/*
    Hurry Curry! - a game about cooking
    Copyright 2024 metamuffin

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License only.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/
use crate::{
    data::Serverdata,
    entity::{Entities, EntityContext},
    interaction::{interact, tick_slot, InteractEffect, TickEffect},
};
use anyhow::{anyhow, bail, Result};
use hurrycurry_client_lib::{Game, Item, Player, Tile};
use hurrycurry_protocol::{
    glam::{IVec2, Vec2},
    movement::MovementBase,
    Gamedata, ItemLocation, Menu, PacketC, PacketS, PlayerID, Score, TileIndex,
};
use log::{info, warn};
use std::{
    collections::{HashMap, VecDeque},
    sync::Arc,
    time::{Duration, Instant},
};

pub struct ServerState {
    pub data: Arc<Serverdata>,
    pub entities: Entities,
    pub lobby: bool,
    pub player_id_counter: PlayerID,
    pub score_changed: bool,
    pub packet_loopback: VecDeque<PacketS>,
    pub last_movement_update: HashMap<PlayerID, Instant>,
}

pub struct Server<'a> {
    pub game: &'a mut Game,
    pub state: &'a mut ServerState,
}

impl Default for ServerState {
    fn default() -> Self {
        Self::new()
    }
}

pub trait GameServerExt {
    fn unload(&mut self, packet_out: &mut VecDeque<PacketC>);
    fn load(
        &mut self,
        gamedata: Gamedata,
        serverdata: &Serverdata,
        timer: Option<Duration>,
        packet_out: &mut VecDeque<PacketC>,
    );
    fn prime_client(&self) -> Vec<PacketC>;
}
impl GameServerExt for Game {
    fn unload(&mut self, packet_out: &mut VecDeque<PacketC>) {
        packet_out.push_back(PacketC::SetIngame {
            state: false,
            lobby: false,
        });
        for (id, _) in self.players.drain() {
            packet_out.push_back(PacketC::RemovePlayer { id })
        }
        for (pos, _) in self.tiles.drain() {
            packet_out.push_back(PacketC::UpdateMap {
                tile: pos,
                kind: None,
                neighbors: [None, None, None, None],
            })
        }
        self.score = Score::default();
        self.end = None;
        self.environment_effects.clear();
        self.walkable.clear();
    }
    fn load(
        &mut self,
        gamedata: Gamedata,
        serverdata: &Serverdata,
        timer: Option<Duration>,
        packet_out: &mut VecDeque<PacketC>,
    ) {
        let players = self
            .players
            .iter()
            .filter(|(_, p)| p.character >= 0)
            .map(|(id, p)| (*id, (p.name.to_owned(), p.character)))
            .collect::<HashMap<_, _>>();

        self.unload(packet_out);

        self.lobby = gamedata.current_map == "lobby";
        self.data = gamedata.into();
        self.score = Score {
            time_remaining: timer.map(|dur| dur.as_secs_f64()).unwrap_or(0.),
            ..Default::default()
        };
        self.end = timer.map(|dur| Instant::now() + dur);

        for (&p, (tile, item)) in &serverdata.initial_map {
            self.tiles.insert(
                p,
                Tile {
                    kind: *tile,
                    item: item.map(|i| Item {
                        kind: i,
                        active: None,
                    }),
                },
            );
            if !self.data.tile_collide[tile.0] {
                self.walkable.insert(p);
            }
        }
        for (id, (name, character)) in players {
            self.players.insert(
                id,
                Player {
                    item: None,
                    character,
                    movement: MovementBase {
                        position: if character < 0 {
                            serverdata.customer_spawn
                        } else {
                            serverdata.chef_spawn
                        },
                        input_direction: Vec2::ZERO,
                        input_boost: false,
                        facing: Vec2::X,
                        rotation: 0.,
                        velocity: Vec2::ZERO,
                        boosting: false,
                        stamina: 0.,
                    },
                    communicate_persist: None,
                    interacting: None,
                    name: name.clone(),
                },
            );
        }

