//! 2d testbed
//!
//! You can switch scene by pressing the spacebar

mod helpers;

use argh::FromArgs;
use bevy::prelude::*;

use helpers::Next;

#[derive(FromArgs)]
/// 2d testbed
pub struct Args {
    #[argh(positional)]
    scene: Option<Scene>,
}

fn main() {
    #[cfg(not(target_arch = "wasm32"))]
    let args: Args = argh::from_env();
    #[cfg(target_arch = "wasm32")]
    let args: Args = Args::from_args(&[], &[]).unwrap();

    let mut app = App::new();
    app.add_plugins((DefaultPlugins,))
        .add_systems(OnEnter(Scene::Shapes), shapes::setup)
        .add_systems(OnEnter(Scene::Bloom), bloom::setup)
        .add_systems(OnEnter(Scene::Text), text::setup)
        .add_systems(OnEnter(Scene::Sprite), sprite::setup)
        .add_systems(OnEnter(Scene::SpriteSlicing), sprite_slicing::setup)
        .add_systems(OnEnter(Scene::Gizmos), gizmos::setup)
        .add_systems(
            OnEnter(Scene::TextureAtlasBuilder),
            texture_atlas_builder::setup,
        )
        .add_systems(OnEnter(Scene::ColorConsistency), color_consistency::setup)
        .add_systems(OnExit(Scene::ColorConsistency), color_consistency::teardown)
        .add_systems(Update, switch_scene)
        .add_systems(Update, gizmos::draw_gizmos.run_if(in_state(Scene::Gizmos)));

    match args.scene {
        None => app.init_state::<Scene>(),
        Some(scene) => app.insert_state(scene),
    };

    #[cfg(feature = "bevy_ci_testing")]
    app.add_systems(Update, helpers::switch_scene_in_ci::<Scene>);

    app.run();
}

#[derive(Debug, Clone, Eq, PartialEq, Hash, States, Default)]
enum Scene {
    #[default]
    Shapes,
    Bloom,
    Text,
    Sprite,
    SpriteSlicing,
    Gizmos,
    TextureAtlasBuilder,
    ColorConsistency,
}

impl std::str::FromStr for Scene {
    type Err = String;

    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
        let mut isit = Self::default();
        while s.to_lowercase() != format!("{isit:?}").to_lowercase() {
            isit = isit.next();
            if isit == Self::default() {
                return Err(format!("Invalid Scene name: {s}"));
            }
        }
        Ok(isit)
    }
}

impl Next for Scene {
    fn next(&self) -> Self {
        match self {
            Scene::Shapes => Scene::Bloom,
            Scene::Bloom => Scene::Text,
            Scene::Text => Scene::Sprite,
            Scene::Sprite => Scene::SpriteSlicing,
            Scene::SpriteSlicing => Scene::Gizmos,
            Scene::Gizmos => Scene::TextureAtlasBuilder,
            Scene::TextureAtlasBuilder => Scene::ColorConsistency,
            Scene::ColorConsistency => Scene::Shapes,
        }
    }
}

fn switch_scene(
    keyboard: Res<ButtonInput<KeyCode>>,
    scene: Res<State<Scene>>,
    mut next_scene: ResMut<NextState<Scene>>,
) {
    if keyboard.just_pressed(KeyCode::Space) {
        info!("Switching scene");
        next_scene.set(scene.get().next());
    }
}

mod shapes {
    use bevy::prelude::*;

    const X_EXTENT: f32 = 900.;

    pub fn setup(
        mut commands: Commands,
        mut meshes: ResMut<Assets<Mesh>>,
        mut materials: ResMut<Assets<ColorMaterial>>,
    ) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::Shapes)));

        let shapes = [
            meshes.add(Circle::new(50.0)),
            meshes.add(CircularSector::new(50.0, 1.0)),
            meshes.add(CircularSegment::new(50.0, 1.25)),
            meshes.add(Ellipse::new(25.0, 50.0)),
            meshes.add(Annulus::new(25.0, 50.0)),
            meshes.add(Capsule2d::new(25.0, 50.0)),
            meshes.add(Rhombus::new(75.0, 100.0)),
            meshes.add(Rectangle::new(50.0, 100.0)),
            meshes.add(RegularPolygon::new(50.0, 6)),
            meshes.add(Triangle2d::new(
                Vec2::Y * 50.0,
                Vec2::new(-50.0, -50.0),
                Vec2::new(50.0, -50.0),
            )),
        ];
        let num_shapes = shapes.len();

