use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::sync::Arc;
use std::time::Instant;

use crossbeam_queue::SegQueue;
use solana_sdk::pubkey::Pubkey;

use crate::common::AnyResult;
use crate::streaming::common::BackpressureStrategy;
use crate::streaming::common::{
    MetricsEventType, MetricsManager, StreamClientConfig as ClientConfig,
};
use crate::streaming::event_parser::common::filter::EventTypeFilter;
use crate::streaming::event_parser::core::account_event_parser::AccountEventParser;
use crate::streaming::event_parser::core::common_event_parser::CommonEventParser;
use crate::streaming::event_parser::core::traits::get_high_perf_clock;
use crate::streaming::event_parser::EventParser;
use crate::streaming::event_parser::{
    core::traits::UnifiedEvent, protocols::mutil::parser::MutilEventParser, Protocol,
};
use crate::streaming::grpc::{BackpressureConfig, EventPretty};
use crate::streaming::shred::TransactionWithSlot;
use once_cell::sync::OnceCell;

/// High-performance Event processor using SegQueue for all strategies
pub struct EventProcessor {
    pub(crate) metrics_manager: MetricsManager,
    pub(crate) config: ClientConfig,
    pub(crate) parser_cache: OnceCell<Arc<dyn EventParser>>,
    pub(crate) protocols: Vec<Protocol>,
    pub(crate) event_type_filter: Option<EventTypeFilter>,
    pub(crate) callback: Option<Arc<dyn Fn(Box<dyn UnifiedEvent>) + Send + Sync>>,
    pub(crate) backpressure_config: BackpressureConfig,
    /// High-performance lockfree queue for gRPC events
    pub(crate) grpc_queue: Arc<SegQueue<(EventPretty, Option<Pubkey>)>>,
    /// High-performance lockfree queue for shred events  
    pub(crate) shred_queue: Arc<SegQueue<(TransactionWithSlot, Option<Pubkey>)>>,
    /// Fast O(1) counter for Drop strategy (avoids expensive SegQueue::len())
    pub(crate) grpc_pending_count: Arc<AtomicUsize>,
    pub(crate) shred_pending_count: Arc<AtomicUsize>,
    /// Processing thread control
    pub(crate) processing_shutdown: Arc<AtomicBool>,
}

impl EventProcessor {
    /// Create a new high-performance event processor
    pub fn new(metrics_manager: MetricsManager, config: ClientConfig) -> Self {
        let backpressure_config = config.backpressure.clone();
        let grpc_queue = Arc::new(SegQueue::new());
        let shred_queue = Arc::new(SegQueue::new());
        let grpc_pending_count = Arc::new(AtomicUsize::new(0));
        let shred_pending_count = Arc::new(AtomicUsize::new(0));
        let processing_shutdown = Arc::new(AtomicBool::new(false));

        Self {
            metrics_manager,
            config,
            parser_cache: OnceCell::new(),
            protocols: vec![],
            event_type_filter: None,
            backpressure_config,
            callback: None,
            grpc_queue,
            shred_queue,
            grpc_pending_count,
            shred_pending_count,
            processing_shutdown,
        }
    }

    pub fn set_protocols_and_event_type_filter(
        &mut self,
        protocols: Vec<Protocol>,
        event_type_filter: Option<EventTypeFilter>,
        backpressure_config: BackpressureConfig,
        callback: Option<Arc<dyn Fn(Box<dyn UnifiedEvent>) + Send + Sync>>,
    ) {
        self.protocols = protocols;
        self.event_type_filter = event_type_filter;

        // Check if Block processing thread should be started (before moving backpressure_config)
        let should_start_block_processing = true;
        // matches!(backpressure_config.strategy, BackpressureStrategy::Block);

        self.backpressure_config = backpressure_config;
        self.callback = callback;
        // Use stored values to initialize parser_cache
        let protocols_ref = &self.protocols;
        let event_type_filter_ref = self.event_type_filter.as_ref();
        self.parser_cache.get_or_init(|| {
            Arc::new(MutilEventParser::new(protocols_ref.clone(), event_type_filter_ref.cloned()))
        });