        packet_out.extend(self.prime_client());
    }

    fn prime_client(&self) -> Vec<PacketC> {
        let mut out = Vec::new();
        out.push(PacketC::Data {
            data: self.data.as_ref().to_owned(),
        });
        out.push(PacketC::Environment {
            effects: self.environment_effects.clone(),
        });
        for (&id, player) in &self.players {
            out.push(PacketC::AddPlayer {
                id,
                position: player.movement.position,
                character: player.character,
                name: player.name.clone(),
            });
            if let Some(item) = &player.item {
                out.push(PacketC::SetItem {
                    location: ItemLocation::Player(id),
                    item: Some(item.kind),
                })
            }
            if let Some(c) = &player.communicate_persist {
                out.push(PacketC::Communicate {
                    player: id,
                    message: Some(c.to_owned()),
                    persist: true,
                })
            }
        }
        for (&tile, tdata) in &self.tiles {
            out.push(PacketC::UpdateMap {
                tile,
                neighbors: [
                    self.tiles.get(&(tile + IVec2::NEG_Y)).map(|e| e.kind),
                    self.tiles.get(&(tile + IVec2::NEG_X)).map(|e| e.kind),
                    self.tiles.get(&(tile + IVec2::Y)).map(|e| e.kind),
                    self.tiles.get(&(tile + IVec2::X)).map(|e| e.kind),
                ],
                kind: Some(tdata.kind),
            });
            if let Some(item) = &tdata.item {
                out.push(PacketC::SetItem {
                    location: ItemLocation::Tile(tile),
                    item: Some(item.kind),
                })
            }
        }
        out.push(PacketC::Score(self.score.clone()));
        out.push(PacketC::SetIngame {
            state: true,
            lobby: self.lobby,
        });
        out
    }
}

impl ServerState {
    pub fn new() -> Self {
        Self {
            lobby: false,
            data: Serverdata::default().into(),
            entities: vec![],
            player_id_counter: PlayerID(1),
            score_changed: false,
            packet_loopback: VecDeque::new(),
            last_movement_update: HashMap::default(),
        }
    }
}
impl Server<'_> {
    pub fn load(
        &mut self,
        (gamedata, serverdata, entities): (Gamedata, Serverdata, Entities),
        timer: Option<Duration>,
        packet_out: &mut VecDeque<PacketC>,
    ) {
        self.game.load(gamedata, &serverdata, timer, packet_out);
        self.state.data = serverdata.into();
        for mut e in self.state.entities.drain(..) {
            e.destructor(EntityContext {
                game: self.game,
                packet_out,
                packet_in: &mut self.state.packet_loopback,
                score_changed: &mut self.state.score_changed,
                dt: 0.,
            });
        }
        self.state.entities = entities;
    }

    pub fn join_player(
        &mut self,
        id: PlayerID,
        name: String,
        character: i32,
        packet_out: &mut VecDeque<PacketC>,
    ) {
        let position = if character < 0 {
            self.state.data.customer_spawn
        } else {
            self.state.data.chef_spawn
        };
        self.game.players.insert(
            id,
            Player {
                item: None,
                character,
                movement: MovementBase {
                    position,
                    input_direction: Vec2::ZERO,
                    input_boost: false,
                    facing: Vec2::X,
                    rotation: 0.,
                    velocity: Vec2::ZERO,
                    boosting: false,
                    stamina: 0.,
                },

                communicate_persist: None,
                interacting: None,
                name: name.clone(),
            },
        );
        self.game.score.players = self.game.score.players.max(self.game.players.len());
        packet_out.push_back(PacketC::AddPlayer {
            id,
            name,
            position,
            character,
        });
    }

    pub fn packet_in(
        &mut self,
        packet: PacketS,
        replies: &mut Vec<PacketC>,
        packet_out: &mut VecDeque<PacketC>,
    ) -> Result<()> {
        match packet {
            PacketS::Join {
                name,
                character,
                id,
            } => {
                let id = id.unwrap_or_else(|| {
                    let id = self.state.player_id_counter;
                    self.state.player_id_counter.0 += 1;
                    id
                });
                self.join_player(id, name, character, packet_out);
                replies.push(PacketC::Joined { id })
            }
            PacketS::Leave { player } => {
                let p = self
                    .game
                    .players
                    .remove(&player)
                    .ok_or(anyhow!("player does not exist"))?;

