/** Holds a list of key frames (timestamped values) */
export class KeyFrames {
    startIndex = -1;
    endIndex = -1;
    factor = 0;
    times = [];
    values = [];
    _lastTime = -1;
    constructor(keyFrames) {
        this.setKeyFrames(keyFrames);
        this.setTime(0);
    }
    setKeyFrames(keyFrames) {
        const numKeys = keyFrames.length;
        this.times.length = numKeys;
        this.values.length = numKeys;
        for (let i = 0; i < numKeys; ++i) {
            this.times[i] = keyFrames[i][0];
            this.values[i] = keyFrames[i][1];
        }
        this._calculateKeys(this._lastTime);
    }
    setTime(time) {
        time = Math.max(0, time);
        if (time !== this._lastTime) {
            this._calculateKeys(time);
            this._lastTime = time;
        }
    }
    getStartTime() {
        return this.times[this.startIndex];
    }
    getEndTime() {
        return this.times[this.endIndex];
    }
    getStartData() {
        return this.values[this.startIndex];
    }
    getEndData() {
        return this.values[this.endIndex];
    }
    _calculateKeys(time) {
        let index = 0;
        const numKeys = this.times.length;
        for (index = 0; index < numKeys - 2; ++index) {
            if (this.times[index + 1] > time) {
                break;
            }
        }
        this.startIndex = index;
        this.endIndex = index + 1;
        const startTime = this.times[this.startIndex];
        const endTime = this.times[this.endIndex];
        this.factor = Math.min(Math.max(0, (time - startTime) / (endTime - startTime)), 1);
    }
}