import {ColorAttachment, DepthAttachment, DepthStencilAttachment} from './value';

import type {Context} from './context';

/**
 * @internal
 * A framebuffer holder object
 */
export class Framebuffer {
    context: Context;
    width: number;
    height: number;
    framebuffer: WebGLFramebuffer;
    colorAttachment: ColorAttachment;
    depthAttachment: DepthAttachment;

    constructor(context: Context, width: number, height: number, hasDepth: boolean, hasStencil: boolean) {
        this.context = context;
        this.width = width;
        this.height = height;
        const gl = context.gl;
        const fbo = this.framebuffer = gl.createFramebuffer();

        this.colorAttachment = new ColorAttachment(context, fbo);
        if (hasDepth) {
            this.depthAttachment = hasStencil ? new DepthStencilAttachment(context, fbo) : new DepthAttachment(context, fbo);
        } else if (hasStencil) {
            throw new Error('Stencil cannot be set without depth');
        }
        if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) !== gl.FRAMEBUFFER_COMPLETE) {
            throw new Error('Framebuffer is not complete');
        }
    }

    destroy() {
        const gl = this.context.gl;

        const texture = this.colorAttachment.get();
        if (texture) gl.deleteTexture(texture);

        if (this.depthAttachment) {
            const renderbuffer = this.depthAttachment.get();
            if (renderbuffer) gl.deleteRenderbuffer(renderbuffer);
        }

        gl.deleteFramebuffer(this.framebuffer);
    }
}