// Copyright (c) 2025 Saorsa Labs Limited

// This file is part of the Saorsa P2P network.

// Licensed under the AGPL-3.0 license:
// <https://www.gnu.org/licenses/agpl-3.0.html>

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Extension methods for coordinator integration
//!
//! This module provides extension traits and implementations for components
//! that need additional methods for full system integration.
//!
//! **Note**: Many methods in this module contain placeholder implementations
//! marked with TODO comments. These are intentional stubs that will be
//! implemented when the full component integration is completed.
//! The TODOs serve as clear markers for future development work.

#![allow(missing_docs)]
#![allow(async_fn_in_trait)]

use super::*;
use crate::adaptive::storage::ContentMetadata;
use crate::{P2PError, Result};
use std::time::Duration;

// Extension trait for TransportManager - only add methods that don't exist
pub trait TransportExtensions {
    async fn connect(&self, address: &str) -> Result<()>;
    async fn stop_accepting(&self) -> Result<()>;
}

impl TransportExtensions for TransportManager {
    async fn connect(&self, _address: &str) -> Result<()> {
        // TODO: Implement actual connection logic
        Ok(())
    }

    async fn stop_accepting(&self) -> Result<()> {
        // TODO: Implement
        Ok(())
    }
}

// Storage strategy type needed by coordinator
#[derive(Debug, Clone)]
pub enum StorageStrategy {
    Performance,
    HighReplication,
    Balanced,
}

// Extension trait for ContentStore - add missing methods needed by coordinator
pub trait ContentStoreExtensions {
    async fn store_with_strategy(&self, data: &[u8], strategy: StorageStrategy) -> Result<()>;
    async fn get_total_size(&self) -> u64;
    async fn flush(&self) -> Result<()>;
    async fn get_heat_score(&self, hash: &ContentHash) -> f64;
}

impl ContentStoreExtensions for ContentStore {
    async fn store_with_strategy(&self, data: &[u8], _strategy: StorageStrategy) -> Result<()> {
        let metadata = ContentMetadata::default();
        let _ = self.store(data.to_vec(), metadata).await.map_err(|e| {
            P2PError::Storage(crate::error::StorageError::Database(e.to_string().into()))
        })?;
        Ok(())
    }

    async fn get_total_size(&self) -> u64 {
        self.get_stats().await.total_bytes
    }

    async fn flush(&self) -> Result<()> {
        // TODO: Implement flush operation
        Ok(())
    }

    async fn get_heat_score(&self, _hash: &ContentHash) -> f64 {
        // TODO: Implement heat score calculation
        0.0
    }
}

// Cache decision type
#[derive(Debug)]
pub enum CacheDecision {
    Cache,
    Skip,
    Evict,
}

// Extension trait for QLearningCacheManager
pub trait QLearningCacheExtensions {
    async fn decide_caching(&self, hash: &ContentHash) -> CacheDecision;
    async fn get(&self, hash: &ContentHash) -> Option<Vec<u8>>;
    async fn save_model(&self) -> Result<()>;
}

impl QLearningCacheExtensions for QLearningCacheManager {
    async fn decide_caching(&self, hash: &ContentHash) -> CacheDecision {
        // Check if content is already cached
        if self.is_cached(hash).await {
            return CacheDecision::Skip;
        }

        // Get available actions for this content
        // Use a reasonable default size estimate (1KB) for decision-making
        let content_size = 1024u64;
        let available_actions = match self.get_available_actions(hash, content_size).await {
            Ok(actions) => actions,
            Err(_) => return CacheDecision::Skip,
        };

        // Get current state
        let state = match self.get_current_state(hash).await {
            Ok(s) => s,
            Err(_) => return CacheDecision::Skip,
        };

        // Use Q-learning to select action
        match self.select_action(&state, available_actions).await {
            Ok(action) => match action {
                super::q_learning_cache::CacheAction::Cache(_) => CacheDecision::Cache,
                super::q_learning_cache::CacheAction::Evict(_) => CacheDecision::Evict,
                super::q_learning_cache::CacheAction::Replicate { .. } => CacheDecision::Cache,
                super::q_learning_cache::CacheAction::DoNothing => CacheDecision::Skip,
            },
            Err(_) => CacheDecision::Skip,
        }
    }

    async fn get(&self, hash: &ContentHash) -> Option<Vec<u8>> {
        // QLearnCacheManager tracks caching decisions but doesn't store actual data
        // The actual data is stored in ContentStore
        // This method checks if we have made a caching decision for this hash
        if self.is_cached(hash).await {
            // Content is tracked as cached, but we don't have the actual bytes
            // The caller should retrieve from ContentStore
            None
        } else {
            None
        }
    }

    async fn save_model(&self) -> Result<()> {
        // Q-learning state is maintained in-memory via the Q-table
        // For persistence, the Q-table would need to be serialized
        // For now, this is a no-op as the Q-table is ephemeral
        Ok(())
    }
}

