/// Performance monitoring and optimization system
pub struct PerformanceMonitor {
    /// Active benchmarks
    benchmarks: HashMap<String, BenchmarkSuite>,

    /// Performance metrics storage
    metrics: PerformanceMetrics,

    /// Optimization engine
    optimizer: PerformanceOptimizer,

    /// Configuration
    config: PerformanceConfig,
}

/// Performance configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceConfig {
    /// Enable continuous monitoring
    pub continuous_monitoring: bool,

    /// Benchmark frequency
    pub benchmark_interval: Duration,

    /// Performance thresholds
    pub thresholds: PerformanceThresholds,

    /// Optimization settings
    pub optimization: OptimizationConfig,

    /// Retention settings
    pub retention: RetentionConfig,
}

/// Performance thresholds for alerting
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceThresholds {
    /// Maximum analysis time per file (ms)
    pub max_analysis_time_ms: u64,

    /// Maximum memory usage (MB)
    pub max_memory_mb: u64,

    /// Maximum CPU usage percentage
    pub max_cpu_percent: f64,

    /// Performance regression threshold (%)
    pub regression_threshold_percent: f64,
}

impl Default for PerformanceThresholds {
    fn default() -> Self {
        Self {
            max_analysis_time_ms: 5000,         // 5 seconds
            max_memory_mb: 1024,                // 1 GB
            max_cpu_percent: 80.0,              // 80%
            regression_threshold_percent: 20.0, // 20% slower
        }
    }
}

/// Optimization configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OptimizationConfig {
    /// Enable automatic optimization
    pub auto_optimize: bool,

    /// Optimization strategies to use
    pub strategies: Vec<OptimizationStrategy>,

    /// Minimum improvement threshold for applying optimization
    pub min_improvement_percent: f64,

    /// Enable experimental optimizations
    pub experimental: bool,
}

/// Performance optimization strategies
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum OptimizationStrategy {
    /// Cache frequently analyzed files
    CacheOptimization,

    /// Parallel processing optimization
    ParallelProcessing,

    /// Memory pooling
    MemoryPooling,

    /// Incremental parsing optimization
    IncrementalParsing,

    /// I/O optimization
    IoOptimization,

    /// AST reuse
    AstReuse,
}

/// Data retention configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RetentionConfig {
    /// Keep detailed metrics for this duration
    pub detailed_retention: Duration,

    /// Keep summary metrics for this duration
    pub summary_retention: Duration,

    /// Automatic cleanup enabled
    pub auto_cleanup: bool,
}

impl Default for RetentionConfig {
    fn default() -> Self {
        Self {
            detailed_retention: Duration::from_secs(7 * 24 * 60 * 60), // 7 days
            summary_retention: Duration::from_secs(90 * 24 * 60 * 60), // 90 days
            auto_cleanup: true,
        }
    }
}

/// Performance metrics collector
#[derive(Debug, Clone)]
pub struct PerformanceMetrics {
    /// Time-series data
    timeseries: HashMap<String, Vec<PerformancePoint>>,

    /// Aggregated statistics
    statistics: PerformanceStatistics,

    /// Baseline measurements
    baselines: HashMap<String, Baseline>,
}

/// Single performance measurement
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformancePoint {
    /// Timestamp
    pub timestamp: SystemTime,

    /// Metric name
    pub metric: String,

    /// Measured value
    pub value: f64,

    /// Context metadata
    pub context: HashMap<String, String>,
}

/// Aggregated performance statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceStatistics {
    /// Analysis performance
    pub analysis: AnalysisStats,

    /// Memory usage statistics
    pub memory: MemoryStats,

    /// I/O performance statistics
    pub io: IoStats,

    /// System resource usage
    pub system: SystemStats,
}

/// Analysis performance statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AnalysisStats {
    /// Average analysis time per file (ms)
    pub avg_analysis_time_ms: f64,

    /// Analysis throughput (files/second)
    pub throughput_fps: f64,

    /// Cache hit ratio
    pub cache_hit_ratio: f64,

    /// Parser efficiency
    pub parser_efficiency: f64,
}

/// Memory usage statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MemoryStats {
    /// Peak memory usage (MB)
    pub peak_memory_mb: f64,

    /// Average memory usage (MB)
    pub avg_memory_mb: f64,

    /// Memory growth rate (MB/hour)
    pub growth_rate_mb_per_hour: f64,

    /// Garbage collection impact
    pub gc_impact_percent: f64,
}

/// I/O performance statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IoStats {
    /// File read performance (MB/s)
    pub read_throughput_mbps: f64,

    /// Average file read time (ms)
    pub avg_read_time_ms: f64,

    /// I/O wait time percentage
    pub io_wait_percent: f64,

    /// Cache effectiveness
    pub cache_effectiveness: f64,
}

/// System resource statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SystemStats {
    /// CPU utilization percentage
    pub cpu_percent: f64,

