import { Fragment, Node } from 'prosemirror-model';

/**
 * Degrades plugin-owned nodes for office exports (issue #79, ADR 0008/0009):
 * pandoc receives GFM, which knows neither the `dorfteich-plugin` fence nor
 * the section fenced div — left alone they would surface as literal fence
 * text in the .docx. So before serializing the export markdown:
 *
 * - a `plugin_block` becomes a paragraph with its fallback text (the caller
 *   resolves it from the manifest snapshot; plugins are a server-side
 *   registry this package knows nothing about);
 * - a `section` becomes a blockquote of its content — the "plain quoted
 *   block" rendition of a styled container in a format with no CSS.
 */
export function replacePluginNodesForExport(
  doc: Node,
  fallbackTextFor: (pluginId: string, blockType: string) => string,
): Node {
  const schema = doc.type.schema;

  function mapNode(node: Node): Node {
    if (node.type.name === 'plugin_block') {
      const text = fallbackTextFor(
        node.attrs.pluginId as string,
        node.attrs.blockType as string,
      ).trim();
      return schema.node('paragraph', null, text === '' ? [] : [schema.text(text)]);
    }
    const children: Node[] = [];
    node.forEach((child) => children.push(mapNode(child)));
    if (node.type.name === 'section') {
      return schema.node('blockquote', null, Fragment.from(children));
    }
    return node.isLeaf ? node : node.copy(Fragment.from(children));
  }

  return mapNode(doc);
}

/** The plugin ids referenced by `plugin_block` nodes in `doc`, for resolving
 * their fallbacks in one batch before {@link replacePluginNodesForExport}. */
export function collectPluginBlockIds(doc: Node): string[] {
  const ids = new Set<string>();
  doc.descendants((node) => {
    if (node.type.name === 'plugin_block') ids.add(node.attrs.pluginId as string);
    return true;
  });
  return [...ids];
}