From 1bd9fac203f09736c1225bbbe19e5d7cc31c0b93 Mon Sep 17 00:00:00 2001
From: Maze <mazewinther@gmail.com>
Date: Sun, 5 Apr 2026 13:15:58 +0200
Subject: refactor: rewrite animation system to use bindings and scalar
 channels

---
 apps/web/src/lib/animation/keyframe-query.ts | 370 +++++++++++++++++++++------
 1 file changed, 298 insertions(+), 72 deletions(-)

(limited to 'apps/web/src/lib/animation/keyframe-query.ts')

diff --git a/apps/web/src/lib/animation/keyframe-query.ts b/apps/web/src/lib/animation/keyframe-query.ts
index 62c8a171..304a6698 100644
--- a/apps/web/src/lib/animation/keyframe-query.ts
+++ b/apps/web/src/lib/animation/keyframe-query.ts
@@ -1,72 +1,298 @@
-import { TIME_EPSILON_SECONDS } from "@/constants/animation-constants";
-import type {
-	AnimationPath,
-	ElementAnimations,
-	ElementKeyframe,
-} from "@/lib/animation/types";
-import { isAnimationPath } from "./target-resolver";
-
-export function getElementKeyframes({
-	animations,
-}: {
-	animations: ElementAnimations | undefined;
-}): ElementKeyframe[] {
-	if (!animations) {
-		return [];
-	}
-
-	return Object.entries(animations.channels).flatMap(
-		([propertyPath, channel]) => {
-			if (
-				!channel ||
-				channel.keyframes.length === 0 ||
-				!isAnimationPath(propertyPath)
-			) {
-				return [];
-			}
-
-			return channel.keyframes.map((keyframe) => ({
-				propertyPath,
-				id: keyframe.id,
-				time: keyframe.time,
-				value: keyframe.value,
-				interpolation: keyframe.interpolation,
-			}));
-		},
-	);
-}
-
-export function hasKeyframesForPath({
-	animations,
-	propertyPath,
-}: {
-	animations: ElementAnimations | undefined;
-	propertyPath: AnimationPath;
-}): boolean {
-	const channel = animations?.channels[propertyPath];
-	return Boolean(channel && channel.keyframes.length > 0);
-}
-
-export function getKeyframeAtTime({
-	animations,
-	propertyPath,
-	time,
-}: {
-	animations: ElementAnimations | undefined;
-	propertyPath: AnimationPath;
-	time: number;
-}): ElementKeyframe | null {
-	const channel = animations?.channels[propertyPath];
-	if (!channel || channel.keyframes.length === 0) return null;
-	const keyframe = channel.keyframes.find(
-		(keyframe) => Math.abs(keyframe.time - time) <= TIME_EPSILON_SECONDS,
-	);
-	if (!keyframe) return null;
-	return {
-		propertyPath,
-		id: keyframe.id,
-		time: keyframe.time,
-		value: keyframe.value,
-		interpolation: keyframe.interpolation,
-	};
-}
+import { TIME_EPSILON_SECONDS } from "@/constants/animation-constants";
+import type {
+	AnimationBindingInstance,
+	AnimationChannel,
+	AnimationPath,
+	ElementAnimations,
+	ElementKeyframe,
+} from "@/lib/animation/types";
+import {
+	type AnimationComponentValue,
+	composeAnimationValue,
+} from "./binding-values";
+import {
+	getChannelValueAtTime,
+	getScalarSegmentInterpolation,
+} from "./interpolation";
+import { isAnimationPath } from "./target-resolver";
+
+function getBindingFallbackValue({
+	channel,
+}: {
+	channel: ElementAnimations["channels"][string];
+}) {
+	if (!channel || channel.keys.length === 0) {
+		return channel?.kind === "discrete" ? false : 0;
+	}
+
+	return channel.keys[0].value;
+}
+
+interface BindingKeyframeMatch {
+	componentIndex: number;
+	channel: AnimationChannel;
+	keyframe: AnimationChannel["keys"][number];
+}
+
+function getBindingKeyframeMatches({
+	animations,
+	binding,
+}: {
+	animations: ElementAnimations;
+	binding: AnimationBindingInstance;
+}): BindingKeyframeMatch[] {
+	return binding.components.flatMap((component, componentIndex) => {
+		const channel = animations.channels[component.channelId];
+		if (!channel || channel.keys.length === 0) {
+			return [];
+		}
+
+		return channel.keys.map((keyframe) => ({
+			componentIndex,
+			channel,
+			keyframe,
+		}));
+	});
+}
+
+function getUniqueBindingKeyframeMatches({
+	animations,
+	binding,
+}: {
+	animations: ElementAnimations;
+	binding: AnimationBindingInstance;
+}): BindingKeyframeMatch[] {
+	const sortedMatches = getBindingKeyframeMatches({
+		animations,
+		binding,
+	}).sort(
+		(leftMatch, rightMatch) =>
+			leftMatch.keyframe.time - rightMatch.keyframe.time ||
+			leftMatch.componentIndex - rightMatch.componentIndex,
+	);
+	const uniqueMatches: BindingKeyframeMatch[] = [];
+
+	for (const match of sortedMatches) {
+		const previousMatch = uniqueMatches[uniqueMatches.length - 1];
+		if (
+			!previousMatch ||
+			Math.abs(previousMatch.keyframe.time - match.keyframe.time) >
+				TIME_EPSILON_SECONDS
+		) {
+			uniqueMatches.push(match);
