//! A basic implementation of a character controller for a kinematic rigid body.
//!
//! This showcases the following:
//!
//! - Basic directional movement and jumping
//! - Support for both keyboard and gamepad input
//! - A configurable maximum slope angle
//! - Collision response for kinematic bodies
//!
//! The character controller logic is contained within the `plugin` module.
//!
//! For a dynamic character controller, see the `dynamic_character_2d` example.
//!
//! ## Warning
//!
//! Note that this is *not* intended to be a fully featured character controller,
//! and the collision logic is quite basic.
//!
//! For a better solution, consider implementing a "collide-and-slide" algorithm,
//! or use an existing third party character controller plugin like Bevy Tnua
//! (a dynamic character controller).

mod plugin;

use avian2d::{math::*, prelude::*};
use bevy::{
    prelude::*,
    render::{render_asset::RenderAssetUsages, render_resource::PrimitiveTopology},
    sprite::MaterialMesh2dBundle,
};
use examples_common_2d::ExampleCommonPlugin;
use plugin::*;

fn main() {
    App::new()
        .add_plugins((
            DefaultPlugins,
            ExampleCommonPlugin,
            // Add physics plugins and specify a units-per-meter scaling factor, 1 meter = 20 pixels.
            // The unit allows the engine to tune its parameters for the scale of the world, improving stability.
            PhysicsPlugins::default().with_length_unit(20.0),
            CharacterControllerPlugin,
        ))
        .insert_resource(ClearColor(Color::srgb(0.05, 0.05, 0.1)))
        .insert_resource(Gravity(Vector::NEG_Y * 1000.0))
        .add_systems(Startup, setup)
        .run();
}

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<ColorMaterial>>,
) {
    // Player
    commands.spawn((
        MaterialMesh2dBundle {
            mesh: meshes.add(Capsule2d::new(12.5, 20.0)).into(),
            material: materials.add(Color::srgb(0.2, 0.7, 0.9)),
            transform: Transform::from_xyz(0.0, -100.0, 0.0),
            ..default()
        },
        CharacterControllerBundle::new(Collider::capsule(12.5, 20.0), Vector::NEG_Y * 1500.0)
            .with_movement(1250.0, 0.92, 400.0, (30.0 as Scalar).to_radians()),
    ));

    // A cube to move around
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.0, 0.4, 0.7),
                custom_size: Some(Vec2::new(30.0, 30.0)),
                ..default()
            },
            transform: Transform::from_xyz(50.0, -100.0, 0.0),
            ..default()
        },
        RigidBody::Dynamic,
        Collider::rectangle(30.0, 30.0),
    ));

    // Platforms
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.7, 0.7, 0.8),
                custom_size: Some(Vec2::new(1100.0, 50.0)),
                ..default()
            },
            transform: Transform::from_xyz(0.0, -175.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        Collider::rectangle(1100.0, 50.0),
    ));
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.7, 0.7, 0.8),
                custom_size: Some(Vec2::new(300.0, 25.0)),
                ..default()
            },
            transform: Transform::from_xyz(175.0, -35.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        Collider::rectangle(300.0, 25.0),
    ));
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.7, 0.7, 0.8),
                custom_size: Some(Vec2::new(300.0, 25.0)),
                ..default()
            },
            transform: Transform::from_xyz(-175.0, 0.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        Collider::rectangle(300.0, 25.0),
    ));
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.7, 0.7, 0.8),
                custom_size: Some(Vec2::new(150.0, 80.0)),
                ..default()
            },
            transform: Transform::from_xyz(475.0, -110.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        Collider::rectangle(150.0, 80.0),
    ));
    commands.spawn((
        SpriteBundle {
            sprite: Sprite {
                color: Color::srgb(0.7, 0.7, 0.8),
                custom_size: Some(Vec2::new(150.0, 80.0)),
                ..default()
            },
            transform: Transform::from_xyz(-475.0, -110.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        Collider::rectangle(150.0, 80.0),
    ));

    // Ramps

    let mut ramp_mesh = Mesh::new(
        PrimitiveTopology::TriangleList,
        RenderAssetUsages::default(),
    );

    ramp_mesh.insert_attribute(
        Mesh::ATTRIBUTE_POSITION,
        vec![[-125.0, 80.0, 0.0], [-125.0, 0.0, 0.0], [125.0, 0.0, 0.0]],
    );

    let ramp_collider = Collider::triangle(
        Vector::new(-125.0, 80.0),
        Vector::NEG_X * 125.0,
        Vector::X * 125.0,
    );

    commands.spawn((
        MaterialMesh2dBundle {
            mesh: meshes.add(ramp_mesh).into(),
            material: materials.add(Color::srgb(0.4, 0.4, 0.5)),
            transform: Transform::from_xyz(-275.0, -150.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        ramp_collider,
    ));

    let mut ramp_mesh = Mesh::new(
        PrimitiveTopology::TriangleList,
        RenderAssetUsages::default(),
    );

    ramp_mesh.insert_attribute(
        Mesh::ATTRIBUTE_POSITION,
        vec![[20.0, -40.0, 0.0], [20.0, 40.0, 0.0], [-20.0, -40.0, 0.0]],
    );

    let ramp_collider = Collider::triangle(
        Vector::new(20.0, -40.0),
        Vector::new(20.0, 40.0),
        Vector::new(-20.0, -40.0),
    );

    commands.spawn((
        MaterialMesh2dBundle {
            mesh: meshes.add(ramp_mesh).into(),
            material: materials.add(Color::srgb(0.4, 0.4, 0.5)),
            transform: Transform::from_xyz(380.0, -110.0, 0.0),
            ..default()
        },
        RigidBody::Static,
        ramp_collider,
    ));

    // Camera
    commands.spawn(Camera2dBundle::default());
}