import { IPoint, ISize } from "./model";

/** Scale stuff from a virtual canvas */
export class Scale {
	public offsetScreen: IPoint;
	private virtualSize: ISize;
	private screenSize: ISize;
	private toScreenScale: IPoint;

	constructor(
		private min: IPoint,
		private max: IPoint,
		private screen: ISize,
		private topLeftMarginVirtual: ISize,
		private bottomRightMarginVirtual: ISize
	) {
		this.offsetScreen = { x: 0, y: 0 };
		this.updateScale();
	}

	public getTransform() {
		return {
			x: this.offsetScreen.x + this.topLeftMarginVirtual.width,
			y: this.offsetScreen.y + this.topLeftMarginVirtual.height,
			scaleX: this.toScreenScale.x,
			scaleY: this.toScreenScale.y
		};
	}

	public getTranslate() {
		return `translate(${this.offsetScreen.x + this.topLeftMarginVirtual.width},${this.offsetScreen.y +
			this.topLeftMarginVirtual.height})`;
	}

	public getScale() {
		return `scale(${this.toScreenScale.x},${this.toScreenScale.y})`;
	}

	private updateScale() {
		this.virtualSize = {
			width: this.max.x - this.min.x + this.bottomRightMarginVirtual.width + this.topLeftMarginVirtual.width,
			height: this.max.y - this.min.y + this.topLeftMarginVirtual.height + this.bottomRightMarginVirtual.height
		};
		this.screenSize = this.screen;
		this.toScreenScale = {
			x: this.screenSize.width / this.virtualSize.width,
			y: this.screenSize.height / this.virtualSize.height
		};
		if (this.toScreenScale.x > 2 * this.toScreenScale.y) this.toScreenScale.x = this.toScreenScale.y * 2;
		if (this.toScreenScale.y > 2 * this.toScreenScale.x) this.toScreenScale.y = this.toScreenScale.x * 2;
	}

	public panTo(screen: IPoint) {
		this.offsetScreen = screen;
	}

	public scaleXToScreen(x: number): number {
		return this.toScreenScale.x * (x + this.topLeftMarginVirtual.width) - this.offsetScreen.x;
	}

	public scaleYToScreen(y: number): number {
		return this.toScreenScale.y * (y + this.topLeftMarginVirtual.height) - this.offsetScreen.y;
	}

	public heightToScreen(height: number): number {
		return this.toScreenScale.y * height;
	}

	public widthToScreen(width: number): number {
		return this.toScreenScale.x * width;
	}

	public avgSizeToScreen(size: number): number {
		return (this.toScreenScale.x + this.toScreenScale.y) / 2.0 * size;
	}

	public smallestSizeToScreen(size: number): number {
		return Math.min(this.toScreenScale.x * size, this.toScreenScale.y * size);
	}

	public screenHeightToVirtual(height: number): number {
		return height / this.toScreenScale.y;
	}
}