import { Plugin } from 'unified';
import { MeldDirectiveNode } from './remarkMeldDirectives';
import { toMarkdown } from 'mdast-util-to-markdown';

interface PluginData {
  [key: string]: unknown[];
}

export const remarkMeldDirectiveHandler: Plugin = function remarkMeldDirectiveHandler() {
  const self = this;
  const data = self.data() as PluginData;

  // Add a handler for meldDirective nodes
  const handle = (node: MeldDirectiveNode) => {
    if (node.meldType === 'cmd' && node.data?.command) {
      return `@cmd[${node.data.command}]`;
    } else if (node.meldType === 'import' && node.data) {
      const { importPath, heading, importSymbol, importSymbolList } = node.data;
      let specifier = '';
      if (heading) {
        specifier = ` # ${heading}`;
      } else if (importSymbolList) {
        if (importSymbolList.length === 1 && importSymbolList[0].startsWith('{')) {
          specifier = ` # ${importSymbolList[0]}`;
        } else {
          specifier = ` # [${importSymbolList.join(', ')}]`;
        }
      } else if (importSymbol) {
        specifier = ` # ${importSymbol}`;
      }
      return importPath ? `@import[${importPath}${specifier}]` : '';
    }
    return '';
  };

  // Register the handler with mdast-util-to-markdown
  const toMarkdownExtension = {
    handlers: {
      meldDirective: handle
    }
  };

  add('toMarkdownExtensions', toMarkdownExtension);

  function add(field: string, value: unknown) {
    const list = data[field] ? data[field] : (data[field] = []);
    list.push(value);
  }
}