use anyhow::Result;
use cm_dashboard_shared::Metric;
use std::collections::HashMap;
use std::time::Instant;
use tracing::{debug, error, info};

use crate::cache::MetricCacheManager;
use crate::collectors::{
    backup::BackupCollector, cpu::CpuCollector, disk::DiskCollector, memory::MemoryCollector,
    systemd::SystemdCollector, Collector,
};
use crate::config::{AgentConfig, CollectorConfig};

/// Manages all metric collectors with intelligent caching
pub struct MetricCollectionManager {
    collectors: Vec<Box<dyn Collector>>,
    cache_manager: MetricCacheManager,
    last_collection_times: HashMap<String, Instant>,
}

impl MetricCollectionManager {
    pub async fn new(config: &CollectorConfig, agent_config: &AgentConfig) -> Result<Self> {
        let mut collectors: Vec<Box<dyn Collector>> = Vec::new();

        // Benchmark mode - only enable specific collector based on env var
        let benchmark_mode = std::env::var("BENCHMARK_COLLECTOR").ok();

        match benchmark_mode.as_deref() {
            Some("cpu") => {
                // CPU collector only
                if config.cpu.enabled {
                    let cpu_collector = CpuCollector::new(config.cpu.clone());
                    collectors.push(Box::new(cpu_collector));
                    info!("BENCHMARK: CPU collector only");
                }
            }
            Some("memory") => {
                // Memory collector only
                if config.memory.enabled {
                    let memory_collector = MemoryCollector::new(config.memory.clone());
                    collectors.push(Box::new(memory_collector));
                    info!("BENCHMARK: Memory collector only");
                }
            }
            Some("disk") => {
                // Disk collector only
                let disk_collector = DiskCollector::new(config.disk.clone());
                collectors.push(Box::new(disk_collector));
                info!("BENCHMARK: Disk collector only");
            }
            Some("systemd") => {
                // Systemd collector only
                let systemd_collector = SystemdCollector::new();
                collectors.push(Box::new(systemd_collector));
                info!("BENCHMARK: Systemd collector only");
            }
            Some("backup") => {
                // Backup collector only
                if config.backup.enabled {
                    let backup_collector = BackupCollector::new(
                        config.backup.backup_paths.first().cloned(),
                        config.backup.max_age_hours,
                    );
                    collectors.push(Box::new(backup_collector));
                    info!("BENCHMARK: Backup collector only");
                }
            }
            Some("none") => {
                // No collectors - test agent loop only
                info!("BENCHMARK: No collectors enabled");
            }
            _ => {
                // Normal mode - all collectors
                if config.cpu.enabled {
                    let cpu_collector = CpuCollector::new(config.cpu.clone());
                    collectors.push(Box::new(cpu_collector));
                    info!("CPU collector initialized");
                }

                if config.memory.enabled {
                    let memory_collector = MemoryCollector::new(config.memory.clone());
                    collectors.push(Box::new(memory_collector));
                    info!("Memory collector initialized");
                }

                let disk_collector = DiskCollector::new(config.disk.clone());
                collectors.push(Box::new(disk_collector));
                info!("Disk collector initialized");

                let systemd_collector = SystemdCollector::new();
                collectors.push(Box::new(systemd_collector));
                info!("Systemd collector initialized");

                if config.backup.enabled {
                    let backup_collector = BackupCollector::new(
                        config.backup.backup_paths.first().cloned(),
                        config.backup.max_age_hours,
                    );
                    collectors.push(Box::new(backup_collector));
                    info!("Backup collector initialized");
                }
            }
        }

        // Initialize cache manager with configuration
        let cache_manager = MetricCacheManager::new(agent_config.cache.clone());

        // Start background cache tasks
        cache_manager.start_background_tasks().await;

        info!(
            "Metric collection manager initialized with {} collectors and caching enabled",
            collectors.len()
        );

        Ok(Self {
            collectors,
            cache_manager,
            last_collection_times: HashMap::new(),
        })
    }

    /// Force collection from ALL collectors immediately (used at startup)
    pub async fn collect_all_metrics_force(&mut self) -> Result<Vec<Metric>> {
        let mut all_metrics = Vec::new();
        let now = Instant::now();

        info!(
            "Force collecting from ALL {} collectors for startup",
            self.collectors.len()
        );

