function isBuiltIn(name: string): boolean {
	return name.startsWith("gl_") || name.startsWith("webgl_");
}

export function getAttribSetters(gl: WebGL2RenderingContext, program: WebGLProgram): void {
	const numUniforms = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);

	const uniformSetters: { [key: string]: any } = {};

	for(let i = 0; i < numUniforms; ++i) {
		const uniformInfo = gl.getActiveUniform(program, i);
		if(!uniformInfo || isBuiltIn(uniformInfo.name)) {
			continue;
		}

		let name = uniformInfo.name;
		if(name.substr(-3) === "[0]") {
			name = name.substr(0, name.length - 3);
		}
		const setter = createUniformSetter(gl, program, uniformInfo);
	}
}

// This gets set the first time getUniformSetters() is called to avoid circular dependency problems
let uniformSetters: Array<[GLUniformType, typeof GLSetter]> | undefined;

function getUniformSetter(type: GLUniformType): typeof GLSetter | undefined {
	if(!uniformSetters) {
		uniformSetters = [
			[GLUniformType.INT, GLIntSetter],
			[GLUniformType.BOOL, GLIntSetter],
			[GLUniformType.FLOAT, GLFloatSetter],
			[GLUniformType.VEC2, GLVec2Setter],
			[GLUniformType.VEC3, GLVec3Setter],
			[GLUniformType.VEC4, GLVec4Setter],
			[GLUniformType.MAT2, GLMat2Setter],
			[GLUniformType.MAT3, GLMat3Setter],
			[GLUniformType.MAT4, GLMat4Setter],
			[GLUniformType.SAMPLER2D, GLSampler2DSetter],
		];
	}

	let setter: typeof GLSetter | undefined;
	for(const i in uniformSetters) {
		if(!uniformSetters[i]) { continue; }
		if(uniformSetters[i][0] === type) {
			setter = uniformSetters[i][1];
		}
	}

	return setter;
}

function createUniformSetter(gl: WebGL2RenderingContext, program: WebGLProgram, info: WebGLActiveInfo): void {
	const loc = gl.getUniformLocation(program, info.name);
	const isArray = (info.size > 1 && info.name.substr(-3) === "[0]");
	const type = info.type;
	const typeInfo = getUniformSetter(type);
	if(!typeInfo) {
		throw new Error(`Program uniform '${info.name}' type 0x${type.toString(16)} is unavailable.`);
	}

	// TODO: Finish creating uniform setters https://github.com/greggman/twgl.js/blob/master/src/programs.js#L840
}