pub mod biped_large;
pub mod bird_medium;
pub mod bird_small;
pub mod character;
pub mod critter;
pub mod dragon;
pub mod fish_medium;
pub mod fish_small;
pub mod fixture;
pub mod object;
pub mod quadruped_medium;
pub mod quadruped_small;

use crate::render::FigureBoneData;
use vek::*;

#[derive(Copy, Clone)]
pub struct Bone {
    pub offset: Vec3<f32>,
    pub ori: Quaternion<f32>,
    pub scale: Vec3<f32>,
}

impl Default for Bone {
    fn default() -> Self {
        Self {
            offset: Vec3::zero(),
            ori: Quaternion::identity(),
            scale: Vec3::broadcast(1.0 / 11.0),
        }
    }
}

impl Bone {
    pub fn compute_base_matrix(&self) -> Mat4<f32> {
        Mat4::<f32>::translation_3d(self.offset)
            * Mat4::scaling_3d(self.scale)
            * Mat4::from(self.ori)
    }

    /// Change the current bone to be more like `target`.
    fn interpolate(&mut self, target: &Bone, dt: f32) {
        // TODO: Make configurable.
        let factor = (15.0 * dt).min(1.0);
        self.offset += (target.offset - self.offset) * factor;
        self.ori = vek::ops::Slerp::slerp(self.ori, target.ori, factor);
        self.scale += (target.scale - self.scale) * factor;
    }
}

pub trait Skeleton: Send + Sync + 'static {
    type Attr;

    fn compute_matrices(&self) -> [FigureBoneData; 18];

    /// Change the current skeleton to be more like `target`.
    fn interpolate(&mut self, target: &Self, dt: f32);
}

pub trait Animation {
    type Skeleton: Skeleton;
    type Dependency;

    /// Returns a new skeleton that is generated by the animation.
    fn update_skeleton(
        skeleton: &Self::Skeleton,
        dependency: Self::Dependency,
        anim_time: f64,
        rate: &mut f32,
        skeleton_attr: &<<Self as Animation>::Skeleton as Skeleton>::Attr,
    ) -> Self::Skeleton;
}