+			continue;
+		}
+
+		if (
+			previousMatch.componentIndex !== 0 &&
+			match.componentIndex === 0
+		) {
+			uniqueMatches[uniqueMatches.length - 1] = match;
+		}
+	}
+
+	return uniqueMatches;
+}
+
+function getPreferredBindingKeyframeMatch({
+	matches,
+}: {
+	matches: BindingKeyframeMatch[];
+}): BindingKeyframeMatch | null {
+	return (
+		matches.find((match) => match.componentIndex === 0) ??
+		matches[0] ??
+		null
+	);
+}
+
+function getComposedBindingValueAtTime({
+	animations,
+	binding,
+	time,
+}: {
+	animations: ElementAnimations;
+	binding: AnimationBindingInstance;
+	time: number;
+}) {
+	const componentValues = Object.fromEntries(
+		binding.components.map((component) => {
+			const channel = animations.channels[component.channelId];
+			return [
+				component.key,
+				getChannelValueAtTime({
+					channel,
+					time,
+					fallbackValue: getBindingFallbackValue({ channel }),
+				}),
+			];
+		}),
+	) as Record<string, AnimationComponentValue | undefined>;
+
+	return composeAnimationValue({
+		binding,
+		componentValues,
+	});
+}
+
+function getKeyframeInterpolation({
+	channel,
+	keyframe,
+}: {
+	channel: AnimationChannel;
+	keyframe: AnimationChannel["keys"][number];
+}) {
+	return channel.kind === "scalar" && "segmentToNext" in keyframe
+		? getScalarSegmentInterpolation({ segment: keyframe.segmentToNext })
+		: "hold";
+}
+
+function toElementKeyframe({
+	animations,
+	binding,
+	propertyPath,
+	keyframeMatch,
+}: {
+	animations: ElementAnimations;
+	binding: AnimationBindingInstance;
+	propertyPath: AnimationPath;
+	keyframeMatch: BindingKeyframeMatch;
+}): ElementKeyframe | null {
+	const value = getComposedBindingValueAtTime({
+		animations,
+		binding,
+		time: keyframeMatch.keyframe.time,
+	});
+	if (value === null) {
+		return null;
+	}
+
+	return {
+		propertyPath,
+		id: keyframeMatch.keyframe.id,
+		time: keyframeMatch.keyframe.time,
+		value,
+		interpolation: getKeyframeInterpolation({
+			channel: keyframeMatch.channel,
+			keyframe: keyframeMatch.keyframe,
+		}),
+	};
+}
+
+export function getElementKeyframes({
+	animations,
+}: {
+	animations: ElementAnimations | undefined;
+}): ElementKeyframe[] {
+	if (!animations) {
+		return [];
+	}
+
+	return Object.entries(animations.bindings).flatMap(
+		([propertyPath, binding]) => {
+			if (!binding || !isAnimationPath(propertyPath)) {
+				return [];
+			}
+
+			return getUniqueBindingKeyframeMatches({
+				animations,
+				binding,
+			}).flatMap((keyframeMatch) => {
+				const keyframe = toElementKeyframe({
+					animations,
+					binding,
+					propertyPath,
+					keyframeMatch,
+				});
+				if (!keyframe) {
+					return [];
+				}
+
+				return [keyframe];
+			});
+		},
+	);
+}
+
+export function hasKeyframesForPath({
+	animations,
+	propertyPath,
+}: {
+	animations: ElementAnimations | undefined;
+	propertyPath: AnimationPath;
+}): boolean {
+	const binding = animations?.bindings[propertyPath];
+	if (!binding) {
+		return false;
+	}
+
+	return binding.components.some((component) =>
+		Boolean(animations?.channels[component.channelId]?.keys.length),
+	);
+}
+
+export function getKeyframeAtTime({
+	animations,
+	propertyPath,
+	time,
+}: {
+	animations: ElementAnimations | undefined;
+	propertyPath: AnimationPath;
+	time: number;
+}): ElementKeyframe | null {
+	const binding = animations?.bindings[propertyPath];
+	if (!binding) {
+		return null;
+	}
+
+	const keyframeMatch = getPreferredBindingKeyframeMatch({
+		matches: getBindingKeyframeMatches({
+			animations,
+			binding,
+		}).filter(({ keyframe }) =>
+			Math.abs(keyframe.time - time) <= TIME_EPSILON_SECONDS,
+		),
+	});
+	if (!keyframeMatch) {
+		return null;
+	}
+
+	return toElementKeyframe({
+		animations,
+		binding,
+		propertyPath,
+		keyframeMatch,
+	});
+}
+
+export function getKeyframeById({
+	animations,
+	propertyPath,
+	keyframeId,
+}: {
+	animations: ElementAnimations | undefined;
+	propertyPath: AnimationPath;
+	keyframeId: string;
+}): ElementKeyframe | null {
+	const binding = animations?.bindings[propertyPath];
+	if (!binding) {
+		return null;
+	}
+
+	const keyframeMatch = getPreferredBindingKeyframeMatch({
+		matches: getBindingKeyframeMatches({
+			animations,
+			binding,
+		}).filter(({ keyframe }) => keyframe.id === keyframeId),
+	});
+	if (!keyframeMatch) {
+		return null;
+	}
+
+	return toElementKeyframe({
+		animations,
+		binding,
+		propertyPath,
+		keyframeMatch,
+	});
+}
-- 
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