// Extension trait for MultiArmedBandit
pub trait MultiArmedBanditExtensions {
    async fn select_retrieval_strategy(&self, hash: &ContentHash) -> RetrievalStrategy;
    async fn update_strategy_performance(
        &self,
        strategy: RetrievalStrategy,
        success: bool,
        latency: Duration,
    );
    async fn select_route(&self, paths: Vec<(RouteId, Vec<NodeId>)>) -> Result<RouteDecision>;
}

impl MultiArmedBanditExtensions for MultiArmedBandit {
    async fn select_retrieval_strategy(&self, _hash: &ContentHash) -> RetrievalStrategy {
        RetrievalStrategy::Parallel
    }

    async fn update_strategy_performance(
        &self,
        _strategy: RetrievalStrategy,
        _success: bool,
        _latency: Duration,
    ) {
        // TODO: Implement performance update
    }

    async fn select_route(&self, paths: Vec<(RouteId, Vec<NodeId>)>) -> Result<RouteDecision> {
        // Select first available path
        if let Some((route_id, _)) = paths.first() {
            Ok(RouteDecision {
                route_id: route_id.clone(),
                probability: 0.8,
                exploration: false,
                confidence_interval: (0.7, 0.9),
                expected_latency_ms: 50.0,
            })
        } else {
            Err(AdaptiveNetworkError::Routing("No routes available".into()).into())
        }
    }
}

// Network churn prediction type
#[derive(Debug)]
pub struct NetworkChurnPrediction {
    pub probability_1h: f64,
    pub probability_6h: f64,
    pub probability_24h: f64,
}

// Extension trait for ChurnPredictor
pub trait ChurnPredictorExtensions {
    async fn predict_network_churn(&self) -> NetworkChurnPrediction;
    async fn save_model(&self) -> Result<()>;
}

impl ChurnPredictorExtensions for ChurnPredictor {
    async fn predict_network_churn(&self) -> NetworkChurnPrediction {
        NetworkChurnPrediction {
            probability_1h: 0.1,
            probability_6h: 0.15,
            probability_24h: 0.2,
        }
    }

    async fn save_model(&self) -> Result<()> {
        // TODO: Implement model saving
        Ok(())
    }
}

// Extension trait for MonitoringSystem
pub trait MonitoringSystemExtensions {
    async fn start_collection(&self) -> Result<()>;
    async fn reduce_collection_frequency(&self, factor: f64);
}

impl MonitoringSystemExtensions for MonitoringSystem {
    async fn start_collection(&self) -> Result<()> {
        // TODO: Implement collection start
        Ok(())
    }

    async fn reduce_collection_frequency(&self, _factor: f64) {
        // TODO: Implement frequency reduction
    }
}

// Extension trait for SecurityManager
pub trait SecurityManagerExtensions {
    async fn check_rate_limit(&self, node_id: &NodeId) -> Result<()>;
    async fn set_temporary_relaxation(&self, duration: Duration) -> Result<()>;
    async fn enable_strict_rate_limiting(&self) -> Result<()>;
}

impl SecurityManagerExtensions for SecurityManager {
    async fn check_rate_limit(&self, node_id: &NodeId) -> Result<()> {
        // Use the underlying SecurityManager's rate limiting with no IP
        SecurityManager::check_rate_limit(self, node_id, None)
            .await
            .map_err(|e| P2PError::Internal(format!("Rate limit check failed: {}", e).into()))
    }

    async fn set_temporary_relaxation(&self, _duration: Duration) -> Result<()> {
        // Rate limit relaxation allows temporary increase in request limits
        // This would be useful during network recovery or high-demand periods
        // The underlying RateLimiter would need a relaxation multiplier field
        // For now, this is a no-op placeholder
        Ok(())
    }

    async fn enable_strict_rate_limiting(&self) -> Result<()> {
        // Strict rate limiting reduces limits to protect against attacks
        // The underlying RateLimiter would need a strict mode flag
        // For now, this is a no-op placeholder
        Ok(())
    }
}

// Extension trait for AdaptiveDHT
pub trait AdaptiveDHTExtensions {
    async fn bootstrap(&self) -> Result<()>;
}

impl AdaptiveDHTExtensions for AdaptiveDHT {
    async fn bootstrap(&self) -> Result<()> {
        // DHT bootstrap connects to well-known nodes to populate the routing table.
        // This would typically:
        // 1. Connect to bootstrap nodes from a hardcoded list or configuration
        // 2. Perform FIND_NODE queries to populate routing table buckets
        // 3. Announce presence to nearby nodes
        //
        // The underlying DhtCoreEngine has join_network(bootstrap_nodes) which can be used.
        // However, AdaptiveDHT would need bootstrap node configuration to implement this.
        // For now, this is a no-op placeholder.
        Ok(())
    }
}

