use crate::execution_manager::async_channel::AsyncChannel;
use crate::execution_manager::memory_tracker::MemoryTrackerManager;
use crate::execution_manager::objects_pool::{ObjectsPool, PoolObjectTrait};
use std::any::Any;
use std::mem::ManuallyDrop;
use std::ops::{Deref, DerefMut};
use std::sync::atomic::{AtomicU64, Ordering};
use std::sync::Arc;

pub trait PacketTrait: PoolObjectTrait + Sync + Send {
    fn get_size(&self) -> usize;
}

trait PacketPoolReturnerTrait: Send + Sync {
    fn send_any(&self, packet: Box<dyn Any>);
}

impl<T: Send + Sync + PacketTrait + 'static> PacketPoolReturnerTrait
    for (
        Arc<(AsyncChannel<Box<T>>, AtomicU64)>,
        Arc<MemoryTrackerManager>,
    )
{
    fn send_any(&self, packet: Box<dyn Any>) {
        self.0 .1.fetch_sub(1, Ordering::Relaxed);
        let mut packet = packet.downcast::<T>().unwrap();
        self.1.remove_queue_packet(packet.deref());
        packet.reset();
        let _ = self.0 .0.send(packet, true);
    }
}

pub struct Packet<T: 'static> {
    object: ManuallyDrop<Box<T>>,
    returner: Option<Arc<dyn PacketPoolReturnerTrait>>,
}

pub struct PacketAny {
    object: ManuallyDrop<Box<dyn Any + Send + Sync>>,
    returner: Option<Arc<dyn PacketPoolReturnerTrait>>,
}

pub struct PacketsPool<T: Sync + Send + 'static> {
    objects_pool: ObjectsPool<Box<T>>,
    returner: Arc<(
        Arc<(AsyncChannel<Box<T>>, AtomicU64)>,
        Arc<MemoryTrackerManager>,
    )>,
}

// Recursively implement the object trait for the pool, so it can be used recursively
impl<T: PacketTrait> PoolObjectTrait for PacketsPool<T> {
    type InitData = (usize, T::InitData, Arc<MemoryTrackerManager>);

    fn allocate_new((cap, init_data, mem_tracker): &Self::InitData) -> Self {
        Self::new(*cap, init_data.clone(), mem_tracker)
    }

    fn reset(&mut self) {}
}

impl<T: PacketTrait> PacketsPool<T> {
    pub fn new(
        cap: usize,
        init_data: T::InitData,
        mem_tracker: &Arc<MemoryTrackerManager>,
    ) -> Self {
        let objects_pool = ObjectsPool::new(cap, init_data);
        let returner = Arc::new((objects_pool.returner.clone(), mem_tracker.clone()));
        Self {
            objects_pool,
            returner,
        }
    }

    pub async fn alloc_packet(&self) -> Packet<T> {
        let mut object = self.objects_pool.alloc_object().await;

        let packet = Packet {
            object: ManuallyDrop::new(unsafe { ManuallyDrop::take(&mut object.value) }),
            returner: Some(self.returner.clone()),
        };

        unsafe {
            std::ptr::drop_in_place(&mut object.returner);
            std::mem::forget(object);
        }

        packet
    }

    pub fn set_size(&self, new_size: usize) {
        self.objects_pool.set_size(new_size);
    }

    pub fn alloc_packet_blocking(&self) -> Packet<T> {
        let mut object = self.objects_pool.alloc_object_blocking();

        let packet = Packet {
            object: ManuallyDrop::new(unsafe { ManuallyDrop::take(&mut object.value) }),
            returner: Some(self.returner.clone()),
        };

        unsafe {
            std::ptr::drop_in_place(&mut object.returner);
            std::mem::forget(object);
        }

        packet
    }

    pub fn get_available_items(&self) -> i64 {
        self.objects_pool.get_available_items()
    }

    // pub fn wait_for_item_timeout(&self, timeout: Duration) {
    //     self.objects_pool.wait_for_item_timeout(timeout)
    // }
}

impl<T: Any + Send + Sync> Packet<T> {
    pub fn new_simple(data: T) -> Self {
        Packet {
            object: ManuallyDrop::new(Box::new(data)),
            returner: None,
        }
    }

    pub fn upcast(mut self) -> PacketAny {
        let packet = PacketAny {
            object: ManuallyDrop::<Box<dyn Any + Send + Sync>>::new(unsafe {
                ManuallyDrop::<Box<T>>::take(&mut self.object)
            }),
            returner: self.returner.clone(),
        };

        unsafe {
            std::ptr::drop_in_place(&mut self.returner);
            std::mem::forget(self);
        }

        packet
    }
}

impl<T: Any + Send + Sync> Deref for Packet<T> {
    type Target = T;
    #[inline(always)]
    fn deref(&self) -> &Self::Target {
        self.object.as_ref()
    }
}

impl<T: Any + Send + Sync> DerefMut for Packet<T> {
    #[inline(always)]
    fn deref_mut(&mut self) -> &mut Self::Target {
        self.object.as_mut()
    }
}

impl PacketAny {
    pub fn downcast<T: 'static>(mut self) -> Packet<T> {
        let packet = Packet {
            object: ManuallyDrop::new(unsafe {
                ManuallyDrop::take(&mut self.object).downcast().unwrap()
            }),
            returner: self.returner.clone(),
        };

        unsafe {
            std::ptr::drop_in_place(&mut self.returner);
            std::mem::forget(self);
        }

        packet
    }
}

impl<T: 'static> Drop for Packet<T> {
    fn drop(&mut self) {
        if let Some(returner) = &self.returner {
            returner.send_any(unsafe { ManuallyDrop::<Box<T>>::take(&mut self.object) });
        } else {
            unsafe { ManuallyDrop::drop(&mut self.object) }
        }
    }
}

impl Drop for PacketAny {
    fn drop(&mut self) {
        // panic!("Cannot drop packet any!");
    }
}

impl PoolObjectTrait for () {
    type InitData = ();
    fn allocate_new(_init_data: &Self::InitData) -> Self {
        panic!("Cannot create () type as object!");
    }

    fn reset(&mut self) {
        panic!("Cannot reset () type as object!");
    }
}
impl PacketTrait for () {
    fn get_size(&self) -> usize {
        0
    }
}