use eyre::Result;
use futures::stream::StreamExt;
use async_trait::async_trait;
use tokio::task::spawn_local;
use std::time::Instant;
use std::sync::Arc;
use tokio::sync::{oneshot,Mutex,mpsc};
use crate::event::EventRaw;
use crate::event::{EventKind,Event,EventResponse,InternalEvent};
use futures::stream::iter;
use crate::endpoint::Endpoint;
use crate::irc_endpoint::IrcEndpoint;


pub struct EndpointReceiverPair {
    endpoint: Arc<dyn Endpoint>,
    sender: Option<mpsc::Sender<Event>>,
}

pub struct RircdState {
    endpoints: Vec<EndpointReceiverPair>,
    //to determine program runtime
    creation_timestamp: Option<Instant>,

    plainlog: Option<()>,
    sqlite_log: Option<()>,
    postgres_log: Option<()>,
}

impl RircdState {
    pub fn new() -> Result<Self> {
        //TODO remove (for testing)
        let ep_pairs: Vec<EndpointReceiverPair> = vec![
            EndpointReceiverPair {
                endpoint: Arc::new(IrcEndpoint {} ),
                sender: None,
            },
        ];

        //TODO impl
        Ok(RircdState {
            endpoints: ep_pairs,
            creation_timestamp: Some(Instant::now()),
            plainlog: None,
            sqlite_log: None,
            postgres_log: None,
        })
    }

    //TODO impl
    pub fn from_config(config: String) -> Result<Self> {
        Self::new()
    }

    pub async fn broadcast_event(self: &Arc<Self>, event: EventRaw) -> Result<()> {
        //TODO impl V
        //let couldnt_send_to = Vec::new();
        //buffer that holds names/ids of the endpoints
        //where the event couldn't be send to +Reason<>
        let mut endpoint_responses: Vec<mpsc::Receiver<EventResponse>> = Vec::new();

        //self.endpoints.iter().filter(|ep| ep.is_active())
        //    .then(|ep| ep.

        Ok(())
    }

    pub async fn run(mut self) -> Result<()> {
        //TODO choose good default/custom chan size
        let (event_sender,mut event_receiver) = mpsc::channel::<Event>(64);

        //try to start each endpoint
        self.endpoints.iter_mut().filter(|ep| ep.endpoint.is_active()).for_each(|endpoint| {
            let endpoint_name = endpoint.endpoint.name();
            let (success_status_send,success_status_recv) = oneshot::channel::<Result<mpsc::Sender<Event>>>();
            tokio::spawn(endpoint.endpoint.clone().listen(success_status_send, event_sender.to_owned()));

            //TODO color err msg
            //TODO paralelize and sync at the end
            println!("starting {} | {}", endpoint_name,
                match futures::executor::block_on(async move {
                    //TODO find out when, why and if V this V can fail
                        success_status_recv.await.unwrap()
                }) {
                    Ok(sender) => {
                        endpoint.sender = Some(sender);
                        format!("SUCCESS |")
                    },
                    Err(e) => format!("FAILED | <{}>", e),
                });
        });


        //TODO Err() if not at least one Endpoint is running because
        //if none is running there is no way to activate further (user locked out)
        //> who needs a daemon that does nothing and where nothing can be configured to be done

        
        

        loop {
            println!("received event");
            tokio::select! {
                event = event_receiver.recv() => {
                    //TODO V find out why when and if  V this can fail
                    let event = event.unwrap();

                    //EVENT MATCHING
                    match &event.kind {

                        //INTERNAL
                        EventKind::Internal(ev) => {
                            match ev {
                                InternalEvent::Shutdown => {
                                    //TODO Output=Result<>
                                    //  -> print warning if
                                    //  some thing couldn't be
                                    //  shut down and maybe do
                                    //  a "waiting for xxx to finish"
                                    //  linux init system style waiting
                                    //  idk thingy
                                    //  
                                    //  TODO uhm why not instead make a
                                    //  shutdown() function and resuse some code
                                    iter(self.endpoints).all(|ep| async {
                                        let (ep_ev,r) = Event::new( EventRaw {
                                            kind: EventKind::Internal(InternalEvent::Shutdown),
                                            sender_name: "".into() //TODO look TODO in event.rs
                                        });
                                        //TODO V find out why when and if  V this can fail
                                        assert!(ep.sender.unwrap().send(ep_ev).await.is_ok());

                                        println!("shutting down | {}", match r.await.unwrap() {
                                            EventResponse::Success => format!("SUCCESS"),
                                            //TODO impl
                                            _ => format!("FAILED | <{}>", "reason :("),
                                        });

                                        true
                                    }).await;
                                    break;
                                },
                                _ => {},
                            }
                            assert!( event.result_sender.send(EventResponse::Success).is_ok());
                        },

                        //MESSAGE
                        EventKind::Message => {
                            //TODO maybe notify sender if one
                            //of the endpoints isn't connected
                            //or just write to log or do nothing depending
                            //on the chosen configuration
                            iter(&self.endpoints).all(|ep| async {
                                if ep.endpoint.name() == event.sender_name {
                                    ep.sender.unwrap().send(event);
                                }
                               false 
                            }).await;
                        },
                    };
                },
            };
        }

        Ok(())
    }
}