/*
 * Philip Crotwell
 * University of South Carolina, 2019
 * https://www.seis.sc.edu
 */
export const AUTO_CLASSED = "autoseisplotjs";
export const AUTO_COLOR_SELECTOR = "seisplotjsautocolor";
export const G_DATA_SELECTOR = "seisplotjsdata";

/**
 * Inserts text as css into the head of an html document. No checking
 * as to validity of the css is done, just inserts a style
 * element at the beginning of the head.
 *
 * @param  cssText textual css for insertion
 * @param id optional id for style element
 * @returns the style html element inserted
 */
export function insertCSS(cssText: string, id: string): HTMLElement {
  const head = document.head;

  if (head === null) {
    throw new Error("document.head is null");
  }

  if (id) {
    for (const c of Array.from(head.children)) {
      // only remove if a <style> element and same id within head
      if (isIdStyleElement(c, id)) {
        document.head.removeChild(c);
      }
    }
  }

  const styleElement = document.createElement("style");

  if (id) {
    styleElement.id = id;
  }

  styleElement.type = "text/css";
  styleElement.appendChild(document.createTextNode(cssText));
  head.insertBefore(styleElement, head.firstChild);
  return styleElement;
}
export function isCSSInserted(id: string): boolean {
  const head = document.head;

  if (head === null) {
    throw new Error("document.head is null");
  }

  for (const c of Array.from(head.children)) {
    if (isIdStyleElement(c, id)) {
      return true;
    }
  }

  return false;
}
export function isIdStyleElement(c: Element, id: string): boolean {
  return (
    c.localName === "style" && c.id === id
  );
}