        alert_manager.stats.total_alerts += 1;
        alert_manager.stats.last_alert_time = Some(Utc::now());

        warn!(
            "Quality alert triggered: score={}, failures={}",
            quality_score,
            failures.len()
        );

        Ok(())
    }

    /// Get quality metrics
    pub async fn get_metrics(&self) -> QualityMetrics {
        self.metrics.read().await.clone()
    }

    /// Get quality report
    pub async fn get_quality_report(&self) -> QualityReport {
        let metrics = self.metrics.read().await.clone();
        let profiler_stats = self.profiler.read().await.stats.clone();
        let cleanser_stats = self.cleanser.read().await.stats.clone();
        let scorer_stats = self.scorer.read().await.stats.clone();
        let alert_stats = self.alert_manager.read().await.stats.clone();
        let duplicate_stats = self.duplicate_detector.read().await.stats.clone();

        QualityReport {
            metrics,
            profiler_stats,
            cleanser_stats,
            scorer_stats,
            alert_stats,
            duplicate_stats,
            generated_at: Utc::now(),
        }
    }
}

/// Quality report
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QualityReport {
    /// Quality metrics
    pub metrics: QualityMetrics,

    /// Profiler statistics
    pub profiler_stats: ProfileStats,

    /// Cleanser statistics
    pub cleanser_stats: CleansingStats,

    /// Scorer statistics
    pub scorer_stats: ScoringStats,

    /// Alert statistics
    pub alert_stats: AlertStats,

    /// Duplicate statistics
    pub duplicate_stats: DuplicateStats,

    /// Generated at
    pub generated_at: DateTime<Utc>,
}

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

    #[tokio::test]
    async fn test_validator_creation() {
        let config = QualityConfig::default();
        let validator = DataQualityValidator::new(config);
        assert!(validator.is_ok());
    }

    #[tokio::test]
    async fn test_add_validation_rule() {
        let config = QualityConfig::default();
        let mut validator = DataQualityValidator::new(config).unwrap();

        let rule = ValidationRule::NotNull {
            field: "subject".to_string(),
        };

        let result = validator.add_rule(rule).await;
        assert!(result.is_ok());

        let rules = validator.rules.read().await;
        assert_eq!(rules.len(), 1);
    }

    #[tokio::test]
    async fn test_validate_event() {
        let config = QualityConfig::default();
        let validator = DataQualityValidator::new(config).unwrap();

        let event = StreamEvent::Heartbeat {
            timestamp: Utc::now(),
            source: "test".to_string(),
            metadata: EventMetadata::default(),
        };

        let result = validator.validate_event(&event).await;
        assert!(result.is_ok());

        let validation_result = result.unwrap();
        assert!(validation_result.is_valid);
        assert_eq!(validation_result.quality_score, 1.0);
    }

    #[tokio::test]
    async fn test_duplicate_detection() {
        let config = QualityConfig {
            enable_duplicate_detection: true,
            ..Default::default()
        };
        let validator = DataQualityValidator::new(config).unwrap();

        let event = StreamEvent::Heartbeat {
            timestamp: Utc::now(),
            source: "test".to_string(),
            metadata: EventMetadata::default(),
        };

        // First event should not be duplicate
        let result1 = validator.validate_event(&event).await.unwrap();
        assert!(result1.is_valid);

        // Second identical event should be duplicate
        let result2 = validator.validate_event(&event).await.unwrap();
        assert!(!result2.is_valid);
        assert!(!result2.failures.is_empty());
    }

    #[tokio::test]
    async fn test_quality_score_computation() {
        let config = QualityConfig::default();
        let validator = DataQualityValidator::new(config).unwrap();

        let failures = vec![
            ValidationFailure {
                rule: "NotNull".to_string(),
                field: "field1".to_string(),
                reason: "Field is null".to_string(),
                severity: FailureSeverity::Low,
                suggested_fix: None,
            },
            ValidationFailure {
                rule: "Format".to_string(),
                field: "field2".to_string(),
                reason: "Invalid format".to_string(),
                severity: FailureSeverity::High,
                suggested_fix: None,
            },
        ];

        let score = validator.compute_quality_score(&failures).await.unwrap();
        assert!(score < 1.0);
        assert!(score > 0.0);
    }

    #[tokio::test]
    async fn test_metrics_collection() {
        let config = QualityConfig::default();
        let validator = DataQualityValidator::new(config).unwrap();

        let event = StreamEvent::Heartbeat {
            timestamp: Utc::now(),
            source: "test".to_string(),
            metadata: EventMetadata::default(),
        };

        validator.validate_event(&event).await.unwrap();

        let metrics = validator.get_metrics().await;
        assert_eq!(metrics.total_events_validated, 1);
        assert_eq!(metrics.valid_events, 1);
    }

    #[tokio::test]
    async fn test_audit_trail() {
        let config = QualityConfig {
            enable_audit_trail: true,
            ..Default::default()
        };
        let validator = DataQualityValidator::new(config).unwrap();

        let event_id = Uuid::new_v4();
        let failures = vec![];

        validator
            .add_audit_entry(event_id, AuditAction::Validation, &failures)
            .await
            .unwrap();

        let audit = validator.audit_trail.read().await;
        assert_eq!(audit.entries.len(), 1);
        assert_eq!(audit.stats.total_entries, 1);
    }

    #[tokio::test]
    async fn test_quality_report() {
        let config = QualityConfig::default();
        let validator = DataQualityValidator::new(config).unwrap();

        let event = StreamEvent::Heartbeat {
            timestamp: Utc::now(),
            source: "test".to_string(),
            metadata: EventMetadata::default(),
        };

        validator.validate_event(&event).await.unwrap();

        let report = validator.get_quality_report().await;
        assert_eq!(report.metrics.total_events_validated, 1);
    }

    #[tokio::test]
    async fn test_alert_triggering() {
        let config = QualityConfig {
            enable_alerting: true,
            alert_threshold: 0.8,
            ..Default::default()
        };
        let validator = DataQualityValidator::new(config).unwrap();

        let event_id = Uuid::new_v4();
        let quality_score = 0.5; // Below threshold
        let failures = vec![];

        validator
            .trigger_alert(event_id, quality_score, &failures)
            .await
            .unwrap();

        let alert_manager = validator.alert_manager.read().await;
        assert_eq!(alert_manager.alerts.len(), 1);
        assert_eq!(alert_manager.stats.total_alerts, 1);
    }

    #[tokio::test]
    async fn test_multiple_validation_rules() {
        let config = QualityConfig::default();
        let mut validator = DataQualityValidator::new(config).unwrap();

        validator
            .add_rule(ValidationRule::NotNull {
                field: "subject".to_string(),
            })
            .await
            .unwrap();

        validator
            .add_rule(ValidationRule::Format {
                field: "timestamp".to_string(),
                pattern: r"^\d{4}-\d{2}-\d{2}".to_string(),
            })
            .await
            .unwrap();

        let rules = validator.rules.read().await;
        assert_eq!(rules.len(), 2);
    }
}