motion-canvas-rs 0.2.3

use crate::core::animation::{Node, Signal};
use glam::Vec2;
use kurbo::Affine;
use std::time::Duration;
#[cfg(feature = "runtime")]
use vello::Scene;

/// A container that groups multiple nodes together and applies a shared transformation.
///
/// `GroupNode` allows you to move, rotate, scale, or fade a set of child nodes as a single unit.
/// It acts like a layer or a folder in traditional graphics software.
///
/// ### Example
/// ```rust
/// # use motion_canvas_rs::prelude::*;
/// let group = GroupNode::default()
///     .with_position(Vec2::new(640.0, 360.0))
///     .with_rotation(0.5);
/// ```
pub struct GroupNode {
    /// The list of child nodes contained within this group.
    pub nodes: Vec<Box<dyn Node>>,
    /// The absolute position of the group's center (before anchor adjustment).
    pub position: Signal<Vec2>,
    /// Rotation in radians.
    pub rotation: Signal<f32>,
    /// Scaling factor for the group and all its children.
    pub scale: Signal<Vec2>,
    /// Opacity factor applied to the entire group (0.0 to 1.0).
    pub opacity: Signal<f32>,
    /// The nominal size of the group, used for anchor calculations.
    pub size: Signal<Vec2>,
    /// The relative transformation origin. (-1,-1) is top-left, (0,0) is center, (1,1) is bottom-right.
    pub anchor: Signal<Vec2>,
}

impl Default for GroupNode {
    fn default() -> Self {
        Self {
            nodes: Vec::new(),
            position: Signal::new(Vec2::ZERO),
            rotation: Signal::new(0.0),
            scale: Signal::new(Vec2::ONE),
            opacity: Signal::new(1.0),
            size: Signal::new(Vec2::ZERO),
            anchor: Signal::new(Vec2::ZERO),
        }
    }
}

impl GroupNode {
    /// Creates a new group containing the specified list of nodes.
    pub fn new(nodes: Vec<Box<dyn Node>>) -> Self {
        Self::default().with_nodes(nodes)
    }

    /// Sets the absolute position of the group.
    pub fn with_position(mut self, pos: Vec2) -> Self {
        self.position = Signal::new(pos);
        self
    }

    /// Sets the opacity of the group (0.0 to 1.0).
    pub fn with_opacity(mut self, a: f32) -> Self {
        self.opacity = Signal::new(a);
        self
    }

    /// Sets the rotation of the group in radians.
    pub fn with_rotation(mut self, angle: f32) -> Self {
        self.rotation = Signal::new(angle);
        self
    }

    /// Sets a uniform scale factor for both axes.
    pub fn with_scale(mut self, scale: f32) -> Self {
        self.scale = Signal::new(Vec2::splat(scale));
        self
    }

    /// Sets non-uniform scaling factors for X and Y axes.
    pub fn with_scale_xy(mut self, scale: Vec2) -> Self {
        self.scale = Signal::new(scale);
        self
    }

    /// Sets the dimensions (width, height) used for anchor calculations.
    pub fn with_size(mut self, size: Vec2) -> Self {
        self.size = Signal::new(size);
        self
    }

    /// Sets the relative transformation origin (anchor).
    /// (-1, -1) is top-left, (0, 0) is center, (1, 1) is bottom-right.
    pub fn with_anchor(mut self, anchor: Vec2) -> Self {
        self.anchor = Signal::new(anchor);
        self
    }

    /// Sets the child nodes of the group.
    pub fn with_nodes(mut self, nodes: Vec<Box<dyn Node>>) -> Self {
        self.nodes = nodes;
        self
    }
}

impl Clone for GroupNode {
    fn clone(&self) -> Self {
        Self {
            nodes: self.nodes.iter().map(|n| n.clone_node()).collect(),
            position: self.position.clone(),
            rotation: self.rotation.clone(),
            scale: self.scale.clone(),
            opacity: self.opacity.clone(),
            size: self.size.clone(),
            anchor: self.anchor.clone(),
        }
    }
}

impl Node for GroupNode {
    #[cfg(feature = "runtime")]
    fn render(&self, scene: &mut Scene, parent_transform: Affine, parent_opacity: f32) {
        let opacity = self.opacity.get();

        let pos = self.position.get();
        let rot = self.rotation.get();
        let sc = self.scale.get();
        let anchor = self.anchor.get();
        let size = self.size.get();

        let anchor_offset = anchor * size * 0.5;

        let local_transform = Affine::translate((pos.x as f64, pos.y as f64))
            * Affine::rotate(rot as f64)
            * Affine::scale_non_uniform(sc.x as f64, sc.y as f64)
            * Affine::translate((-anchor_offset.x as f64, -anchor_offset.y as f64));

        let combined_transform = parent_transform * local_transform;
        let combined_opacity = parent_opacity * opacity;

        if combined_opacity <= 0.0 {
            return;
        }

        for node in &self.nodes {
            node.render(scene, combined_transform, combined_opacity);
        }
    }

    fn update(&mut self, dt: Duration) {
        for node in &mut self.nodes {
            node.update(dt);
        }
    }

    fn state_hash(&self) -> u64 {
        use crate::assets::hash::Hasher;
        let mut h = Hasher::new();
        h.update_u64(self.position.state_hash());
        h.update_u64(self.rotation.state_hash());
        h.update_u64(self.scale.state_hash());
        h.update_u64(self.opacity.state_hash());
        h.update_u64(self.size.state_hash());
        h.update_u64(self.anchor.state_hash());

        for node in &self.nodes {
            h.update_u64(node.state_hash());
        }

        h.finish()
    }

    fn clone_node(&self) -> Box<dyn Node> {
        Box::new(self.clone())
    }

    fn reset(&mut self) {
        self.position.reset();
        self.rotation.reset();
        self.scale.reset();
        self.opacity.reset();
        self.size.reset();
        self.anchor.reset();
        for node in &mut self.nodes {
            node.reset();
        }
    }
}