animato-driver 1.6.0

//! [`AnimationDriver`] — owns and ticks multiple animations simultaneously.

use animato_core::{AnimationIntrospection, Inspectable, Update};

#[cfg(feature = "std")]
use crate::recorder::AnimationRecorder;

/// An opaque handle to an animation registered with [`AnimationDriver`].
///
/// Returned by [`AnimationDriver::add`]. Use it to cancel or query animations.
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
pub struct AnimationId(u64);

/// Snapshot of one inspectable animation registered with [`AnimationDriver`].
#[derive(Clone, Debug, PartialEq)]
pub struct DriverSnapshot {
    /// Stable animation id returned by the driver.
    pub id: AnimationId,
    /// Optional user-facing label.
    pub label: Option<String>,
    /// Runtime state reported by the animation.
    pub introspection: AnimationIntrospection,
}

/// Per-animation update cost produced by [`AnimationDriver::tick_profiled`].
#[derive(Clone, Debug, PartialEq)]
pub struct AnimationUpdateCost {
    /// Stable animation id returned by the driver.
    pub id: AnimationId,
    /// Optional user-facing label.
    pub label: Option<String>,
    /// Wall-clock time spent updating this animation.
    pub update_time_ms: f32,
}

/// Timing data produced by a profiled driver tick.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct DriverFrameProfile {
    /// Delta seconds passed to the tick.
    pub dt: f32,
    /// Total wall-clock update time for all active animations.
    pub total_update_time_ms: f32,
    /// Per-animation update costs.
    pub animation_costs: Vec<AnimationUpdateCost>,
}

enum SlotAnimation {
    Basic(Box<dyn Update + Send>),
    Inspectable(Box<dyn Inspectable + Send>),
}

impl SlotAnimation {
    fn update(&mut self, dt: f32) -> bool {
        match self {
            Self::Basic(animation) => animation.update(dt),
            Self::Inspectable(animation) => animation.update(dt),
        }
    }

    fn introspect(&self) -> Option<AnimationIntrospection> {
        match self {
            Self::Basic(_) => None,
            Self::Inspectable(animation) => Some(animation.introspect()),
        }
    }
}

impl std::fmt::Debug for SlotAnimation {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Basic(_) => f.write_str("Basic(..)"),
            Self::Inspectable(_) => f.write_str("Inspectable(..)"),
        }
    }
}

struct Slot {
    id: AnimationId,
    label: Option<String>,
    animation: SlotAnimation,
    remove: bool,
    #[cfg(feature = "std")]
    recorder: Option<RecordedSampler>,
}

#[cfg(feature = "std")]
struct RecordedSampler {
    label: String,
    sample: Box<dyn Fn() -> f64 + Send + 'static>,
}

#[cfg(feature = "std")]
impl std::fmt::Debug for RecordedSampler {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("RecordedSampler")
            .field("label", &self.label)
            .finish()
    }
}

impl std::fmt::Debug for Slot {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Slot")
            .field("id", &self.id)
            .field("label", &self.label)
            .field("remove", &self.remove)
            .finish()
    }
}

/// Manages a collection of animations, ticking them each frame and
/// automatically removing completed ones.
///
/// # Example
///
/// ```rust
/// use animato_driver::{AnimationDriver, MockClock, Clock};
/// use animato_tween::Tween;
/// use animato_core::Easing;
///
/// let mut driver = AnimationDriver::new();
/// let id = driver.add(
///     Tween::new(0.0_f32, 1.0).duration(1.0).build()
/// );
///
/// assert!(driver.is_active(id));
/// assert_eq!(driver.active_count(), 1);
///
/// // Tick past completion:
/// driver.tick(2.0);
/// assert!(!driver.is_active(id));
/// assert_eq!(driver.active_count(), 0);
/// ```
#[derive(Debug, Default)]
pub struct AnimationDriver {
    slots: Vec<Slot>,
    next_id: u64,
    completed_count: usize,
}

impl AnimationDriver {
    /// Create a new, empty driver.
    pub fn new() -> Self {
        Self {
            slots: Vec::new(),
            next_id: 0,
            completed_count: 0,
        }
    }