                self.game.players_spatial_index.remove_entry(player);

                if let Some(item) = p.item {
                    let pos = p.movement.position.floor().as_ivec2();
                    if let Some(tile) = self.game.tiles.get_mut(&pos) {
                        if tile.item.is_none() {
                            packet_out.push_back(PacketC::SetItem {
                                location: ItemLocation::Tile(pos),
                                item: Some(item.kind),
                            });
                            tile.item = Some(item);
                        }
                    }
                }
                packet_out.push_back(PacketC::RemovePlayer { id: player })
            }
            PacketS::Movement {
                pos,
                boost,
                dir: direction,
                player,
            } => {
                let pd = self
                    .game
                    .players
                    .get_mut(&player)
                    .ok_or(anyhow!("player does not exist"))?;

                pd.movement.input(direction, boost);

                if let Some(pos) = pos {
                    let last_position_update = self
                        .state
                        .last_movement_update
                        .entry(player)
                        .or_insert_with(|| Instant::now());
                    let dt = last_position_update.elapsed();
                    *last_position_update += dt;
                    let diff = pos - pd.movement.position;
                    pd.movement.position += diff.clamp_length_max(dt.as_secs_f32());

                    if diff.length() > 1. {
                        replies.push(PacketC::MovementSync { player });
                    }
                }
            }
            PacketS::Interact { pos, player } => {
                let pid = player;
                let player = self
                    .game
                    .players
                    .get_mut(&pid)
                    .ok_or(anyhow!("player does not exist"))?;

                let (pos, edge) = match (pos, player.interacting) {
                    (None, None) => return Ok(()), // this is silent because of auto release
                    (None, Some(pos)) => (pos, false),
                    (Some(pos), None) => (pos, true),
                    (Some(_), Some(_)) => bail!("already interacting"),
                };

                let entpos = pos.as_vec2() + Vec2::splat(0.5);
                if edge && entpos.distance(player.movement.position) > 2. {
                    bail!("interacting too far from player");
                }

                let tile = self
                    .game
                    .tiles
                    .get_mut(&pos)
                    .ok_or(anyhow!("tile does not exist"))?;

                // No going back from here on

                player.interacting = if edge { Some(pos) } else { None };

                let other_pid = if !self.game.data.is_tile_interactable(tile.kind) {
                    self.game
                        .players
                        .iter()
                        .find(|(id, p)| **id != pid && p.movement.position.distance(entpos) < 0.7)
                        .map(|(&id, _)| id)
                } else {
                    None
                };

                if let Some(base_pid) = other_pid {
                    let [other, this] = self
                        .game
                        .players
                        .get_many_mut([&pid, &base_pid])
                        .ok_or(anyhow!("interacting with yourself. this is impossible"))?;

                    if this.character < 0 || other.character < 0 {
                        bail!("You shall not interact with customers.")
                    }

                    interact_effect(
                        &self.game.data,
                        edge,
                        &mut this.item,
                        ItemLocation::Player(base_pid),
                        &mut other.item,
                        ItemLocation::Player(pid),
                        None,
                        packet_out,
                        &mut self.game.score,
                        &mut self.state.score_changed,
                        false,
                    )
                } else {
                    let player = self
                        .game
                        .players
                        .get_mut(&pid)
                        .ok_or(anyhow!("player does not exist"))?;

