/**
 * `equation` — inline math node (LaTeX source).
 *
 * Stores `latex` (the source) + `alt` (fallback text). Rendering (KaTeX) is
 * the apps/web layer's concern; the package owns the node definition only.
 * The block-level `equation` block type (PRODUCT-SPEC §4) uses the same
 * LaTeX string in `content.text` — this inline node is for in-sentence math.
 */

import { mergeAttributes, Node } from "@tiptap/core";

export interface EquationOptions {
  readonly HTMLAttributes: Record<string, unknown>;
}

declare module "@tiptap/core" {
  interface Config {
    options: EquationOptions;
  }
}

export const EquationNode = Node.create<EquationOptions>({
  name: "factoryEquation",
  group: "inline",
  inline: true,
  atom: true,
  selectable: true,

  addOptions() {
    return {
      HTMLAttributes: {
        class: "factory-equation",
      },
    };
  },

  addAttributes() {
    return {
      latex: {
        default: "",
        parseHTML: (element) => element.getAttribute("data-latex") ?? "",
        renderHTML: (attributes) => ({ "data-latex": attributes.latex }),
      },
      alt: {
        default: null,
        parseHTML: (element) => element.getAttribute("data-alt"),
        renderHTML: (attributes) =>
          attributes.alt === null ? {} : { "data-alt": attributes.alt },
      },
    };
  },

  parseHTML() {
    return [{ tag: "span.factory-equation" }];
  },

  renderHTML({ node, HTMLAttributes }) {
    return [
      "span",
      mergeAttributes(this.options.HTMLAttributes, HTMLAttributes),
      (node.attrs.alt as string | null) ?? (node.attrs.latex as string) ?? "",
    ];
  },
});