use anyhow::Result;
use std::time::Duration;
use tokio::time::interval;
use tracing::{info, error, debug};
use gethostname::gethostname;

use crate::config::AgentConfig;
use crate::communication::{ZmqHandler, AgentCommand};
use crate::metrics::MetricCollectionManager;
use crate::notifications::NotificationManager;
use cm_dashboard_shared::{Metric, MetricMessage};

pub struct Agent {
    hostname: String,
    config: AgentConfig,
    zmq_handler: ZmqHandler,
    metric_manager: MetricCollectionManager,
    notification_manager: NotificationManager,
}

impl Agent {
    pub async fn new(config_path: Option<String>) -> Result<Self> {
        let hostname = gethostname().to_string_lossy().to_string();
        info!("Initializing agent for host: {}", hostname);
        
        // Load configuration
        let config = if let Some(path) = config_path {
            AgentConfig::load_from_file(&path)?
        } else {
            AgentConfig::default()
        };
        
        info!("Agent configuration loaded");
        
        // Initialize ZMQ communication
        let zmq_handler = ZmqHandler::new(&config.zmq).await?;
        info!("ZMQ communication initialized on port {}", config.zmq.publisher_port);
        
        // Initialize metric collection manager with cache config
        let metric_manager = MetricCollectionManager::new(&config.collectors, &config).await?;
        info!("Metric collection manager initialized");
        
        // Initialize notification manager
        let notification_manager = NotificationManager::new(&config.notifications, &hostname)?;
        info!("Notification manager initialized");
        
        Ok(Self {
            hostname,
            config,
            zmq_handler,
            metric_manager,
            notification_manager,
        })
    }
    
    pub async fn run(&mut self, mut shutdown_rx: tokio::sync::oneshot::Receiver<()>) -> Result<()> {
        info!("Starting agent main loop with separated collection and transmission");
        
        // CRITICAL: Collect ALL data immediately at startup before entering the loop
        info!("Performing initial FORCE collection of all metrics at startup");
        if let Err(e) = self.collect_all_metrics_force().await {
            error!("Failed to collect initial metrics: {}", e);
        } else {
            info!("Initial metric collection completed - all data cached and ready");
        }
        
        // Separate intervals for collection and transmission
        let mut collection_interval = interval(Duration::from_secs(self.config.collection_interval_seconds));
        let mut transmission_interval = interval(Duration::from_secs(1)); // ZMQ broadcast every 1 second
        let mut notification_check_interval = interval(Duration::from_secs(30)); // Check notifications every 30s
        
        loop {
            tokio::select! {
                _ = collection_interval.tick() => {
                    // Only collect and cache metrics, no ZMQ transmission
                    if let Err(e) = self.collect_metrics_only().await {
                        error!("Failed to collect metrics: {}", e);
                    }
                }
                _ = transmission_interval.tick() => {
                    // Send all cached metrics via ZMQ every 1 second
                    if let Err(e) = self.broadcast_all_cached_metrics().await {
                        error!("Failed to broadcast cached metrics: {}", e);
                    }
                }
                _ = notification_check_interval.tick() => {
                    // Handle any pending notifications
                    self.notification_manager.process_pending().await;
                }
                // Handle incoming commands (check periodically)
                _ = tokio::time::sleep(Duration::from_millis(100)) => {
                    if let Err(e) = self.handle_commands().await {
                        error!("Error handling commands: {}", e);
                    }
                }
                _ = &mut shutdown_rx => {
                    info!("Shutdown signal received, stopping agent loop");
                    break;
                }
            }
        }
        
        info!("Agent main loop stopped");
        Ok(())
    }
    
    async fn collect_all_metrics_force(&mut self) -> Result<()> {
        info!("Starting FORCE metric collection for startup");
        
        // Force collect all metrics from all collectors immediately
        let metrics = self.metric_manager.collect_all_metrics_force().await?;
        
        if metrics.is_empty() {
            error!("No metrics collected during force collection!");
            return Ok(());
        }
        
        info!("Force collected and cached {} metrics", metrics.len());
        
        // Check for status changes and send notifications
        self.check_status_changes(&metrics).await;
        
        Ok(())
    }
    
    async fn collect_metrics_only(&mut self) -> Result<()> {
        debug!("Starting metric collection cycle (cache only)");
        
        // Collect all metrics from all collectors and cache them
        let metrics = self.metric_manager.collect_all_metrics().await?;
        
        if metrics.is_empty() {
            debug!("No metrics collected this cycle");
            return Ok(());
        }
        
        debug!("Collected and cached {} metrics", metrics.len());
        
        // Check for status changes and send notifications
        self.check_status_changes(&metrics).await;
        
        Ok(())
    }
    
    async fn broadcast_all_cached_metrics(&mut self) -> Result<()> {
        debug!("Broadcasting all cached metrics via ZMQ");
        
        // Get all cached metrics from the metric manager
        let cached_metrics = self.metric_manager.get_all_cached_metrics().await?;
        
        if cached_metrics.is_empty() {
            debug!("No cached metrics to broadcast");
            return Ok(());
        }
        
        debug!("Broadcasting {} cached metrics", cached_metrics.len());
        
        // Create and send message with all cached data
        let message = MetricMessage::new(self.hostname.clone(), cached_metrics);
        self.zmq_handler.publish_metrics(&message).await?;
        
        debug!("Cached metrics broadcasted successfully");
        Ok(())
    }
    
    async fn check_status_changes(&mut self, metrics: &[Metric]) {
        for metric in metrics {
            if let Some(status_change) = self.notification_manager.update_metric_status(&metric.name, metric.status) {
                info!("Status change detected for {}: {:?} -> {:?}", 
                      metric.name, status_change.old_status, status_change.new_status);
                
                // Send notification for status change
                if let Err(e) = self.notification_manager.send_status_change_notification(status_change, metric).await {
                    error!("Failed to send notification: {}", e);
                }
            }
        }
    }
    
    async fn handle_commands(&mut self) -> Result<()> {
        // Try to receive commands (non-blocking)
        match self.zmq_handler.try_receive_command() {
            Ok(Some(command)) => {
                info!("Received command: {:?}", command);
                self.process_command(command).await?;
            }
            Ok(None) => {
                // No command available - this is normal
            }
            Err(e) => {
                error!("Error receiving command: {}", e);
            }
        }
        Ok(())
    }
    
    async fn process_command(&mut self, command: AgentCommand) -> Result<()> {
        match command {
            AgentCommand::CollectNow => {
                info!("Processing CollectNow command");
                if let Err(e) = self.collect_metrics_only().await {
                    error!("Failed to collect metrics on command: {}", e);
                }
            }
            AgentCommand::SetInterval { seconds } => {
                info!("Processing SetInterval command: {} seconds", seconds);
                // Note: This would require modifying the interval, which is complex
                // For now, just log the request
                info!("Interval change requested but not implemented yet");
            }
            AgentCommand::ToggleCollector { name, enabled } => {
                info!("Processing ToggleCollector command: {} -> {}", name, enabled);
                // Note: This would require dynamic collector management
                info!("Collector toggle requested but not implemented yet");
            }
            AgentCommand::Ping => {
                info!("Processing Ping command - agent is alive");
                // Could send a response back via ZMQ if needed
            }
        }
        Ok(())
    }
}