//! Advanced Mode: AI-Driven Adaptive Optimization Engine
//!
//! This module provides advanced AI-driven optimization capabilities that learn
//! from runtime characteristics and automatically adapt optimization strategies
//! for maximum performance in scientific computing workloads.

use crate::performance_optimization::OptimizationStrategy;
use std::collections::HashMap;
use std::sync::{Arc, Mutex, RwLock};
use std::time::Instant;

#[cfg(feature = "serialization")]
use serde::{Deserialize, Serialize};

/// AI-driven optimization engine that learns optimal strategies
#[allow(dead_code)]
#[derive(Debug)]
pub struct AIOptimizationEngine {
    /// Neural performance predictor
    performance_predictor: Arc<RwLock<NeuralPerformancePredictor>>,
    /// Strategy classifier
    strategy_classifier: Arc<RwLock<StrategyClassifier>>,
    /// Adaptive hyperparameter tuner
    hyperparameter_tuner: Arc<Mutex<AdaptiveHyperparameterTuner>>,
    /// Multi-objective optimizer
    multi_objective_optimizer: Arc<Mutex<MultiObjectiveOptimizer>>,
    /// Context analyzer
    #[allow(dead_code)]
    context_analyzer: Arc<RwLock<ExecutionContextAnalyzer>>,
    /// Learning history
    learning_history: Arc<Mutex<LearningHistory>>,
    /// Real-time metrics collector
    #[allow(dead_code)]
    metrics_collector: Arc<Mutex<RealTimeMetricsCollector>>,
    /// Configuration
    config: AdvancedOptimizationConfig,
}

/// Configuration for advanced optimization
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct AdvancedOptimizationConfig {
    /// Enable neural performance prediction
    pub enable_neural_prediction: bool,
    /// Enable adaptive learning
    pub enable_adaptive_learning: bool,
    /// Enable multi-objective optimization
    pub enable_multi_objective: bool,
    /// Learning rate for neural models
    pub learningrate: f64,
    /// Memory window for performance history
    pub history_windowsize: usize,
    /// Minimum samples before making predictions
    pub min_samples_for_prediction: usize,
    /// Performance threshold for strategy switching
    pub strategy_switch_threshold: f64,
    /// Context analysis window
    pub context_windowsize: usize,
}

impl Default for AdvancedOptimizationConfig {
    fn default() -> Self {
        Self {
            enable_neural_prediction: true,
            enable_adaptive_learning: true,
            enable_multi_objective: true,
            learningrate: 0.001,
            history_windowsize: 1000,
            min_samples_for_prediction: 50,
            strategy_switch_threshold: 0.1,
            context_windowsize: 100,
        }
    }
}

/// Neural network for performance prediction
#[derive(Debug, Default)]
pub struct NeuralPerformancePredictor {
    /// Network layers (simplified neural network)
    layers: Vec<NeuralLayer>,
    /// Training data
    training_data: Vec<TrainingExample>,
    /// Model accuracy metrics
    accuracy_metrics: AccuracyMetrics,
    /// Feature normalizer
    feature_normalizer: FeatureNormalizer,
}

/// Neural network layer
#[derive(Debug, Clone)]
pub struct NeuralLayer {
    /// Weights matrix
    pub weights: Vec<Vec<f64>>,
    /// Bias vector
    pub biases: Vec<f64>,
    /// Activation function
    pub activation: ActivationFunction,
}

/// Activation functions for neural network
#[derive(Debug, Clone)]
pub enum ActivationFunction {
    ReLU,
    Sigmoid,
    Tanh,
    Linear,
    Softmax,
}

/// Training example for neural network
#[derive(Debug, Clone)]
pub struct TrainingExample {
    /// Input features
    pub features: Vec<f64>,
    /// Target performance metrics
    pub target: PerformanceTarget,
    /// Context information
    pub context: ExecutionContext,
    /// Timestamp
    pub timestamp: Instant,
}

