import * as plugins from './smartmarkdown.plugins.js';

export type TFrontmatterData = Record<string, unknown>;

type TYamlNode = plugins.RootContent & {
  type: 'yaml';
  value: string;
};

const isYamlNode = (nodeArg: plugins.RootContent): nodeArg is TYamlNode => {
  return nodeArg.type === 'yaml' && 'value' in nodeArg && typeof nodeArg.value === 'string';
};

export class MdParsedResult {
  public static async createFromMarkdownString(mdStringArg: string): Promise<MdParsedResult> {
    const mdParsedResult = new MdParsedResult();
    await mdParsedResult.updateFromMarkdownString(mdStringArg);
    return mdParsedResult;
  }

  public originalString = '';
  public title = '';
  public html = '';
  public frontmatterData: TFrontmatterData = {};

  public async updateFromMarkdownString(mdStringArg: string): Promise<void> {
    this.originalString = mdStringArg;
    let yamlString: string | undefined;
    const result = await plugins.unified()
      .use(plugins.remarkParse)
      .use(plugins.remarkGfm)
      .use(plugins.remarkFrontmatter, ['yaml', 'toml'])
      .use(plugins.remarkStringify)
      .use(plugins.remarkHtml)
      .use((): plugins.Transformer<plugins.Root> => (tree) => {
        const yamlChild = tree.children.find(isYamlNode);
        if (yamlChild) {
          yamlString = yamlChild.value;
        }
      })
      .process(mdStringArg);
    this.html = result.toString();
    if (yamlString) {
      this.frontmatterData = await plugins.smartyaml.yamlStringToObject(yamlString);
    } else {
      this.frontmatterData = {};
    }
  }
}