#![cfg_attr(coverage_nightly, coverage(off))]
//! Event system for quality monitoring

use crate::unified_quality::metrics::Metrics;
use serde::{Deserialize, Serialize};
use std::path::PathBuf;

/// Quality events for notifications and tracking
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum QualityEvent {
    /// File added to monitoring
    FileAdded { path: PathBuf, metrics: Metrics },

    /// File removed from monitoring
    FileRemoved {
        path: PathBuf,
        last_metrics: Metrics,
    },

    /// Metrics updated for a file
    MetricsUpdated {
        path: PathBuf,
        old_metrics: Metrics,
        new_metrics: Metrics,
    },

    /// Quality threshold violated
    ThresholdViolated {
        path: PathBuf,
        violation: ThresholdViolation,
    },

    /// Quality improved significantly
    QualityImproved {
        path: PathBuf,
        old_score: f64,
        new_score: f64,
    },

    /// Quality degraded significantly
    QualityDegraded {
        path: PathBuf,
        old_score: f64,
        new_score: f64,
    },

    /// Batch analysis completed
    BatchAnalysisComplete {
        files_analyzed: usize,
        violations_found: usize,
        avg_quality_score: f64,
    },
}

/// Threshold violation details
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ThresholdViolation {
    pub metric: String,
    pub value: f64,
    pub threshold: f64,
    pub severity: ViolationSeverity,
}

/// Violation severity levels
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ViolationSeverity {
    Warning,
    Error,
    Critical,
}

impl QualityEvent {
    /// Check if event is a violation
    #[must_use]
    #[provable_contracts_macros::contract("pmat-core.yaml", equation = "check_compliance")]
    pub fn is_violation(&self) -> bool {
        matches!(
            self,
            QualityEvent::ThresholdViolated { .. } | QualityEvent::QualityDegraded { .. }
        )
    }

    /// Check if event is an improvement
    #[must_use]
    #[provable_contracts_macros::contract("pmat-core.yaml", equation = "check_compliance")]
    pub fn is_improvement(&self) -> bool {
        matches!(self, QualityEvent::QualityImproved { .. })
    }

    /// Get event severity
    #[must_use]
    #[provable_contracts_macros::contract("pmat-core.yaml", equation = "check_compliance")]
    pub fn severity(&self) -> Option<ViolationSeverity> {
        match self {
            QualityEvent::ThresholdViolated { violation, .. } => Some(violation.severity.clone()),
            QualityEvent::QualityDegraded {
                old_score,
                new_score,
                ..
            } => {
                let delta = old_score - new_score;
                if delta > 0.3 {
                    Some(ViolationSeverity::Critical)
                } else if delta > 0.1 {
                    Some(ViolationSeverity::Error)
                } else {
                    Some(ViolationSeverity::Warning)
                }
            }
            _ => None,
        }
    }
}

#[cfg_attr(coverage_nightly, coverage(off))]
#[cfg(test)]
mod tests {
    use super::*;
    #[allow(unused_imports)]
    use std::time::SystemTime;

    #[test]
    fn test_event_is_violation() {
        let event = QualityEvent::ThresholdViolated {
            path: PathBuf::from("test.rs"),
            violation: ThresholdViolation {
                metric: "complexity".to_string(),
                value: 25.0,
                threshold: 20.0,
                severity: ViolationSeverity::Error,
            },
        };

        assert!(event.is_violation());
        assert!(!event.is_improvement());
    }

    #[test]
    fn test_event_severity() {
        let event = QualityEvent::QualityDegraded {
            path: PathBuf::from("test.rs"),
            old_score: 0.9,
            new_score: 0.5,
        };

        match event.severity() {
            Some(ViolationSeverity::Critical) => (),
            _ => panic!("Expected critical severity"),
        }
    }

    #[test]
    fn test_event_is_improvement() {
        let event = QualityEvent::QualityImproved {
            path: PathBuf::from("test.rs"),
            old_score: 0.5,
            new_score: 0.9,
        };

        assert!(event.is_improvement());
        assert!(!event.is_violation());
    }

    #[test]
    fn test_file_added_event() {
        let event = QualityEvent::FileAdded {
            path: PathBuf::from("new_file.rs"),
            metrics: Metrics::default(),
        };

        assert!(!event.is_violation());
        assert!(!event.is_improvement());
        assert!(event.severity().is_none());
    }

    #[test]
    fn test_file_removed_event() {
        let event = QualityEvent::FileRemoved {
            path: PathBuf::from("old_file.rs"),
            last_metrics: Metrics::default(),
        };

        assert!(!event.is_violation());
        assert!(!event.is_improvement());
    }

    #[test]
    fn test_metrics_updated_event() {
        let event = QualityEvent::MetricsUpdated {
            path: PathBuf::from("file.rs"),
            old_metrics: Metrics::default(),
            new_metrics: Metrics::default(),
        };

        assert!(!event.is_violation());
        assert!(!event.is_improvement());
    }

    #[test]
    fn test_batch_analysis_complete_event() {
        let event = QualityEvent::BatchAnalysisComplete {
            files_analyzed: 100,
            violations_found: 5,
            avg_quality_score: 0.85,
        };

        assert!(!event.is_violation());
        assert!(!event.is_improvement());
        assert!(event.severity().is_none());
    }

    #[test]
    fn test_quality_degraded_severity_error() {
        let event = QualityEvent::QualityDegraded {
            path: PathBuf::from("test.rs"),
            old_score: 0.8,
            new_score: 0.6, // Delta of 0.2, should be Error
        };

        match event.severity() {
            Some(ViolationSeverity::Error) => (),
            _ => panic!("Expected error severity"),
        }
    }

    #[test]
    fn test_quality_degraded_severity_warning() {
        let event = QualityEvent::QualityDegraded {
            path: PathBuf::from("test.rs"),
            old_score: 0.8,
            new_score: 0.75, // Delta of 0.05, should be Warning
        };

        match event.severity() {
            Some(ViolationSeverity::Warning) => (),
            _ => panic!("Expected warning severity"),
        }
    }

    #[test]
    fn test_threshold_violation_creation() {
        let violation = ThresholdViolation {
            metric: "complexity".to_string(),
            value: 25.0,
            threshold: 20.0,
            severity: ViolationSeverity::Error,
        };

        assert_eq!(violation.metric, "complexity");
        assert_eq!(violation.value, 25.0);
        assert_eq!(violation.threshold, 20.0);
    }

    #[test]
    fn test_violation_severity_variants() {
        let warning = ViolationSeverity::Warning;
        let error = ViolationSeverity::Error;
        let critical = ViolationSeverity::Critical;

        assert!(matches!(warning, ViolationSeverity::Warning));
        assert!(matches!(error, ViolationSeverity::Error));
        assert!(matches!(critical, ViolationSeverity::Critical));
    }

    #[test]
    fn test_quality_degraded_is_violation() {
        let event = QualityEvent::QualityDegraded {
            path: PathBuf::from("test.rs"),
            old_score: 0.9,
            new_score: 0.7,
        };

        assert!(event.is_violation());
    }

    #[test]
    fn test_event_threshold_violated_severity() {
        let event = QualityEvent::ThresholdViolated {
            path: PathBuf::from("test.rs"),
            violation: ThresholdViolation {
                metric: "lines_of_code".to_string(),
                value: 1000.0,
                threshold: 500.0,
                severity: ViolationSeverity::Warning,
            },
        };

        match event.severity() {
            Some(ViolationSeverity::Warning) => (),
            _ => panic!("Expected warning severity from threshold violation"),
        }
    }
}