        for (i, shape) in shapes.into_iter().enumerate() {
            // Distribute colors evenly across the rainbow.
            let color = Color::hsl(360. * i as f32 / num_shapes as f32, 0.95, 0.7);

            commands.spawn((
                Mesh2d(shape),
                MeshMaterial2d(materials.add(color)),
                Transform::from_xyz(
                    // Distribute shapes from -X_EXTENT/2 to +X_EXTENT/2.
                    -X_EXTENT / 2. + i as f32 / (num_shapes - 1) as f32 * X_EXTENT,
                    0.0,
                    0.0,
                ),
                DespawnOnExit(super::Scene::Shapes),
            ));
        }
    }
}

mod bloom {
    use bevy::{core_pipeline::tonemapping::Tonemapping, post_process::bloom::Bloom, prelude::*};

    pub fn setup(
        mut commands: Commands,
        mut meshes: ResMut<Assets<Mesh>>,
        mut materials: ResMut<Assets<ColorMaterial>>,
    ) {
        commands.spawn((
            Camera2d,
            Tonemapping::TonyMcMapface,
            Bloom::default(),
            DespawnOnExit(super::Scene::Bloom),
        ));

        commands.spawn((
            Mesh2d(meshes.add(Circle::new(100.))),
            MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))),
            Transform::from_translation(Vec3::new(-200., 0., 0.)),
            DespawnOnExit(super::Scene::Bloom),
        ));

        commands.spawn((
            Mesh2d(meshes.add(RegularPolygon::new(100., 6))),
            MeshMaterial2d(materials.add(Color::srgb(6.25, 9.4, 9.1))),
            Transform::from_translation(Vec3::new(200., 0., 0.)),
            DespawnOnExit(super::Scene::Bloom),
        ));
    }
}

mod text {
    use bevy::color::palettes;
    use bevy::prelude::*;
    use bevy::sprite::Anchor;
    use bevy::text::TextBounds;

    pub fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::Text)));

        for (i, justify) in [
            Justify::Left,
            Justify::Right,
            Justify::Center,
            Justify::Justified,
        ]
        .into_iter()
        .enumerate()
        {
            let y = 230. - 150. * i as f32;
            spawn_anchored_text(&mut commands, -300. * Vec3::X + y * Vec3::Y, justify, None);
            spawn_anchored_text(
                &mut commands,
                300. * Vec3::X + y * Vec3::Y,
                justify,
                Some(TextBounds::new(150., 60.)),
            );
        }

        let sans_serif = TextFont::from(asset_server.load("fonts/FiraSans-Bold.ttf"));

        const NUM_ITERATIONS: usize = 10;
        for i in 0..NUM_ITERATIONS {
            let fraction = i as f32 / (NUM_ITERATIONS - 1) as f32;

            commands.spawn((
                Text2d::new("Bevy"),
                sans_serif.clone(),
                Transform::from_xyz(0.0, fraction * 200.0, i as f32)
                    .with_scale(1.0 + Vec2::splat(fraction).extend(1.))
                    .with_rotation(Quat::from_rotation_z(fraction * core::f32::consts::PI)),
                TextColor(Color::hsla(fraction * 360.0, 0.8, 0.8, 0.8)),
                DespawnOnExit(super::Scene::Text),
            ));
        }

        commands.spawn((
            Text2d::new("This text is invisible."),
            Visibility::Hidden,
            DespawnOnExit(super::Scene::Text),
        ));
    }

    fn spawn_anchored_text(
        commands: &mut Commands,
        dest: Vec3,
        justify: Justify,
        bounds: Option<TextBounds>,
    ) {
        commands.spawn((
            Sprite {
                color: palettes::css::YELLOW.into(),
                custom_size: Some(5. * Vec2::ONE),
                ..Default::default()
            },
            Transform::from_translation(dest),
            DespawnOnExit(super::Scene::Text),
        ));

