quantrs2-device 0.1.3

//! Quantum Error Correction Type Definitions
//!
//! This module defines the core types used in quantum error correction:
//! - Pauli operators and stabilizer groups
//! - Syndrome patterns and detection results
//! - Correction operations and error models
//! - Performance tracking and adaptive systems

use std::collections::HashMap;
use std::time::{Duration, SystemTime};

use quantrs2_core::qubit::QubitId;
use serde::{Deserialize, Serialize};

use crate::DeviceError;

use super::QECResult;

/// Stabilizer group definition for quantum error correction codes
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StabilizerGroup {
    pub operators: Vec<PauliOperator>,
    pub qubits: Vec<QubitId>,
    pub stabilizer_type: StabilizerType,
    pub weight: usize,
}

/// Type of stabilizer (X or Z)
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum StabilizerType {
    XStabilizer,
    ZStabilizer,
}

/// Pauli operator enumeration
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum PauliOperator {
    I,
    X,
    Y,
    Z,
}

/// Logical operator for encoded quantum information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LogicalOperator {
    pub operators: Vec<PauliOperator>,
    pub operator_type: LogicalOperatorType,
}

/// Type of logical operator
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum LogicalOperatorType {
    LogicalX,
    LogicalZ,
}

/// Result of syndrome detection
#[derive(Debug, Clone)]
pub struct SyndromeResult {
    pub syndrome: Vec<bool>,
    pub confidence: f64,
}

/// Type of syndrome indicating error type
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum SyndromeType {
    XError,
    ZError,
    YError,
}

/// Complete syndrome pattern with metadata
#[derive(Debug, Clone)]
pub struct SyndromePattern {
    pub timestamp: SystemTime,
    pub syndrome_bits: Vec<bool>,
    pub error_locations: Vec<usize>,
    pub correction_applied: Vec<String>,
    pub success_probability: f64,
    pub execution_context: ExecutionContext,
    pub syndrome_type: SyndromeType,
    pub confidence: f64,
    pub stabilizer_violations: Vec<i32>,
    pub spatial_location: (usize, usize),
}

/// Execution context for quantum operations
#[derive(Debug, Clone)]
pub struct ExecutionContext {
    pub device_id: String,
    pub timestamp: SystemTime,
    pub circuit_depth: usize,
    pub qubit_count: usize,
    pub gate_sequence: Vec<String>,
    pub environmental_conditions: HashMap<String, f64>,
    pub device_state: DeviceState,
}

/// Device state information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DeviceState {
    pub temperature: f64,
    pub magnetic_field: f64,
    pub coherence_times: HashMap<usize, f64>,
    pub gate_fidelities: HashMap<String, f64>,
    pub readout_fidelities: HashMap<usize, f64>,
}

/// Type of correction operation
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum CorrectionType {
    PauliX,
    PauliY,
    PauliZ,
    Identity,
}

/// Correction operation to apply
#[derive(Debug, Clone)]
pub struct CorrectionOperation {
    pub operation_type: CorrectionType,
    pub target_qubits: Vec<QubitId>,
    pub confidence: f64,
    pub estimated_fidelity: f64,
}

/// QEC performance metrics for monitoring
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QECPerformanceMetrics {
    pub logical_error_rate: f64,
    pub syndrome_detection_rate: f64,
    pub correction_success_rate: f64,
    pub average_correction_time: Duration,
    pub resource_overhead: f64,
    pub throughput_impact: f64,
    pub total_correction_cycles: usize,
    pub successful_corrections: usize,
}

/// Adaptive QEC system for dynamic threshold adjustment
pub struct AdaptiveQECSystem {
    config: super::adaptive::AdaptiveQECConfig,
    current_threshold: f64,
    current_strategy: super::QECStrategy,
}

impl AdaptiveQECSystem {
    pub const fn new(config: super::adaptive::AdaptiveQECConfig) -> Self {
        Self {
            config,
            current_threshold: 0.95,
            current_strategy: super::QECStrategy::ActiveCorrection,
        }
    }

    pub const fn update_thresholds(&mut self, _performance_data: &[f64]) {
        // Implementation provided by adaptive module
    }

    pub const fn adapt_strategy(&mut self, _error_rates: &[f64]) {
        // Implementation provided by adaptive module
    }

    pub const fn get_current_threshold(&self) -> f64 {
        self.current_threshold
    }

    pub const fn update_performance(&mut self, _metrics: &QECPerformanceMetrics) {
        self.current_threshold = 0.90;
    }

    pub fn get_current_strategy(&self) -> super::QECStrategy {
        self.current_strategy.clone()
    }

    pub fn evaluate_strategies(&mut self, strategy_performance: &HashMap<super::QECStrategy, f64>) {
        if let Some((best_strategy, _)) = strategy_performance
            .iter()
            .max_by(|a, b| a.1.partial_cmp(b.1).unwrap_or(std::cmp::Ordering::Equal))
        {
            self.current_strategy = best_strategy.clone();
        }
    }
}

/// Performance tracker for QEC operations
pub struct QECPerformanceTracker {
    metrics: HashMap<String, f64>,
    metrics_history: Vec<QECPerformanceMetrics>,
}

impl QECPerformanceTracker {
    pub fn new() -> Self {
        Self {
            metrics: HashMap::new(),
            metrics_history: Vec::new(),
        }
    }

    pub const fn record_correction(&mut self, _correction_type: CorrectionType, _success: bool) {
        // Record correction for statistics
    }

    pub const fn get_success_rate(&self) -> f64 {
        0.95
    }

    pub fn update_metrics(&mut self, metrics: QECPerformanceMetrics) {
        self.metrics_history.push(metrics);
    }

    pub const fn get_metrics_history(&self) -> &Vec<QECPerformanceMetrics> {
        &self.metrics_history
    }

    pub const fn analyze_trends(&self) -> TrendAnalysis {
        TrendAnalysis {
            error_rate_trend: Some(0.1),
            detection_rate_trend: Some(-0.05),
        }
    }
}

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

/// Trend analysis results
#[derive(Debug, Clone)]
pub struct TrendAnalysis {
    pub error_rate_trend: Option<f64>,
    pub detection_rate_trend: Option<f64>,
}

/// Error model for QEC testing
#[derive(Debug, Clone)]
pub enum ErrorModel {
    Depolarizing {
        rate: f64,
    },
    AmplitudeDamping {
        rate: f64,
    },
    PhaseDamping {
        rate: f64,
    },
    Correlated {
        single_qubit_rate: f64,
        two_qubit_rate: f64,
        correlation_length: f64,
    },
}

impl ErrorModel {
    pub const fn apply_to_qubits(&self, _qubits: &[QubitId]) -> QECResult<()> {
        Ok(())
    }
}