        // Start Block processing thread if using Block strategy
        if should_start_block_processing {
            self.start_block_processing_thread();
        }
    }

    pub fn get_parser(&self) -> Arc<dyn EventParser> {
        self.parser_cache.get().unwrap().clone()
    }

    /// Create adapter callback
    fn create_adapter_callback(&self) -> Arc<dyn Fn(Box<dyn UnifiedEvent>) + Send + Sync> {
        let callback = self.callback.clone().unwrap();
        let metrics_manager = self.metrics_manager.clone();

        Arc::new(move |event: Box<dyn UnifiedEvent>| {
            let processing_time_us = event.program_handle_time_consuming_us() as f64;
            callback(event);
            metrics_manager.update_metrics(MetricsEventType::Transaction, 1, processing_time_us);
        })
    }

    pub async fn process_grpc_event_transaction_with_metrics(
        &self,
        event_pretty: EventPretty,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        self.apply_backpressure_control(event_pretty, bot_wallet).await
    }

    /// Apply backpressure control strategy  
    async fn apply_backpressure_control(
        &self,
        event_pretty: EventPretty,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        match self.backpressure_config.strategy {
            BackpressureStrategy::Block => {
                // Block strategy: async wait if queue is full (backpressure control)
                loop {
                    let current_pending = self.grpc_pending_count.load(Ordering::Relaxed);
                    if current_pending < self.backpressure_config.permits {
                        self.grpc_queue.push((event_pretty, bot_wallet));
                        self.grpc_pending_count.fetch_add(1, Ordering::Relaxed);
                        break;
                    }
                    // Async yield to avoid blocking gRPC data source
                    tokio::task::yield_now().await;
                }
                Ok(())
            }
            BackpressureStrategy::Drop => {
                // Drop strategy: Use O(1) atomic counter instead of expensive O(n) len()
                // If pending count >= permits, DROP the event immediately
                let current_pending = self.grpc_pending_count.load(Ordering::Relaxed);
                if current_pending >= self.backpressure_config.permits {
                    self.metrics_manager.increment_dropped_events();
                    Ok(())
                } else {
                    self.grpc_pending_count.fetch_add(1, Ordering::Relaxed);
                    let processor = self.clone();
                    tokio::spawn(async move {
                        match processor
                            .process_grpc_event_transaction(event_pretty, bot_wallet)
                            .await
                        {
                            Ok(_) => {
                                processor.grpc_pending_count.fetch_sub(1, Ordering::Relaxed);
                            }
                            Err(e) => {
                                log::error!("Error in async gRPC processing: {}", e);
                            }
                        }
                    });
                    Ok(())
                }
            }
        }
    }

    async fn process_grpc_event_transaction(
        &self,
        event_pretty: EventPretty,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        if self.callback.is_none() {
            return Ok(());
        }
        match event_pretty {
            EventPretty::Account(account_pretty) => {
                self.metrics_manager.add_account_process_count();
                let account_event = AccountEventParser::parse_account_event(
                    &self.protocols,
                    account_pretty,
                    self.event_type_filter.as_ref(),
                );
                if let Some(event) = account_event {
                    let processing_time_us = event.program_handle_time_consuming_us() as f64;
                    self.invoke_callback(event);
                    self.update_metrics(MetricsEventType::Account, 1, processing_time_us);
                }
            }
            EventPretty::Transaction(transaction_pretty) => {
                self.metrics_manager.add_tx_process_count();
                let slot = transaction_pretty.slot;
                let signature = transaction_pretty.signature;
                let tx = transaction_pretty.tx;
                let block_time = transaction_pretty.block_time;
                let program_received_time_us = transaction_pretty.program_received_time_us;
                let transaction_index = transaction_pretty.transaction_index;
                // Use cache to get parser
                let parser = self.get_parser();
                let adapter_callback = self.create_adapter_callback();
                parser
                    .parse_transaction_owned(
                        tx,
                        signature,
                        Some(slot),
                        block_time,
                        program_received_time_us,
                        bot_wallet,
                        transaction_index,
                        adapter_callback,
                    )
                    .await?;
            }
            EventPretty::BlockMeta(block_meta_pretty) => {
                self.metrics_manager.add_block_meta_process_count();
                let block_time_ms = block_meta_pretty
                    .block_time
                    .map(|ts| ts.seconds * 1000 + ts.nanos as i64 / 1_000_000)
                    .unwrap_or_else(|| chrono::Utc::now().timestamp_millis());
                let block_meta_event = CommonEventParser::generate_block_meta_event(
                    block_meta_pretty.slot,
                    &block_meta_pretty.block_hash,
                    block_time_ms,
                    block_meta_pretty.program_received_time_us,
                );
                let processing_time_us = block_meta_event.program_handle_time_consuming_us() as f64;
                self.invoke_callback(block_meta_event);
                self.update_metrics(MetricsEventType::BlockMeta, 1, processing_time_us);
            }
        }

