//! Configuration for elastic training.

use serde::{Deserialize, Serialize};

/// Scaling policy for elastic training
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum ScalingPolicy {
    /// Manual scaling only
    Manual,
    /// Scale based on resource availability
    ResourceBased,
    /// Scale based on training throughput
    ThroughputBased,
    /// Scale based on cost efficiency
    CostBased,
}

/// Worker state in elastic cluster
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
pub enum WorkerState {
    /// Worker is initializing
    Initializing,
    /// Worker is active and training
    Active,
    /// Worker is draining (preparing to leave)
    Draining,
    /// Worker is paused
    Paused,
    /// Worker has failed
    Failed,
    /// Worker is being removed
    Removing,
}

/// Configuration for elastic training
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ElasticConfig {
    /// Minimum number of workers
    pub min_workers: usize,
    /// Maximum number of workers
    pub max_workers: usize,
    /// Initial number of workers
    pub initial_workers: usize,
    /// Scaling policy
    pub scaling_policy: ScalingPolicy,
    /// Heartbeat interval (ms)
    pub heartbeat_interval_ms: u64,
    /// Failure detection timeout (ms)
    pub failure_timeout_ms: u64,
    /// Enable automatic checkpointing before scale events
    pub checkpoint_on_scale: bool,
    /// Enable automatic state redistribution
    pub redistribute_state: bool,
    /// Cooldown period between scale events (ms)
    pub scale_cooldown_ms: u64,
    /// Maximum pending scale operations
    pub max_pending_scales: usize,
}

impl Default for ElasticConfig {
    fn default() -> Self {
        Self {
            min_workers: 1,
            max_workers: 64,
            initial_workers: 4,
            scaling_policy: ScalingPolicy::Manual,
            heartbeat_interval_ms: 1000,
            failure_timeout_ms: 30000,
            checkpoint_on_scale: true,
            redistribute_state: true,
            scale_cooldown_ms: 60000,
            max_pending_scales: 4,
        }
    }
}