//! DBN Statistical Analysis Example
//!
//! This example demonstrates advanced statistical analysis and data transformation
//! features of the DBN repository.
//!
//! ## Usage
//!
//! ```bash
//! cargo run --example dbn_statistical_analysis
//! ```

use backtesting_service::dbn_repository::DbnMarketDataRepository;
use std::collections::HashMap;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    println!("=== DBN Statistical Analysis Example ===\n");

    // 1. Setup repository
    let mut file_mapping = HashMap::new();
    file_mapping.insert(
        "ES.FUT".to_string(),
        "test_data/real/databento/ES.FUT_ohlcv-1m_2024-01-02.dbn".to_string(),
    );

    let repo = DbnMarketDataRepository::new(file_mapping).await?;

    // 2. Load all data
    println!("Loading data...");
    let symbols = vec!["ES.FUT".to_string()];
    let start_time = 1704153600_000_000_000i64; // 2024-01-02 00:00:00
    let end_time = 1704240000_000_000_000i64; // 2024-01-03 00:00:00

    let bars = repo.load_historical_data(&symbols, start_time, end_time).await?;
    println!("✅ Loaded {} bars\n", bars.len());

    // 3. Summary Statistics
    println!("=== Summary Statistics ===");
    let stats = repo.generate_summary_stats(&bars);

    println!("Count:        {}", stats.get("count").unwrap());
    println!("Mean Close:   ${:.2}", stats.get("mean_close").unwrap());
    println!("Std Close:    ${:.2}", stats.get("std_close").unwrap());
    println!("Min Close:    ${:.2}", stats.get("min_close").unwrap());
    println!("Max Close:    ${:.2}", stats.get("max_close").unwrap());
    println!("Mean Volume:  {:.0}", stats.get("mean_volume").unwrap());
    println!("Total Volume: {:.0}", stats.get("total_volume").unwrap());

    // 4. Rolling Window Statistics
    println!("\n=== Rolling 20-Bar Window Statistics ===");
    let window_size = 20;
    let rolling_stats = repo.calculate_rolling_stats(&bars, window_size);

    println!("Window size: {} bars", window_size);
    println!("Windows calculated: {}", rolling_stats.len());

    // Display last 5 windows
    println!("\nLast 5 windows:");
    for (i, (mean, std, min, max)) in rolling_stats.iter().rev().take(5).enumerate() {
        println!(
            "  Window {}: mean=${:.2}, std=${:.2}, range=[${:.2}, ${:.2}]",
            rolling_stats.len() - i,
            mean,
            std,
            min,
            max
        );
    }

    // 5. Bar Resampling
    println!("\n=== Bar Resampling ===");

    // Resample to different timeframes
    for target_minutes in [5, 15, 60] {
        let resampled = repo.resample_bars(&bars, target_minutes)?;
        let reduction = (1.0 - (resampled.len() as f64 / bars.len() as f64)) * 100.0;

        println!(
            "{:>2}-minute bars: {:>3} bars ({:.1}% reduction)",
            target_minutes,
            resampled.len(),
            reduction
        );

        // Show first resampled bar
        if let Some(first) = resampled.first() {
            println!(
                "    First: {} @ {} | O={} H={} L={} C={} V={}",
                first.symbol,
                first.timestamp.format("%H:%M"),
                first.open,
                first.high,
                first.low,
                first.close,
                first.volume
            );
        }
    }

    // 6. Regime Detection (Simple Heuristic)
    println!("\n=== Regime Detection ===");

    let regime_types = ["trending", "ranging", "volatile", "stable"];
    for regime_type in regime_types.iter() {
        match repo.load_regime_samples(regime_type, 5, &symbols).await {
            Ok(samples) => {
                println!("{:<10} regime: {} sample bars found", regime_type, samples.len());

                if !samples.is_empty() {
                    let sample = &samples[0];
                    let range = sample.high - sample.low;
                    let avg_price = (sample.high + sample.low) / rust_decimal::Decimal::from(2);
                    let range_pct = (range / avg_price * rust_decimal::Decimal::from(10000))
                        .to_string()
                        .parse::<f64>()
                        .unwrap()
                        / 100.0;

                    println!("    Example: {} @ {} (range: {:.2}%)", sample.symbol, sample.timestamp, range_pct);
                }
            }
            Err(e) => {
                println!("{:<10} regime: Error - {}", regime_type, e);
            }
        }
    }

    // 7. Price Return Analysis
    println!("\n=== Price Return Analysis ===");

    let mut returns: Vec<f64> = Vec::new();
    for i in 1..bars.len() {
        let prev_close = bars[i - 1].close.to_string().parse::<f64>().unwrap();
        let curr_close = bars[i].close.to_string().parse::<f64>().unwrap();
        let ret = (curr_close - prev_close) / prev_close;
        returns.push(ret);
    }

    let mean_return = returns.iter().sum::<f64>() / returns.len() as f64;
    let variance = returns
        .iter()
        .map(|r| (r - mean_return).powi(2))
        .sum::<f64>()
        / returns.len() as f64;
    let std_dev = variance.sqrt();

    println!("Mean return:      {:.6} ({:.4}%)", mean_return, mean_return * 100.0);
    println!("Std dev:          {:.6} ({:.4}%)", std_dev, std_dev * 100.0);
    println!(
        "Min return:       {:.6} ({:.4}%)",
        returns.iter().cloned().fold(f64::INFINITY, f64::min),
        returns.iter().cloned().fold(f64::INFINITY, f64::min) * 100.0
    );
    println!(
        "Max return:       {:.6} ({:.4}%)",
        returns.iter().cloned().fold(f64::NEG_INFINITY, f64::max),
        returns.iter().cloned().fold(f64::NEG_INFINITY, f64::max) * 100.0
    );

    // Sharpe ratio (annualized, assuming 252 trading days)
    let sharpe = (mean_return / std_dev) * (252.0 * 390.0_f64).sqrt(); // 390 bars per day
    println!("Sharpe ratio:     {:.2}", sharpe);

    // 8. Volume Analysis
    println!("\n=== Volume Analysis ===");

    let volumes: Vec<f64> = bars
        .iter()
        .map(|b| b.volume.to_string().parse().unwrap())
        .collect();

    let mean_volume = volumes.iter().sum::<f64>() / volumes.len() as f64;
    let max_volume = volumes.iter().cloned().fold(f64::NEG_INFINITY, f64::max);
    let min_volume = volumes.iter().cloned().fold(f64::INFINITY, f64::min);

    println!("Mean volume: {:.0}", mean_volume);
    println!("Max volume:  {:.0}", max_volume);
    println!("Min volume:  {:.0}", min_volume);

    // Find high-volume bars
    let high_volume_threshold = mean_volume * 2.0;
    let high_volume_bars: Vec<_> = bars
        .iter()
        .filter(|b| b.volume.to_string().parse::<f64>().unwrap() > high_volume_threshold)
        .collect();

    println!("\nHigh-volume bars (>2x mean): {}", high_volume_bars.len());
    for bar in high_volume_bars.iter().take(3) {
        println!(
            "  {} @ {} | Volume: {}",
            bar.symbol, bar.timestamp, bar.volume
        );
    }

    println!("\n✅ Example completed successfully!");

    Ok(())
}