#![warn(missing_docs)]
#![deny(clippy::unwrap_used)]
#![deny(clippy::expect_used)]

//! # Foxhunt Backtesting Service
//!
//! Standalone backtesting service for the Foxhunt HFT trading system.
//! This service provides comprehensive strategy testing and performance analysis capabilities.

use anyhow::{Context, Result};
use std::net::SocketAddr;
use tonic::transport::Server;
use tracing::{info, warn};
use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};

mod model_loader_stub;
mod performance;
mod repositories;
mod repository_impl;
mod service;
mod storage;
mod strategy_engine;

// Import the generated gRPC code
mod foxhunt {
    pub mod tli {
        tonic::include_proto!("foxhunt.tli");
    }
}

use config::structures::BacktestingDatabaseConfig;
use model_loader_stub::backtesting_cache::{BacktestCacheConfig, BacktestingModelCache};
use repository_impl::create_repositories;
use service::BacktestingServiceImpl;
use std::sync::Arc;
use storage::StorageManager;

/// Main entry point for the backtesting service
#[tokio::main]
async fn main() -> Result<()> {
    // Initialize logging
    init_logging()?;

    info!("Starting Foxhunt Backtesting Service");

    // Get database configuration from environment
    let database_url =
        std::env::var("DATABASE_URL").context("DATABASE_URL environment variable is required")?;

    // Wave 67 Agent 2: Optimized database configuration for backtesting workloads
    // Based on Wave 66 Agent 8 analysis - increased statement cache for better performance
    let database_config = BacktestingDatabaseConfig {
        database_url,
        max_connections: Some(10),
        min_connections: Some(2),
        acquire_timeout_ms: Some(5000),
        statement_cache_capacity: Some(500),  // Increased from 100 to 500 for better cache hit rate
        enable_logging: Some(false),
    };

    // Configuration loaded from environment
    info!("Configuration loaded from environment variables");

    info!("Backtesting configuration loaded successfully");

    // Initialize storage manager
    let storage_manager = Arc::new(
        StorageManager::new(&database_config)
            .await
            .context("Failed to initialize storage manager")?,
    );

    // Initialize model cache for backtesting with shared directory
    let cache_config = BacktestCacheConfig {
        cache_dir: std::env::var("MODEL_CACHE_DIR")
            .unwrap_or_else(|_| "/tmp/foxhunt/model_cache".to_string())
            .into(),
        ..Default::default()
    };

    let mut model_cache = BacktestingModelCache::new(cache_config)
        .await
        .context("Failed to create BacktestingModelCache for backtesting")?;

    // Initialize model cache - this will scan for existing models
    model_cache
        .initialize()
        .await
        .context("Failed to initialize ModelCache")?;

    let model_cache = Arc::new(model_cache);
    info!("Backtesting model cache initialized with historical version support");

    // Create repositories with dependency injection
    let repositories = Arc::new(
        create_repositories(storage_manager)
            .await
            .context("Failed to create repositories")?,
    );

    // Initialize the service with repository injection and model cache
    let service = BacktestingServiceImpl::new(repositories, Some(Arc::clone(&model_cache)))
        .await
        .context("Failed to initialize backtesting service")?;

    // Setup gRPC server
    let grpc_port = std::env::var("GRPC_PORT")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(50052);
    let addr: SocketAddr = format!("0.0.0.0:{}", grpc_port)
        .parse()
        .context("Invalid server address in configuration")?;

    info!("Starting gRPC server on {}", addr);

    // Wave 67 Agent 3: HTTP/2 streaming performance optimizations
    // Apply same optimizations as other services for consistency
    let enable_http2_opts = std::env::var("ENABLE_HTTP2_OPTIMIZATIONS")
        .ok()
        .and_then(|v| v.parse().ok())
        .unwrap_or(true);

    if enable_http2_opts {
        info!("✅ HTTP/2 optimizations enabled:");
        info!("   - tcp_nodelay: true (-40ms Nagle delay)");
        info!("   - Stream window: 1MB");
        info!("   - Connection window: 10MB");
        info!("   - Adaptive window: true");
        info!("   - Max streams: 1000");
    } else {
        info!("⚠️  HTTP/2 optimizations disabled via feature flag");
    }

    // Start the server with HTTP/2 optimizations
    let mut server_builder = Server::builder();

    if enable_http2_opts {
        server_builder = server_builder
            .tcp_nodelay(true)  // Critical: eliminates 40ms Nagle delay
            .http2_keepalive_interval(Some(std::time::Duration::from_secs(30)))
            .http2_keepalive_timeout(Some(std::time::Duration::from_secs(10)))
            .initial_stream_window_size(Some(1024 * 1024))  // 1MB
            .initial_connection_window_size(Some(10 * 1024 * 1024))  // 10MB
            .http2_adaptive_window(Some(true))
            .max_concurrent_streams(Some(1000));
    }

    server_builder
        .add_service(
            foxhunt::tli::backtesting_service_server::BacktestingServiceServer::new(service),
        )
        .serve(addr)
        .await
        .context("gRPC server failed")?;

    Ok(())
}

/// Initialize logging with structured output
fn init_logging() -> Result<()> {
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::EnvFilter::try_from_default_env()
                .unwrap_or_else(|_| "backtesting_service=info,tower=warn".into()),
        )
        .with(tracing_subscriber::fmt::layer())
        .try_init()
        .context("Failed to initialize logging")?;

    Ok(())
}