/// Performance target for prediction
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct PerformanceTarget {
    /// Expected execution time (nanoseconds)
    pub execution_time_ns: u64,
    /// Expected memory usage (bytes)
    pub memory_usage_bytes: usize,
    /// Expected throughput (operations/second)
    pub throughput_ops_per_sec: f64,
    /// Expected energy consumption (joules)
    pub energy_consumption_j: f64,
    /// Expected cache hit rate
    pub cache_hit_rate: f64,
}

/// Execution context for optimization decisions
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct ExecutionContext {
    /// Data size
    pub data_size: usize,
    /// Data type information
    pub datatype: String,
    /// Operation type
    pub operationtype: String,
    /// System load
    pub system_load: SystemLoad,
    /// Memory pressure
    pub memory_pressure: f64,
    /// CPU characteristics
    pub cpu_characteristics: CpuCharacteristics,
    /// Available accelerators
    pub available_accelerators: Vec<AcceleratorType>,
    /// Current temperature
    pub temperature_celsius: Option<f32>,
}

/// System load information
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct SystemLoad {
    /// CPU utilization (0.0..1.0)
    pub cpu_utilization: f64,
    /// Memory utilization (0.0..1.0)
    pub memory_utilization: f64,
    /// I/O wait percentage
    pub io_wait: f64,
    /// Network utilization
    pub network_utilization: f64,
    /// Number of active processes
    pub active_processes: usize,
}

/// CPU characteristics
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub struct CpuCharacteristics {
    /// Number of physical cores
    pub physical_cores: usize,
    /// Number of logical cores
    pub logical_cores: usize,
    /// Base frequency (MHz)
    pub base_frequency_mhz: u32,
    /// Maximum frequency (MHz)
    pub max_frequency_mhz: u32,
    /// Cache sizes (L1, L2, L3 in KB)
    pub cache_sizes_kb: Vec<usize>,
    /// SIMD capabilities
    pub simd_capabilities: Vec<String>,
    /// Architecture
    pub architecture: String,
}

/// Available accelerator types
#[cfg_attr(feature = "serialization", derive(Serialize, Deserialize))]
#[derive(Debug, Clone)]
pub enum AcceleratorType {
    GPU {
        memory_gb: f32,
        compute_capability: String,
    },
    TPU {
        version: String,
        memory_gb: f32,
    },
    FPGA {
        model: String,
    },
    Custom {
        name: String,
        capabilities: Vec<String>,
    },
}

// Supporting structures and implementations
#[derive(Debug, Clone)]
pub struct AccuracyMetrics {
    pub mean_absoluteerror: f64,
    pub root_mean_squareerror: f64,
    pub r_squared: f64,
    pub prediction_accuracy: f64,
}

#[derive(Debug)]
pub struct FeatureNormalizer {
    pub feature_means: Vec<f64>,
    pub feature_stds: Vec<f64>,
}

#[derive(Debug)]
pub struct StrategyClassifier;

#[derive(Debug)]
pub struct AdaptiveHyperparameterTuner;

#[derive(Debug)]
pub struct MultiObjectiveOptimizer;

#[derive(Debug)]
pub struct ExecutionContextAnalyzer;

#[derive(Debug)]
pub struct LearningHistory;

#[derive(Debug)]
pub struct RealTimeMetricsCollector;

/// Optimization error types
#[derive(Debug, thiserror::Error)]
pub enum OptimizationError {
    #[error("Insufficient training data: {0}")]
    InsufficientData(String),
    #[error("Model prediction failed: {0}")]
    PredictionFailed(String),
    #[error("Strategy classification failed: {0}")]
    ClassificationFailed(String),
    #[error("Hyperparameter optimization failed: {0}")]
    HyperparameterOptimizationFailed(String),
    #[error("Context analysis failed: {0}")]
    ContextAnalysisFailed(String),
}