    /// Register an animation and return its [`AnimationId`].
    ///
    /// The animation will be ticked on every call to [`tick`](Self::tick)
    /// and automatically removed when it returns `false` from `update`.
    pub fn add<A: Update + Send + 'static>(&mut self, anim: A) -> AnimationId {
        let id = AnimationId(self.next_id);
        self.next_id += 1;
        self.slots.push(Slot {
            id,
            label: None,
            animation: SlotAnimation::Basic(Box::new(anim)),
            remove: false,
            #[cfg(feature = "std")]
            recorder: None,
        });
        id
    }

    /// Register an inspectable animation with a user-facing label.
    ///
    /// Inspectable animations can be captured by [`snapshots`](Self::snapshots)
    /// and [`snapshots_into`](Self::snapshots_into). Ordinary animations added
    /// through [`add`](Self::add) continue to work but do not appear in
    /// snapshots.
    pub fn add_inspectable<A>(&mut self, label: impl Into<String>, anim: A) -> AnimationId
    where
        A: Inspectable + Send + 'static,
    {
        let id = AnimationId(self.next_id);
        self.next_id += 1;
        self.slots.push(Slot {
            id,
            label: Some(label.into()),
            animation: SlotAnimation::Inspectable(Box::new(anim)),
            remove: false,
            #[cfg(feature = "std")]
            recorder: None,
        });
        id
    }

    /// Register an animation with a scalar sampler for [`tick_recorded`](Self::tick_recorded).
    #[cfg(feature = "std")]
    pub fn add_recorded<A, F>(
        &mut self,
        label: impl Into<String>,
        anim: A,
        sampler: F,
    ) -> AnimationId
    where
        A: Update + Send + 'static,
        F: Fn() -> f64 + Send + 'static,
    {
        let label = label.into();
        let id = AnimationId(self.next_id);
        self.next_id += 1;
        self.slots.push(Slot {
            id,
            label: Some(label.clone()),
            animation: SlotAnimation::Basic(Box::new(anim)),
            remove: false,
            recorder: Some(RecordedSampler {
                label,
                sample: Box::new(sampler),
            }),
        });
        id
    }

    /// Advance all active animations by `dt` seconds.
    ///
    /// Animations that return `false` from `update` are marked and removed
    /// at the end of the tick — no allocation during the tick itself.
    pub fn tick(&mut self, dt: f32) {
        for slot in self.slots.iter_mut() {
            if slot.remove {
                continue;
            }
            let still_running = slot.animation.update(dt);
            if !still_running {
                slot.remove = true;
            }
        }
        self.drain_completed();
    }

    /// Advance all active animations and record sampled values after the tick.
    #[cfg(feature = "std")]
    pub fn tick_recorded(&mut self, dt: f32, time: f32, recorder: &mut AnimationRecorder) {
        for slot in self.slots.iter_mut() {
            if slot.remove {
                continue;
            }
            let still_running = slot.animation.update(dt);
            if let Some(recorded) = &slot.recorder {
                recorder.record(&recorded.label, time, (recorded.sample)());
            }
            if !still_running {
                slot.remove = true;
            }
        }
        self.drain_completed();
    }

    /// Advance all active animations and return wall-clock update costs.
    pub fn tick_profiled(&mut self, dt: f32) -> DriverFrameProfile {
        let dt = dt.max(0.0);
        let frame_start = std::time::Instant::now();
        let mut animation_costs = Vec::with_capacity(self.slots.len());

        for slot in self.slots.iter_mut() {
            if slot.remove {
                continue;
            }
            let animation_start = std::time::Instant::now();
            let still_running = slot.animation.update(dt);
            let update_time_ms = animation_start.elapsed().as_secs_f32() * 1000.0;
            animation_costs.push(AnimationUpdateCost {
                id: slot.id,
                label: slot.label.clone(),
                update_time_ms,
            });
            if !still_running {
                slot.remove = true;
            }
        }

        self.drain_completed();
        DriverFrameProfile {
            dt,
            total_update_time_ms: frame_start.elapsed().as_secs_f32() * 1000.0,
            animation_costs,
        }
    }

    /// Cancel an animation by id.
    ///
    /// The animation is removed immediately, before the next tick.
    /// No-op if the id is not found (e.g. already completed).
    pub fn cancel(&mut self, id: AnimationId) {
        self.slots.retain(|s| s.id != id);
    }

    /// Cancel all active animations.
    pub fn cancel_all(&mut self) {
        self.slots.clear();
    }

    /// Number of currently active animations.
    pub fn active_count(&self) -> usize {
        self.slots.len()
    }

    /// Number of animations that completed naturally during driver ticks.
    pub fn completed_count(&self) -> usize {
        self.completed_count
    }