        for anchor in [
            Anchor::TOP_LEFT,
            Anchor::TOP_RIGHT,
            Anchor::BOTTOM_RIGHT,
            Anchor::BOTTOM_LEFT,
        ] {
            let mut text = commands.spawn((
                Text2d::new("L R\n"),
                TextLayout::justify(justify),
                Transform::from_translation(dest + Vec3::Z),
                anchor,
                DespawnOnExit(super::Scene::Text),
                ShowAabbGizmo {
                    color: Some(palettes::tailwind::AMBER_400.into()),
                },
                children![
                    (
                        TextSpan::new(format!("{}, {}\n", anchor.x, anchor.y)),
                        TextFont::from_font_size(14.0),
                        TextColor(palettes::tailwind::BLUE_400.into()),
                    ),
                    (
                        TextSpan::new(format!("{justify:?}")),
                        TextFont::from_font_size(14.0),
                        TextColor(palettes::tailwind::GREEN_400.into()),
                    ),
                ],
            ));
            if let Some(bounds) = bounds {
                text.insert(bounds);

                commands.spawn((
                    Sprite {
                        color: palettes::tailwind::GRAY_900.into(),
                        custom_size: Some(Vec2::new(bounds.width.unwrap(), bounds.height.unwrap())),
                        ..Default::default()
                    },
                    Transform::from_translation(dest - Vec3::Z),
                    anchor,
                    DespawnOnExit(super::Scene::Text),
                ));
            }
        }
    }
}

mod sprite {
    use bevy::color::palettes::css::{BLUE, LIME, RED};
    use bevy::prelude::*;
    use bevy::sprite::Anchor;

    pub fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::Sprite)));
        for (anchor, flip_x, flip_y, color) in [
            (Anchor::BOTTOM_LEFT, false, false, Color::WHITE),
            (Anchor::BOTTOM_RIGHT, true, false, RED.into()),
            (Anchor::TOP_LEFT, false, true, LIME.into()),
            (Anchor::TOP_RIGHT, true, true, BLUE.into()),
        ] {
            commands.spawn((
                Sprite {
                    image: asset_server.load("branding/bevy_logo_dark.png"),
                    flip_x,
                    flip_y,
                    color,
                    ..default()
                },
                anchor,
                DespawnOnExit(super::Scene::Sprite),
            ));
        }
    }
}

mod sprite_slicing {
    use bevy::prelude::*;
    use bevy::sprite::{BorderRect, SliceScaleMode, SpriteImageMode, TextureSlicer};

    pub fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::SpriteSlicing)));

        let texture = asset_server.load("textures/slice_square_2.png");
        let font = asset_server.load("fonts/FiraSans-Bold.ttf");

        commands.spawn((
            Sprite {
                image: texture.clone(),
                ..default()
            },
            Transform::from_translation(Vec3::new(-150.0, 50.0, 0.0)).with_scale(Vec3::splat(2.0)),
            DespawnOnExit(super::Scene::SpriteSlicing),
        ));

        commands.spawn((
            Sprite {
                image: texture,
                image_mode: SpriteImageMode::Sliced(TextureSlicer {
                    border: BorderRect::all(20.0),
                    center_scale_mode: SliceScaleMode::Stretch,
                    ..default()
                }),
                custom_size: Some(Vec2::new(200.0, 200.0)),
                ..default()
            },
            Transform::from_translation(Vec3::new(150.0, 50.0, 0.0)),
            DespawnOnExit(super::Scene::SpriteSlicing),
        ));

        commands.spawn((
            Text2d::new("Original"),
            TextFont {
                font: FontSource::from(font.clone()),
                font_size: FontSize::Px(20.0),
                ..default()
            },
            Transform::from_translation(Vec3::new(-150.0, -80.0, 0.0)),
            DespawnOnExit(super::Scene::SpriteSlicing),
        ));

        commands.spawn((
            Text2d::new("Sliced"),
            TextFont {
                font: FontSource::from(font.clone()),
                font_size: FontSize::Px(20.0),
                ..default()
            },
            Transform::from_translation(Vec3::new(150.0, -80.0, 0.0)),
            DespawnOnExit(super::Scene::SpriteSlicing),
        ));
    }
}

