//! # Ballista Execution Engine
//!
//! This module provides an implementation of the ExecutionEngine interface using Ballista.

use crate::error::Result;
use crate::distributed::config::DistributedConfig;
use crate::distributed::execution::{ExecutionEngine, ExecutionContext};

/// Ballista execution engine implementation
pub struct BallistaEngine {
    /// Whether the engine is initialized
    initialized: bool,
    /// Cluster configuration
    #[cfg(feature = "distributed")]
    cluster: Option<super::BallistaCluster>,
}

impl BallistaEngine {
    /// Creates a new Ballista engine
    pub fn new() -> Self {
        Self {
            initialized: false,
            #[cfg(feature = "distributed")]
            cluster: None,
        }
    }
}

impl Default for BallistaEngine {
    fn default() -> Self {
        Self::new()
    }
}

impl ExecutionEngine for BallistaEngine {
    fn initialize(&mut self, config: &DistributedConfig) -> Result<()> {
        #[cfg(feature = "distributed")]
        {
            // Check if scheduler is specified
            if let Some(scheduler) = config.option("scheduler") {
                self.cluster = Some(super::BallistaCluster::new(scheduler.clone()));
            }
        }
        
        self.initialized = true;
        Ok(())
    }
    
    fn is_initialized(&self) -> bool {
        self.initialized
    }
    
    fn create_context(&self, _config: &DistributedConfig) -> Result<Box<dyn ExecutionContext>> {
        if !self.initialized {
            return Err(crate::error::Error::InvalidOperation(
                "Engine is not initialized".to_string()
            ));
        }
        
        // Will be implemented in the next phase
        Err(crate::error::Error::NotImplemented("Ballista context creation will be implemented in the next phase".into()))
    }
}