        // Force collection from every collector regardless of intervals
        for collector in &self.collectors {
            let collector_name = collector.name();

            match collector.collect().await {
                Ok(metrics) => {
                    info!(
                        "Force collected {} metrics from {} collector",
                        metrics.len(),
                        collector_name
                    );

                    // Cache all new metrics
                    for metric in &metrics {
                        self.cache_manager.cache_metric(metric.clone()).await;
                    }

                    all_metrics.extend(metrics);
                    self.last_collection_times
                        .insert(collector_name.to_string(), now);
                }
                Err(e) => {
                    error!(
                        "Collector '{}' failed during force collection: {}",
                        collector_name, e
                    );
                    // Continue with other collectors even if one fails
                }
            }
        }

        info!(
            "Force collection completed: {} total metrics cached",
            all_metrics.len()
        );
        Ok(all_metrics)
    }

    /// Collect metrics from all collectors with intelligent caching
    pub async fn collect_all_metrics(&mut self) -> Result<Vec<Metric>> {
        let mut all_metrics = Vec::new();
        let now = Instant::now();

        // Collecting metrics from collectors (debug logging disabled for performance)

        // Keep track of which collector types we're collecting fresh data from
        let mut collecting_fresh = std::collections::HashSet::new();

        // For each collector, check if we need to collect based on time intervals
        for collector in &self.collectors {
            let collector_name = collector.name();

            // Determine cache interval for this collector type based on data volatility
            let cache_interval_secs = match collector_name {
                "cpu" | "memory" => 5,    // Fast updates for volatile metrics
                "systemd" => 30,          // Service status changes less frequently
                "disk" => 300,            // SMART data changes very slowly (5 minutes)
                "backup" => 600,          // Backup status changes rarely (10 minutes)
                _ => 30,                  // Default: moderate frequency
            };

            let should_collect =
                if let Some(last_time) = self.last_collection_times.get(collector_name) {
                    now.duration_since(*last_time).as_secs() >= cache_interval_secs
                } else {
                    true // First collection
                };

            if should_collect {
                collecting_fresh.insert(collector_name.to_string());
                match collector.collect().await {
                    Ok(metrics) => {
                        // Collector returned fresh metrics (debug logging disabled for performance)

                        // Cache all new metrics
                        for metric in &metrics {
                            self.cache_manager.cache_metric(metric.clone()).await;
                        }

                        all_metrics.extend(metrics);
                        self.last_collection_times
                            .insert(collector_name.to_string(), now);
                    }
                    Err(e) => {
                        error!("Collector '{}' failed: {}", collector_name, e);
                        // Continue with other collectors even if one fails
                    }
                }
            } else {
                let _elapsed = self
                    .last_collection_times
                    .get(collector_name)
                    .map(|t| now.duration_since(*t).as_secs())
                    .unwrap_or(0);
                // Collector skipped (debug logging disabled for performance)
            }
        }

        // For 2-second intervals, skip cached metrics to avoid duplicates
        // (Cache system disabled for realtime updates)

        // Collected metrics total (debug logging disabled for performance)
        Ok(all_metrics)
    }

    /// Get names of all registered collectors
    pub fn get_collector_names(&self) -> Vec<String> {
        self.collectors
            .iter()
            .map(|c| c.name().to_string())
            .collect()
    }

    /// Get collector statistics
    pub fn get_stats(&self) -> HashMap<String, bool> {
        self.collectors
            .iter()
            .map(|c| (c.name().to_string(), true)) // All collectors are enabled
            .collect()
    }

    /// Get all cached metrics from the cache manager
    pub async fn get_all_cached_metrics(&self) -> Result<Vec<Metric>> {
        let cached_metrics = self.cache_manager.get_all_cached_metrics().await;
        debug!(
            "Retrieved {} cached metrics for broadcast",
            cached_metrics.len()
        );
        Ok(cached_metrics)
    }

    /// Determine which collector handles a specific metric
    fn get_collector_for_metric(&self, metric_name: &str) -> String {
        if metric_name.starts_with("cpu_") {
            "cpu".to_string()
        } else if metric_name.starts_with("memory_") {
            "memory".to_string()
        } else if metric_name.starts_with("disk_") {
            "disk".to_string()
        } else if metric_name.starts_with("service_") {
            "systemd".to_string()
        } else if metric_name.starts_with("backup_") {
            "backup".to_string()
        } else {
            "unknown".to_string()
        }
    }
}