mod gizmos {
    use bevy::{color::palettes::css::*, prelude::*};

    pub fn setup(mut commands: Commands) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::Gizmos)));
    }

    pub fn draw_gizmos(mut gizmos: Gizmos) {
        gizmos.rect_2d(
            Isometry2d::from_translation(Vec2::new(-200.0, 0.0)),
            Vec2::new(200.0, 200.0),
            RED,
        );
        gizmos
            .circle_2d(
                Isometry2d::from_translation(Vec2::new(-200.0, 0.0)),
                200.0,
                GREEN,
            )
            .resolution(64);

        gizmos.text_2d(
            Isometry2d::from_translation(Vec2::new(-200.0, 0.0)),
            "text_2d gizmo",
            15.,
            Vec2 { x: 0., y: 0. },
            Color::WHITE,
        );

        // 2d grids with all variations of outer edges on or off
        for i in 0..4 {
            let x = 200.0 * (1.0 + (i % 2) as f32);
            let y = 150.0 * (0.5 - (i / 2) as f32);
            let mut grid = gizmos.grid(
                Vec3::new(x, y, 0.0),
                UVec2::new(5, 4),
                Vec2::splat(30.),
                Color::WHITE,
            );
            if i & 1 > 0 {
                grid = grid.outer_edges_x();
            }
            if i & 2 > 0 {
                grid.outer_edges_y();
            }
        }
    }
}

mod texture_atlas_builder {
    use bevy::{
        asset::RenderAssetUsages,
        image::ImageSampler,
        prelude::*,
        render::render_resource::{Extent3d, TextureDimension, TextureFormat},
        sprite::Anchor,
    };

    const ATLAS_SIZE: UVec2 = UVec2::splat(64);
    const IMAGE_SIZE: UVec2 = UVec2::splat(28);
    const PADDING_SIZE: UVec2 = UVec2::splat(2);
    const ATLAS_SCALE: f32 = 4.;
    const IMAGE_SCALE: f32 = 4.;

    pub fn setup(
        mut commands: Commands,
        mut textures: ResMut<Assets<Image>>,
        mut texture_atlases: ResMut<Assets<TextureAtlasLayout>>,
    ) {
        commands.spawn((Camera2d, DespawnOnExit(super::Scene::TextureAtlasBuilder)));

        for (i, padding) in [UVec2::ZERO, PADDING_SIZE].into_iter().enumerate() {
            // generate solid red green and blue and yellow images
            let images = [
                [255, 0, 0, 255],
                [0, 255, 0, 255],
                [0, 0, 255, 255],
                [255, 255, 0, 255],
            ]
            .map(|pixel| {
                Image::new_fill(
                    Extent3d {
                        width: 28,
                        height: 28,
                        depth_or_array_layers: 1,
                    },
                    TextureDimension::D2,
                    &pixel,
                    TextureFormat::Rgba8UnormSrgb,
                    RenderAssetUsages::MAIN_WORLD | RenderAssetUsages::RENDER_WORLD,
                )
            });

            let mut texture_atlas_builder = TextureAtlasBuilder::default();
            texture_atlas_builder
                .initial_size(ATLAS_SIZE)
                .max_size(ATLAS_SIZE)
                .padding(padding);
            for image in &images {
                texture_atlas_builder.add_texture(None, image);
            }

            let (atlas_layout, _, atlas_texture) = texture_atlas_builder.build().expect(
                "The images are 28 pixels square, so they should fit with 4 pixels left over",
            );
            let atlas_layout = texture_atlases.add(atlas_layout);

            let mut nearest_atlas_image = atlas_texture.clone();
            nearest_atlas_image.sampler = ImageSampler::nearest();

            let atlas_handle = textures.add(atlas_texture);
            let nearest_atlas_handle = textures.add(nearest_atlas_image);

            let position = ((2. * i as f32 - 1.) * (0.625 * ATLAS_SIZE.x as f32 * ATLAS_SCALE))
                .round()
                * Vec3::X;

