import ScaleManager = Phaser.Scale.ScaleManager;

interface Size {
    width: number;
    height: number;
}

export class HdpiManager {
    private _zoomModifier: number = 1;

    public constructor(private minGamePixelsNumber: number) {
    }

    /**
     * Returns the optimal size in "game pixels" based on the screen size in "real pixels".
     *
     * Note: the function is returning the optimal size in "game pixels" in the "game" property,
     * but also recommends resizing the "real" pixel screen size of the canvas.
     * The proposed new real size is a few pixels bigger than the real size available (if the size is not a multiple of the pixel size) and should overflow.
     *
     * @param realPixelScreenSize
     */
    public getOptimalGameSize(realPixelScreenSize: Size): { game: Size, real: Size } {
        const realPixelNumber = realPixelScreenSize.width * realPixelScreenSize.height;
        // If the screen has not a definition small enough to match the minimum number of pixels we want to display,
        // let's make the canvas the size of the screen (in real pixels)
        if (realPixelNumber <= this.minGamePixelsNumber) {
            return {
                game: realPixelScreenSize,
                real: realPixelScreenSize
            };
        }

        let i = 1;

        while (true) {
            if (realPixelNumber <= this.minGamePixelsNumber * i * i) {
                break;
            }

            i++;
        }

        return {
            game: {
                width: Math.ceil(realPixelScreenSize.width / (i - 1) / this._zoomModifier),
                height: Math.ceil(realPixelScreenSize.height / (i - 1) / this._zoomModifier),
            },
            real: {
                width: Math.ceil(realPixelScreenSize.width / (i - 1)) * (i - 1),
                height: Math.ceil(realPixelScreenSize.height / (i - 1)) * (i - 1),
            }
        }
    }

    public get zoomModifier(): number {
        return this._zoomModifier;
    }

    public set zoomModifier(zoomModifier: number) {
        this._zoomModifier = zoomModifier;
    }
}