        Ok(())
    }

    pub fn invoke_callback(&self, event: Box<dyn UnifiedEvent>) {
        if let Some(callback) = self.callback.as_ref() {
            callback(event);
        }
    }

    /// Process a single transaction immediately
    pub async fn process_shred_transaction_immediate(
        &self,
        transaction_with_slot: TransactionWithSlot,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        self.process_shred_transaction(transaction_with_slot, bot_wallet).await
    }

    /// Process shred transaction with backpressure control and performance monitoring
    pub async fn process_shred_transaction_with_metrics(
        &self,
        transaction_with_slot: TransactionWithSlot,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        // Backpressure control logic
        self.apply_shred_backpressure_control(transaction_with_slot, bot_wallet).await
    }

    /// Apply shred backpressure control strategy
    async fn apply_shred_backpressure_control(
        &self,
        transaction_with_slot: TransactionWithSlot,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        match self.backpressure_config.strategy {
            BackpressureStrategy::Block => {
                // Block strategy: async wait if queue is full (backpressure control)
                loop {
                    let current_pending = self.shred_pending_count.load(Ordering::Relaxed);
                    if current_pending < self.backpressure_config.permits {
                        self.shred_queue.push((transaction_with_slot, bot_wallet));
                        self.shred_pending_count.fetch_add(1, Ordering::Relaxed);
                        break;
                    }
                    // Async yield to avoid blocking shred data source
                    tokio::task::yield_now().await;
                }
                Ok(())
            }
            BackpressureStrategy::Drop => {
                // Drop strategy: Use O(1) atomic counter instead of expensive O(n) len()
                let current_pending = self.shred_pending_count.load(Ordering::Relaxed);
                if current_pending >= self.backpressure_config.permits {
                    self.metrics_manager.increment_dropped_events();
                    Ok(())
                } else {
                    self.shred_pending_count.fetch_add(1, Ordering::Relaxed);
                    let processor = self.clone();
                    tokio::spawn(async move {
                        match processor
                            .process_shred_transaction(transaction_with_slot, bot_wallet)
                            .await
                        {
                            Ok(_) => {
                                processor.shred_pending_count.fetch_sub(1, Ordering::Relaxed);
                            }
                            Err(e) => {
                                log::error!("Error in async shred processing: {}", e);
                            }
                        }
                    });
                    Ok(())
                }
            }
        }
    }

    pub async fn process_shred_transaction(
        &self,
        transaction_with_slot: TransactionWithSlot,
        bot_wallet: Option<Pubkey>,
    ) -> AnyResult<()> {
        if self.callback.is_none() {
            return Ok(());
        }
        self.metrics_manager.add_tx_process_count();
        let tx = transaction_with_slot.transaction;

        let slot = transaction_with_slot.slot;
        let signature = tx.signatures[0];
        let program_received_time_us = transaction_with_slot.program_received_time_us;
        // Use cache to get parser
        let parser = self.get_parser();
        let adapter_callback = self.create_adapter_callback();
        parser
            .parse_versioned_transaction_owned(
                tx,
                signature,
                Some(slot),
                None,
                program_received_time_us,
                bot_wallet,
                None,
                &[],
                adapter_callback,
            )
            .await?;