// Extension trait for EigenTrustEngine
pub trait EigenTrustEngineExtensions {
    async fn start_computation(&self) -> Result<()>;
    async fn get_average_trust(&self) -> f64;
    async fn get_storage_candidates(&self, count: usize) -> Vec<(NodeId, f64)>;
}

impl EigenTrustEngineExtensions for EigenTrustEngine {
    async fn start_computation(&self) -> Result<()> {
        // Trigger an initial trust computation
        // Note: start_background_updates requires Arc<Self> which we don't have here
        // Instead, trigger a single computation which updates caches
        let _ = self.compute_global_trust().await;
        tracing::info!("EigenTrust computation started - global trust scores computed");
        Ok(())
    }

    async fn get_average_trust(&self) -> f64 {
        let global_trust = self.get_global_trust();
        if global_trust.is_empty() {
            return 0.5; // Default trust for empty network
        }
        let sum: f64 = global_trust.values().sum();
        sum / global_trust.len() as f64
    }

    async fn get_storage_candidates(&self, count: usize) -> Vec<(NodeId, f64)> {
        let global_trust = self.get_global_trust();
        let mut candidates: Vec<(NodeId, f64)> = global_trust.into_iter().collect();
        // Sort by trust descending
        candidates.sort_by(|a, b| b.1.partial_cmp(&a.1).unwrap_or(std::cmp::Ordering::Equal));
        candidates.truncate(count);
        candidates
    }
}

// Extension trait for AdaptiveGossipSub
pub trait AdaptiveGossipSubExtensions {
    async fn start(&self) -> Result<()>;
    async fn announce_departure(&self) -> Result<()>;
}

impl AdaptiveGossipSubExtensions for AdaptiveGossipSub {
    async fn start(&self) -> Result<()> {
        // TODO: Implement gossip start
        Ok(())
    }

    async fn announce_departure(&self) -> Result<()> {
        // TODO: Implement departure announcement
        Ok(())
    }
}

// Extension trait for AdaptiveRouter
pub trait AdaptiveRouterExtensions {
    async fn get_kademlia_path(&self, target: &NodeId) -> Result<Vec<NodeId>>;
    async fn get_hyperbolic_path(&self, target: &NodeId) -> Result<Vec<NodeId>>;
    async fn get_trust_path(&self, target: &NodeId) -> Result<Vec<NodeId>>;
    async fn enable_aggressive_caching(&self);
}

impl AdaptiveRouterExtensions for AdaptiveRouter {
    async fn get_kademlia_path(&self, _target: &NodeId) -> Result<Vec<NodeId>> {
        Ok(vec![]) // TODO: Implement
    }

    async fn get_hyperbolic_path(&self, _target: &NodeId) -> Result<Vec<NodeId>> {
        Ok(vec![]) // TODO: Implement
    }

    async fn get_trust_path(&self, _target: &NodeId) -> Result<Vec<NodeId>> {
        Ok(vec![]) // TODO: Implement
    }

    async fn enable_aggressive_caching(&self) {
        // TODO: Implement aggressive caching
    }
}

// Extension trait for ChurnHandler
pub trait ChurnHandlerExtensions {
    async fn start_monitoring(&self);
    async fn get_stats(&self) -> ChurnStats;
}

impl ChurnHandlerExtensions for ChurnHandler {
    async fn start_monitoring(&self) {
        // TODO: Implement monitoring
    }

    async fn get_stats(&self) -> ChurnStats {
        ChurnStats {
            churn_rate: 0.05,
            nodes_joined_last_hour: 10,
            nodes_left_last_hour: 5,
        }
    }
}

#[derive(Debug)]
pub struct ChurnStats {
    pub churn_rate: f64,
    pub nodes_joined_last_hour: usize,
    pub nodes_left_last_hour: usize,
}

// Extension trait for ReplicationManager
pub trait ReplicationManagerExtensions {
    async fn determine_strategy(&self, hash: &ContentHash) -> Result<ReplicationStrategy>;
    async fn replicate(
        &self,
        hash: &ContentHash,
        data: Vec<u8>,
        strategy: ReplicationStrategy,
    ) -> Result<()>;
    async fn start_monitoring(&self);
    async fn increase_global_replication(&self, factor: f64);
}

impl ReplicationManagerExtensions for ReplicationManager {
    async fn determine_strategy(&self, _hash: &ContentHash) -> Result<ReplicationStrategy> {
        Ok(ReplicationStrategy::Composite)
    }

    async fn replicate(
        &self,
        _hash: &ContentHash,
        _data: Vec<u8>,
        _strategy: ReplicationStrategy,
    ) -> Result<()> {
        // TODO: Implement replication
        Ok(())
    }

    async fn start_monitoring(&self) {
        // TODO: Implement monitoring
    }

    async fn increase_global_replication(&self, _factor: f64) {
        // TODO: Implement global replication increase
    }
}

// Extension trait for AdaptiveGossipSub (add reduce_fanout)
pub trait AdaptiveGossipSubMoreExtensions {
    async fn reduce_fanout(&self, factor: f64);
}

impl AdaptiveGossipSubMoreExtensions for AdaptiveGossipSub {
    async fn reduce_fanout(&self, _factor: f64) {
        // TODO: Implement fanout reduction
    }
}
