use std::{collections::HashMap, net::SocketAddr, time::Duration};

use bevy::prelude::*;
use uuid::Uuid;

#[derive(Debug, Default)]
struct Timing {
    timestamp: Option<Duration>,
}

#[derive(Component, Debug, Default)]
pub struct PeerSendTiming(Timing);

impl PeerSendTiming {
    pub fn update(&mut self, time: &Res<Time>) {
        self.0.timestamp = Some(time.elapsed())
    }

    pub fn timestamp(&self) -> Option<Duration> {
        self.0.timestamp
    }
}

#[derive(Component, Debug, Default)]
pub struct PeerReceiveTiming(Timing);

impl PeerReceiveTiming {
    pub fn new(time: &Res<Time>) -> Self {
        Self(Timing {
            timestamp: Some(time.elapsed()),
        })
    }

    pub fn update(&mut self, time: &Res<Time>) {
        self.0.timestamp = Some(time.elapsed())
    }

    pub fn timestamp(&self) -> Option<Duration> {
        self.0.timestamp
    }
}

#[derive(Component, Debug)]
#[require(PeerSendTiming, PeerReceiveTiming)]
pub struct Peer {
    pub addr: SocketAddr,
    pub uuid: Uuid,
}

impl Peer {
    pub fn new(addr: SocketAddr, uuid: Uuid) -> Self {
        Self { addr, uuid }
    }
}

#[derive(Debug, Default, Resource)]
pub struct PeerMap {
    map: HashMap<Uuid, Entity>,
}

impl PeerMap {
    pub fn insert(&mut self, uuid: Uuid, id: Entity) {
        self.map.insert(uuid, id);
    }

    pub fn get(&self, uuid: &Uuid) -> Option<&Entity> {
        self.map.get(uuid)
    }

    pub fn try_get(&self, uuid: &Uuid) -> Result<&Entity, String> {
        self.get(uuid).ok_or(format!("No entity with uuid: {uuid}"))
    }

    pub fn remove(&mut self, uuid: &Uuid) -> Option<Entity> {
        self.map.remove(uuid)
    }

    pub fn len(&self) -> usize {
        self.map.len()
    }
}

#[derive(Debug, Event)]
pub struct PeerChangeEvent {
    peer: Uuid,
    addr: Option<SocketAddr>,
}

impl PeerChangeEvent {
    pub fn new(peer: Uuid, addr: Option<SocketAddr>) -> Self {
        Self { peer, addr }
    }
}

pub fn handle_peer_change(
    mut changes: EventReader<PeerChangeEvent>,
    mut peer_map: ResMut<PeerMap>,
    mut peers: Query<&mut Peer>,
    mut commands: Commands,
    time: Res<Time>,
) -> Result {
    for change in changes.read() {
        if let Some(entity) = peer_map.get(&change.peer) {
            if let Some(addr) = change.addr {
                if let Ok(mut peer) = peers.get_mut(*entity) {
                    peer.addr = addr;
                } else {
                    warn!("Peer {} doesn't exist (just added?)", change.peer);
                }
            } else {
                commands.get_entity(*entity)?.despawn();
                peer_map.remove(&change.peer);
            }
        } else if let Some(addr) = change.addr {
            info!("Adding peer {} ({:?})", change.peer, change.addr);
            peer_map.insert(
                change.peer,
                commands
                    .spawn((Peer::new(addr, change.peer), PeerReceiveTiming::new(&time)))
                    .id(),
            );
        } else {
            warn!("Peer {} already deleted", change.peer);
        }
    }
    if peer_map.len() > 1 {
        if let Some(entity) = peer_map.remove(&Uuid::nil()) {
            commands.get_entity(entity)?.despawn();
        }
    }
    Ok(())
}