import WebGLRenderingContextWithId from "./WebGLRenderingContextWithId";

/**
 * Registry of gl related stuff. These instance are singleton for each gl context.
 */
export default class GLRelatedRegistryBase {

    private static _glRelatedRegistry: { [id: string]: { [registryName: string]: any } } = {};

    /**
     * Get specified resource by glContext and constructor of registry
     * @param gl
     * @param ctor
     */
    protected static __get<T>(gl: WebGLRenderingContext, ctor: { new(gl: WebGLRenderingContext): T, registryName: string }): T {
        const glWithId = gl as WebGLRenderingContextWithId;
        if (glWithId.__id__ === void 0) {
            throw new Error("Supplied gl context seems not initialized by Grimoire.js");
        }
        if (GLRelatedRegistryBase._glRelatedRegistry[glWithId.__id__] === void 0) {
            GLRelatedRegistryBase._glRelatedRegistry[glWithId.__id__] = {};
        }
        if (GLRelatedRegistryBase._glRelatedRegistry[glWithId.__id__][ctor.registryName] !== void 0) {
            return GLRelatedRegistryBase._glRelatedRegistry[glWithId.__id__][ctor.registryName];
        }
        const newInstance = new ctor(glWithId);
        GLRelatedRegistryBase._glRelatedRegistry[glWithId.__id__][ctor.registryName] = newInstance;
        return newInstance;
    }

    protected static __getAll<T>(ctor: { new(gl: WebGLRenderingContext): T, registryName: string }): T[] {
        const result = [] as T[];
        for (const key in GLRelatedRegistryBase._glRelatedRegistry) {
            const contextContainer = GLRelatedRegistryBase._glRelatedRegistry[key];
            if (contextContainer[ctor.registryName] !== void 0) {
                result.push(contextContainer[ctor.registryName]);
            }
        }
        return result;
    }
}