/// <reference types="astro/astro-jsx" />

import type { SVGAttributes } from "../../types";
import { type DocumentNode, type Node, parse, render } from "ultrahtml";

const EMPTY_STRING_ERR = "`svgSource` must have content";
const MUST_START_WITH_SVG = "`svgSource` must begin with `<svg`";

export async function overrideSvgAttributes(
  svgSource: string,
  attributeOverrides: SVGAttributes = {},
): Promise<string> {
  if (!svgSource) {
    throw new Error(EMPTY_STRING_ERR);
  }
  if (!svgSource.trimStart().toLowerCase().startsWith("<svg")) {
    throw new Error(MUST_START_WITH_SVG);
  }

  const doc = parse(svgSource) as DocumentNode;

  const firstSVGNode = doc.children.find(
    ({ type, name }: Node) => type === 1 && /svg/i.test(name),
  );

  const mergedAttributes = Object.fromEntries(
    Object.entries({
      ...firstSVGNode.attributes,
      ...attributeOverrides,
    }).filter(([, value]) => !!value),
  );

  const updatedSVG = {
    ...firstSVGNode,
    attributes: mergedAttributes,
  };

  return render(updatedSVG);
}