    /// Return snapshots for all active inspectable animations.
    pub fn snapshots(&self) -> Vec<DriverSnapshot> {
        let mut snapshots = Vec::new();
        self.snapshots_into(&mut snapshots);
        snapshots
    }

    /// Write snapshots for all active inspectable animations into a reusable buffer.
    pub fn snapshots_into(&self, out: &mut Vec<DriverSnapshot>) {
        out.clear();
        out.extend(self.slots.iter().filter_map(|slot| {
            slot.animation
                .introspect()
                .map(|introspection| DriverSnapshot {
                    id: slot.id,
                    label: slot.label.clone(),
                    introspection,
                })
        }));
    }

    /// `true` if the animation with the given id is still active.
    pub fn is_active(&self, id: AnimationId) -> bool {
        self.slots.iter().any(|s| s.id == id)
    }

    fn drain_completed(&mut self) {
        let completed = self.slots.iter().filter(|slot| slot.remove).count();
        self.completed_count = self.completed_count.saturating_add(completed);
        self.slots.retain(|slot| !slot.remove);
    }
}

// ──────────────────────────────────────────────────────────────────────────────
// Tests
// ──────────────────────────────────────────────────────────────────────────────

#[cfg(test)]
mod tests {
    use super::*;
    use animato_core::Easing;
    use animato_tween::Tween;

    #[test]
    fn auto_removes_completed() {
        let mut driver = AnimationDriver::new();
        let id = driver.add(Tween::new(0.0_f32, 1.0).duration(1.0).build());
        assert!(driver.is_active(id));
        driver.tick(2.0); // well past duration
        assert!(!driver.is_active(id));
        assert_eq!(driver.active_count(), 0);
    }

    #[test]
    fn cancel_removes_mid_animation() {
        let mut driver = AnimationDriver::new();
        let id = driver.add(Tween::new(0.0_f32, 1.0).duration(10.0).build());
        driver.tick(1.0);
        assert!(driver.is_active(id));
        driver.cancel(id);
        assert!(!driver.is_active(id));
    }

    #[test]
    fn cancel_noop_on_missing_id() {
        let mut driver = AnimationDriver::new();
        let id = driver.add(Tween::new(0.0_f32, 1.0).duration(1.0).build());
        driver.tick(2.0); // completes, auto-removed
        driver.cancel(id); // should not panic
        assert_eq!(driver.active_count(), 0);
    }

    #[test]
    fn active_count_tracks_correctly() {
        let mut driver = AnimationDriver::new();
        let _a = driver.add(Tween::new(0.0_f32, 1.0).duration(1.0).build());
        let _b = driver.add(Tween::new(0.0_f32, 1.0).duration(2.0).build());
        let _c = driver.add(Tween::new(0.0_f32, 1.0).duration(3.0).build());
        assert_eq!(driver.active_count(), 3);

        driver.tick(1.5); // first one completes
        assert_eq!(driver.active_count(), 2);

        driver.tick(1.0); // second completes
        assert_eq!(driver.active_count(), 1);
    }

    #[test]
    fn cancel_all_clears_everything() {
        let mut driver = AnimationDriver::new();
        for _ in 0..10 {
            driver.add(Tween::new(0.0_f32, 1.0).duration(5.0).build());
        }
        assert_eq!(driver.active_count(), 10);
        driver.cancel_all();
        assert_eq!(driver.active_count(), 0);
    }

    #[test]
    fn multiple_concurrent_animations_tick_independently() {
        let mut driver = AnimationDriver::new();
        let slow = driver.add(Tween::new(0.0_f32, 1.0).duration(2.0).build());
        let fast = driver.add(
            Tween::new(0.0_f32, 1.0)
                .duration(0.5)
                .easing(Easing::Linear)
                .build(),
        );

        driver.tick(1.0); // fast completes, slow still running
        assert!(!driver.is_active(fast));
        assert!(driver.is_active(slow));

        driver.tick(2.0); // slow completes
        assert!(!driver.is_active(slow));
    }

    #[test]
    fn animation_id_is_unique() {
        let mut driver = AnimationDriver::new();
        let ids: Vec<_> = (0..100)
            .map(|_| driver.add(Tween::new(0.0_f32, 1.0).duration(1.0).build()))
            .collect();
        let unique: std::collections::HashSet<_> = ids.iter().collect();
        assert_eq!(unique.len(), 100);
    }
}