class Options {
	constructor(opts) {
		this.scaleIndex = 0;
		this.scaleList = [
			0.5, 0.6, 0.7, 0.8, 0.9,
			1, 1.2, 1.4, 1.6, 1.8,
			2, 2.2, 2.4, 2.6, 2.8,
			3, 3.2, 3.4, 3.6, 3.8,
			4, 4.2, 4.4, 4.6, 4.8,
			5, 5.2, 5.4, 5.6, 5.8,
			6, 6.2, 6.4, 6.6, 6.8,
			7, 7.2, 7.4, 7.6, 7.8,
			8, 8.2, 8.4, 8.6, 8.8
		];

		if (Number.isFinite(opts.scaleRate)) {
			const idx = this.scaleList.indexOf(opts.scaleRate);
			if (idx >= 0) {
				this.scaleIndex = idx;
			}
		}

		this.scaleRate = opts.scaleRate || this.scaleList[this.scaleIndex]; // 缩放比例

		this.offsetX = opts.offsetX || 0; // x偏移

		this.offsetY = opts.offsetY || 0; // y偏移

		this.throttle = opts.throttle || 17; // 刷新频率
	}

	update(payload) {
		if (Number.isFinite(payload.dx)) {
			this.offsetX -= payload.dx;
		}
		if (Number.isFinite(payload.dy)) {
			this.offsetY -= payload.dy;
		}

		if (Number.isFinite(payload.offsetX)) {
			this.offsetX = payload.offsetX;
		}
		if (Number.isFinite(payload.offsetY)) {
			this.offsetY = payload.offsetY;
		}

		if (Number.isFinite(payload.scale)) {
			if (Number.isFinite(payload.scale)) {
				if ((this.scaleIndex + payload.scale) >= 0 && (this.scaleIndex + payload.scale) < this.scaleList.length) {
					this.scaleIndex = this.scaleIndex + payload.scale;
				}
			}
			this.scaleRate = this.scaleList[this.scaleIndex];
		}

		if (Number.isFinite(payload.scaleRate)) {
			const idx = this.scaleList.indexOf(payload.scaleRate);
			if (idx < 0) {
				return;
			}
			this.scaleIndex = idx;
			this.scaleRate = payload.scaleRate;
		}
	}

	getScaleRate(scale) {
		if (Number.isFinite(scale)) {
			if ((this.scaleIndex + scale) >= 0 && (this.scaleIndex + scale) < this.scaleList.length) {
				return this.scaleList[this.scaleIndex + scale];
			}
		}
		return this.scaleList[this.scaleIndex];
	}
}

export default Options;