                    interact_effect(
                        &self.game.data,
                        edge,
                        &mut tile.item,
                        ItemLocation::Tile(pos),
                        &mut player.item,
                        ItemLocation::Player(pid),
                        Some(tile.kind),
                        packet_out,
                        &mut self.game.score,
                        &mut self.state.score_changed,
                        false,
                    )
                }
            }
            PacketS::Communicate {
                message,
                persist,
                player,
            } => {
                info!("{player:?} message {message:?}");
                if persist {
                    if let Some(player) = self.game.players.get_mut(&player) {
                        player.communicate_persist = message.clone()
                    }
                }
                packet_out.push_back(PacketC::Communicate {
                    player,
                    message,
                    persist,
                })
            }
            PacketS::ReplaceHand { item, player } => {
                let pdata = self
                    .game
                    .players
                    .get_mut(&player)
                    .ok_or(anyhow!("player does not exist"))?;
                pdata.item = item.map(|i| Item {
                    kind: i,
                    active: None,
                });
                packet_out.push_back(PacketC::SetItem {
                    location: ItemLocation::Player(player),
                    item,
                })
            }
            PacketS::ApplyScore(score) => {
                self.game.score.demands_completed += score.demands_completed;
                self.game.score.demands_failed += score.demands_failed;
                self.game.score.points += score.points;
                self.state.score_changed = true;
            }
            PacketS::ReplayTick { .. } => bail!("packet not supported in this session"),
        }
        Ok(())
    }

    /// Returns true if the game should end
    pub fn tick(&mut self, dt: f32, packet_out: &mut VecDeque<PacketC>) -> bool {
        if self.state.score_changed {
            self.state.score_changed = false;
            packet_out.push_back(PacketC::Score(self.game.score.clone()));
        }

        for (&pos, tile) in &mut self.game.tiles {
            if let Some(effect) = tick_slot(
                dt,
                &self.game.data,
                Some(tile.kind),
                &mut tile.item,
                &mut self.game.score,
            ) {
                match effect {
                    TickEffect::Progress(warn) => packet_out.push_back(PacketC::SetProgress {
                        warn,
                        item: ItemLocation::Tile(pos),
                        progress: tile
                            .item
                            .as_ref()
                            .unwrap()
                            .active
                            .as_ref()
                            .map(|i| i.progress),
                    }),
                    TickEffect::Produce => {
                        packet_out.push_back(PacketC::SetProgress {
                            warn: false,
                            item: ItemLocation::Tile(pos),
                            progress: None,
                        });
                        packet_out.push_back(PacketC::SetItem {
                            location: ItemLocation::Tile(pos),
                            item: tile.item.as_ref().map(|i| i.kind),
                        });
                    }
                }
            }
        }

        for (&pid, player) in &mut self.game.players {
            player.movement.update(&self.game.walkable, dt);

            self.game
                .players_spatial_index
                .update_entry(pid, player.movement.position);
        }

        self.game.players_spatial_index.all(|p1, pos1| {
            self.game
                .players_spatial_index
                .query(pos1, 2., |p2, _pos2| {
                    if let Some([a, b]) = self.game.players.get_many_mut([&p1, &p2]) {
                        a.movement.collide(&mut b.movement, dt)
                    }
                })
        });

        for (&pid, player) in &mut self.game.players {
            packet_out.push_back(PacketC::Movement {
                player: pid,
                pos: player.movement.position,
                dir: player.movement.input_direction,
                boost: player.movement.boosting,
                rot: player.movement.rotation,
            });

            if let Some(effect) = tick_slot(
                dt,
                &self.game.data,
                None,
                &mut player.item,
                &mut self.game.score,
            ) {
                match effect {
                    TickEffect::Progress(warn) => packet_out.push_back(PacketC::SetProgress {
                        warn,
                        item: ItemLocation::Player(pid),
                        progress: player
                            .item
                            .as_ref()
                            .unwrap()
                            .active
                            .as_ref()
                            .map(|i| i.progress),
                    }),
                    TickEffect::Produce => {
                        packet_out.push_back(PacketC::SetProgress {
                            warn: false,
                            item: ItemLocation::Player(pid),
                            progress: None,
                        });
                        packet_out.push_back(PacketC::SetItem {
                            location: ItemLocation::Player(pid),
                            item: player.item.as_ref().map(|i| i.kind),
                        });
                    }
                }
            }
        }