            commands.spawn((
                Sprite {
                    image: nearest_atlas_handle,
                    custom_size: Some(ATLAS_SIZE.as_vec2() * ATLAS_SCALE),
                    ..default()
                },
                Anchor::BOTTOM_CENTER,
                ShowAabbGizmo {
                    color: Some(Color::WHITE),
                },
                DespawnOnExit(super::Scene::TextureAtlasBuilder),
                Transform::from_translation(position),
            ));

            for (index, anchor) in [
                Anchor::BOTTOM_RIGHT,
                Anchor::BOTTOM_LEFT,
                Anchor::TOP_LEFT,
                Anchor::TOP_RIGHT,
            ]
            .into_iter()
            .enumerate()
            {
                commands.spawn((
                    Sprite {
                        image: atlas_handle.clone(),
                        texture_atlas: Some(TextureAtlas {
                            layout: atlas_layout.clone(),
                            index,
                        }),
                        custom_size: Some(IMAGE_SIZE.as_vec2() * IMAGE_SCALE),
                        ..default()
                    },
                    Transform::from_translation(
                        position
                            + -2.
                                * IMAGE_SCALE
                                * (Vec3::Y * IMAGE_SIZE.y as f32 + anchor.as_vec().extend(0.)),
                    ),
                    anchor,
                    DespawnOnExit(super::Scene::TextureAtlasBuilder),
                ));
            }
        }
    }
}

mod color_consistency {
    //! Visual regression test for <https://github.com/bevyengine/bevy/issues/23577>.
    //!
    //! The clear color and shapes rendered using different pipelines (sprites,
    //! 2D meshes, UI background) should produce identical pixel values for the
    //! same sRGB input color.
    //!
    //! If the color conversion paths are consistent, the entire window will appear
    //! as a uniform solid color with no visible boundaries between the strips.

    use bevy::{core_pipeline::tonemapping::Tonemapping, prelude::*};

    // We've chosen the sRGB value from issue #23577, in case it can be reproduced elsewhere.
    const TEST_COLOR: Color = Color::srgb(0.1, 0.1, 0.1);
    const DEFAULT_WIDTH: f32 = 1280.0;
    const DEFAULT_HEIGHT: f32 = 720.0;
    const STRIP_WIDTH: f32 = DEFAULT_WIDTH / 3.0;
    const STRIP_HEIGHT: f32 = DEFAULT_HEIGHT / 3.0;

    pub fn setup(
        mut commands: Commands,
        mut meshes: ResMut<Assets<Mesh>>,
        mut materials: ResMut<Assets<ColorMaterial>>,
    ) {
        // The window background is drawn with the clear color.
        commands.insert_resource(ClearColor(TEST_COLOR));

        // Make sure there's no tonemapping
        commands.spawn((
            Camera2d,
            Tonemapping::None,
            DespawnOnExit(super::Scene::ColorConsistency),
        ));

        // Top third for sprites
        commands.spawn((
            Sprite {
                color: TEST_COLOR,
                custom_size: Some(Vec2::new(STRIP_WIDTH, STRIP_HEIGHT)),
                ..default()
            },
            Transform::from_xyz(0.0, STRIP_HEIGHT, 0.0),
            DespawnOnExit(super::Scene::ColorConsistency),
        ));

        // Middle third for 2D meshes
        commands.spawn((
            Mesh2d(meshes.add(Rectangle::new(STRIP_WIDTH, STRIP_HEIGHT))),
            MeshMaterial2d(materials.add(ColorMaterial::from_color(TEST_COLOR))),
            Transform::from_xyz(0.0, 0.0, 0.0),
            DespawnOnExit(super::Scene::ColorConsistency),
        ));

        // Bottom third for UI nodes
        commands.spawn((
            Node {
                position_type: PositionType::Absolute,
                bottom: Val::Px(0.0),
                left: Val::Px(0.0),
                width: Val::Percent(33.3),
                height: Val::Px(STRIP_HEIGHT),
                ..default()
            },
            BackgroundColor(TEST_COLOR),
            DespawnOnExit(super::Scene::ColorConsistency),
        ));
    }

    // Remember to reset the clear color
    // Tonemapping is per-camera, and is reset when the camera despawns
    pub fn teardown(mut commands: Commands) {
        commands.insert_resource(ClearColor::default());
    }
}