/** What a component icon receives from the surface that draws it. */
export interface PluginIconProps {
  size: number;
  color: string;
}

/** Inline SVG markup. Paseo validates it when the contribution registers. */
export interface PluginSvgIcon {
  svg: string;
}

/** An icon that can be stored or sent: a Lucide icon name, or inline SVG. */
export type PluginSerializableIcon = string | PluginSvgIcon;

export const PLUGIN_SVG_ICON_MAX_BYTES = 64 * 1024;

const EXTERNAL_HREF = /\s(?:href|xlink:href)\s*=\s*(?:(["'])(.*?)\1|([^\s>]+))/gi;

/**
 * Why Paseo refuses to render this SVG, or null when it is a self-contained document.
 * The daemon applies it to provider and usage-source icon files; the app to inline plugin icons.
 */
export function findSvgIconProblem(svg: string): string | null {
  if (new TextEncoder().encode(svg).byteLength > PLUGIN_SVG_ICON_MAX_BYTES) {
    return "exceeds 64 KiB";
  }
  if (!/^\s*<svg(?:\s|>)/i.test(svg)) return "not an SVG document";
  if (/<script(?:\s|>)/i.test(svg)) return "script elements are not allowed";
  if (/<foreignObject(?:\s|>)/i.test(svg)) return "foreignObject elements are not allowed";
  if (/<style(?:\s|>)/i.test(svg)) return "style elements are not allowed";
  if (/\son[a-z0-9_-]*\s*=/i.test(svg)) return "event-handler attributes are not allowed";
  if (/javascript\s*:/i.test(svg)) return "javascript URLs are not allowed";
  for (const match of svg.matchAll(EXTERNAL_HREF)) {
    const href = match[2] ?? match[3] ?? "";
    if (!href.startsWith("#")) return "external href references are not allowed";
  }
  return null;
}