// src/corporate/aggregation.rs
use super::types::CompanyPrice;
use super::storage::*;
use crate::util::directories::DataPaths;
use tokio::fs;
use std::collections::HashMap;

#[derive(Debug)]
struct DayData {
    sources: Vec<(CompanyPrice, String)>, // (price, source_ticker)
    total_volume: u64,
    vwap: f64,
    open: f64,
    high: f64,
    low: f64,
    close: f64,
}

/// Aggregate price data from multiple exchanges, converting all to USD
pub async fn aggregate_best_price_data(paths: &DataPaths, lei: &str) -> anyhow::Result<()> {
    let company_dir = get_company_dir(paths, lei);

    for timeframe in ["daily", "5min"].iter() {
        let source_dir = company_dir.join(timeframe);
        if !source_dir.exists() {
            continue;
        }

        let mut all_prices: Vec<(CompanyPrice, String)> = Vec::new();
        let mut by_date_time: HashMap<String, DayData> = HashMap::new();

        // Load all sources with their ticker names
        let mut entries = tokio::fs::read_dir(&source_dir).await?;
        let mut source_count = 0;
        let mut sources_used = std::collections::HashSet::new();
        
        while let Some(entry) = entries.next_entry().await? {
            let source_dir_path = entry.path();
            if !source_dir_path.is_dir() { continue; }
            
            let source_ticker = source_dir_path
                .file_name()
                .and_then(|n| n.to_str())
                .unwrap_or("unknown")
                .to_string();
            
            let prices_path = source_dir_path.join("prices.json");
            if !prices_path.exists() { continue; }

            let content = tokio::fs::read_to_string(&prices_path).await?;
            let mut prices: Vec<CompanyPrice> = serde_json::from_str(&content)?;
            
            if !prices.is_empty() {
                sources_used.insert(source_ticker.clone());
                source_count += 1;
            }
            
            for price in prices {
                all_prices.push((price, source_ticker.clone()));
            }
        }

        if all_prices.is_empty() {
            continue;
        }

        println!("    Aggregating from {} exchanges: {}", 
            sources_used.len(),
            sources_used.iter()
                .map(|s| s.as_str())
                .collect::<Vec<_>>()
                .join(", ")
        );

        // Group by date + time (for 5min) or just date
        for (p, source) in all_prices {
            let key = if timeframe == &"5min" && !p.time.is_empty() {
                format!("{}_{}", p.date, p.time)
            } else {
                p.date.clone()
            };

            // Convert to USD immediately
            let usd_rate = super::fx::get_usd_rate(&p.currency).await.unwrap_or(1.0);
            
            let mut p_usd = p.clone();
            p_usd.open *= usd_rate;
            p_usd.high *= usd_rate;
            p_usd.low *= usd_rate;
            p_usd.close *= usd_rate;
            p_usd.adj_close *= usd_rate;
            p_usd.currency = "USD".to_string();

            let entry = by_date_time.entry(key.clone()).or_insert(DayData {
                sources: vec![],
                total_volume: 0,
                vwap: 0.0,
                open: p_usd.open,
                high: p_usd.high,
                low: p_usd.low,
                close: p_usd.close,
            });

            let volume = p.volume.max(1); // avoid div0
            let vwap_contrib = p_usd.close * volume as f64;

            entry.sources.push((p_usd.clone(), source));
            entry.total_volume += volume;
            entry.vwap += vwap_contrib;

            // Use first open, last close, max high, min low
            if entry.sources.len() == 1 {
                entry.open = p_usd.open;
            }
            entry.close = p_usd.close;
            entry.high = entry.high.max(p_usd.high);
            entry.low = entry.low.min(p_usd.low);
        }

        // Finalize aggregated data
        let mut aggregated: Vec<CompanyPrice> = Vec::new();

        for (key, data) in by_date_time {
            let vwap = data.vwap / data.total_volume as f64;

            let (date, time) = if key.contains('_') {
                let parts: Vec<&str> = key.split('_').collect();
                (parts[0].to_string(), parts[1].to_string())
            } else {
                (key, "".to_string())
            };

            // Track which exchange contributed most volume
            let best_source = data.sources.iter()
                .max_by_key(|(p, _)| p.volume)
                .map(|(_, src)| src.clone())
                .unwrap_or_else(|| "unknown".to_string());

            aggregated.push(CompanyPrice {
                ticker: format!("{lei}@agg"), // Mark as aggregated
                date,
                time,
                open: data.open,
                high: data.high,
                low: data.low,
                close: data.close,
                adj_close: vwap,
                volume: data.total_volume,
                currency: "USD".to_string(),
            });
        }

        aggregated.sort_by_key(|p| (p.date.clone(), p.time.clone()));

        // Save aggregated result
        let agg_dir = company_dir.join("aggregated").join(timeframe);
        fs::create_dir_all(&agg_dir).await?;
        let path = agg_dir.join("prices.json");
        fs::write(&path, serde_json::to_string_pretty(&aggregated)?).await?;
        
        // Save aggregation metadata
        let meta = AggregationMetadata {
            lei: lei.to_string(),  // ← CHANGE THIS
            timeframe: timeframe.to_string(),
            sources: sources_used.into_iter().collect(),
            total_bars: aggregated.len(),
            date_range: (
                aggregated.first().map(|p| p.date.clone()).unwrap_or_default(),
                aggregated.last().map(|p| p.date.clone()).unwrap_or_default(),
            ),
            aggregated_at: chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string(),
        };
                
        let meta_path = agg_dir.join("metadata.json");
        fs::write(&meta_path, serde_json::to_string_pretty(&meta)?).await?;
        
        println!("    ✓ {} {} bars from {} sources (USD)", 
            aggregated.len(), 
            timeframe,
            source_count
        );
    }

    Ok(())
}

#[derive(Debug, serde::Serialize, serde::Deserialize)]
struct AggregationMetadata {
    lei: String,
    timeframe: String,
    sources: Vec<String>,
    total_bars: usize,
    date_range: (String, String),
    aggregated_at: String,
}