use std::sync::Arc;
use tokio::sync::{Mutex, MutexGuard};
use tokio::time::{timeout, Duration};

/// Provides a 30 second timeout for lock attempts
const LOCK_TIMEOUT: u64 = 30;

#[derive(Clone)]
pub struct Shard<T> {
    pub data: Arc<Mutex<T>>,
}

impl<T> Shard<T> {
    pub fn new(data: T) -> Self {
        Shard {
            data: Arc::new(Mutex::new(data)),
        }
    }

    /// Acquire lock
    ///
    /// Using:
    /// ```
    /// {
    ///    let data = shared.lock().await;
    ///    // make changes to T
    /// }
    /// ```
    pub async fn lock(&self) -> MutexGuard<'_, T> {
        let result = timeout(Duration::from_secs(LOCK_TIMEOUT), self.data.lock()).await;
        if let Ok(guard) = result {
            return guard;
        }
        panic!(
            "Failed to acquire lock in {} seconds.  Deadlock?",
            LOCK_TIMEOUT
        );

        // self.data.lock().await
    }
}