//! Basic DBN Loading Example
//!
//! This example demonstrates the simplest way to load OHLCV bars from a DBN file.
//!
//! ## Usage
//!
//! ```bash
//! cargo run --example dbn_basic_loading
//! ```

use backtesting_service::dbn_data_source::DbnDataSource;
use std::collections::HashMap;

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

    // 1. Create file mapping (symbol -> file path)
    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(),
    );

    println!("Creating data source with 1 symbol...");

    // 2. Create data source
    let data_source = DbnDataSource::new(file_mapping).await?;

    println!("Available symbols: {:?}", data_source.available_symbols());

    // 3. Load OHLCV bars
    println!("\nLoading OHLCV bars for ES.FUT...");
    let bars = data_source.load_ohlcv_bars("ES.FUT").await?;

    println!("✅ Loaded {} bars from DBN file\n", bars.len());

    // 4. Display first and last bars
    println!("First bar:");
    let first = &bars[0];
    println!(
        "  {} @ {} (open={}, high={}, low={}, close={}, volume={})",
        first.symbol,
        first.timestamp,
        first.open,
        first.high,
        first.low,
        first.close,
        first.volume
    );

    println!("\nLast bar:");
    let last = &bars[bars.len() - 1];
    println!(
        "  {} @ {} (open={}, high={}, low={}, close={}, volume={})",
        last.symbol,
        last.timestamp,
        last.open,
        last.high,
        last.low,
        last.close,
        last.volume
    );

    // 5. Validate data quality
    println!("\n=== Data Quality Checks ===");

    // Check OHLCV relationships
    let mut valid_count = 0;
    for bar in &bars {
        if bar.high >= bar.low
            && bar.high >= bar.open
            && bar.high >= bar.close
            && bar.low <= bar.open
            && bar.low <= bar.close
        {
            valid_count += 1;
        }
    }

    println!("OHLCV validation: {}/{} bars passed", valid_count, bars.len());

    // Check timestamp ordering
    let mut ordered = true;
    for i in 1..bars.len() {
        if bars[i].timestamp < bars[i - 1].timestamp {
            ordered = false;
            break;
        }
    }

    println!("Timestamp ordering: {}", if ordered { "✅ Sorted" } else { "❌ Not sorted" });

    // Check price ranges (ES.FUT typical: $3,000-$6,000)
    let mut realistic_prices = 0;
    for bar in &bars {
        let close_f64 = bar.close.to_string().parse::<f64>().unwrap();
        if close_f64 > 3000.0 && close_f64 < 6000.0 {
            realistic_prices += 1;
        }
    }

    println!(
        "Realistic prices: {}/{} bars in range",
        realistic_prices,
        bars.len()
    );

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

    Ok(())
}