    /// Thread count
    pub thread_count: u32,

    /// System load average
    pub load_average: f64,

    /// Network usage (KB/s)
    pub network_kbps: f64,
}

/// Baseline performance measurement
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Baseline {
    /// Baseline identifier
    pub id: String,

    /// Measured performance values
    pub measurements: HashMap<String, f64>,

    /// Measurement timestamp
    pub measured_at: SystemTime,

    /// Context information
    pub context: BaselineContext,
}

/// Baseline measurement context
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BaselineContext {
    /// System configuration
    pub system_info: SystemInfo,

    /// Codebase characteristics
    pub codebase_info: CodebaseInfo,

    /// Configuration used
    pub config_hash: String,
}

/// System information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SystemInfo {
    /// CPU model
    pub cpu_model: String,

    /// Total memory (MB)
    pub total_memory_mb: u64,

    /// Operating system
    pub os: String,

    /// Rust version
    pub rust_version: String,
}

/// Codebase characteristics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CodebaseInfo {
    /// Total lines of code
    pub total_loc: u64,

    /// Number of files
    pub file_count: u64,

    /// Average complexity
    pub avg_complexity: f64,

    /// Primary language
    pub primary_language: String,
}

/// Benchmark suite definition
#[derive(Debug, Clone)]
pub struct BenchmarkSuite {
    /// Suite name
    pub name: String,

    /// Individual benchmarks
    pub benchmarks: Vec<Benchmark>,

    /// Suite configuration
    pub config: BenchmarkConfig,
}

/// Individual benchmark
#[derive(Debug, Clone)]
pub struct Benchmark {
    /// Benchmark name
    pub name: String,

    /// Benchmark function
    pub benchmark_fn: BenchmarkFn,

    /// Setup function
    pub setup_fn: Option<SetupFn>,

    /// Teardown function
    pub teardown_fn: Option<TeardownFn>,

    /// Expected performance characteristics
    pub expected: ExpectedPerformance,
}

/// Benchmark function type
pub type BenchmarkFn = fn(&BenchmarkContext) -> Result<BenchmarkResult>;
pub type SetupFn = fn() -> Result<BenchmarkContext>;
pub type TeardownFn = fn(BenchmarkContext) -> Result<()>;

/// Benchmark execution context
#[derive(Debug, Clone)]
pub struct BenchmarkContext {
    /// Test data
    pub test_data: HashMap<String, Vec<u8>>,

    /// Temporary directory
    pub temp_dir: PathBuf,

    /// Configuration
    pub config: HashMap<String, String>,
}

/// Benchmark result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BenchmarkResult {
    /// Execution time
    pub execution_time: Duration,

    /// Memory used (bytes)
    pub memory_used: u64,

    /// CPU time
    pub cpu_time: Duration,

    /// Throughput (operations/second)
    pub throughput: f64,

    /// Success indicator
    pub success: bool,

    /// Additional metrics
    pub metrics: HashMap<String, f64>,
}

/// Expected performance characteristics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ExpectedPerformance {
    /// Maximum execution time
    pub max_execution_time: Duration,

    /// Maximum memory usage
    pub max_memory_bytes: u64,

    /// Minimum throughput
    pub min_throughput: f64,

    /// Performance regression threshold
    pub regression_threshold: f64,
}

/// Benchmark configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BenchmarkConfig {
    /// Number of iterations
    pub iterations: u32,

    /// Warmup iterations
    pub warmup_iterations: u32,

    /// Timeout for each benchmark
    pub timeout: Duration,

    /// Parallel execution
    pub parallel: bool,
}

impl Default for BenchmarkConfig {
    fn default() -> Self {
        Self {
            iterations: 100,
            warmup_iterations: 10,
            timeout: Duration::from_secs(60),
            parallel: false,
        }
    }
}

/// Performance optimizer
pub struct PerformanceOptimizer {
    /// Active optimizations
    optimizations: Vec<ActiveOptimization>,

    /// Optimization history
    history: Vec<OptimizationResult>,

    /// Configuration
    config: OptimizationConfig,
}

/// Active optimization
#[derive(Debug, Clone)]
pub struct ActiveOptimization {
    /// Optimization strategy
    pub strategy: OptimizationStrategy,

    /// Target metric
    pub target_metric: String,

    /// Expected improvement
    pub expected_improvement: f64,

    /// Implementation status
    pub status: OptimizationStatus,
}

/// Optimization status
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum OptimizationStatus {
    /// Being analyzed
    Analyzing,

    /// Ready to implement
    Ready,

    /// Currently implementing
    Implementing,

    /// Testing performance impact
    Testing,

    /// Successfully applied
    Applied,

    /// Failed to apply
    Failed(String),

    /// Rolled back due to issues
    RolledBack(String),
}

/// Optimization result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct OptimizationResult {
    /// Applied strategy
    pub strategy: OptimizationStrategy,

    /// Measured improvement
    pub improvement_percent: f64,

    /// Affected metrics
    pub metrics_changed: HashMap<String, f64>,

    /// Application timestamp
    pub applied_at: SystemTime,

    /// Success indicator
    pub success: bool,
}