        Ok(())
    }

    fn update_metrics(&self, ty: MetricsEventType, count: u64, time_us: f64) {
        self.metrics_manager.update_metrics(ty, count, time_us);
    }

    /// Start dedicated processing threads for all strategies
    fn start_block_processing_thread(&self) {
        // Reset shutdown flag
        self.processing_shutdown.store(false, Ordering::Relaxed);

        let grpc_queue = Arc::clone(&self.grpc_queue);
        let shred_queue = Arc::clone(&self.shred_queue);
        let grpc_pending_count = Arc::clone(&self.grpc_pending_count);
        let shred_pending_count = Arc::clone(&self.shred_pending_count);
        let shutdown_flag = Arc::clone(&self.processing_shutdown);
        let shutdown_flag_clone = Arc::clone(&self.processing_shutdown);
        let processor = self.clone();
        let processor_clone = self.clone();
        // 1. 专用线程 + 2. Busy-wait + 4. 无锁处理
        std::thread::spawn(move || {
            // 创建blocking runtime for async processing
            let rt = tokio::runtime::Builder::new_current_thread().enable_all().build().unwrap();
            while !shutdown_flag.load(Ordering::Relaxed) {
                if let Some((event_pretty, bot_wallet)) = grpc_queue.pop() {
                    // Decrement pending counter when consuming from queue
                    grpc_pending_count.fetch_sub(1, Ordering::Relaxed);
                    // Process event in blocking runtime
                    if let Err(e) = rt.block_on(
                        processor.process_grpc_event_transaction(event_pretty, bot_wallet),
                    ) {
                        println!("Error processing gRPC event: {}", e);
                    }
                } else {
                    // 2. 优化忙等待: 使用轻量级休眠减少CPU占用
                    std::thread::yield_now();
                }
            }
        });

        // Shred处理也使用相同的低延迟优化
        std::thread::spawn(move || {
            let rt = tokio::runtime::Builder::new_current_thread().enable_all().build().unwrap();

            while !shutdown_flag_clone.load(Ordering::Relaxed) {
                if let Some((transaction_with_slot, bot_wallet)) = shred_queue.pop() {
                    // Decrement pending counter when consuming from queue
                    shred_pending_count.fetch_sub(1, Ordering::Relaxed);
                    // Process transaction in blocking runtime
                    if let Err(e) = rt.block_on(
                        processor_clone
                            .process_shred_transaction(transaction_with_slot, bot_wallet),
                    ) {
                        log::error!("Error processing shred transaction: {}", e);
                    }
                } else {
                    // 优化忙等待: 使用轻量级休眠减少CPU占用
                    std::thread::yield_now();
                }
            }
        });
    }

    /// Stop processing threads
    pub fn stop_processing(&self) {
        self.processing_shutdown.store(true, Ordering::Relaxed);
    }
}

// Implement Clone trait to support sharing between modules
impl Clone for EventProcessor {
    fn clone(&self) -> Self {
        Self {
            metrics_manager: self.metrics_manager.clone(),
            config: self.config.clone(),
            parser_cache: self.parser_cache.clone(),
            protocols: self.protocols.clone(),
            event_type_filter: self.event_type_filter.clone(),
            backpressure_config: self.backpressure_config.clone(),
            callback: self.callback.clone(),
            grpc_queue: self.grpc_queue.clone(),
            shred_queue: self.shred_queue.clone(),
            grpc_pending_count: self.grpc_pending_count.clone(),
            shred_pending_count: self.shred_pending_count.clone(),
            processing_shutdown: self.processing_shutdown.clone(),
        }
    }
}