use std::{collections::HashMap, io, sync::Arc};

use azalea_auth::game_profile::GameProfile;
use azalea_core::ChunkPos;
use azalea_ecs::component::Component;
use azalea_ecs::entity::Entity;
use azalea_ecs::{query::Added, system::Query};
use azalea_protocol::packets::game::ServerboundGamePacket;
use azalea_world::{
    entity::{self, Dead},
    PartialWorld, World,
};
use derive_more::{Deref, DerefMut};
use parking_lot::RwLock;
use thiserror::Error;
use tokio::{sync::mpsc, task::JoinHandle};
use uuid::Uuid;

use crate::{
    events::{Event, LocalPlayerEvents},
    ClientInformation, PlayerInfo, WalkDirection,
};

/// This is a component for our local player entities that are probably in a
/// world. If you have access to a [`Client`], you probably don't need to care
/// about this since `Client` gives you access to everything here.
///
/// You can also use the [`Local`] marker component for queries if you're only
/// checking for a local player and don't need the contents of this component.
///
/// [`Local`]: azalea_world::entity::Local
/// [`Client`]: crate::Client
#[derive(Component)]
pub struct LocalPlayer {
    packet_writer: mpsc::UnboundedSender<ServerboundGamePacket>,
    /// Some of the "settings" for this client that are sent to the server, such
    /// as render distance.
    pub client_information: ClientInformation,
    /// A map of player UUIDs to their information in the tab list
    pub players: HashMap<Uuid, PlayerInfo>,
    /// The partial world is the world this client currently has loaded. It has
    /// a limited render distance.
    pub partial_world: Arc<RwLock<PartialWorld>>,
    /// The world is the combined [`PartialWorld`]s of all clients in the same
    /// world. (Only relevant if you're using a shared world, i.e. a swarm)
    pub world: Arc<RwLock<World>>,

    /// A list of async tasks that are running and will stop running when this
    /// LocalPlayer is dropped or disconnected with [`Self::disconnect`]
    pub(crate) tasks: Vec<JoinHandle<()>>,
}

/// Component for entities that can move and sprint. Usually only in
/// [`LocalPlayer`] entities.
#[derive(Default, Component)]
pub struct PhysicsState {
    /// Minecraft only sends a movement packet either after 20 ticks or if the
    /// player moved enough. This is that tick counter.
    pub position_remainder: u32,
    pub was_sprinting: bool,
    // Whether we're going to try to start sprinting this tick. Equivalent to
    // holding down ctrl for a tick.
    pub trying_to_sprint: bool,

    pub move_direction: WalkDirection,
    pub forward_impulse: f32,
    pub left_impulse: f32,
}

/// A component only present in players that contains the [`GameProfile`] (which
/// you can use to get a player's name).
///
/// Note that it's possible for this to be missing in a player if the server
/// never sent the player info for them (though this is uncommon).
#[derive(Component, Clone, Debug, Deref, DerefMut)]
pub struct GameProfileComponent(pub GameProfile);

/// Marks a [`LocalPlayer`] that's in a loaded chunk. This is updated at the
/// beginning of every tick.
#[derive(Component)]
pub struct LocalPlayerInLoadedChunk;

impl LocalPlayer {
    /// Create a new `LocalPlayer`.
    pub fn new(
        entity: Entity,
        packet_writer: mpsc::UnboundedSender<ServerboundGamePacket>,
        world: Arc<RwLock<World>>,
    ) -> Self {
        let client_information = ClientInformation::default();

        LocalPlayer {
            packet_writer,

            client_information: ClientInformation::default(),
            players: HashMap::new(),

            world,
            partial_world: Arc::new(RwLock::new(PartialWorld::new(
                client_information.view_distance.into(),
                Some(entity),
            ))),

            tasks: Vec::new(),
        }
    }

    /// Write a packet directly to the server.
    pub fn write_packet(&mut self, packet: ServerboundGamePacket) {
        self.packet_writer
            .send(packet)
            .expect("write_packet shouldn't be able to be called if the connection is closed");
    }

    /// Disconnect this client from the server by ending all tasks.
    ///
    /// The OwnedReadHalf for the TCP connection is in one of the tasks, so it
    /// automatically closes the connection when that's dropped.
    pub fn disconnect(&self) {
        for task in &self.tasks {
            task.abort();
        }
    }
}

/// Update the [`LocalPlayerInLoadedChunk`] component for all [`LocalPlayer`]s.
pub fn update_in_loaded_chunk(
    mut commands: azalea_ecs::system::Commands,
    query: Query<(Entity, &LocalPlayer, &entity::Position)>,
) {
    for (entity, local_player, position) in &query {
        let player_chunk_pos = ChunkPos::from(position);
        let in_loaded_chunk = local_player
            .world
            .read()
            .chunks
            .get(&player_chunk_pos)
            .is_some();
        if in_loaded_chunk {
            commands.entity(entity).insert(LocalPlayerInLoadedChunk);
        } else {
            commands.entity(entity).remove::<LocalPlayerInLoadedChunk>();
        }
    }
}

/// Send the "Death" event for [`LocalPlayer`]s that died with no reason.
pub fn death_event(query: Query<&LocalPlayerEvents, Added<Dead>>) {
    for local_player_events in &query {
        local_player_events.send(Event::Death(None)).unwrap();
    }
}

#[derive(Error, Debug)]
pub enum HandlePacketError {
    #[error("{0}")]
    Poison(String),
    #[error(transparent)]
    Io(#[from] io::Error),
    #[error(transparent)]
    Other(#[from] anyhow::Error),
    #[error("{0}")]
    Send(#[from] mpsc::error::SendError<Event>),
}

impl<T> From<std::sync::PoisonError<T>> for HandlePacketError {
    fn from(e: std::sync::PoisonError<T>) -> Self {
        HandlePacketError::Poison(e.to_string())
    }
}