pub mod movement;
mod pathfinding;

use crate::{
    data::Gamedata,
    game::Game,
    protocol::{ItemIndex, Message, PacketC, PacketS, PlayerID},
};
use glam::{IVec2, Vec2};
use log::{debug, error};
use movement::MovementBase;
use pathfinding::{find_path, Path};
use rand::thread_rng;
use std::{
    collections::{HashMap, HashSet},
    sync::Arc,
    time::Duration,
};
use tokio::{
    sync::{broadcast, RwLock},
    time::interval,
};

struct DemandState {
    data: Gamedata,
    walkable: HashSet<IVec2>,
    chairs: HashMap<IVec2, bool>,
    items: HashMap<IVec2, ItemIndex>,
    customers: HashMap<PlayerID, Customer>,
}

enum CustomerState {
    WalkingToChair { path: Path, chair: IVec2 },
    Waiting { chair: IVec2, demand: ItemIndex },
    Exiting { path: Path },
}

struct Customer {
    movement: MovementBase,
    state: CustomerState,
}

pub async fn customer(game: Arc<RwLock<Game>>, mut grx: broadcast::Receiver<PacketC>) {
    let mut state = DemandState {
        walkable: Default::default(),
        chairs: Default::default(),
        items: Default::default(),
        customers: Default::default(),
        data: Gamedata::default(),
    };
    let initial = game.write().await.prime_client(-1);
    for p in initial {
        match p {
            PacketC::Init { data, .. } => {
                state.data = data;
            }
            PacketC::UpdateMap { pos, tile, .. } => {
                let tilename = &state.data.tile_names[tile];
                if tilename == "floor" || tilename == "door" || tilename == "chair" {
                    state.walkable.insert(pos);
                }
                if tilename == "chair" {
                    state.chairs.insert(pos, true);
                }
            }
            _ => (),
        }
    }

    let mut interval = interval(Duration::from_millis(40));
    let mut packets_out = Vec::new();
    loop {
        tokio::select! {
            packet = grx.recv() => {
                match packet.unwrap() {
                    PacketC::PutItem { .. }
                    | PacketC::TakeItem { .. }
                    | PacketC::ProduceItem { .. }
                    | PacketC::ConsumeItem { .. } => {
                        let g = game.read().await;
                        update_items(&mut state, &g)
                    },
                    _ => ()
                }
            }
            _ = interval.tick() => {
                state.tick(&mut packets_out, 0.04);
                for (player,packet) in packets_out.drain(..) {
                    if let Err(e) = game.write().await.packet_in(player, packet) {
                        error!("customer misbehaved: {e}")
                    }
                }
            }
        }
    }
}

fn update_items(state: &mut DemandState, game: &Game) {
    state.items.clear();
    for (&pos, tile) in game.tiles() {
        if let Some(item) = &tile.item {
            state.items.insert(pos, item.kind);
        }
    }
}

impl DemandState {
    pub fn tick(&mut self, packets_out: &mut Vec<(PlayerID, PacketS)>, dt: f32) {
        if self.customers.is_empty() {
            let id = -1;
            packets_out.push((
                id,
                PacketS::Join {
                    name: "George".to_string(),
                    character: 0,
                },
            ));
            let chair = select_chair(&mut self.chairs);
            let path = find_path(&self.walkable, self.data.customer_spawn.as_ivec2(), chair)
                .expect("no path");
            self.customers.insert(
                id,
                Customer {
                    movement: MovementBase {
                        position: self.data.customer_spawn,
                        facing: Vec2::X,
                        vel: Vec2::ZERO,
                    },
                    state: CustomerState::WalkingToChair { path, chair },
                },
            );
        }
        let mut customers_to_remove = Vec::new();
        for (&id, p) in &mut self.customers {
            match &mut p.state {
                CustomerState::WalkingToChair { path, chair } => {
                    packets_out.push((id, path.execute_tick(&mut p.movement, &self.walkable, dt)));
                    if path.is_done() {
                        let demand = self.data.get_item("tomato").unwrap();
                        packets_out.push((
                            id,
                            PacketS::Communicate {
                                message: Some(Message::Item(demand)),
                            },
                        ));
                        p.state = CustomerState::Waiting {
                            chair: *chair,
                            demand,
                        };
                    }
                }
                CustomerState::Waiting { chair, demand } => {
                    let demand_pos = [IVec2::NEG_X, IVec2::NEG_Y, IVec2::X, IVec2::Y]
                        .into_iter()
                        .find_map(|off| {
                            let pos = *chair + off;
                            if self.items.get(&pos) == Some(demand) {
                                Some(pos)
                            } else {
                                None
                            }
                        });
                    if let Some(pos) = demand_pos {
                        if self.items.get(&pos) == Some(demand) {
                            packets_out.push((id, PacketS::Communicate { message: None }));
                            let path = find_path(
                                &self.walkable,
                                p.movement.position.as_ivec2(),
                                self.data.customer_spawn.as_ivec2(),
                            )
                            .expect("no path to exit");
                            p.state = CustomerState::Exiting { path }
                        }
                    }
                    debug!("waiting")
                }
                CustomerState::Exiting { path } => {
                    packets_out.push((id, path.execute_tick(&mut p.movement, &self.walkable, dt)));
                    if path.is_done() {
                        packets_out.push((id, PacketS::Leave));
                        customers_to_remove.push(id);
                    }
                }
            }
        }
        for c in customers_to_remove {
            self.customers.remove(&c).unwrap();
        }
    }
}

pub fn select_chair(chairs: &mut HashMap<IVec2, bool>) -> IVec2 {
    use rand::seq::IteratorRandom;
    let (chosen, free) = chairs
        .iter_mut()
        .filter(|(_p, free)| **free)
        .choose(&mut thread_rng())
        .unwrap();
    *free = false;
    *chosen
}