import type { WebGLCanvas } from "./WebGLCanvas";

/**
 * Used for management, caching, encapsulation, WebGL context.
 */
abstract class WebGLStateAbstract {

    private _canvas: WebGLCanvas | undefined;

    /**
     * binded canvas.
     */
    public get canvas(): WebGLCanvas {
        if (this._canvas) {
            return this._canvas;
        }
        else {
            throw new Error(
                "[ray-lab WebGLStateBasic] Please get canvas instance after context binding."
            );
        }
    };

    /**
     * Bind new WebGLCanvas.
     */
    public bindCanvas(canvas: WebGLCanvas) {
        this.contextWillBind(canvas);
        this._canvas = canvas;
    };

    /**
     * Life cycle hook function.
     * Triggered when the context is rebound.
     * @param newcanvas - New canvas object to be bound.
     */
    public abstract contextWillBind(newcanvas: WebGLCanvas): any;

    /**
     * Life cycle hook function.
     * Triggered when the context is lost.
     */
    public abstract contextLost(): any;

    /**
     * Reset all states.
     */
    public abstract resetState(): any;

    /**
     * Triggered when destroyed.
     */
    public abstract destroy(): any;
}

export { WebGLStateAbstract };