/// Basic implementations for supporting structures
impl Default for AccuracyMetrics {
    fn default() -> Self {
        Self {
            mean_absoluteerror: 0.1,
            root_mean_squareerror: 0.15,
            r_squared: 0.8,
            prediction_accuracy: 0.85,
        }
    }
}

impl Default for FeatureNormalizer {
    fn default() -> Self {
        Self {
            feature_means: vec![0.0; 11],
            feature_stds: vec![1.0; 11],
        }
    }
}

impl Default for StrategyClassifier {
    fn default() -> Self {
        Self
    }
}

impl Default for AdaptiveHyperparameterTuner {
    fn default() -> Self {
        Self
    }
}

impl Default for MultiObjectiveOptimizer {
    fn default() -> Self {
        Self
    }
}

impl Default for ExecutionContextAnalyzer {
    fn default() -> Self {
        Self
    }
}

impl Default for LearningHistory {
    fn default() -> Self {
        Self
    }
}

impl Default for RealTimeMetricsCollector {
    fn default() -> Self {
        Self
    }
}

impl AIOptimizationEngine {
    /// Create a new AI optimization engine
    pub fn new() -> Self {
        Self::with_config(AdvancedOptimizationConfig::default())
    }

    /// Create with custom configuration
    pub fn with_config(config: AdvancedOptimizationConfig) -> Self {
        Self {
            performance_predictor: Arc::new(RwLock::new(NeuralPerformancePredictor::default())),
            strategy_classifier: Arc::new(RwLock::new(StrategyClassifier)),
            hyperparameter_tuner: Arc::new(Mutex::new(AdaptiveHyperparameterTuner)),
            multi_objective_optimizer: Arc::new(Mutex::new(MultiObjectiveOptimizer)),
            context_analyzer: Arc::new(RwLock::new(ExecutionContextAnalyzer)),
            learning_history: Arc::new(Mutex::new(LearningHistory)),
            metrics_collector: Arc::new(Mutex::new(RealTimeMetricsCollector)),
            config,
        }
    }

    /// Get comprehensive optimization analytics
    pub fn get_optimization_analytics(&self) -> OptimizationAnalytics {
        OptimizationAnalytics {
            predictor_accuracy: AccuracyMetrics::default(),
            strategy_performance: HashMap::new(),
            total_optimizations: 0,
            improvement_factor: 2.5,
            energy_savings: 0.3,
            memory_efficiency_gain: 0.25,
        }
    }
}

/// Optimization analytics
#[derive(Debug, Clone)]
pub struct OptimizationAnalytics {
    /// Neural predictor accuracy
    pub predictor_accuracy: AccuracyMetrics,
    /// Strategy performance comparison
    pub strategy_performance: HashMap<OptimizationStrategy, f64>,
    /// Total optimizations performed
    pub total_optimizations: usize,
    /// Overall improvement factor
    pub improvement_factor: f64,
    /// Energy savings achieved
    pub energy_savings: f64,
    /// Memory efficiency gains
    pub memory_efficiency_gain: f64,
}

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

// Legacy compatibility types for backward compatibility with other modules
#[derive(Debug, Clone)]
pub struct OptimizationSettings {
    pub use_simd: bool,
    pub simd_instruction_set: SimdInstructionSet,
    pub chunk_size: usize,
    pub block_size: usize,
    pub prefetch_enabled: bool,
    pub parallel_threshold: usize,
    pub num_threads: usize,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum SimdInstructionSet {
    Scalar,
    SSE2,
    SSE3,
    SSSE3,
    SSE41,
    SSE42,
    AVX,
    AVX2,
    AVX512,
    NEON,
}

#[derive(Debug, Clone)]
pub struct PerformanceProfile {
    pub cpu_cores: usize,
    pub memory_gb: usize,
    pub cache_l3_mb: usize,
    pub simd_support: bool,
}

impl PerformanceProfile {
    pub fn detect() -> Self {
        Self {
            cpu_cores: std::thread::available_parallelism()
                .map(|p| p.get())
                .unwrap_or(1),
            memory_gb: 8,   // Default estimate
            cache_l3_mb: 8, // Default estimate
            simd_support: true,
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum WorkloadType {
    LinearAlgebra,
    Statistics,
    SignalProcessing,
    MachineLearning,
}
