use anyhow::{Context, Result};
use clap::Parser;
use redis::AsyncCommands;
use tokio::time::{interval, Duration};
use tracing::{info, warn, error};

#[derive(Parser, Debug)]
#[command(author, version, about, long_about = None)]
struct Args {
    /// Network interface to attach XDP program
    #[arg(short, long, default_value = "eth0")]
    interface: String,

    /// Redis connection URL
    #[arg(short, long, default_value = "redis://127.0.0.1/")]
    redis_url: String,

    /// Stats sync interval in seconds
    #[arg(short, long, default_value = "1")]
    sync_interval: u64,
}

#[tokio::main]
async fn main() -> Result<()> {
    // Initialize tracing
    tracing_subscriber::fmt()
        .with_target(false)
        .compact()
        .init();

    dotenv::dotenv().ok();
    let args = Args::parse();

    info!("Starting Packet Gateway");
    info!("Interface: {}", args.interface);
    info!("Redis URL: {}", args.redis_url);

    // NOTE: This is a simplified version
    // For full eBPF implementation, you need:
    // 1. Compile eBPF program with aya-bpf
    // 2. Load and attach XDP program
    // 3. Access eBPF maps for packet stats and credit control
    
    // Connect to Redis
    let redis_client = redis::Client::open(args.redis_url.as_str())?;
    let mut redis_conn = redis_client.get_multiplexed_async_connection().await?;
    
    // Test connection
    let _: () = redis::cmd("PING").query_async(&mut redis_conn).await?;
    info!("Connected to Redis successfully");

    // Simulate packet processing loop
    // In production, this would read from eBPF maps
    let mut ticker = interval(Duration::from_secs(args.sync_interval));
    
    info!("Packet gateway running. Press Ctrl+C to exit.");
    
    loop {
        ticker.tick().await;
        
        // Simulate updating packet statistics to Redis
        // In real implementation, read from eBPF map
        let test_ip = "10.0.0.1";
        let test_bytes: u64 = 1024 * 1024; // 1 MB
        
        let key = format!("usage:{}", test_ip);
        let _: () = redis_conn.set_ex(&key, test_bytes, 3600).await?;
        
        info!("Updated usage for {}: {} bytes", test_ip, test_bytes);
        
        // Check credit status
        let credit_key = format!("credit:{}", test_ip);
        let credit: i64 = redis_conn.get(&credit_key).await.unwrap_or(0);
        
        if credit <= 0 {
            warn!("User {} has no credit - would block traffic in eBPF", test_ip);
        }
    }
}