ranim-anims 0.1.5

use ranim_core::{
    animation::{AnimationSpan, EvalDynamic, Evaluator},
    primitives::vitem::DEFAULT_STROKE_WIDTH,
    traits::{Empty, FillColor, Interpolatable, Partial, StrokeColor, StrokeWidth},
    utils::rate_functions::smooth,
};
use tracing::warn;

// MARK: Creation

/// The requirement of [`Create`] and [`UnCreate`]
pub trait CreationRequirement: Clone + Partial + Empty + Interpolatable {}
impl<T: Clone + Partial + Empty + Interpolatable> CreationRequirement for T {}

/// The methods to create animations for `T` that satisfies [`CreationRequirement`]
pub trait CreationAnim<T: CreationRequirement + 'static> {
    /// Create a [`Create`] anim for `T`.
    fn create(self) -> AnimationSpan<T>;
    /// Create an [`UnCreate`] anim for `T`.
    fn uncreate(self) -> AnimationSpan<T>;
}

impl<T: CreationRequirement + 'static> CreationAnim<T> for T {
    fn create(self) -> AnimationSpan<T> {
        AnimationSpan::from_evaluator(Evaluator::new_dynamic(Create::new(self)))
            .with_rate_func(smooth)
    }
    fn uncreate(self) -> AnimationSpan<T> {
        AnimationSpan::from_evaluator(Evaluator::new_dynamic(UnCreate::new(self)))
            .with_rate_func(smooth)
    }
}

// MARK: Writing
/// The requirement of [`Write`] and [`Unwrite`]
pub trait WritingRequirement: CreationRequirement + StrokeWidth + StrokeColor + FillColor {}
impl<T: CreationRequirement + StrokeWidth + StrokeColor + FillColor> WritingRequirement for T {}

/// The methods to create animations for `T` that satisfies [`WritingRequirement`]
pub trait WritingAnim<T: WritingRequirement + 'static> {
    /// Create a [`Write`] anim for `T`.
    fn write(self) -> AnimationSpan<T>;
    /// Create a [`Unwrite`] anim for `T`.
    fn unwrite(self) -> AnimationSpan<T>;
}

impl<T: WritingRequirement + 'static> WritingAnim<T> for T {
    fn write(self) -> AnimationSpan<T> {
        Write::new(self)
            .into_animation_span()
            .with_rate_func(smooth)
    }
    fn unwrite(self) -> AnimationSpan<T> {
        Unwrite::new(self)
            .into_animation_span()
            .with_rate_func(smooth)
    }
}

// ---------------------------------------------------- //

// MARK: Impl
/// The create anim.
///
/// This anim uses [`Partial::get_partial_closed`] to create the item
pub struct Create<T: CreationRequirement> {
    /// The original object
    pub original: T,
}

impl<T: CreationRequirement> Create<T> {
    /// Constructor
    pub fn new(target: T) -> Self {
        Self { original: target }
    }
}

impl<T: CreationRequirement> EvalDynamic<T> for Create<T> {
    fn eval_alpha(&self, alpha: f64) -> T {
        if alpha == 0.0 {
            T::empty()
        } else if 0.0 < alpha && alpha < 1.0 {
            self.original.get_partial_closed(0.0..alpha)
        } else if alpha == 1.0 {
            self.original.clone()
        } else {
            unreachable!()
        }
    }
}

/// The uncreate anim
///
/// This anim uses [`Partial::get_partial_closed`] to uncreate the item
pub struct UnCreate<T: CreationRequirement> {
    /// The original object
    pub original: T,
}

impl<T: CreationRequirement> UnCreate<T> {
    /// Constructor
    pub fn new(target: T) -> Self {
        Self { original: target }
    }
}

impl<T: CreationRequirement> EvalDynamic<T> for UnCreate<T> {
    fn eval_alpha(&self, mut alpha: f64) -> T {
        if !(0.0..=1.0).contains(&alpha) {
            warn!("the alpha is out of range: {alpha}, clampped to 0.0..=1.0");
            alpha = alpha.clamp(0.0, 1.0)
        }
        // trace!("{alpha}");
        if alpha == 0.0 {
            self.original.clone()
        } else if 0.0 < alpha && alpha < 1.0 {
            self.original.get_partial_closed(0.0..1.0 - alpha)
        } else if alpha == 1.0 {
            T::empty()
        } else {
            panic!("the alpha is out of range: {alpha}");
        }
    }
}

/// Write
///
/// First update with partial from 0.0..0.0 to 0.0..1.0, then lerp fill_opacity to 1.0
pub struct Write<T: WritingRequirement> {
    pub(crate) original: T,
    pub(crate) outline: T,
}

impl<T: WritingRequirement> Write<T> {
    /// Constructor
    pub fn new(target: T) -> Self {
        let mut outline = target.clone();
        outline.set_fill_opacity(0.0).set_stroke_opacity(1.0);
        if outline.stroke_width() == 0.0 {
            outline.set_stroke_width(DEFAULT_STROKE_WIDTH);
        }
        Self {
            original: target,
            outline,
        }
    }
}

impl<T: WritingRequirement> EvalDynamic<T> for Write<T> {
    fn eval_alpha(&self, alpha: f64) -> T {
        let alpha = alpha * 2.0;
        if (0.0..1.0).contains(&alpha) {
            self.outline.get_partial(0.0..alpha)
        } else if alpha == 1.0 {
            self.outline.clone()
        } else if (1.0..2.0).contains(&alpha) {
            self.outline.lerp(&self.original, alpha - 1.0)
        } else if alpha == 2.0 {
            self.original.clone()
        } else {
            unreachable!()
        }
    }
}

/// Unwrite
///
/// First lerp fill_opacity to 0.0, then update with partial from 0.0..1.0 to 0.0..0.0
pub struct Unwrite<T: WritingRequirement> {
    pub(crate) original: T,
    pub(crate) outline: T,
}

impl<T: WritingRequirement> Unwrite<T> {
    /// Constructor
    pub fn new(target: T) -> Self {
        let mut outline = target.clone();
        outline.set_fill_opacity(0.0).set_stroke_opacity(1.0);
        if outline.stroke_width() == 0.0 {
            outline.set_stroke_width(DEFAULT_STROKE_WIDTH);
        }
        Self {
            original: target,
            outline,
        }
    }
}

impl<T: WritingRequirement> EvalDynamic<T> for Unwrite<T> {
    fn eval_alpha(&self, alpha: f64) -> T {
        let alpha = alpha * 2.0;
        if (0.0..1.0).contains(&alpha) {
            self.original.lerp(&self.outline, alpha)
        } else if alpha == 1.0 {
            self.outline.clone()
        } else if (1.0..2.0).contains(&alpha) {
            self.outline.get_partial(0.0..2.0 - alpha)
        } else if alpha == 2.0 {
            T::empty()
        } else if alpha == 0.0 {
            self.original.clone()
        } else {
            panic!("the alpha is out of range: {alpha}");
        }
    }
}