        let mut players_auto_release = Vec::new();
        for (pid, player) in &mut self.game.players {
            if let Some(pos) = player.interacting {
                if let Some(tile) = self.game.tiles.get(&pos) {
                    if let Some(item) = &tile.item {
                        if let Some(involvement) = &item.active {
                            if involvement.progress >= 1. {
                                players_auto_release.push(*pid);
                            }
                        }
                    }
                }
            }
        }
        for player in players_auto_release.drain(..) {
            let _ = self.packet_in(
                PacketS::Interact { pos: None, player },
                &mut vec![],
                packet_out,
            );
        }

        for entity in self.state.entities.iter_mut() {
            if let Err(e) = entity.tick(EntityContext {
                game: self.game,
                packet_out,
                score_changed: &mut self.state.score_changed,
                packet_in: &mut self.state.packet_loopback,
                dt,
            }) {
                warn!("entity tick failed: {e}")
            }
        }

        while let Some(p) = self.state.packet_loopback.pop_front() {
            if let Err(e) = self.packet_in(p, &mut vec![], packet_out) {
                warn!("internal packet errored: {e}");
            }
        }

        let now = Instant::now();

        if let Some(end) = self.game.end {
            self.game.score.time_remaining = (end - now).as_secs_f64();
            if end < now {
                let relative_score =
                    (self.game.score.points * 100) / self.state.data.score_baseline.max(1);
                self.game.score.stars = match relative_score {
                    100.. => 3,
                    70.. => 2,
                    40.. => 1,
                    _ => 0,
                };
                packet_out.push_back(PacketC::Menu(Menu::Score(self.game.score.clone())));
                true
            } else {
                false
            }
        } else {
            false
        }
    }

    pub fn count_chefs(&self) -> usize {
        self.game
            .players
            .values()
            .map(|p| if p.character >= 0 { 1 } else { 0 })
            .sum()
    }
}

pub fn interact_effect(
    data: &Gamedata,
    edge: bool,
    this: &mut Option<Item>,
    this_loc: ItemLocation,
    other: &mut Option<Item>,
    other_loc: ItemLocation,
    this_tile_kind: Option<TileIndex>,
    packet_out: &mut VecDeque<PacketC>,
    score: &mut Score,
    score_changed: &mut bool,
    automated: bool,
) {
    let this_had_item = this.is_some();
    let other_had_item = other.is_some();

    if let Some(effect) = interact(data, edge, this_tile_kind, this, other, score, automated) {
        match effect {
            InteractEffect::Put => {
                info!("put {this_loc} <- {other_loc}");
                packet_out.push_back(PacketC::MoveItem {
                    from: other_loc,
                    to: this_loc,
                })
            }
            InteractEffect::Take => {
                info!("take {this_loc} -> {other_loc}");
                packet_out.push_back(PacketC::MoveItem {
                    from: this_loc,
                    to: other_loc,
                })
            }
            InteractEffect::Produce => {
                info!("produce {this_loc} <~ {other_loc}");
                *score_changed = true;
                if this_had_item {
                    packet_out.push_back(PacketC::SetProgress {
                        item: this_loc,
                        progress: None,
                        warn: false,
                    });
                    packet_out.push_back(PacketC::SetItem {
                        location: this_loc,
                        item: None,
                    });
                }
                if other_had_item {
                    packet_out.push_back(PacketC::MoveItem {
                        from: other_loc,
                        to: this_loc,
                    });
                    packet_out.push_back(PacketC::SetItem {
                        location: this_loc,
                        item: None,
                    });
                }
                if let Some(i) = &other {
                    packet_out.push_back(PacketC::SetItem {
                        location: this_loc,
                        item: Some(i.kind),
                    });
                    packet_out.push_back(PacketC::MoveItem {
                        from: this_loc,
                        to: other_loc,
                    })
                }
                if let Some(i) = &this {
                    packet_out.push_back(PacketC::SetItem {
                        location: this_loc,
                        item: Some(i.kind),
                    });
                }
            }
        }
    }
}