/*
    Undercooked - 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::protocol::PacketS;
use glam::{IVec2, Vec2};
use std::collections::HashSet;

const PLAYER_SIZE: f32 = 0.4;
const PLAYER_SPEED: f32 = 65.;
pub const PLAYER_SPEED_LIMIT: f32 = f32::INFINITY; // 10.;

pub struct MovementBase {
    pub position: Vec2,
    pub facing: Vec2,
    pub vel: Vec2,
}

impl MovementBase {
    pub fn update(&mut self, map: &HashSet<IVec2>, direction: Vec2, dt: f32) -> PacketS {
        let direction = direction.clamp_length_max(1.);
        if direction.length() > 0.1 {
            self.facing = direction + (self.facing - direction) * (-dt * 10.).exp();
        }
        let rot = self.facing.x.atan2(self.facing.y);
        self.vel += direction * dt * PLAYER_SPEED;
        self.position += self.vel * dt;
        self.vel = self.vel * (-dt * 15.).exp();
        collide_player(self, map);

        PacketS::Position {
            pos: self.position,
            rot,
        }
    }
}

pub fn collide_player(p: &mut MovementBase, map: &HashSet<IVec2>) {
    for xo in -1..=1 {
        for yo in -1..=1 {
            let tile = IVec2::new(xo, yo) + p.position.as_ivec2();
            if map.contains(&tile) {
                continue;
            }
            let tile = tile.as_vec2();
            let d = aabb_point_distance(tile, tile + Vec2::ONE, p.position);
            if d > PLAYER_SIZE {
                continue;
            }
            let h = 0.01;
            let d_sample_x =
                aabb_point_distance(tile, tile + Vec2::ONE, p.position + Vec2::new(h, 0.));
            let d_sample_y =
                aabb_point_distance(tile, tile + Vec2::ONE, p.position + Vec2::new(0., h));
            let grad = (Vec2::new(d_sample_x, d_sample_y) - d) / h;

            p.position += (PLAYER_SIZE - d) * grad;
            p.vel -= grad * grad.dot(p.vel);
        }
    }
}

pub fn aabb_point_distance(min: Vec2, max: Vec2, p: Vec2) -> f32 {
    (p - p.clamp(min, max)).length()
}