use bevy::prelude::*;

use crate::{
    domain::{End, SnakePath, Tail},
    observers::{cleanup_snake_path, schedule_set_velocity, tail_observer},
};

/// Инициализация игрового мира
pub fn startup(mut commands: Commands, mut timer: ResMut<Time<Fixed>>) {
    timer.set_timestep_hz(32.0);
    spawn_snake(&mut commands);
    crate::debug::spawn_grid(&mut commands);
    commands.spawn(Camera2d);
}

/// Создать голову змеи
fn spawn_snake(commands: &mut Commands) {
    use crate::domain::{Direction, HEAD_SIZE, Head, Inert, SNAKE_VELOCITY, Velocity};

    commands.insert_resource(SnakePath::default());
    commands.spawn(Observer::new(cleanup_snake_path));

    /*
    commands.spawn(Observer::new(|e: On<GridBarier>| {
        let entity = e.entity;
        let src = e.src_pos;
        let dst = e.dst_pos;
        trace!("...<{entity:?}> moving {src:>16} => {dst:>16}");
    }));
    */

    let head = commands
        .spawn((
            Head,
            Direction::default(),
            Inert::default(),
            Velocity(SNAKE_VELOCITY as f32),
            Sprite::from_color(Color::srgb(1., 1., 1.), vec2(HEAD_SIZE as f32, HEAD_SIZE as f32)),
            Transform {
                translation: vec3(0.0, 0.0, 1.0),
                ..Default::default()
            },
        ))
        .id();
    commands.spawn((
        Sprite::from_color(Color::srgb(1., 0., 0.), vec2(HEAD_SIZE as f32 * 0.3, HEAD_SIZE as f32 * 0.3)),
        Transform {
            translation: vec3(HEAD_SIZE as f32 * -0.25, HEAD_SIZE as f32 * 0.25, 1.0),
            ..Default::default()
        },
        ChildOf(head),
    ));
    commands.spawn((
        Sprite::from_color(Color::srgb(0., 0., 1.), vec2(HEAD_SIZE as f32 * 0.2, HEAD_SIZE as f32 * 0.2)),
        Transform {
            translation: vec3(HEAD_SIZE as f32 * 0.25, HEAD_SIZE as f32 * 0.25, 1.0),
            ..Default::default()
        },
        ChildOf(head),
    ));

    let tail = commands
        .spawn((
            Tail,
            End,
            Direction::default(),
            Inert::default(),
            Velocity(0.0),
            Sprite::from_color(Color::srgb(0.7, 0.7, 0.7), vec2(HEAD_SIZE as f32 * 0.8, HEAD_SIZE as f32 * 0.8)),
            Transform {
                translation: vec3(0.0, 0.0, 0.0),
                ..Default::default()
            },
            Observer::new(tail_observer),
        ))
        .id();
    commands.entity(head).observe(schedule_set_velocity(tail));
}