/**
 * Copyright (c) 2026 Dominic Masters
 *
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

/** A single keyframe descriptor passed to the Animation constructor. */
interface AnimationKeyframe {
  /** Time offset in seconds. */
  time: number;
  /** Value at this keyframe. */
  value: number;
  /** Easing type (EASING_* constant). Defaults to EASING_LINEAR. */
  easing?: number;
}

/** Keyframe-based float animation. */
interface AnimationInstance {
  /**
   * Interpolates the animation at the given time.
   * @param time Time in seconds.
   * @returns Interpolated value.
   */
  getValue(time: number): number;
}

/** Constructs a new Animation from an array of keyframe descriptors. */
declare var Animation: {
  new (keyframes: AnimationKeyframe[]): AnimationInstance;
};

/** Easing function utilities. */
interface EasingNamespace {
  /**
   * Applies the given easing function to normalized time t.
   * @param type An EASING_* constant.
   * @param t Normalized time in [0, 1].
   * @returns Eased value in [0, 1].
   */
  apply(type: number, t: number): number;
}

declare var Easing: EasingNamespace;

declare var EASING_LINEAR: number;
declare var EASING_IN_SINE: number;
declare var EASING_OUT_SINE: number;
declare var EASING_IN_OUT_SINE: number;
declare var EASING_IN_QUAD: number;
declare var EASING_OUT_QUAD: number;
declare var EASING_IN_OUT_QUAD: number;
declare var EASING_IN_CUBIC: number;
declare var EASING_OUT_CUBIC: number;
declare var EASING_IN_OUT_CUBIC: number;
declare var EASING_IN_QUART: number;
declare var EASING_OUT_QUART: number;
declare var EASING_IN_OUT_QUART: number;
declare var EASING_IN_BACK: number;
declare var EASING_OUT_BACK: number;
declare var EASING_IN_OUT_BACK: number;